ACKNOWLEDGEMENTS This report was led by a World Bank team comprised of Sarah Moyer and Noor Mohammed and a project team from Zutari comprised of James Cullis, Anya Eilers, Mookho Monnapula, Reneilwe Malatji, Mpho Khashole, Johan Viktor, Gabi Wojtowitz and Christina Papadouris. We gratefully acknowledge the numerous experts and stakeholders from government and civil society who participated in the workshops, field visits, and/or provided written inputs during the course of this work. Special thanks go to Diego Rodriguez, Pratap Tvgssshrk, and Juanita Whitfield for providing peer review. This work was possible because of strong commitment and support from Kikine Khasapane of the Roads Directorate, Ministry of Public Work of Lesotho; Makamoreng Fanana, Matsolo Migwi, Nthatuoa Kuleile of the Integrated Catchment Management Unit, Ministry of Water of Lesotho; and Phomolo Khonthu, catchment manager for Hlotse sub- catchment and Motlalepula Rasekoele, catchment manager for Makhaleng sub-catchment. Our thanks to them for fostering multi-sectoral approach to integrated catchment management in Lesotho. This work was supported with funding from PROGREEN (https://www.worldbank.org/en/programs/progreen), an umbrella multi-donor trust fund housed at the World Bank that supports the sustainable and integrated development of land resources. © 2023 International Bank for Reconstruction and Development / The World Bank 1818 H Street NW Washington DC 20433 Telephone: 202-473-1000 Internet: www.worldbank.org This work is a product of the staff of The World Bank with external contributions. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of The World Bank, its Board of Executive Directors, or the governments they represent. The World Bank does not guarantee the accuracy, completeness, or currency of the data included in this work and does not assume responsibility for any errors, omissions, or discrepancies in the information, or liability with respect to the use of or failure to use the information, methods, processes, or conclusions set forth. The boundaries, colors, denominations, and other information shown on any map in this work do not imply any judgment on the part of The World Bank concerning the legal status of any territory or the endorsement or acceptance of such boundaries. Nothing herein shall constitute or be construed or considered to be a limitation upon or waiver of the privileges and immunities of The World Bank, all of which are specifically reserved. Rights and Permissions The material in this work is subject to copyright. Because The World Bank encourages dissemination of its knowledge, this work may be reproduced, in whole or in part, for non-commercial purposes as long as full attribution to this work is given. Any queries on rights and licenses, including subsidiary rights, should be addressed to World Bank Publications, The World Bank Group, 1818 H Street NW, Washington, DC 20433, USA; fax: 202-522- 2625; e-mail: pubrights@worldbank.org. Cover image credit: James Cullis Other Image credits: Anya Eilers Executive Summary Lesotho is already experiencing the negative impacts of climate change, including increased frequency of extreme weather events, floods, droughts, increased rates of soil erosion and catchment degradation that also threaten the road network. In 2022, the country experienced heavy rainfall and floods that left many parts of Lesotho impassable and disconnected. The impacts of heavy rains were more apparent in rural areas than in urban areas. Some rural areas have become inaccessible due to landslides, rock falls, and damaged drainage systems causing flooding of roads and bridges. In addition, Lesotho’s topography influences its climatic conditions and further exacerbates the country's vulnerability to climate variability and long-term climate change. Information from the Lesotho Roads Management System (LRMS) indicates that there are currently in excess of 7,500 km of roads under the managemetn of the Roads Directorate (RD) including major roadways (i.e., “A” and “B” roads) which amount to 5,844 km of this network, of which only 1,527 km is paved, and the rest are gravel (3,015 km), earth (1,170 km), and tracks (132 km). The Ministry of Local Government and Chieftainship (MLGC) manages secondary roads (i.e., “C” and “D” roads) totalling 1,636 km, which are largely unpaved. Data from the LRMS suggests that most paved roads are in fair to poor condition, with very few roads in good condition, while most unpaved roads are poor to very poor. The Lesotho Extreme Climate Indices Report1 predicts increasing temperatures across the whole country and increasing rainfall frequency and severity, particularly in the lowlands. Lesotho is therefore likely to experience significant impacts of climate change which will impact the condition of the existing roads infrastructure and catchment areas, particularly in the form of increasing temperatures and rainfall intensity. This report summarises the methodology and outcome of a Climate Risk Vulnerability Assessment (CRVA) for roads in Lesotho based on existing risk frameworks and policies. This was done using a risk-based spatial approach, as summarised below. RISK = HAZARD x VULNERABILITY x EXPOSURE • Condition of the roads • • Rainfall impacts Where the (paved and unpaved) (Δmax Precip) hazards and • Condition of the • Temperature roads, bridges, bridges impacts (Δmax and culverts • Condition of the overlap spatially Temp) culverts The inputs to the national-level CRVA include:  The current state and location of roads, bridges and culverts obtained from the LRMS.  Expected changes in maximum temperature and maximum one-day rainfall by 2070 across all of Lesotho and derived from the Lesotho Extreme Climate Indices Report. The outcome was a climate hazard, vulnerability, and risk rating for each section of road extracted from the LRMS. This spatial tool is based on LRMS and climate change data, and can easily be incorporated into the LRMS to assess future risks and prioritise hotspots. It is recommended that this framework be used to identify national priority road infrastructure . This framework should be used in collaboration with existing frameworks for climate related planning. For the priority road segments, these additional frameworks could consider issues such as: i) cost to the economy of inaction; ii) distributional effects of different investments; iii) potential gains in different economic sectors from investing in catchment and flood management; and iv) funding and financing strategy behind a portfolio of interventions. 1The analysis is based on the data from the Coupled Model inter-comparison Project Phase 5 (CMIP5) set of global climate models (GCMs) and downscaled under the Coordinated Regional Climate Downscaling Experiment (CORDEX) for Africa. The results of the national level CRVA for roads in Lesotho (shown below) sugest that most paved roads are likely to be subject to a high level of climate-related risk. In addition, most unpaved roads are likely to experience high to very high levels of climate risk. While the assessment attributes some of these observations to the expected increase in extreme rainfall and maximum temperatures, the most significant contributor to the overall risk is the current poor condition of the roads. Added to this are the additional “risk amplifiers” related to catchment degradation. Paved roads climate risk per district 500 450 No. of 1km road segments 400 350 300 250 Very high 200 High 150 Median 100 Low 50 Very low 0 District Unpaved roads climate risk per district 500 450 No. of 1km road segments 400 350 300 250 Very high 200 High 150 Median 100 Low 50 Very low 0 District While climate change will undoubtably have a significant impact on rainfall and temperature patterns in Lesotho and place increasing strain on transport-related infrastructure, most of the current road- related challenges/hazards are not caused by changing weather patterns. Instead climate change will aggravate these hazards. Therefore, in most cases, implementing the current design standards will help improve the climate resilience of critical transport infrastructure. A review of the current design standards and guidelines for roads in Lesotho revealed that these can be updated relatively easily to account for the likely impacts of climate change but that this will require further analysis of particular climate scenarios and agreement on the acceptable level or risk given the level of uncertainty of future climate change scenarios. There are alread examples of where climate chagne is being included in the design of new roads. However, one case study revealed that the capacity of existing road drainage structures needs to be increased to meet existing design standards, let alone an increase of around 12% to account for the expected impacts of climate change. The review of guidelines also revealed that often the concern is not the design guidelines themselves but rather the implementation of these. Due to a lack of funds, the Government of Lesotho can only meet the minimum standards, significantly increasing the overall climate-related risks. For example, road side drains are often unlined and there is no paving of the shoulders of the roadway. In many cases, while the drainage structure itself may be adequate, the bridge approaches are often unprotected or insufficient to deal with expected changes in extreme rainfall. The report makes the following general recommendations regarding the potential for improving the climate resilience of critical road infrastructure and updating the design guidelines in Lesotho:  Prioritise investments that improve the climate resilience of roads with a high overall climate- related risk or which are determined to be most critical for connectivity.  Consider adding paved shoulders to all major roads (A and B roads) to protect the main section of the road from erosion and to improve connectivity of the road with drainage structures.  Consider increasing design flood requirements for all new drainage structures based on a review of the latest climate change scenarios from the World Bank Climate Change Knowledge Portal.  Apply a minimum of 900mm culverts to make it easier for maintenance and clearing.  Factor the impacts of increasing rainfall intensities and temperatures due to climate change into all new road designs and rehabilitation projects.  Reduce the erosion of minor connecting roads and the subsequent impact on intersecting major roads by paving the first 25m of the minor road where it connects with a major road (A and B) and ensuring the provision of adequate drainage.  Undertake a review of the conditions of all major bridges to determine their ability to manage increased flood frequencies, including a review of the approaches and embankments. The approaches and embarkments are particularly vulnerable. Additionally, consider flood protection across the entire flood plain and not just at the location of the current river channel.  Engage with local communities to support the clearing of culverts and identification of priority interventions to reduce the risk to roads as part of a catchment management plan and with support from the local council and technical support from the Roads Directorate. In addition to this report on the national level climate risk and vulnerability assessment and review of existing design standards and guidelines, a separate report details the application of the climate risk and vulnerability assessment framework for two pilot catchments in Lesotho: the Makhaleng and Upper Mohokare catchments. Contents Executive Summary ...............................................................................................................................ii 1 Introduction........................................................................................................................................1 1.1 Background and Context ................................................................................................1 1.2 Climate Change Risks for Lesotho .................................................................................3 1.3 Climate Change Risks for Roads and Bridges ...............................................................5 1.4 Funding Opportunities for Improved Climate Resilience ................................................5 1.5 Catchment Degradation as a Climate Risk Amplifier .....................................................7 1.6 Study Aim and Objectives ..............................................................................................8 1.7 Purpose of this Report ....................................................................................................9 2 Review of Existing Frameworks and Plans. ................................................................................ 11 2.1 Review of Existing Risk Assessment Frameworks ..................................................... 11 2.2 Review of Existing National Policies ........................................................................... 14 2.3 Overview of Climate Change Risk and Vulnerability ................................................... 14 2.4 Adapted CRVA Framework for Roads in Lesotho ....................................................... 15 3 National Climate Change Risk and Vulnerability Assessment (CRVA) for Roads in Lesotho. .................................................................................................................................................. 18 3.1 Current State of Roads, Bridges and Culverts ............................................................ 18 3.2 Overview of the Approach and Methodology .............................................................. 20 3.3 Climate Related Hazards for Lesotho Roads .............................................................. 24 3.3.1 Overview of available climate change indices and scenarios ...................... 24 3.3.2 Selected climate change scenarios .............................................................. 27 3.3.3 Selected climate hazards ............................................................................. 28 3.4 Current Condition and Vulnerability of Roads ............................................................. 36 3.5 Overall Climate Change Risk for Roads in Lesotho .................................................... 45 3.6 Consideration for Additional Risk Amplifiers. .............................................................. 47 3.6.1 Soil Erodibility Risk ....................................................................................... 47 3.6.2 Catchment Degradation ............................................................................... 49 3.6.3 Increasing Landslide Susceptibility .............................................................. 50 3.7 Summary Conclusions and Recommendations .......................................................... 51 3.8 Updating Climate Risk Information in the LRMS ......................................................... 52 4 Catchment Level Climate Risk Assessment ................................................................................ 53 4.1 Aim and Objectives...................................................................................................... 53 4.2 Summary Feedback from Communities ...................................................................... 54 4.3 Summary of specific hazards identified ....................................................................... 57 4.4 Conclusions and Recommendations ........................................................................... 66 5 Incorporating Climate Change into Current Road Design Standards and Design Guidelines .................................................................................................................................................. 67 5.1 Review of Existing Road Design Guidelines ............................................................... 67 5.1.1 Volume 1: Design Standards for Geometric Design .................................... 67 5.1.2 Volume 2: Design Standards and Explanatory Notes for Bridges, Culverts, and Low-Level Structures. ............................................................................ 68 5.1.3 Volume 3: Design Standards and Guidelines for Pavement Materials Design ...................................................................................................................... 68 5.1.4 Volume 4: Design Guidelines and Explanatory Notes for Hydrology and Drainage of the Roadway Prism ................................................................... 69 5.1.5 Volume 9: Guidelines for Environmental Control ......................................... 70 5.1.6 Summary Review of Updating Road Design Guidelines .............................. 70 5.2 Incorporating Climate Change into Design Guidelines ............................................... 71 5.2.1 Temperature Impacts ................................................................................... 71 5.2.2 Precipitation Impacts .................................................................................... 74 5.2.3 Freeze Thaw Cycles ..................................................................................... 75 5.2.4 Runoff Impacts (flooding and drainage) ....................................................... 77 5.2.5 Climate Change Impacts on RI Design Flood Determination ...................... 79 5.2.6 Geological and Geotechnical Risks for Roads in Lesotho ........................... 81 5.2.7 Climate Change Risk Screening Tools......................................................... 81 5.3 Guidelines for Sustainable Roads in Rural Areas ....................................................... 83 6 Conclusions and Recommendations ........................................................................................... 89 7 References ...................................................................................................................................... 92 Figures Figure 1-1: Population density of Lesotho (data taken from WorldPop) Figure 1-2: Rainfall in Lesotho Figure 1-3: Expected impact of climate change on mean temperature (left) and maximum daily temperature (right) for Lesotho. (Source: World Bank Climate Portal) Figure 1-4: Expected impact of climate change on mean annual precipitation (left) and 1-day maximum rainfall (right) for Lesotho. (Source: World Bank Climate Portal). Figure 1-5: Climate related risks for critical infrastructure. Figure 1-6: Sources of Adaptation Finance (Burmeister et al., 2019) Figure 1-7: Examples of project elements that qualify as adaptation activities (AfDB, 2013) Figure 1-8: Bridge damaged due to flooding near Mohale’s Hoek Figure 1-9: Map of Priority Catchment Areas in Lesotho. Figure 1-10: Key deliverables of this project Figure 2-1: Summary of the ReCAP Framework's guidelines and supporting documents Figure 2-2: Summary of climate change exposure, risk & vulnerability (IPCC, 2007) Figure 2-3: Summary of the Climate Resilience and Sustainable Development Framework for Lesotho Roads and Intended Outcomes Figure 3-1: Visual condition map of paved roads survey in 2021 as part of the LRMS update project Figure 3-2: Visual condition map of unpaved roads survey in 2021 as part of the LRMS update project Figure 3-3: Visual condition map of bridges survey in 2021 as part of the LRMS update project Figure 3-4: Visual condition map of culverts survey in 2021 as part of the LRMS update project Figure 3-5: Formula used for assessing the risks of Lesotho’s roads network Figure 3-6: Methodology used to calculate climate related hazards and road infrastructure vulnerability. Figure 3-7: Summary of the methodology used to calculate climate related risks Figure 3-8: Spatial pattern of trends in total precipitation (PRCPTOT), for the emission scenarios RCP4.5 and RCP8.5 for the periods: 2011-2040, 2041-2070, 2071-2100 (Source: CORDEX Data, LMS, 2018) Figure 3-9: Projected temperature change over Lesotho. Source: Third National Communication Figure 3-10: Historical (1972-2000) hottest day (monthly maximum value of daily max temperature) Figure 3-11: Predicted change in hottest day from historical to present (2011-2040) Figure 3-12: Predicted change in hottest day from historical to near future (2040-2070) Figure 3-13: Historical (1972-2000) monthly maximum 1-day precipitation Figure 3-14: Predicted change in monthly maximum 1-day precipitation from historical to present (2011-2040) Figure 3-15: Predicted change in monthly maximum 1-day precipitation from historical to near future (2040-2070) Figure 3-16: Historical (1972-2000) coldest day (monthly minimum value of daily max temperature) Figure 3-17: Predicted change in coldest day from historical to present (2011-2040) Figure 3-18: Predicted change in coldest day from historical to near future (2040-2070) Figure 3-19: Rainfall, temperature, and climate hazards for the LRMS roads network Figure 3-20: Rainfall, temperature and climate hazards for the LRMS roads network, summarised per district Figure 3-21: Distribution of surfaced roads distress and other characteristic ratings by percentage of road length (2021 surveyed road network) (Roads Directorate, 2022) Figure 3-22: Distresses and characteristics for gravel roads by percentage of road length (2021 surveyed network) (Roads Directorate, 2022) Figure 3-23: Distresses and characteristics for earth and track roads by percentage of road length (2021 surveyed road network) (Roads Directorate, 2022) Figure 3-24: Paved roads: Overall historical VCI (2010-2021) (% road per condition category) (Roads Directorate, 2022) Figure 3-25: Unpaved roads: Overall historical VGI (2010-2021) (% road per condition category) (Roads Directorate, 2022) Figure 3-26: Paved and unpaved roads overall condition per district Figure 3-27: Summary of roads condition and vulnerability for all of roads in Lesotho. Figure 3-28: Overall conditions of bridges and culverts in LRMS Figure 3-29: Current capacity of drainage structures on the Thaba Tseka to Katse Road, required capacity, and future deficit based on a 12% increase to account for climate change. Figure 3-30: Temperature, rainfall, and climate risk categories for paved and unpaved roads Figure 3-31: Total length of roads in each category of climate related risk (i.e. combination of hazard, vulnerability, and exposure) for paved (top) and unpaved roads (bottom) in each district Figure 3-32: Map showing soil erodibility risk for Lesotho (Source: Le Roux, 2008) Figure 3-33: Erodibility index of roads (paved and unpaved), bridges and culverts in Lesotho Figure 3-34: Erosion risk per district, for paved and unpaved roads Figure 3-35: Land degradation per district, using Land Cover Change as a key indicator (WFP, 2015) Figure 3-36: Extensive erosion scars in Mohale’s Hoek district, Makhaleng catchment. This area has experienced some of the worst land degradation in Lesotho. Figure 3-37: Landslide susceptibility map for South Africa that could be developed for Lesotho (Source: Singh et al, 2011) Figure 4-1: Meetings with 4 Community Watershed Teams in the northern Mohokare and Makhaleng catchments Figure 4-2: A poorly maintained side drainage channel in the Makhaleng catchment has resulted in erosion of both the road and the adjacent farmland. Figure 4-3: Example of a handmade concrete tamper Figure 4-4: A community-built road in the Makhaleng catchment that is resurfaced on an annual basis after extreme rainfall events. The eroded soil is deposited in the Makhaleng river. Figure 4-5: An unprotected community-built side drain which has resulted in erosion Figure 4-6: Culvert possibly blocked by community (left) and field immediately downstream of the culvert outlet (right). Mohokare catchment. Figure 4-7: Alien vegetation growing in a riparian area in the Northern Mohokare catchment Figure 4-8: Eroded side drain (left) which has resulted in further degradation downstream (right) Figure 4-9: Small check dams used to prevent erosion of side drains in the Makhaleng catchment Figure 5-1: 7-day average maximum asphalt temperatures for South Africa Figure 5-2: Minimum asphalt temperatures for South Africa Figure 5-3: Climate zones for consideration in road pavement design (after Weinert, 1980) Figure 5-4: Example of Graph Showing Freezing and Thawing Indexes (Northern Hemisphere) Figure 5-5: Lesotho Freeze/Thaw influence lines (Source: Government of Lesotho) Figure 5-6: SCS-SA rainfall intensity distribution types for Southern Africa (Left) Unit Hydrograph Veld Zones for Southern Africa (Right) Figure 5-7: Procedure for Incorporating Climate Change Allowances in Detailed Engineering Design Figure 5-8: Conceptual framework of the World bank Climate Screening tool (https://climatescreeningtools.worldbank.org/) Figure 5-9: Issue identification for integrated catchment management (Braid, 2019) Figure 5-10: Example of a problem tree for land degradation from the South African Catchment Management Guidelines (Braid, 2019) Figure 5-11: Sustainable land management implementation options (Braid, 2019) Figure 5-12: Erosion management along roadside part I (Braid, 2019) Figure 5-13: Erosion management along roadside part II (Braid, 2019) Figure 5-14: Erosion management along roadside part III (Braid, 2019) Figure 6-1: Overview of approach for determine the impact of environmental conditions on road degradation which can then be used to determine overall maintenance costs and impacts of climate change. Tables Table 1-1: NSDP Strategic objectives and interventions regarding sustainable transport network Table 1-2: Summary of climate change related risks for transport globally (Thibault, 2015). Table 1-3: Summary of financing instruments for adaptation funding (Burmeister et al., 2019) Table 2-1: Summary of the review of climate risk and vulnerability assessment frameworks for roads. Table 2-2: CRVA framework for roads in Lesotho Table 3-1: Climate Change Extreme Indices and their explanation (red fill for temperature related indices and blue fill for precipitation) (taken from LMS, 2018) Table 3-2: Climate models used for the Lesotho Third National Communication Table 3-3: Climate drivers, the impact in Lesotho and the corresponding CORDEX data used Table 3-4: Rating scales for paved roads (binder condition and side drainage condition) Table 3-5: Rating scales for unpaved roads (side drainage condition and adequacy) Table 3-6: Overall Road condition - VCI and VGI values Table 3-7: Overall condition ratings for bridges and culverts Table 5-1: List of existing roads design standards and guidelines for Lesotho Table 5-2: Road drainage manual Table 5-3: Application and limitations of flood calculations methods (SANRAL, 2013) Table 5-4: Change in Return Period for the Largest 1 Day Precipitation for Lesotho (2035-2064) Table 5-5: Summary of climate related geotechnical risks for roads Table 5-6: Indicators considered within the World Bank Climate Screening tools Table 6-1: Primary roads hazards, and the impacts of climate change on these List of Acronyms AF Adaptation Fund AfDB African Development Bank ADB Asian Development Bank AfCAP Africa Community Access Partnership CMP Catchment Management Plan CORDEX Coordinated Regional Climate Change Downscaling Experiment CRVA Climate Risk and Vulnerability Assessment CMIP5 Coupled Model Inter-Comparison Project Phase 5 CSIR Council for Scientific and Industrial Research CWT Community Watershed Team DRR Department of Rural Roads EIAs Environmental Impact Assessments ETCCDI Expert Team on Climate Change Detection and Indices GCF Green Climate Fund GCM Global Circulation Model GDP Gross Domestic Product GoL Government of Lesotho ICM Integrated Catchment Management ICU Integrated Catchment Management Unit IDF Intensity-Duration-Frequency IMT Intermediate Means of Transport IPCC Intergovernmental Panel on Climate Change LMS Lesotho Meteorological Services LoCAL Local Climate Adaptive Living Facility LRMS Lesotho’s Road Management Information System MDB Multilateral Development Banks MLGC Ministry of Local Government and Chieftainship NCCP National Climate Change Policy NGOs Non-Governmental Organisations NSDP National Strategic Development Plan PPP Public-Private Partnership RCM Regional Climate Model RD Roads Directorate RCP Representative Concentration Pathway ReCAP Research for Community Access Partnership SADC Southern African Development Community SANRAL South African Roads Agency Limited SMHI Swedish Meteorological and Hydrological Institute SSP Shared Socioeconomic Pathways ToR Terms of Reference TNC Third National Communication UNCDF United Nations Capital Development Fund UNFCCC United Nations Framework Convention on Climate Change VCI Visual Condition Index VGI Visual Gravel Index WFP World Food Programme WMO World Meteorological Organisation 1 Introduction 1.1 Background and Context The Kingdom of Lesotho is a landlocked country in Southern Africa. The country covers an area of approximately 30,000 km² and supports a Basotho population of about 1.8 million (Figure 1-1). A high percentage of the population is settled along the lowlands from Botha Bothe and Leribe in the north- east through the Berea District and the capital district of Maseru to the southwestern region via Mafeteng to Mohales’ Hoek Districts, where there is a primarily developed road network. Large pockets of the population reside along the Senqu River Valley in the southeastern reaches of the country, and some of the roads traverse this river to connect to the mountainous areas. Subsistence agriculture is the mainstay of the country’s economy, with more than 60% of the population dependent on it. The rest of the country consists of rolling to highly mountainous sections from Mokhotlong and Thaba-Tseka Districts in the east to Qacha’s Nek and Quthing in the south , where accessibility remains a challenge. Figure 1-1: Population density of Lesotho (data taken from WorldPop) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 1 Sustained land degradation, soil erosion, and increased demand for ecosystem services threaten infrastructure and the health of Lesotho’s natural ecosystems, including wetlands. These threats cost the country an estimated 3.6 percent of GDP per year. Increasing temperatures and changing rainfall patterns due to climate change negatively impacts Lesotho’s road network. Increased temperatures and flooding contributes to issues such as asphalt pavement deformation, slope instabilities, landslides, gulley formation, sedimentation of rivers, unexpected washouts, material losses from gravel roads and erosion and scour of bridge foundations and abutments, all of which contribute to increasing the risk of road and bridge failures. Temporary road closures due to washouts have caused extensive disruption to key transport routes in recent years. Road closures due to washouts places an excessive burden on the Government of Lesotho’s (GoL) infrastructure budgets, particularly financing road maintenance and repairs. The GoL recognises the need to reverse environmental degradation and adapt to climate change. As described in the National Strategic Development Plan (NSDP) 2018/19-2022/23 — with the theme, “In pursuit of economic and institutional transformation for private sector-led job creation and inclusive growth”, the government of Lesotho intends to pursue a development path that is more resilient to climate-related shocks. The plan stresses the need to revive infrastructure assets, including roads, through climate- resilient methods. Figure 1-2: Rainfall in Lesotho The strategic framework defines the key objectives and strategies for the four key strategic goals that will support the realisation of greater employment creation and inclusive growth. The key priority area aligned to sustainable infrastructure development is to “Build enabling infrastructure” and includes several strategic objectives shown in Table 1-1. The NSDP II mainstreams climate change, environmental protection, gender, and social inclusion across all sectors. It notes that climate change has implications for employment creation and economic growth since it impacts all sectors of the economy. Therefore, the NSDPII strategy recognises the importance of climate change adaptation and mitigation. A key part of implementing the objectives of the NSDPII for a sustainable transport network is to: Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 2 1. Update the current design standards for roads, bridges and culverts; 2. Account for the expected impact of climate change; and 3. Apply this in rehabilitating existing roads and developing new roads and bridge using these updated climate-proof standards. The NSDP also recognises the importance of sustainable catchment management and the need to consider climate-proofing roads to reduce the impacts of poorly designed and maintained roads on natural and human resources, particularly in rural areas. Table 1-1: NSDP Strategic objectives and interventions regarding sustainable transport network Strategic Objectives Interventions Enhance Enabling  Review Roads Act of 1969 and subsidiary laws. Environment for Road  Develop Road Infrastructure Asset Management Policy. Infrastructure  Develop Road Infrastructure Master Plan and Financing Development Policy and Strategy.  Review and update Lesotho Design Standards.  Formulate Construction Industry Development Policy, enact Construction Bill, and develop Axle  Load Control Policy  Harmonise land allocating legislation to observe road reserves  Develop early warning system to provide reliable detection and response plan.  Improve monitoring and evaluation systems for infrastructure development Maintain Existing Roads  Rehabilitate and maintain existing transport infrastructure and Access Routes (main arterial roads) as asset recovery to climate-proof standards.  Construct new infrastructure conforming to environmental, clean mobility, and climate-proof standards.  Introduce performance and output-based maintenance contracting system for all primary roads Improve Access to Main  Design, upgrade, and construct main corridors conforming Towns, Key Border to environmental, clean mobility, and climate-proof Posts, and Productive standards to key productive sectors Sectors  Build or upgrade new roads to connect main towns, border posts, and communities Improve Urban and  Design major intersections along main arterial roads Rural Transportation  Construct climate-proof footbridges and rural roads from Systems earth to gravel. Note: Strategic policy objectives related to road infrastructure only included in table above. 1.2 Climate Change Risks for Lesotho Lesotho's topography and location influence its climatic conditions and exacerbate its vulnerability to climate variability and long-term climate change. The country is already experiencing the negative impacts of climate change, including increased frequency of extreme weather events, floods, droughts, increased rates of soil erosion and desertification that affect road conditions. In 2022, the country experienced heavy rainfall and floods that left many parts of Lesotho impassable and disconnected. The impacts of heavy rains were more apparent in rural than urban areas, where some Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 3 settlements have become inaccessible due to landslides, rock falls, and damaged drainage systems causing flooding of roads and bridges. Lesotho is likely to experience significant impacts of climate change which will impact the condition of the existing roads infrastructure and catchment areas, particularly in the form of increasing temperatures and rainfall intensity. Climate change will likely have the most significant impact on rural communities with limited infrastructure and on rural roads. Further, climate change will impact roads, bridges and culverts not designed with sufficient capacity. The latest scenarios of climate change impacts from the International Panel on Climate Change (IPCC) averaged over Lesotho are shown in the figures below for the different global emission scenarios (i.e. SSP1-2.6 to SSP5-8.5). Figure 1-3: Expected impact of climate change on mean temperature (left) and maximum daily temperature (right) for Lesotho. (Source: World Bank Climate Portal) Figure 1-4: Expected impact of climate change on mean annual precipitation (left) and 1-day maximum rainfall (right) for Lesotho. (Source: World Bank Climate Portal). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 4 1.3 Climate Change Risks for Roads and Bridges Future climate change will impact infrastructure globally, including roads, as shown in Figure 1-5. Table 1-2 describes the main climate-related risks for roads and bridges. Figure 1-5: Climate related risks for critical infrastructure. Table 1-2: Summary of climate change related risks for transport globally (Thibault, 2015). Sector Climate Risk Drivers Associated Climate Change Impacts • Extreme heat • Extreme heat- softening paved roads, requiring resurfacing with • More intense rainfall more durable materials, or higher quality binders, etc. • Increased flooding • More frequent and extreme freeze-thaw cycles- in cold regions - will damage the base and paved surface. • Freeze-thaw cycles • Increased maintenance & investment in drainage & protection. • Increasing fire risk Upgraded design specifications in new construction and • Higher winds retrofitting due to bridges exposed to flooding. Road • Sea level rise and • Unpaved roads are most vulnerable to these impacts storms • Increased disruption as a result of flooding or sea-level rise. • Reduced visibility and driving hazard due to more wildfires. • Higher wind speeds will increase safety risks for trucks, etc. Sea level rise and increased storm surges and cyclones will impact on coastal roadways and associated infrastructure. • Higher lake levels will impact on some roads and rail infrastructure as well as port infrastructure. • Increased • Greater thermal expansion and freeze-thaw cycles. temperatures. • Bridges Increased risk of damage due to flooding. • Flooding • Higher wind speeds threaten the structure of the bridge • Higher winds (particularly suspension bridges), but also increase the risk to • Freeze-thaw cycles traffic, particularly large trucks. 1.4 Funding Opportunities for Improved Climate Resilience Several sources of financial support for climate change adaptation and resilience in transport infrastructure exist (Figure 1-6). These include various actors, such as national, international, public, and private institutions. Donor governments and organisations, multilateral climate funds (such as the Green Climate and Adaptation Funds), and development finance organisations are some public climate finance providers. The latter group consists of the Multilateral Development Banks (MDBs), Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 5 other national and regional development banks (like the IDFC members), and financial organisations. The private sector includes project creators, corporates, households, and financial institutions. These institutions deliver climate finance through different financing instruments which are summarised in Table 1-3 . Often these instruments may be used in a blended approach. Figure 1-6: Sources of Adaptation Finance (Burmeister et al., 2019) Table 1-3: Summary of financing instruments for adaptation funding (Burmeister et al., 2019) Financing Description Key attributes Instrument Grant Financial transfer typically made by the public Grants are often provided for sector or charitable organisations. Money does not project preparation and have to be repaid and is usually exempted from technical assistance. tax. Grant providers closely monitor the impact of the funding provided. Loan Debt with a fixed time period for repayment, and Many donors have different fixed or variable interest rate payable periodically. degrees of concessionality, Usually, the repayment starts immediately after depending on the recipient. loan is taken out by a recipient. Equity Financing provided by an investor in exchange for Often provided by private partial or full ownership of a (often for-profit) rather than public financiers; company by acquiring its shares. also available for (PPP-) projects. A strong evidence base is required to establish the context of climate change vulnerability and anticipated impacts of climate change before an activity qualifies eligible for climate financing. The Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 6 climate risk assessment conducted under this project provides this evidence base for building the climate rationale to justify climate adaptation financing. According to the African Development Bank, a project must fulfil the following three criteria to qualify for adaptation finance (as shown in Figure 1-7) (AfDB, 2013):  A statement of purpose or intent for the project is required to show how it will alleviate present and future climate vulnerabilities  It should set out the context of climate vulnerability specific to the location of the project based on currently available data (climate data, exposure and sensitivity), considering both the possible impacts from climate change-related risks as well as climate variability-related risks  The project objectives should be linked to the context of climate vulnerability (e.g., socio- economic conditions and geographical location). Figure 1-7: Examples of project elements that qualify as adaptation activities (AfDB, 2013) 1.5 Catchment Degradation as a Climate Risk Amplifier Many of Lesotho’s roads and bridges pass through environmentally sensitive areas, wetlands, and key water source catchments. Construction in these areas has not always been done in an environmentally sustainable manner, contributing to land degradation, soil erosion, and flooding. Catchment degradation negatively impacts Lesotho’s roads and is exacerbated by climate change. Eroded catchments increase the risk of flooding, landslides and sedimentation, creating gullies and damaging road infrastructure. This observation is particularly prevalent for roads crossing natural drainage lines in degraded catchments. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 7 Figure 1-8: Bridge damaged due to flooding near Mohale’s Hoek Implementating sustainable catchment and land management practices to protect, rehabilitate and where possible, enhance existing natural systems is therefore not only important in terms of improving the livelihoods of local communities. It also reduces the risks to critical infrastructure, particularly when added to the increasing risks of climate change. In addition, roads themselves can contribute to increasing environmental risks if not designed and maintained appropriately. Further, consideration of the design of sustainable roads in catchments is critical. Finally, Section 5.3 provides some guidelines for the design of sustainable roads in rural catchment areas. 1.6 Study Aim and Objectives To support the Government of Lesotho in addressing these challenges, the World Bank is conducting Analytical and Advisory Services to provide support in three areas: 1. Improving governance and aligning incentives related to integrated catchment management (ICM); 2. Operationalizing ICM and climate change considerations into transport investments (to maintain and manage hydrological ecosystem services); and 3. Improving data collection and management to improve collaboration, knowledge sharing and decision making. This study relates to component 2 of the overall program, conducted in close collaboration with ReNOKA, Lesotho’s ICM strategic network that is responsible for managing the coordination in the six priority sub-catchments shown in Figure 1-9. The primary aim of this study is to undertake a review of existing frameworks for climate and environment vulnerability assessments for roads and to adapt these to the Lesotho context in line with the Southern African Development Community (SADC) protocol on transport, the National Strategic Development Plan of Lesotho, and the South African National Roads Agency (SANRAL) Design Guidelines. The adapted climate and environmental risk framework will form the basis for developing a climate change risk and vulnerability assessment methodology/tool. This tool will be applied at a Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 8 national level and tested in two catchment areas: the Makhaleng and Upper Mohokare catchments, shown in Figure 1-9. Figure 1-9: Map of Priority Catchment Areas in Lesotho. The specific objectives of this component of the study are as follows:  Review and adapt existing relevant climate and environmental risk and vulnerability assessment frameworks for roads, bridges and culverts to the Lesotho context.  Review current design standards for roads in the context of climate change.  Undertake a national climate risk and vulnerability assessment for roads in Lesotho.  Undertake a climate risk and vulnerability assessment for roads in two priority catchment areas and preliminary recommendations on potential adaption options.  Provide recommendations for improving the climate resilience of roads in Lesotho and the development of sustainable roads to reduce the risk to catchments. 1.7 Purpose of this Report Below are the primary deliverables from this study. This Report contains the results of the National climate risk and vulnerability assessment (CRVA) for the Lesotho roads study but also includes a summary of observations from the Catchment level climate risk and vulnerability assessment (CRVA) for roads in two priority sub-catchments in Lesotho. The data from this study will be able to be included as additional layers in the Lesotho Roads Management System (LRMS) and can be used for future updates of the national climate risk and vulnerability assessment. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 9 National climate risk and Review of Frameworks Report vulnerability assessment (CRVA) for Lesotho roads. Catchment level climate risk and National level climate risk and vulnerability assessment vulnerability data for roads (CRVA) for roads in two priority provided to Lesotho Roads sub-catchments in Lesotho. Management System (LRMS). Figure 1-10: Key deliverables of this project Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 10 2 Review of Existing Frameworks and Plans. 2.1 Review of Existing Risk Assessment Frameworks The study reviewed relevant climate change risk and vulnerability assessment frameworks and roads tools. These included:  The Infrastructure Planning Support System (IPSS)  World Bank Climate Screening tools  ROADAPT Guidelines (CEDR, 2015)  Asian Development Bank Guidelines: Climate Proofing Investment in the Transport Sector: Road Infrastructure (2011)  ReCAP Framework  FHWA Vulnerability Assessment & Adaptation Framework  PIEVC climate vulnerability assessment protocol A summary of the review, including the evaluation criteria, is included in Table 2-1, and the Review of Frameworks Report provides a full and more detailed review. During this review process, it became apparent that the ReCAP framework is the most applicable in the Lesotho context. The Council of Scientific and Industrial Research (CSIR), in collaboration with Paige-Green Consulting (Pty) and St Helens Consulting Ltd, under the ReCAP project, developed a geospatial climate risk and vulnerability assessment framework for rural roads in Africa (le Roux et al, 2019). The ReCAP Framework aims to help countries determine where rural access roads and the communities they serve are most at risk of the effects of a changing climate. Through prioritisation, the ReCAP framework provides guidance to identify high-risk areas where appropriate climate adaptation measures would be most effective in reducing the impacts of climate variability and change by way of a climate change risk and vulnerability assessment guideline. The ReCAP framework also consists of an Adaptation Handbook and several supporting guidelines, including the Change Management and Engineering Adaptation guidelines, that describe the various processes required for developing climate-resilient roads and risk management. These are all useful tools for application in Lesotho. Figure 2-1 shows ReCAP’s framework guidelines and supporting documents. The ReCAP framework is very similar to the US Federal Highways Association (FHA) Guidelines for assessing the impact of climate change on roads and is well aligned with the Public Infrastructure Engineering Vulnerability Committee (PIEVC) Protocol. Figure 2-1: Summary of the ReCAP Framework's guidelines and supporting documents Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 11 Table 2-1: Summary of the review of climate risk and vulnerability assessment frameworks for roads. World Bank Climate Road Infrastructure Asian Development FHWA Vulnerability ReCAP Framework Guidelines (CEDR, The Infrastructure Transport Sector: Planning Support Investment in the Bank Guidelines: Climate Proofing Screening tools Specific steps for risk Assessment & System (IPSS) PIEVC climate and adaption vulnerability assessment Criteria Framework Adaptation ROADAPT assessment for roads protocol infrastructure (2011) 2015). 1. Is methodology simple to use?* No Yes Yes Yes Yes Yes Yes 2. Is it relevant for Lesotho (considering the climate of Lesotho is unique compared to other countries within the region)? Yes Yes No No Yes No Yes 3. Are the guidelines elaborate and do they Methodology for provide evidence of application (in a form of Identification of risks case studies)? No No Yes Yes Yes Yes Yes and hazards affecting the vulnerability of roads 4. Is it specific to the transport sector or may require it to be customized to the sector? No No Yes Yes Yes Yes Yes 5. Does it acknowledge the IPCC approach to risk? Yes Yes Yes Yes Yes Yes Yes 6. Does the tool have an ability to geospatially quantify risk and vulnerability? Yes No Yes Yes Yes Yes No 1. Does it provide guidance in terms of identifying data sources and collection of the correct type of the data necessary to do climate-risk screening? No No No Yes Yes Yes Yes Data collection, 2. Does it provide evidence of application preparation, and (in a form of case studies)? No No No No Yes Yes Yes analysis 3. Does it spatially and geospatially analyse data? Yes No Yes Yes Yes Yes No 4. Is it simple to use or require training or other inputs? No Yes Yes Yes Yes Yes Yes Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 12 World Bank Climate Road Infrastructure Asian Development FHWA Vulnerability ReCAP Framework Guidelines (CEDR, The Infrastructure Transport Sector: Planning Support Investment in the Bank Guidelines: Climate Proofing Screening tools Specific steps for risk Assessment & System (IPSS) PIEVC climate and adaption vulnerability assessment Criteria Framework Adaptation ROADAPT assessment for roads protocol infrastructure (2011) 2015). Embedment in the Road 1. Does it promote integration with Asset Management development planning and management such System (RAMS) (if as the Road Asset Management System available) (RAMS)? No No No No Yes No Yes 1. Is it simple to use? No Yes Yes Yes Yes Yes Yes 2. Is it relevant to the needs and concerns? No No No No Yes No Yes 3. Does it promote integration with the sector’s planning processes? Yes No No No Yes Yes Yes Adaptation assessment 4. Does it provide guidance on Change including prioritization Management and Engineering Adaptation? Yes No Yes Yes Yes Yes Yes 5. Does it consider relevant social, environmental, and economic issues and impact analysis? No Yes Yes Yes Yes Yes Yes 6. Does it consider issues related to gender and minority groups? No Yes No No Yes No Yes Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 13 2.2 Review of Existing National Policies Lesotho has several policies and legal frameworks aligned with the United Nations (UN) Sustainable Development Goals (SDGs), the African Union Agenda 2063 Goals, the SADC Regional Indicative Strategic Development Plan (RISDP) and Vision 2020 to transform the economy of Lesotho, eradicate poverty and respond to climate change. The Review of Frameworks Report reviewed different policy documents to identify relevant policies used to manage climate change impacts for Lesotho. The report also reviewed the implementation arrangements to adapt and respond positively to climate change. The review included the following relevant policies and guidelines and considered the documents’ key components for the adapted framework for the Lesotho context:  National Environmental Policy (1998)  Lesotho Transport Sector Policy (2006)  Basic Access and Mobility Standards and Needs (2007)  Integrated Transport and Policies Development (2012)  National Climate Change Policy (2017)  Lesotho’s Extreme Climate Indices: Climate Hind-cast and Future projections Report (2018)  Road Infrastructure Asset Management Policy (2018)  National Strategic Development Plan II (2019) 2.3 Overview of Climate Change Risk and Vulnerability The IPCC defines climate change risk as “the propensity or predisposition to be adversely affected” (IPCC, 2014). Climate change vulnerability is the function of exposure, sensitivity, and adaptive capacity (Figure 2-2). A system is most vulnerable to climate change if it has a high sensitivity and exposure to the effects of climate change and an inadequate or low capacity to adapt in this context. Therefore, to determine climate change risk, it is necessary to consider all three aspects. This undertsanding forms the bases for the adapted framework for evaluating the climate-related risks for roads, bridges, and culverts in Lesotho. Figure 2-2: Summary of climate change exposure, risk & vulnerability (IPCC, 2007) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 14 Climate vulnerability is defined as the propensity to be adversely affected by climate change (IPCC 2014). It encompasses a variety of concepts and elements, including sensitivity or susceptibility to harm and lack of capacity to cope with and adapt to future changes (IPCC, 2014). The three key elements of vulnerability are exposure, sensitivity, and adaptive capacity. Exposure is the nature and degree to which a system is exposed to significant climatic variations. Exposure in a climate context is “the nature and degree to which a system is exposed to significant climatic variations” (McCarthy et al., 2001) or the degree of climat e stress upon a particular unit of analysis (Smit et al., 2000). Exposure refers to ‘the amount of external stress or change likely to affect a system/community’. Exposure is most often used to measure the biophysical forces of nature or “disturbances” that impact a system. Sensitivity is the degree to which a system is adversely or beneficially affected by climate-related stimuli. The effect may be direct or indirect (e.g., a change in crop yield in response to a change in the mean, range or variability of temperature) or indirect (e.g., damages caused by an increase in the frequency of coastal flooding due to sea level rise), (McCarthy et al., 2001). These attributes affect the degree to which the system may be affected as a result of being directly or indirectly exposed to the changes in the climate system (McCarthy, et al. 2001). The sensitivities to these exposures could include areas of high population density, people living in low-lying areas exposed to the effects of flooding, or the elderly who may be further exposed to extreme heat waves. Sensitivities also consider assets in exposed areas, proximity to neighbours, population by age and gender, dependency structures, and factors such as the number of people in a property. Adaptive capacity is the ability of a system to evolve to accommodate climate changes or to expand the range of variability with which it can cope. The IPCC’s 4th Assessment report further explains that the adaptive capacity of communities to cope with the effects of severe climate impacts declines when there is a lack of physical, economic, and institutional capacities. These capacities reduce climate- related risks and thus the vulnerability of high-risk communities and groups. But even a high adaptive capacity may not translate into effective adaptation if there is no commitment to sustained action (IPCC, 2007). 2.4 Adapted CRVA Framework for Roads in Lesotho The review of several frameworks that outline an approach to determine road climate change risks led to the development of an adapted framework for Lesotho. Table 2-2 below describes the components and objectives of the adapted framework. Table 2-2: CRVA framework for roads in Lesotho Components of the Framework Purposes and Objective National Level Climate Change Risk and Highlight climate related risks for roads in Lesotho Vulnerability Assessment for Roads. and identify priority risk areas. Catchment level Climate Change Risk and Raise the importance of climate-resilient roads, Vulnerability Assessment for Roads for two sustainable catchment management and priority catchments in Lesotho, Makhaleng sustainable livelihoods and identify priority and Northern Mohokare. interventions. Review and Recommendations for adapting Guidance on how to incorporate climate change Lesotho design guidelines for climate into road infrastructure design. change. Review and Recommendations for Assisting with ideas for implementation as part of a developing sustainable rural roads catchment management plan. infrastructure. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 15 Components of the Framework Purposes and Objective Recommended Adaptation Options. Initial recommendations for adapting to climate change at national and local. Climate Risk Data Provided to LRMS. Assist with decision making for roads and supporting cost benefit analysis for roads. The framework is unique to Lesotho in that it addresses the key focus areas identified by the Roads Directorate (RD), ReNOKA and the World Bank:  Climate change risk information into LRMS.  Initial baseline study for funding applications.  Incorporating road rehabilitation in the Catchment Management Plans (CMPs).  Recommendations for road design guidelines. Figure 2-3 show the project outputs, deliverables and opportunities for further work (identified as critical by the RD and the World Bank technical assistance). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 16 Figure 2-3: Summary of the Climate Resilience and Sustainable Development Framework for Lesotho Roads and Intended Outcomes Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 17 3 National Climate Change Risk and Vulnerability Assessment (CRVA) for Roads in Lesotho. 3.1 Current State of Roads, Bridges and Culverts The national road network is currently over 7,500 km. According to information in the LRMS, major roadways (i.e., “A” and “B” roads) amount to 5,864 km of this network consisting of paved (1,527 km), gravel (3,015 km), earth (1,170 km), and tracks (132 km). The RD manages these major roads. The Ministry of Local Government and Chieftainship (MLGC) manages secondary roads (i.e., “C” and “D” roads) totalling 1,636 km, which are mainly unpaved. In 2021, the Lesotho RD completed a visual condition assessment for most major roads, bridges and culverts in Lesotho as captured in the updated LRMS. Figures 3-1 to 3-4 below show the current state of Lesotho’s roads (paved and unpaved), bridges and culverts. Figure 3-1: Visual condition map of paved roads survey in 2021 as part of the LRMS update project Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 18 Figure 3-2: Visual condition map of unpaved roads survey in 2021 as part of the LRMS update project Figure 3-3: Visual condition map of bridges survey in 2021 as part of the LRMS update project Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 19 Figure 3-4: Visual condition map of culverts survey in 2021 as part of the LRMS update project 3.2 Overview of the Approach and Methodology To evaluate the impact of climate change on the road network, Zutari (Pty) Ltd developed an excel- based CRVA tool. The input data for this tool was directly extracted from the LRMS and contains all the condition-related data for primary roads, bridges and culverts in Lesotho. The Lesotho RD can therefore easily update the tool with new LRMS data. In addition, the tool overlaid the LRMS spatial data of all roads, bridges, and culverts with climate change risk and erodibility spatial data (discussed further in Sections 3.3 and 3.6.1, respectively) to extract the relevant climate change and erodibility indices for each road segment, bridge and culvert. The critical thresholds for temperature and precipitation impacts can be toggled in the CRVA excel- based tool to produce updated climate hazard, road condition vulnerability, and overall climate change risk maps and histograms. Figure 3-6 shows the current critical thresholds. The histogram plots presented in Sections 3.3 to 3.6 are the graphical output of the CRVA. The histogram plots will update if the precipitation or temperature critical thresholds are updated. The methodology used in this tool is synonymous with other climate risk methodologies and the ReCAP framework (Figure 3-5). Figure 3-6 shows the methodology used to calculate the hazard and vulnerability scores for paved roads, unpaved roads, bridges, and culverts . In addition, Figure 3-7 shows the methodology used to calculate the overall climate risk scores for Lesotho’s paved roads, unpaved roads, bridges, and culverts. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 20 RISK = HAZARD x VULNERABILITY x EXPOSURE • Condition of the roads • Rainfall impacts • Where the (Δmax Precip) (paved and unpaved) hazards and • Temperature • Condition of the roads, bridges impacts (Δmax bridges and culverts Temp) • Condition of the overlap spatially culverts Figure 3-5: Formula used for assessing the risks of Lesotho’s roads network Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 21 Figure 3-6: Methodology used to calculate climate related hazards and road infrastructure vulnerability. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 22 Figure 3-7: Summary of the methodology used to calculate climate related risks Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 23 3.3 Climate Related Hazards for Lesotho Roads 3.3.1 Overview of available climate change indices and scenarios The Government of Lesotho, through the Lesotho Meteorological Services (LMS), developed a climate change scenarios report as part of its Third National Communication (TNC) on Climate Change to the United Nations Framework Convention on Climate Change (UNFCCC). The 2018 Lesotho Extreme Climate Indices Report presents information about historical and projected extreme climate events in Lesotho (LMS, 2018). Calculating extreme climate indices, maximum and minimum temperatures, and seasonal precipitation changes is undertaken in a methodology consistent with the multi-model ensemble climate change simulations under different emission scenarios. The analysis is based on the data from the Coupled Model inter-comparison Project Phase 5 (CMIP5) set of global circulation models (GCMs) and downscaled under the Coordinated Regional Climate Downscaling Experiment (CORDEX) for Africa. The study determined 27 indices recommended by the World Meteorological Organisation (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Of the twenty-seven indices, sixteen are for the analysis of extremes in temperature, and eleven indices are related to precipitation (shown in Table 3-1). Table 3-1: Climate Change Extreme Indices and their explanation (red fill for temperature related indices and blue fill for precipitation) (taken from LMS, 2018) Category ID Indicator Name Explanation Units Absolute TXx Hottest day Monthly maximum value of daily max °C indices temperature TNx Warmest night Monthly maximum value of daily min °C temperature TXn Coldest day Monthly minimum value of daily max °C temperature TNn Coldest night Monthly minimum value of daily min °C temperature Rx1day Max 1 day precipitation Monthly maximum 1 day precipitation mm amount Rx5day Max 5-day precipitation Monthly maximum consecutive 5-day Mm amount precipitation Percentile- TN10p Cool nights Percentage of time when daily min days based indices temperature < 10th percentile TX10p Cool days Percentage of time when daily max days temperature < 10th percentile TN90p Warm nights Percentage of time when daily min days temperature > 90th percentile TX90p Warm days Percentage of time when daily max days temperature > 90th percentile R95p Very wet days Annual total precipitation from days > 95th mm percentile R99p Extremely wet days Annual total precipitation from days > 99th mm percentile Threshold ID Ice days Annual count when daily maximum days indices temperature < 0°C FD Frost days Annual count when daily minimum days temperature < 0°C SU Summer days Annual count when daily max days temperature > 25°C TR Tropical nights Annual count when daily min days temperature > 20°C R10mm Number of heavy Annual count when precipitation ≥10mm days precipitation days R20mm number of very heavy Annual count when precipitation ≥ 20mm days precipitation days Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 24 Category ID Indicator Name Explanation Units Rnnmm Count of days where Let PRij be the daily precipitation days precipitation is greater than Amount on day i in period j. Then 1 mm. count the number of days when PRij >1mm. Duration GSL Growing season length Annual (1st Jan to 31st Dec in NH, 1st July days indices to 30th June in SH) count between first span of at least 6 days with TG>5C and first span after July 1 (January 1 in SH) of 6 days with TG<5C (where TG is daily mean temperature) WSDI Warm spell duration index Annual count when at least six consecutive days days of max temperature > 90th percentile CSDI Cold spell duration index Annual count when at least six consecutive days days of min temperature <10th percentile CDD Consecutive dry days Maximum number of consecutive days days when precipitation < 1mm CWD Consecutive wet days Maximum number of consecutive days days when precipitation ≥ 1mm Others DTR Diurnal temperature range Monthly mean difference between daily °C max and min temperature PRCPTOT Annual total wet day Annual total precipitation from days ≥ 1mm mm precipitation ETR Extreme temperature range TXx – TNn °C SDII Simple daily intensity The ratio of annual total precipitation to the mm/day index number of wet days (≥ 1 mm) R95pTOT Contribution from very wet 100 * R95p / PRCPTOT days days R99pTOT Contribution from 100 * R99p / PRCPTOT days extremely wet days The computing of indice trends over the historical period (1971-2000) is critical to test their significance. The study results provide a good basis for assessing climate risk and vulnerability in Lesotho. The computing of indices used the following historical values and future climate change scenarios:  Historical: Absolute rainfall and temperature values based on the historical average from 1971- 2000, under RCP 4.5 and RCP 8.5.  Present climate scenario: Relative change in rainfall and temperature from the historical to the predicted present-day climate (average from 2011 – 2040), under RCP 4.5 and RCP 8.5.  Near future climate scenario: Relative change in rainfall and temperature from the historical to the predicted near future climate (average from 2041 – 2070), under RCP 4.5 and RCP 8.5.  Distant future climate scenario: Relative change in rainfall and temperature from the historical to the predicted distant future climate (average from 2071 – 2100), under RCP 4.5 and RCP 8.5. The study concluded that the gradual increase in minimum and maximum temperatures would occur during the 21st century, with a peak happening in the last period (2071-2100) under RCP 4.5 and RCP 8.5. The highest increase will occur under the worst-case scenario, RCP8.5. The increase is evident in, but not limited to, mean minimum and maximum temperatures, the number of hot days and nights and growing season length, and a decrease in the number of cold days and nights and number of frost days. All zones under all scenarios reflect a day and night temperature increase. The summer precipitation indicates the possibility of wet conditions in the Lowlands under RCP 4.5 and RCP 8.5 emission scenarios across all projection periods (LMS, 2018). However, there is no projected change in the Senqu River Valley under RCP4.5, while drier conditions will occur under the worst-case scenario (RCP 8.5) (Figure 3-8). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 25 Figure 3-8: Spatial pattern of trends in total precipitation (PRCPTOT), for the emission scenarios RCP4.5 and RCP8.5 for the periods: 2011-2040, 2041-2070, 2071-2100 (Source: CORDEX Data, LMS, 2018) The change signal is inconclusive for the other agro-ecological zones of Lesotho under the two emission scenarios (i.e. RCP4.5 and RCP 8.5) during the distant future period. In autumn, the near- future projections indicate dry conditions along the Foothills, Senqu River Valley and Mountains, although the signal of change for the Lowlands is inconclusive. Winter projections indicate a high possibility of no change in precipitation relative to the baseline period in the Lowlands. However, the changes along the Foothills and Mountains reflect a possibility of relatively wet conditions under RCP4.5 and intense dry conditions under the worst-case scenario (LMS, 2018). For spring projections for near-future (2011-2040), precipitation will likely decline under both scenarios relative to the baseline for all agroecological zones. However, in the distant future (2071-2100), models project dry conditions in spring under the worst-case scenario. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 26 Figure 3-9: Projected temperature change over Lesotho. Source: Third National Communication 3.3.2 Selected climate change scenarios Several climate change scenarios for Lesotho could inform the risk assessment. The national level risk and vulnerability assessment presented in this report used the climate scenarios provided as part of the Lesotho Third National Communication, as discussed in the previous section. This data is based on an ensemble of GCM scenarios derived from the CMIP 5 and then downscaled using the Swedish Meteorological and Hydrological Institute (SMHI) regional climate model (RCM). Table 3-2 provides a list of the climate models used. Any significant shift in current climate patterns is likely to worsen the vulnerability of Lesotho and have a considerable impact on the infrastructure, economics, ecology, and population. Identifying the extreme weather occurrences and shifts in climate patterns and their impacts is crucial to guiding short- to long-term climate-proofed infrastructural developments and managing climate risks. In addition, the LMS generated extreme indices (Table 3-1) based on the indices developed by the WMO ETCCDI (Wang and Feng, 2013). The national level risk assessment only used the ensemble median of the GCMs because individual GCM simulations using the same inputs can produce different results over different time scales ranging from several years to decades. The differences are due to normal, natural variability and how models characterise various small-scale processes. There are also inherent uncertainties in the emission scenarios themselves and potential data uncertainty concerning historical climate conditions and extreme weather events. Finally, several model simulations consolidated into an ensemble mean removes the effects of naturally occurring variability and makes it easier to discern the impact of both human and natural external drivers on the climate system. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 27 Table 3-2: Climate models used for the Lesotho Third National Communication 3.3.3 Selected climate hazards Table 3-3 includes the key climate change related transport risks from Thibault (2015). The table also discusses the relevance of these climate drivers to Lesotho and the relevant CORDEX indices selected for analysis as part of the national level risk assessment. Table 3-3: Climate drivers, the impact in Lesotho and the corresponding CORDEX data used Climate Driver Infrastructure at Relevance to Lesotho risk Extreme heat Paved roads Extreme heat will primarily impact the paved roads and (temperature bridges in Lesotho. Maximum temperatures will likely increase Bridges impacts). by 1.3 to 1.5°C in the present-day scenario and 2.9 to 3.2°C in the near future scenario (Figure 3-10 toFigure 3-12). Extreme temperatures will soften paved roads, requiring resurfacing with more durable materials (Farrag-Thibault, 2014). Increasing the cover thickness and quality of concrete used for bridges will also need to be considered. The absolute Change in Hottest Day2 (°C) CORDEX variable for the near future scenario (2041 – 2070) will therefore act as the index for extreme heat impacts. More intense Paved Roads Increasing rainfall intensity and flooding will impact both the rainfall and an paved and unpaved road network in Lesotho, and the Unpaved Roads increased risk maximum 1-day precipitation amount is a good indicator for of flooding. Bridges both. Therefore, maximum 1-day precipitation will likely Culverts increase by a maximum of 1.6% in the present-day scenario, and 8.9% in the near future scenario (Figure 3-13 toFigure 3-15). 2 Monthly maximum value of daily max temperature Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 28 Climate Driver Infrastructure at Relevance to Lesotho risk More frequent flooding will increase the need for maintenance and investment in drainage and the protection of roads. Unpaved roads are especially vulnerable to intense rainfall. Bridges are exposed to flood events, requiring upgraded design specifications in new construction and retrofitting (Farrag-Thibault, 2014). The absolute Max 1 day precipitation amount 3 (mm) CORDEX variable for the near future scenario (2041 – 2070) will therefore act as the index for extreme precipitation and flooding impacts. Increased in Paved Roads Minimum temperatures will likely increase across Lesotho Freeze-thaw (Figure 3-16 to Figure 3-18); therefore freeze-thaw cycles will Bridges cycles become less prominent and thus excluded from the analysis. Fire risk Paved Roads Limited detailed wildfire risk data is available for Lesotho and was therefore not considered in this analysis. However, the Unpaved Roads immediate physical risk to roads from increased wildfires is Bridges limited. Large-area wildfires can impact traffic. Higher winds Paved Roads Higher wind speed was not considered as an index in this study due to limited data. This indice would be most relevant Unpaved Roads for bridges. Bridges Sea level rise Paved Roads Not applicable to Lesotho. and storms Unpaved Roads Bridges 3 Monthly maximum 1 day precipitation Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 29 Figure 3-10: Historical (1972-2000) hottest day (monthly maximum value of daily max temperature) Figure 3-11: Predicted change in hottest day from historical to present (2011-2040) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 30 Figure 3-12: Predicted change in hottest day from historical to near future (2040-2070) Figure 3-13: Historical (1972-2000) monthly maximum 1-day precipitation Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 31 Figure 3-14: Predicted change in monthly maximum 1-day precipitation from historical to present (2011-2040) Figure 3-15: Predicted change in monthly maximum 1-day precipitation from historical to near future (2040-2070) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 32 Figure 3-16: Historical (1972-2000) coldest day (monthly minimum value of daily max temperature) Figure 3-17: Predicted change in coldest day from historical to present (2011-2040) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 33 Figure 3-18: Predicted change in coldest day from historical to near future (2040-2070) The assessment extracted the relevant climate data from CORDEX for each 1km road segment (paved and unpaved) from the LRMS, which was includes in the national CRVA tool. Figures 3-19 to 3-20 summarize the national climate related hazards. Rainfall hazard Temperature hazard Climate hazard category category category 3000 2500 No. of 1km road segments 2000 1500 1000 500 0 Paved Unpaved Paved Unpaved Paved Unpaved Figure 3-19: Rainfall, temperature, and climate hazards for the LRMS roads network Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 34 Rainfall hazard per district - paved and unpaved roads No. of 1km road segments 900 800 700 600 500 Very high 400 300 High 200 Median 100 0 Low Very low District Temperature hazard per district - paved and unpaved roads 900 No. of 1km road segments 800 700 600 500 Very high 400 300 High 200 Median 100 0 Low Very low District Overall climate hazard per district - paved and unpaved roads 900 No. of 1km road segments 800 700 600 500 Very high 400 300 High 200 Median 100 0 Low Very low District Figure 3-20: Rainfall, temperature and climate hazards for the LRMS roads network, summarised per district Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 35 3.4 Current Condition and Vulnerability of Roads Information on the current road conditions are available from the LRMS and act as indicators of the likely vulnerability of a particular road section to the impacts of climate change. The assumption is that a road in a poorer condition is more likely to be negatively impacted by climate change (i.e. increasing temperature, rainfall or flooding risk) than a road in good condition. However, it is important to note that the assumption is based primarily on the assessment of the visual condition of the road. In addition, the assumption does not factor whether the road has been built to the appropriate design standard and/or structural integrity. The current road condition is derived from the 2021 visual inspection, which considered 16 characteristics of paved roads, 14 characteristics of gravel roads and 11 characteristics of earth and track roads, scored on a scale of 1 (very good) to 5 (very poor). Figures 3-21 show the individual road characteristics assessed and their national ratings for paved roads and Figure 3-22 toFigure 3-23 for unpaved roads. The assessment completed a visual inspection every 1 km along a road’s length, although this may sometimes deviate slightly. These are combined in an overall visual condition index (VCI) score for paved roads and a visual gravel index (VGI) for unpaved roads, summarising the road’s overall condition. Hence, its vulnerability to current and future climate change impacts. The national change in VCI and VGI scores from 2010 to 2021 for roads in Lesotho are shown in Figure 3-24 and Figure 3-25. . Figure 3-21: Distribution of surfaced roads distress and other characteristic ratings by percentage of road length (2021 surveyed road network) (Roads Directorate, 2022) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 36 Figure 3-22: Distresses and characteristics for gravel roads by percentage of road length (2021 surveyed network) (Roads Directorate, 2022) Figure 3-23: Distresses and characteristics for earth and track roads by percentage of road length (2021 surveyed road network) (Roads Directorate, 2022) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 37 Figure 3-24: Paved roads: Overall historical VCI (2010-2021) (% road per condition category) (Roads Directorate, 2022) Figure 3-25: Unpaved roads: Overall historical VGI (2010-2021) (% road per condition category) (Roads Directorate, 2022) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 38 To determine the vulnerability score for each road segment, we considered the following:  For paved roads (Table 3-4): • Binder condition – Vulnerability to direct temperature impacts. • Drainage condition (Side drains) – Vulnerability to direct precipitation impacts  For unpaved roads (Table 3-5): • Drainage condition and adequacy – Vulnerability to direct precipitation impacts  For all roads (Table 3-6): • Overall Condition – Vulnerability to combined temperature and precipitation impacts (VCI condition categories for paved roads and VGI condition categories for unpaved roads) Table 3-4: Rating scales for paved roads (binder condition and side drainage condition) BINDER CONDITION SCALE DESCRIPTION 1 Binder not fresh but sticky, colour bright black 2 Between 1 and 3 3 Appears dull, brittle, shrinkage cracks may be evident 4 Between 3 and 5 5 Dull, very brittle, shrinkage cracks evident, not sticky at all, binder elasticity low SIDE DRAINAGE CONDITION SCALE DEFINITION DESCRIPTION 1 Adequate Side drainage system is adequate, or if no side drains exist, the terrain is of such a nature as to be able to handle runoff 2 Between Adequate and Warning 3 Warning Parts of side drainage system are inadequate, or parts of the terrain prohibit successful runoff conveyance 4 Between Warning and Inadequate 5 Inadequate Side drainage system is extensively damaged or eroded or non-existent and totally ineffective. Where no system exists, the areas adjacent to road are largely eroded or ponding of water occurs frequently next to road Table 3-5: Rating scales for unpaved roads (side drainage condition and adequacy) DRAINAGE CONDITION (Side Drains & Culverts) SCALE RATING EROSION OBSTRUCTIONS 1 Very good None None 2 Good 3 Fair Moderate Moderately overgrown/ obstructed 4 Poor 5 Very poor Severe Totally overgrown/ obstructed DRAINAGE ADEQUACY (Drainage away from the road) SCALE RATING CAMBER/CROSS-FALL PONDING 1 Very good Good None 2 Good Good to flat Few 3 Fair Flat General 4 Poor Flat to inverted Extensive 5 Very poor Inverted Severe problems Table 3-6: Overall Road condition - VCI and VGI values Scale Description VCI/VGI values 1 Very good More than 85 Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 39 Scale Description VCI/VGI values 2 Good 70 to 85 3 Fair 50 to 70 4 Poor 30 to 50 5 Very poor Below 30 Paved roads overall condition per district 500 No. of 1km road segments 400 300 Very poor 200 Poor Fair 100 Good 0 Very good District Unpaved roads overall condition per district 500 No. of 1km road segments 400 300 Very poor 200 Poor Fair 100 Good 0 Very good District Figure 3-26: Paved and unpaved roads overall condition per district Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 40 Unpaved drainage condition and adequacy No. of 1km road segments 3000 2500 2000 1500 Unpaved drainage condition Unpaved drainage adequacy 1000 500 0 Very poor Poor Fair Good Very good Paved binder condition Paved side drainage condition 3000 No. of 1km road segments 2500 2000 1500 1000 500 0 Very Poor Fair Good Very Very Poor Fair Good Very poor good poor good Paved Paved Overall roads condition 3000 2500 No. of 1km road segments 2000 1500 Unpaved Paved 1000 500 0 Very poor Poor Fair Good Very good Figure 3-27: Summary of roads condition and vulnerability for all of roads in Lesotho. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 41 In addition to the road condition data, the conditions of the bridges and culverts was obtained from the LRMS. This assessment analysed the data in terms of their current condition. The overall rating in the LRMS is given in Table 3-7, and is scored according to the following sub-categories:  Bridges: • Condition rating for the approaches of the bridge • Condition rating for the waterway below the bridge • Rating for the condition of the substructure of the bridge (foundations, abutments, piers) • Rating for the superstructure of the bridge ('spans') • Rating for the section of roadway on top of the bridge  Culverts: • Condition rating for the waterway below the major culvert • Condition rating for the cells in the major culvert • Condition rating for the corrugated (Armco) pipes or cells in the major culvert • Condition rating for the section of roadway on top of the major culvert • Condition rating for the inlet and outlets of the major culvert Table 3-7: Overall condition ratings for bridges and culverts Scale Description 0 Beyond repair 1 Critical 2 Very Poor 3 Poor 4 Marginal 5 Fair 6 Satisfactory 7 Good 8 Very Good 9 Excellent The overall condition ratings for bridges and culverts only consider the infrastructure’s condition and not its hydraulics or design capacity. Hydraulic or design capacity is impertitive when considering the impacts of climate change. One example is a recent design capacity review of drainage structures undertaken as part of the upgrading of the Thaba Tseka to Katse Road (Box 1Box 1: Design Capacity Review of the Thaba-Tseka to Katse Road). The review found that almost all culverts are inadequate for both the required current hydraulics design capacity and the future hydraulic design capacity, considering a 12% increase in the design flood to account for climate change. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 42 Overall conditions of bridges and culverts 140 120 100 Number 80 60 Bridges 40 Culverts 20 0 Figure 3-28: Overall conditions of bridges and culverts in LRMS Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 43 Box 1: Design Capacity Review of the Thaba-Tseka to Katse Road The design report for the Thaba Tseka to Katse Road includes a recommendation to increase the design flood estimate for all drainage structures by around 12% to account for the expected increase in rainfall intensity. What was clear from this design report is that the current culvert capacities are too small for the current design standards. The culvert capacities would therefore be insufficient to handle any potential impacts of climate change and/or increases in flood frequencies, sedimentation, or debris as a result of catchment management practices. The current capacity and design flood estimates are shown in Figure 3-26, along with the additional capacity requirements to account for potential climate change impacts (i.e. an additional 12% design capacity). This data shows that only three of the 34 culverts have sufficient capacity for the current design standards. On average, the culverts’ capacities need to be increased by around 70% to account for the current flood estimates. The capacity of the culverts, on average, would need to be increased by a factor of three (3) to account for the potential impacts of climate change. The increase will have a significant impact on the overall costs of the rehabilitation of the road to make it climate resilient. In this case, the urgent need to replace all the existing drainage structures could be considered a necessary requirement to improve the climate resilience of the road and is something that the Lesotho RD should explore with potential climate change financing. Figure 3-29: Current capacity of drainage structures on the Thaba Tseka to Katse Road, required capacity, and future deficit based on a 12% increase to account for climate change. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 44 3.5 Overall Climate Change Risk for Roads in Lesotho The national temperature, rainfall and overall climate risk categories are shown in Figure 3-30. Temperature Rainfall Climate risk category risk category risk category 3000 No. of 1km road segments 2500 2000 1500 1000 500 0 Paved Paved Unpaved Paved Unpaved Figure 3-30: Temperature, rainfall, and climate risk categories for paved and unpaved roads Figure 3-31 presents the climate change risks for paved and unpaved roads in each district. The northern districts (Butha-Buthe, Leribe and Mokhotlong) show the lowest level of risk. This observation is primarily because these regions have a lower risk of increasing extreme rainfall events. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 45 Paved roads climate risk per district 500 450 No. of 1km road segments 400 350 300 250 Very high 200 High 150 Median 100 Low 50 Very low 0 District Unpaved roads climate risk per district 500 450 No. of 1km road segments 400 350 300 250 Very high 200 High 150 Median 100 Low 50 Very low 0 District Figure 3-31: Total length of roads in each category of climate related risk (i.e. combination of hazard, vulnerability, and exposure) for paved (top) and unpaved roads (bottom) in each district Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 46 3.6 Consideration for Additional Risk Amplifiers. The assessment considers several factors as additional “risk amplifiers” which would increase the risk posed by climate change to the road infrastructure. The most significant of these is a lack of routine maintenance and appropriate design considerations, rehabilitation and upgrading of roads where needed. Several examples of lack of maintenance, including clearing culverts and unblocking side drains were observed during the field visit and would increase the climate-related risks. These additional risk amplifiers will ultimately result in the deterioration of the road infrastructure and are reflected in the overall visual assessment scores used as the indicator of vulnerability of individual roads. Several other risk amplifiers can also be considered and added to the information available in the LRMS. These include:  Soil Erodibility Risk  Catchment Degradation  Increasing Landslide Susceptibility 3.6.1 Soil Erodibility Risk Soil erosion is considered a major threat to downstream reservoirs and increases the potential impact on roads and other infrastructure. Lesotho has the highest natural erosion risk of any single county in southern and central Africa (Chakela, et. al 1988). The soil erodibility risk map (Figure 3-32) shows high soil erosion hazards in the foothills and mountain areas due to steep slopes, high rainfalls, poor lithosols and average vegetation cover. The Lowlands have suffered years of mismanagement, which accounts for the history of severe soil erosion. Shallow slopes and low rainfall counteract the high erodibility of the soil. The risk of high-level soil erosion is significantly increased as a result of changes in land cover, poor land management and climate change. Slope and rainfall are the dominant factors that contribute to the erosion risk in Lesotho. Hence a change in rainfall will likely increase the risk. The soil erodibility risk map is important when considering the design of drainage structures and is a particular concern in the Lowlands. Figure 3-33 shows the number of road segments, bridges and culverts at risk of soil erosion on a national scale. Further, figure 3-34 shows the erosion risk per district for paved and unpaved roads. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 47 Figure 3-32: Map showing soil erodibility risk for Lesotho (Source: Le Roux, 2008) Erodibility index 1200 No. of 1km road segments 1000 800 Unpaved 600 Paved 400 200 0 120 100 80 Number 60 Bridges 40 Culverts 20 0 Figure 3-33: Erodibility index of roads (paved and unpaved), bridges and culverts in Lesotho Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 48 Erosion risk per district - paved and unpaved roads 900 800 700 No. of 1km road segments 600 500 Very high 400 High 300 Median 200 Low Very low 100 0 District Figure 3-34: Erosion risk per district, for paved and unpaved roads 3.6.2 Catchment Degradation Figure 3-35 shows current estimates of the extent of land degradation per district in Lesotho (WFP, 2015). The analysis highlighted that land degradation was most severe in the districts of Mafeteng, Mohale’s Hoek and Berea. Quthing, Maseru and Leribe experience medium negative land cover change. Qacha’s Nek, Thaba Tseka and Butha Buthe have low land degradation, while Mokhotlong has the lowest. The districts facing high catchment degradation correlate with those with high erodability and high climate risks, as discussed in the previous section. In addition, the catchment degradation and poor land management practices would exacerbate the road’s climate and erosion risks (blocked culverts and side drains, flooding, overtopping of bridges etc.). Currently, there is no readily available and sufficiently detailed data on the extent of catchment degradation or the application of sustainable land management practices. However, should this data become available, it would be useful to consider it an additional risk amplifier or risk mitigation layer. This could also be investigated further in the priority sub-catchments of the ReNOKA program. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 49 Figure 3-35: Land degradation per district, using Land Cover Change as a key indicator (WFP, 2015) Figure 3-36: Extensive erosion scars in Mohale’s Hoek district, Makhaleng catchment. This area has experienced some of the worst land degradation in Lesotho. 3.6.3 Increasing Landslide Susceptibility Climate change will likely increase the geotechnical risks associated with transport infrastructure, particularly regarding the potential for increased risk of landslides induced by an increase in heavy rain events. Landslide occurrence is related to various factors, including among other things, steep rugged topography, high relief, and humid climate. Currently, Lesotho is considered to haveconsists of a medium to high level of landslide risk based on the Global Landslide Hazard Map, but this varies significantly across the country as a result of both changes in topography and soil type, with the most significant level of risk in the high mountain areas. A study by the Council for Geosciences in South Africa (Singh et al, 2011) developed a landslide susceptibility map for South Africa (Figure 3-37). Lesotho could develop a similar map, which would be a very useful additional hazard layer because rainfall is one of the key driver variables. In addition, Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 50 Lesotho could consider the expected impacts of climate change which could result in an updated, projected landslide susceptibility map for Lesotho. Figure 3-37: Landslide susceptibility map for South Africa that could be developed for Lesotho (Source: Singh et al, 2011) 3.7 Summary Conclusions and Recommendations The national scale risk assessment presented in this section has shown that GCMs downscaled to fit local contexts are useful for setting the broader context of climate risk. However, they do not incorporate the local vulnerabilities to climate change that is needed to inform investment and policy choices (Ray and Brown, 2015). For example, the magnitude of climate change’s effects on water resources or infrastructure might be small relative to the impact of changes in other variables, such as population, technology, and demand, over medium- to long-range periods (Ray and Brown, 2015). Therefore, other contributing factors (such as catchment degradation, traffic volumes, community-built roads, and poor maintenance) may have significantly more impact on the roads in Lesotho than climate change. The Catchment level climate risk and vulnerability assessment for roads in two priority sub- catchments in Lesotho Report will address other contributing factors. However, it is important to continually update the national level risk assessment tool to ensure that it contains important information for addressing road criticality on both a local and national scale. For example, currently, the prioritisation procedures of the Department of Rural Roads (DRR) for roads to be upgraded or constructed are based on the following criteria:  An initial list is compiled by the road authority and is sent to the District Councils.  Based on the initial list, the road authority requests District Council Secretaries to submit lists of proposed roads with their preliminary ranking (District Planning Unit priorities).  Traffic counts are conducted on the priority roads and upgraded according to the priority lists. Current traffic volumes provide for a “traffic priority” score .  A “population priority” score is given based on the population served by each road. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 51  Taking into account developments in the area such as agricultural production, schools, clinics, churches, and markets, and the imprtance of the road segments for accessing these. This information was not readily available for this climate risk assessment but would provide important information for assessing the road’s criticality. Therefore, the RD should consider including this information in any further analysis. If it is not readily available, it would be useful information to collect for each road segment in the LRMS. 3.8 Updating Climate Risk Information in the LRMS The LRMS can include calculated climate information and vulnerability data for each road segment used in the national level climate change risk and vulnerability assessment for roads as additional risk layers. The GoL must review the results and where possible update either with additional climate change scenarios (when these become available) or with updated information on the condition and vulnerability of individual roads, bridges and culverts. In addition, the GoL can assess the results through an annual review or whenever data in the LRMS is updated. As discussed in the previous sections, it is possible to consider additional data to assess climate- related risks for roads in Lesotho. The data must be considered when available at a national level for strengthening the data available in the LRMS to support further investigations and potential prioritisation for improving climate resilience. For example, Lesotho can consider the following additional data that could be captured in the LRMS:  Information on the “criticality” of a particular road or segment. Th e information could include whether a specific road is a major access road to community facilities such as clinics, schools, council buildings, churches, graveyards or other cultural and spiritual sites.  Information on current drainage structures capacities indicate the degree to which they are adequate for current design estimates in addition to climate change impacts. Based on the review of the current design standards and available climate scenarios for Lesotho, it would be useful to consider adding recommendations to the LRMS, such as the recommended increase in the design rainfall estimates for different rainfall return periods. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 52 4 Catchment Level Climate Risk Assessment 4.1 Aim and Objectives Climate change studies are often addressed through top-down approaches using climate projections and modelled impacts. However, a bottom-up approach is also required to focus on the recent past and present vulnerabilities. Whilst top-down and bottom-up approaches generate complementary insights into who and what is at risk, integrating their results is a much-needed step towards developing relevant information to address the needs of immediate adaptation decisions (Conway et al., 2019). The national level risk assessment presented in this report is a top-down approach to climate risk analysis. Therefore, there is a need to conduct a bottom-up or catchment-level risk assessment, particularly in the focus catchments and their associated priority sub-catchments. Between 1 and 9 November 2022, the study team visited the key catchments their associated priority sub-catchments to conduct a catchment-level risk assessment. These included:  Makhaleng catchment and the Makhalaneng priority sub-catchment  Northern Mohokare catchment and the Hlotse priority sub-catchment Figure 4-1: Meetings with 4 Community Watershed Teams in the northern Mohokare and Makhaleng catchments The aim of this mission was two-fold. Firstly, the study team met with four Community Watershed Teams (CWTs) from the two catchments that are part of the ReNOKA catchment management programme. The CWTs represent a diverse group of individuals from the community involved in sustainable farming practices and catchment restoration in the community. These engagements aimed to identify the key climate drivers impacting the roads and livelihoods in the local communities. A proper understanding of the local nuances is necessary to develop actions and policies that will have the greatest impact. The community also provided significant insight into other drivers negatively impacting the road network, such as poor land management, unstainable road-building practices etc. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 53 Section 4.2 summarises the key issues raised by the community, with additional details, locations and specific recommendations given in the local-level risk assessment report. The second objective of the local-level risk assessment was to visually and spatially document specific risks impacting the road network based on sites identified by the community and the technical specialists. To support the visual assessment of current and potential future risks, the field team included a roads engineer, a climate change specialist and a catchment/water resource management specialist to address the range of risks impacting the roads networks. During the visits to the two catchments, 57 sites were visually assessed and spatially recorded, including relevant technical insights, actions and recommendations. Section 4.3 summarises the outcome further described in the Catchment level climate risk and vulnerability assessment for roads in two priority sub-catchments in Lesotho Report. 4.2 Summary Feedback from Communities Below are the general issues and observations from the CWTs. Heavy rainfall and flooding were highlighted as the number one hazard impacting the roads by all the CWTs. They all presented examples of where flooding and associated damage to road infrastructure (including bridges, roads and footbridges) has impacted their ability to access important sites, such as burial grounds, schools, clinics and neighbouring villages. In addition, some villages have been left virtually inaccessible due to infrastructure damaged by flooding. Landslides and rockfalls were identified as the second key hazard impacting the road networks, especially during heavy rain and hailstorm events. Hail storms and frost were identified as a third key hazard for the communities, although the impact on the roads is limited. Ha Khabo CWT in the Hlotse catchment said that they can see the impacts of climate change over the past 5 to 10 years. The planting season used to be August but has shifted to October/November due to frost, and the planting season has shortened overall. Heavy rains and poorly maintained side drainage channels ultimately result in erosion and the formation of dongas that damage the roads and encroach on neighbouring fields (Figure 4-2). Therefore, increasing climate change resilience impacts the communities’ infrastructure and livelihoods. Figure 4-2: A poorly maintained side drainage channel in the Makhaleng catchment has resulted in erosion of both the road and the adjacent farmland. Communities build their rural access roads using soil from adjacent quarries and handmade soil compaction equipment (see example in Figure 4-3). There is often no engineering or technical support. These roads wash away during heavy rains, and the sediment ends up in streams, houses, Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 54 agricultural fields, and major roads at intersections. The cycle re-occurs on an annual basis after the heavy rains. Figure 4-3: Example of a handmade Figure 4-4: A community-built road in the concrete tamper4 Makhaleng catchment that is resurfaced on an annual basis after extreme rainfall events. The eroded soil is deposited in the Makhaleng river. Some community road management interventions end up causing more significant erosion problems and damage to transport infrastructure (Figure 4-5). For example, communities dig side drains for rural access roads without implementing proper erosion control, such as small check dams (Figure 4-9). In addition, the communities requested technical and engineering support to guide them on how to build and maintain their infrastructure. Figure 4-5: An unprotected community-built side drain which has resulted in erosion Some community members purposefully block culverts to prevent outflow into agricultural fields (Figure 4-6). 4 https://insteading.com/blog/how-to-make-your-own-concrete-tamper/ Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 55 Figure 4-6: Culvert possibly blocked by community (left) and field immediately downstream of the culvert outlet (right). Mohokare catchment. Alien vegetation is a massive concern in the catchments, particularly the Upper Mohokare. The community notes that the dongas and riparian areas have high alien vegetation growth (Figure 4-7). During heavy rains, this vegetation gets washed down the rivers, blocking culverts and damaging infrastructure further downstream. Figure 4-7: Alien vegetation growing in a riparian area in the Northern Mohokare catchment The CWTs were knowledgeable about the importance of Nature-Based Solutions and proper catchment management in general and regarding roads. Some of the interventions they are involved with through ReNOKA include the following:  Reclamation of dongas  Removal of alien vegetation and brush control. The communities did note that minimal revegetation does result in further increased erosion. The debris from clearing alien vegetation could also contribute to blocked culverts downstream.  Development of silt traps and other catchment management initiatives Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 56 4.3 Summary of specific hazards identified Road related hazard Example from the field 1 Unprotected side drains or riverbanks Highly eroded side drains have formed a gully, resulting in In Ha-Mpalipali, erosion of a natural stream increased damage to the road infrastructure and catchment degradation due to minimal protection of the road infrastructure. further downstream (Makhaleng catchment). Gabion boxes have been used to stabilise the river-bank slopes and protect the road from erosion but have not been sufficient (Makhaleng catchment). 2 Damage to causeways and bridge embankments Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 57 Road related hazard Example from the field Blocked culverts and inadequate scour protection at Sedimentation has increased the risk of overtopping, Maphutseng River Crossing resulted in overtopping and damaging the stone-pitching bridge scour protection at damage to the bridge embankments (Makhaleng the embankments (Makhaleng catchment). catchment). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 58 Road related hazard Example from the field 3 Eroding of the Shoulder of the Road Eroding of the shoulder of the road is a common issue across most of Lesotho and can be seen on most paved roads outside the cities. Insufficient connection with the side drains increases the risk of erosion (Nothern Mohokare catchment). 4 Slope Instability, Erosion, and Landslide Risk The Raboletsi CWT identified this roadside cutting An unprotected roadside cutting (Makhaleng that is prone to rockfalls during both winter and catchment). summer, blocking the road and impacting traffic. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 59 Road related hazard Example from the field 5 Lack of Downstream Erosion Protection Severe scouring of a drift that is damaging the Due to heavy floods, the apron of the culvert has washed away, and road infrastructure and increasing erosion in the the fill embankment slope and stone-pitched outlet wall have eroded, downstream catchment (Makhaleng catchment). resulting in increased scouring (Makhaleng catchment). 6 Unrehabiliated borrow pits The excavator marks of an The community uses this old borrow pit as a source of gravel for road unrehabilitated slope are seen construction. The unrehabilitated slopes have increased erosion, (Makhaleng catchment) blocking the side drains (Makhaleng catchment) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 60 Road related hazard Example from the field 7 Blocked and/or Insufficient Side Drains Blocked culvert due to plant debris causing increased overtopping Inlet to a culvert completely blocked by sediment during flooding and eroded pavement. Due to the blockage, the river (left) due to severe erosion upstream (middle). course is changing and beginning to erode an adjacent field (Northern The culvert is in good condition, as can be seen Mohokare catchment). by the outlet (right), and only requires regular desiltation (Makhaleng catchment) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 61 Road related hazard Example from the field 8 Blocked and/or Insufficient Side Drains Insufficient side drains causing flooding of the Blocked and insufficient side drains cause erosion of an unpaved road (Northern Mohokare catchment) road (Makhaleng catchment) 9 Insufficient Drainage of Unpaved Roads Earth road with inadequate surface and side drainage (Northern Mohokare catchment) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 62 Road related hazard Example from the field 10 Lack of Connection to Main Drainage Channels A natural drainage channel crossing a gravel road. Diverting the channel slightly to the right would cause the water to flow into a culvert and discharge into the main drainage channel (Northern Mohokare catchment). 11 Damage to Formal Roads from Rural Access Roads A poorly built rural access road with limited protection works has resulted in erosion and sediment deposition onto the primary road (Northern Mohokare catchment) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 63 Road related hazard Example from the field 12 Inadequate Infrastructure for River Crossings The community can only access the earth road to Kotanyane Village during low flow periods (left). During high flow periods, the community must rely on a footbridge to access clinics, schools etc. (right) (Northern Mohokare catchment) 13 Unsustainable Land Management Practices Impacting Roads An agricultural field depositing sediment on the RD road (Makhaleng catchment) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 64 Road related hazard Example from the field 14 Dynamic River Channels and Wide Flood Plains. The third bridge constructed since 1992 as the Hlotse river course is meandering and changing (Northern Mohokare catchment). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 65 4.4 Conclusions and Recommendations In rural Lesotho, a network of footpaths, an estimated 221 footbridges, a network of about 44 river ferry crossing sites, and some bridle paths facilitate Intermediate means of transport (IMTs). Access roads and rural tracks are also important elements of rural IMTs infrastructure. Access roads and rural tracks provide opportunities for isolated rural communities to access socio-economic services and other modes of transport. This project mainly assessed A, B, C and D roads under the RD’s and the MLGC. However, it was evident from the field assessment and conversations with the CWTs that the key issues lie between the IMTs and rural access roads. The community members typically build these roads and tracks with limited technical know-how and equipment. Since no institution has the mandate to provide the legal and regulatory framework to plan, implement and monitor IMT projects, such projects do not conduct EIAs as required by the Environment Act 2001. As such, rural access roads are particularly prone to the impacts of climate change and pose the greatest threat to catchment degradation. Many of the risks facing the paved and unpaved road networks in the catchment are not due to climate change but are exacerbated by the impacts of climate change and increasing rainfall intensity and temperatures. Poor maintenance, catchment degradation, erosion, and community interventions (such as clearing of alien vegetation that blocks culverts) pose significant risks to the roads and associated infrastructure, which will only worsen with climate change. While this assessment mainly focussed on the impact of climate change on the road network, it was evident that the roads often significantly impact the environment. Figure 4-8 shows the compounding effects that poor road rehabilitation can have on the catchments. Poor management of roadside drainage has resulted in erosion providing a channel for increased runoff and sediment delivery, creating more gullies downstream (Figure 4-8). This observation shows how unmanaged small gully erosion produces larger gullies, highlighting that prevention is always better than rehabilitation. Local communities can easily implement preventive interventions, such as small check dams (Figure 4-9). Figure 4-8: Eroded side drain (left) which has resulted in further degradation downstream (right) Figure 4-9: Small check dams used to prevent erosion of side drains in the Makhaleng catchment Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 66 5 Incorporating Climate Change into Current Road Design Standards and Design Guidelines Incorporating climate change considerations into existing policy and design guidelines for Lesotho roads is critical to ensure the future resilience and sustainability of the road network. In this regard, it is important to consider critical aspects such as the likely changes in temperature and rainfall in designing future roads and rehabilitating and upgrading existing roads. 5.1 Review of Existing Road Design Guidelines Lesotho’s road network is a critical part of the national economy and is necessary to ensure social well-being. Climate change will impact the road infrastructure through changes in temperature, precipitation and runoff. These impacts are discussed briefly below concerning the relevant design standards and guidelines for the Kingdom of Lesotho. The Lesotho Design guidelines are based on the SANRAL deisgn guidelines. Table 5-1 includes a list of existing guidelines. Below are the most relevant in terms of climate change:  Standard specifications for roads and bridges – Volume 1  Design guidelines for low volume roads – Volume 2  Design Standards and Guidelines for Pavement Materials Design - Volume 3  Design Guidelines and Explanatory Notes for Hydrology and Drainage of the Roadway Prism – Volume 4  Design Standards and Guideline for Pavement Rehabilitation - Volume 8  Guidelines for Environmental Control – Volume 9 Table 5-1: List of existing roads design standards and guidelines for Lesotho Design Guideline Title Volume 1: Design Standards for Geometric Design Volume 2: Design Standards and Explanatory Notes for Bridges, Culverts and Low- Level Structures Volume 3: Design Standards and Guidelines for Pavement Materials Design Volume 4: Design Guidelines and Explanatory Notes for Hydrology and Drainage of the Roadway Prism Volume 5: Standards for Implementation of Quality Volume 6: Standards for Preparation of Tender/Contract Documentation Volume 7: Guidelines for Preparation of Terms of Reference Volume 8: Design Standards and Guidelines for Pavement Rehabilitation and Upgrading Design Volume 9: Guidelines for Environmental Control 5.1.1 Volume 1: Design Standards for Geometric Design Volume 1 of the Guidelines deals with the geometric design of roads and guides the most economical design considering the relevant environmental conditions. Section 5.5 of the Guideline deals with requirements for slopes and side drains. The recommended slope differs with the height of the Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 67 embankment. In cases where the fill is greater than 1m, it recommends that the slope should be 1:2 and where the fill is less than 1m should be 1:4. For cut slopes where the height is less than 1m, the slope should be 1:2. Where the height is greater than 1m, the slope should be 1:1.5 in soils and between 1:0.33 to 1:0.1 in rocks. It further recommends that the soil properties be checked and considered based on the local climate conditions. In this regard, it is necessary to consider potential future climate scenarios as these impact slopes and may require additional protection. Section 10 of the Guidelines also deals with drainage: slopes, side drains and culverts. Volume 4 covers the design process in detail. Due to changing climatic conditions, the slopes are prone to erosion, whilst culverts and drains are prone to silting and clogging. Culvert outlets are also prone to erosion if slopes are not well protected and maintained. In addition, Lesotho should consult relevant experts to check the slopes and soil properties. It will also be essential to consider future climate impacts in this regard. 5.1.2 Volume 2: Design Standards and Explanatory Notes for Bridges, Culverts, and Low-Level Structures. Volume 2 of the Guidelines deals with the planning and design of concrete structures carrying roadways. The structures that carry road traffic aim to convey stormwater, for road-over-road crossings, road-over-river crossings, road-over-railway line crossings, road-over-canal crossings, and pedestrian underpasses or cattle creeps. In addition, the Volume provides brief explanations or recommendations on the various aspects of planning and design, including comprehensive information the designer might require. The standard design requirements for bridges are that the river flow lines should be interfered with as little as possible. The bridge should be located perpendicular to the river and not at bends where the velocities are high. The standard referred to the latest version of the South African Road Drainage Manual and TRH 25 (DoT, 1994a) for calculating the recommended flood return period and is addressed in more detail in Volume 4. The climatic conditions that affect the flood return periods may have already changed and are likely to be impacted by climate change. As a result, it is necessary to review changes in observed floods and rainfall that may have already impacted the standard design flood recommendations and consider future climate scenarios. Volume III of TRH 25 outlines information on the protection of the road embankment. The riverbanks are steep and susceptible to collapse due to soil and climate conditions. Furthermore, water flow can erode embarkments built on the side slopes and most low-level bridges and pipe culverts are already eroding on the embarkments. Implementating and applying the TRH 25 and selecting protection works should be regarded highly. The use of gabion boxes and stone pitching for the protection of slopes is evident in most bridges and culverts. However, with time, gabion boxes and stone pitching erode due to scouring caused by inlet blockages that result in the overtopping of water. In this regard, it is important to consider the need to protect the embankments adjacent to the road or bridge and across the entire floodplain in cases where the road crosses a wide floodplain. The need for protection is particularly relevant in the Lowland areas of Lesotho. The Lowland areas consist of highly erodible soils and naturally eroding landscapes that result in highly dynamic river channels and wide flood plains. 5.1.3 Volume 3: Design Standards and Guidelines for Pavement Materials Design Volume 3 details the standards with which road pavements and pavement materials must comply. The Volume recommends using the TRH 4 (DoT, 1996) for the relevant specifications for the design of pavement materials. In addition, the Volume also considers that some parts of the country are prone to freezing and therefore recommends the application of a Design Freezing Index, which is particularly relevant to the highlands of Lesotho. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 68 Basalt weathering is also significant for road construction in Lesotho, as the rock is crystalline and subject to disintegration and decomposition. Weathering by decomposition is the dominant form and its products range from completely weathered soft orange clay to un-weathered rock with weathered material along joints. Climatic conditions determine the amount of weathering influenced by precipitation and temperature/evaporation. The pavement design depends on the pavement’s bearing capacity and other factors. The design should consider the traffic spectrum and primary load the road will carry. The pavement design should use a specific bearing expressed in terms of the number of Standard (80kN) Axle (SA) load repetitions that will result in a condition of deterioration, thus defining the required material and thickness of the road pavement materials. Due to climate change, some parts of the country are likely to become hotter, which may result in higher standards required for pavement design. Climate change may also lead to a reduced risk of freezing conditions. This observation requires a detailed study to analyse the full impact. Furthermore, the rock weathering results in collapsing slopes on embankments. 5.1.4 Volume 4: Design Guidelines and Explanatory Notes for Hydrology and Drainage of the Roadway Prism Volume 4 deals with hydrology and drainage of the roadway prism Design guidelines and explanatory notes. The Volume consists of two parts, namely surface drainage and hydrology. Hydrology deals with determining runoff from rainfall. The applicable guidelines specified are the following:  Road drainage manual 4th edition of 1986  Hydrological map of Lesotho of 1994  Hydrological information provided by gauging stations. Surface drainage deals with the disposal of stormwater through kerbs, chutes or drains, taking water from the road surface and treating water in the road subgrade through subsurface drainage. The applicable guidelines are the road drainage manual and TRH 15 (DoT, 1994b). There are guidelines which apply to both hydrology and surface drainage. These include the determination of design flood, rainfall area, hydrographs sediment yield, return periods, site investigations, design flood estimations, etc. Lesotho exhibits a high sediment yield and the specifications state that all drainage structure inlets and outlets must be designed and constructed to eliminate erosion caused by the constricted openings of the drainage crossings. However, debris collected in the water causeway silts most culverts and low-level bridges. This includes tree branches from the upstream catchment and sediment from collapsing banks. It has resulted in bridge approaches, culverts being scoured, overtopping water into the road prism resulting in eroded asphalt layers, and eroding carriageways on gravel roads. Regular cleaning by removing the debris from the structure inlets and outlets can minimise the effects. The flood frequencies presented in the Road Drainage Manual note that the flood flow is the most significant factor in the damage done to road structures. The basis for classification uses peak flow calculated for a flood with a return period of 20 years. Appropriate design return periods for various classes of road/structure are then related to the 1:20 year peak discharge. Table 5-2 is an extract from the South African Road Drainage Manual, made specifically for Lesotho by introducing the applicable road classes. Table 5-2: Road drainage manual 1:20 YEAR PEAK DESIGN RETURN PERIOD (YEARS) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 69 DISCHARGE C and D Class B Class A Class (m³/sec) 0 to 20 1:5 1:10 1:20 20 to 150 1:10 1:20 1:50 more than 150 1:20 1:50 1:100 The return period plays a major role in determining peak flow where C and I are runoff coefficient and rainfall intensity. CIA Q= , 3,6 where, Q = peak flow (m³/s) C = runoff coefficient I = average rainfall intensity over catchment (mm/h) A = effective area of catchment (km²) 3,6 = conversion factor The application of the formula is based on the following: (1) The rainfall has a uniform area distribution across the catchment. (2) The rainfall has a uniform time distribution during the time of concentration. (3) The peak discharge occurs at the end of the time of concentration. (4) The runoff coefficient C remains constant throughout the duration of the storm. (5) The return period of the peak flow is the same as that of the rainfall intensity. Due to climate change, rainfall patterns have changed. The change might have affected the rainfall return periods and the rainfall intensity. The culvert capacities may need to be improved to accommodate increased rainfall intensities and the return periods might have changed. Lesotho would require a detailed study to assess the impacts of climate change on the current design flood return periods. 5.1.5 Volume 9: Guidelines for Environmental Control Volume 9 deals with Environmental control guidelines. The Volume recommends that a competent person do the Environmental Impact Assessment (EIA) and be project specific. This volume is a guideline and not a specification, therefore the person conducting the EIA must adhere to the Lesotho Environment Secretariat EIA requirements and guidelines. The person conducting the EIA must submit it to the Ministry of Tourism and Environment for approval and recommendations. The EIA will form part of the project tender as project specifications. In addition, the RD will monitor the adherence to the EIA specifications, either through an RD employee or a consultant to act on its behalf. Volume 9 of the Guidelines provides different slope stability examples. It specifies that the environmentalist should guide on the use of appropriate measures that are relevant to Lesotho. Proper guidance from environmentalists and application of the approved EIAs may reduce the effects of degraded river banks and cut slopes on the roads. 5.1.6 Summary Review of Updating Road Design Guidelines A summary of the key recommendations from the review of guidelines is given below. Design Guideline Related Climate Change Hazards and Recommendations Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 70 Volume 1: General reference to design approach (not climate specific) – could include reference to climate related hazards in design. Volume 2: References to the SANRAL Road Drainage Manual (6 th Edition) Implementation of TRH25 as a guideline for design of embankments for bridges and larger culverts. Volume 3: Consider increasing maximum temperature, changes in precipitation, and changes to freeze/thaw cycles into design. Volume 4: Include possible change in design rainfall into calculating runoff and design flood estimates for culverts and bridges, etc. Volume 8: Included update climate variables into rehabilitation and design. Volume 9: Include a Climate Impact Assessment (CIA) as part of the EIA and developed monitoring standards for ensuring climate resilience and sustainability of all components of the road infrastructure (including road, bridges, rivers, catchments, borrow pits, etc). 5.2 Incorporating Climate Change into Design Guidelines The review of the guidelines section identified priority areas for incorporating the impacts of climate change and improving the climate resilience of roads in Lesotho. Below is a brief overview of some of the critical considerations. 5.2.1 Temperature Impacts For road pavements, increased air temperatures affect the road surface temperature. Maximum road surface temperatures are generally higher than the local air temperature, and in the Southern African region, the road surface can reach temperatures close to 70°C but is generally between 45-55 °C in summer (Figure 5-1) According to SABITA Manual 35 (2021), South Africa adopted three maximum pavement design temperatures, namely, 58°C, 64°C and 70°C with their associated low temperatures of - 22°C, -16°C and -10°C. Typically, the 58-22 and 64-16 performance grade binders would apply to Lesotho, but future climate change impacts could increase the binder requirements. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 71 Figure 5-1: 7-day average maximum asphalt temperatures for South Africa Figure 5-2: Minimum asphalt temperatures for South Africa Road surface temperatures are typically much higher than air surface temperatures but can be approximated as a function of changes in air temperature using equations such as given below: Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 72 An increase in the frequency of very hot days and heat waves on bituminous pavement layers will increase the risk of rutting, bleeding and flushing of the asphalt surfacing in the short term. Specifically, the bituminous binder phase loses stiffness when the asphalt mixture (or thin surface seal) temperature increases. The creep deformations caused by dynamic and static traffic loading will accumulate much faster when the stress level and load duration stay the same. In the long term, higher temperatures accompanied by increased intensity and duration of ultraviolet radiation will cause an increase in severity and rate of ageing and hardening of the binder phase in the exposed upper parts of the bituminous surfacing. Ageing and hardening of the binder phase decreases the bitumen’s binding ability (i.e. becomes brittle). A decreased binding ability makes the road unable to withstand any forces imposed by traffic and the climate resulting in increased cracking development and aggregate loss from the surfacing. Cracking will allow moisture to ingress the pavement structure, manifesting as increased rutting and deformation of the whole pavement structure over time. Only high-trafficked primary roads and urban areas use asphalt pavements because they are costly to construct. Most of the Lesotho paved road network consists of thin bituminous surface seals. Because the temperature-sensitive bituminous materials are limited to 10 to 20 mm, road surface temperature will increase as bleeding or flushing increases resulting in a general loss of surface texture, unsafe slippery road conditions, and a need for more regular maintenance and repair. Engineers already understand how to accommodate ambient road surface temperatures into pavement design, particularly in asphalt mixtures and surface seal designs. The following approaches exist; however, the industry does not practice all of them due to cost constraints:  The adjustment of bituminous mixture design (performance-related binder selection including polymer modification of bitumen)  Adjustment of maintenance plan (e.g. more frequent surfacing)  Forced cooling of thick asphalt pavements. Long-term solutions could be adopted to deal with the increased frequency of very hot days. These solutions can include the use of material technologies such as concrete pavements instead of bituminous (asphalt of thin surface seals), as concrete is less sensitive to temperature fluctuations. Concrete pavements are, however, not completely insensitive to temperature variations. Concrete slabs expand, curl and warp due to changes in surface temperature, which increase the stress situation in the concrete slab. Concrete pavements, particularly continuously reinforced concrete pavements, will also be sensitive to thermal expansion effects that can cause blow-up failures due to temperature rise or slab fracture due to temperature fall, resulting in higher maintenance costs. Concrete bridges are also subject to expansion and contraction due to temperature changes; thus concrete bridge design should consider this. Higher temperatures could lead to significant expansion, which, unless adequately addressed through the design process, could increase the risk of failure. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 73 5.2.2 Precipitation Impacts Increases in precipitation lead to generally higher ground moisture conditions. For example, road pavements in southern Africa are predominantly constructed using moisture-sensitive granular materials (gravels and crushed rock), which lose their load-bearing capacity when wet. This, together with the fact that road surface seals are generally very thin (10–20 mm) and prone to surface water ingress if not adequately maintained, makes a strong case for taking increased precipitation effects very seriously when considering improved climate proofing of roads. Climate influences different materials used in constructing roads. Road construction materials are susceptible to two primary forms of weathering – disintegration and decomposition. Disintegration is a physical process, and decomposition is a chemical weathering process. Decomposition harms road- building materials’ quality and durability because this process tends to generate more moisture- sensitive clay minerals. A road constructed in an arid region will not have to endure the chemical weathering processes brought about by large amounts of precipitation. Subsequently, the changes in climate to wetter conditions may significantly shorten the life span of roads. For pavement design purposes, southern Africa divides into certain climatic zones with a clear boundary where disintegration and decomposition occur. Areas with moderate to higher precipitation (inlcuding Lesotho) are prone to increased decomposition of road-building materials. Evaporation also plays a large part in the process of decomposition and disintegration. Weinert (1980) developed a formula referred to as the Weinert’s N-value, shown in Figure 5-3, which takes into account the evaporation in the warmest month (typically January in southern Africa) divided by the total annual precipitation: N = 12 Ej / Pa where Ej = Evaporation in warmest month (January in southern Africa) Pa = Total annual precipitation in mm Figure 5-3: Climate zones for consideration in road pavement design (after Weinert, 1980) In areas where N < 5, rocks typically decompose in moderate to wet areas. Thus drainage (both surface and subsurface) requires special attention in these areas. Also, road pavements constructed Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 74 in these areas are provided with additional supporting layers to compensate for the expected poorer materials. Where N > 5, disintegration is the main form of weathering. These are typically the dry areas that record less than 500 mm of precipitation annually and enable the construction of lighter and cheaper pavement structures. Lesotho falls within the moderate (N = 3 - 4) zone, and decomposition in this zone is more prevalent than in lower zones. However, precipitation and temperature/evaporation changes could change the Weinert N value. The following techniques help mitigate the risk of increasing precipitation impacts on weathering of the road material. For implementation, the GoL should consider current, or even historical, climatic conditions with an understanding of how these may change over time:  Increasing the load-bearing capacity through increased/additional supporting layers  The adaptation of the drainage capacity of roads, including cross fall adaptation and transportation of the water via drainage systems or other means away from the road to prevent water from penetrating the lower layers  Maintenance to ensure water is transported from the road to the verge  Informed pavement material selection linked to structural design  Improvement or upgrading of stormwater systems. 5.2.3 Freeze Thaw Cycles In Lesotho, the maximum day and minimum night temperatures vary significantly, and the stark contrast between temperatures makes Lesotho unique in Africa. While fluctuating temperatures do not significantly impact roads in other African countries, Lesotho roads experience significant freeze-thaw cycles. Most parts of Lesotho experience at least occasional detrimental frost action causing damage to roads. The damage is primarily due to the build-up of ice lenses in the upper pavement layers that cause de-compaction when the ice thaws, resulting in a need for maintenance, hazardous operational conditions, or the destruction of pavements and structures. Roads designs should retain their stability and effectiveness under both current and future freeze- thaw conditions. For example, granular pavement layers should typically have lower levels of fine materials to reduce their ability to absorb moisture through capillary action from high water tables. When adapting a framework to the Lesotho context, it is important to consider the freeze-thaw cycle. Designing all-weather, stable, and effective roads under frozen conditions is based on a “Design Freezing Index” calculated from weather station data. The freezing index measures the combined duration and magnitude of below-freezing point temperatures over a period during which the average daily temperature is below 0°C. The design freezing index is the freezing index of the coldest winter in a 10-year design period, or for a 20-year design period, the design freezing index is the average freezing index of the two coldest winters in 20-years. The freezing index is the degree days between the highest and lowest points on a curve of cumulative degree days versus time for one freezing season. The freezing index measures the duration and magnitude of below-freezing temperatures in the freezing season. Figure 5-4 gives an example. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 75 Figure 5-4: Example of Graph Showing Freezing and Thawing Indexes (Northern Hemisphere) The degree days for any one day equals the difference between the average daily air temperature and 0°C (32°F). The degree days are negative when the average daily temperature is below 0°C (freezing degree days) and positive when above 0°C (thawing degree days). The freezing season is when the average daily temperature is below 0°C (32°F). Figure 5-5 shows Lesotho’s freeze/thaw influence lines. The region to the east (right) of the blue influence line and the region to the west (left) of the green influence line has the potential to freeze. This observation means that the area adjacent to the Mohokare River and the mountainous terrain of Lesotho has the potential for freezing conditions. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 76 Figure 5-5: Lesotho Freeze/Thaw influence lines (Source: Government of Lesotho) 5.2.4 Runoff Impacts (flooding and drainage) An increased frequency of extreme precipitation events is likely to cause flooding if not adequately addressed through adaptation. Some existing drainage infrastructure (bridges, causeways, and culverts) may need to be improved to convey the higher flow rates anticipated during extreme storm events. Increases in precipitation intensity would require the future use of larger drainage structures. Where the drainage is inadequate and leads to standing water or wash aways, then road closure (the worst-case scenario) may be necessary for safety reasons. However, the economic costs of such road closures can be significant. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 77 Flooding and drainage design procedures for roads in Lesotho typically use South African design standards. As such, Lesotho typically uses the South African National Roads Agency Limited (SANRAL) Drainage Manual 6th Edition for design flood determination. The Drainage Manual references several different design methods based on measured data (e.g. statistical method), a deterministic basis (e.g. Rational, Unit Hydrograph, SDF, SCS-SA methods) or empirical relationships (e.g. Kovacs/RMF method). Besides the statistical method, all methods have been adapted for South Africa and are applicable for certain return periods, catchment areas and input data. As the methods have been developed for use in Southern Africa, they are also applicable to Lesotho, as demonstrated by Figure 5-6 showing the SCS-SA storm type distribution (left) and the Unit Hydrograph veld types (right) across Lesotho and South Africa. Figure 5-6: SCS-SA rainfall intensity distribution types for Southern Africa (Left) Unit Hydrograph Veld Zones for Southern Africa (Right) Table 5-3 is a guide for deciding which design flood determination method to use, depending on the data available and catchment size. As each method has uncertainties, it is critical to use multiple methods and select the most appropriate ones. Design rainfall is the primary input for most methods. Table 5-3: Application and limitations of flood calculations methods (SANRAL, 2013) Return Periods Rainfall/ Recommend of floods that can Runoff Method Input Data ed Maximum be determined based Area (km2) (years) method No limitation 2 – 200 Statistical  Historical flood peak (best for large (Dependent on Runoff Method records catchments) record length)  Catchment area  Watercourse length  Average slope of watercourse Rational  Catchment 0 – 15 2 – 200, PMF Rainfall Method characteristics (land cover, steepness, porosity)  Design rainfall intensity Unit  Design rainfall (for Hydrograph required return period) 15 – 5000 2 – 100, PMF Runoff Method  Catchment area  Watercourse length Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 78 Return Periods Rainfall/ Recommend of floods that can Runoff Method Input Data ed Maximum be determined based Area (km2) (years) method  Length to catchment centroid  Mean annual rainfall  Veld type  Synthetic regional unit hydrograph  Catchment area Standard  Watercourse length Design  Average slope of No limitation 2 – 200 Runoff Flood watercourse Method  SDF basin number  Design rainfall depth (fro required return peroid) SCS-SA  Catchment area 0 – 30 2 – 100 Rainfall Method  SCS Curve number (a function of soil and land cover)  Catchment lag time  Catchment area  Watercourse length No limitation Empirical  Length to catchment (best for large 10 – 100, RMF Runoff Methods centroid catchments)  Mean annual rainfall 5.2.5 Climate Change Impacts on RI Design Flood Determination The SANRAL Road Drainage Manual provides no guide on the impact of climate change on design floods. As climate change and changing rainfall intensity is likely to impact the design of flood peaks, Lesotho can modify the rainfall used as input into deterministic methods for flood determination to account for various climate change projections. The modification would typically involve estimates of the likely increase in maximum daily rainfall used to adjust the relevant rainfall intensity-duration- frequency (IDF) curves. Sources of information on changes in the maximum daily rainfall would include the latest global climate models accessed through the World Bank Climate Change Knowledge Portal, the CORDEX dataset of downscaled climate models for Lesotho, or other downscaled climate models such as those provided by the CSIR Greenbook for South Africa. Table 5-4 provides an example showing how the likelihood of the current design flood estimates for Lesotho might change in future. Derived from the World Bank climate change knowledge portal, the table shows how what is currently estimated to be a 1 in 20 year maximum design one day rainfall event could become anything between a 1 in 5.5- year event (SSP2-4.5 10th percentile) and a 1 in 25.5-year event (SSP1-2.6 90th percentile) by 2050 based on a range of future climate scenarios. Even the median value from the full range of climate models suggests that the 1 in 20-year event will become between a 1 in 11-year event and a 1 in 14-year even by 2050. Lesotho can use this data to develop guidelines for how to increase the design rainfall estimates to account for the impacts of climate change across Lesotho and update the design flood estimate using Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 79 the appropriate method described in the current guidelines. Furthermore, Lesotho should review recently observed data for rainfall and streamflow (where available) to see whether there has already been any changes. Table 5-4: Change in Return Period for the Largest 1 Day Precipitation for Lesotho (2035-2064) Largest 1-Day Precipitation for Lesotho Future Return Period, 2035-2064 (center 2050) (years) Event 20-yr 100-yr 10th median 90th 10th median 90th SSP1-1.9 8.02 14.19 25.19 30.54 62.88 131.73 SSP1-2.6 7.64 13.52 25.51 28.67 59.7 138.65 SSP2-4.5 5.53 12.8 21.92 18.49 53.46 108.71 SSP3-7.0 6.8 10.98 19.36 24.06 43.56 94.1 SSP5-8.5 5.59 10.88 18.86 18.25 44.05 88.15 (Source: https://climateknowledgeportal.worldbank.org/country/lesotho/extremes) One of the challenges in developing updated design standards for floods is that the available climate models need to estimate the likely impact on sub-daily rainfall characteristics.However, these shorter- duration rainfall events often have the greatest impact, particularly for smaller catchments. As a result, most current approaches rely on some form of expert judgement in scaling the one-day impacts based on changes in a maximum one-day rainfall. For runoff-based design flood methods, such as the statistical and empirical methods, Lesotho may incorporate climate change adjustment into the design flood determined for the required return periods, often with the same relative change as the design rainfall. Figure 5-7 shows a recommended approach for incorporating climate change into detailed engineering design standards for roads (ADB, 2020). Figure 5-7: Procedure for Incorporating Climate Change Allowances in Detailed Engineering Design Lesotho is already applying the approach of increasing the design rainfall estimate to consider the possible impacts of climate change. For example, the design report for the Thaba Tseka to Katse Road includes a recommendation to increase the design flood estimate for all drainage structures by around 12% to account for the expected increase in rainfall intensity. What was clear from this design report is that the current culvert capacities are too small for the current design standards, let alone for the potential impacts of climate change and increasing flood frequencies, sedimentation, or debris as a result of catchment management practices (Refer to Box 1: Design Capacity Review of the Thaba- Tseka to Katse Road). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 80 5.2.6 Geological and Geotechnical Risks for Roads in Lesotho Incorporating future climate change into the design of geological and geotechnical-related risks is critical. It requires a detailed understanding of the local soil conditions and current and future climate risks. Therefore, Lesotho must consult technical specialists when considering these additional risks. Table 5-5 summarises how an increase in precipitation, temperatures changes, and freeze-thaw cycles associated with climate change can impact the geotechnical risks to road networks. Table 5-5: Summary of climate related geotechnical risks for roads Condition due to climate change Geotechnical risk Changes in in-situ water levels, rise  Soil slope instability in groundwater levels, saturated in-  Rock slope instability situ materials  Poor subgrade drainage especially over clay sub-grade or shallow rock  Destabilization of retaining structures Flood events, higher precipitation  Undermining of bridge foundations due to scour and increase in surface flows  Destabilization of abutments  Differential settlement of embankments and structure  Erosion of road and embankments  Erosion and destabilization of retaining structures Temperature changes and freeze  Rock slope instability thaw cycles  Destabilization of rock slopes causing rock falls Change in biodiversity and  Erosion causing slope instability vegetation  Loss of vegetation cover causing slope instability The geology of Lesotho poses several unique risks that respond to climate change, including: Highlands – The geology of the Lesotho highlands consists of basalts and is affected by heavy rainfall and cold temperatures. Geotechnical hazards associated with the highlands, especially along the road cuttings, include slope failures such as wedge and toppling (more dominant on basalt). Landslides have occasionally occurred on the completely weathered basalt and the alluvial deposits encountered near streams or rivers. In this region, there is almost no transported soil material or soil cover. This material is thicker in the lowlands and presents similar challenges to thick alluvium. Lowlands – The exposed geology here is dominantly sandstone and mudstones of the Karoo Supergroup. The main geotechnical hazard in this region is slope failures along road cuttings caused by mudstone undermining/ undercutting due to weathering, posing a risk of overhanging sandstone blocks falling onto the road. In addition, Lesotho must protect mudstone against slaking and disintegration due to sun, air, and water exposure. Dolerite intrusions – These igneous intrusions cut through the highlands and lowlands and pose a similar geotechnical risk of a wedge and toppling failure as the basalts exposed on the highlands. When encountered along road cuttings, dolerite intrusions are usually a good source of construction material. They are generally more durable than basalt rock, particularly those from highly and moderately amygdaloidal basalts. 5.2.7 Climate Change Risk Screening Tools The World Bank has designed and developed a screening tool to support the World Bank staff and other development practitioners in mainstreaming climate and disaster risk reduction into Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 81 developments. The tool provides high-level screening and considers short and long-term climate and disaster risks from the inception stage of project design. Table 5-6 presents indicators considered during the screening process. It is a non-detailed risk assessment tool that does not recommend sector-specific adaptation measures. Instead, it facilitates dialogue about the impacts of climate risks on the different sectors (Figure 5-8). The World Bank Decision Tree Framework aims to assist with identifying and prioritising the relevant climate change risks to support decision-making under the uncertainty of climate change. The framework uses a bottom-up approach that helps prioritise key aspects of climate change risk and assists in the identification of priority options to improve climate resilience. In addition, the framework was developed primarily to apply to climate risk screening for critical water supply infrastructure and hydropower but is also applicable to roads. Figure 5-8: Conceptual framework of the World bank Climate Screening tool (https://climatescreeningtools.worldbank.org/) Table 5-6: Indicators considered within the World Bank Climate Screening tools Risk assessment Variables (Raw Data) Variables Post Assessment components Exposure  Extreme Temperature Overall exposure rating per  Extreme Precipitation & hazard for both the current  Flooding situation and future predictions  Sea level Rise  Storm Surge  Strong Wind  Geophysical Hazards Potential impact  Road infrastructure spatial data Overall rating for the level of (primary, secondary, and tertiary potential impact from natural roads, highways, bridges, hazards on the physical tunnels) components of the project  Road Infrastructure attribute data (elevation, erosion ratings, asphalt binder, wind ratings) Adaptative capacity  Policy development and Overall rating for how non- implementation physical components might  Long-term strategic planning reduce or increase the risks  Capacity building, training and posed by climate and outreach geophysical hazards  Emergency protocols Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 82 Risk assessment Variables (Raw Data) Variables Post Assessment components  Budgeting processes  Data gathering and information management system Socio economic  Current population density and Overall rating for how the impact analysis distribution broader transportation sector  Number of children estimated to and social-economic factors be under 5 years old per 1000 reduce or increase the persons impacts due to climate and  Number of children under 5 years other natural hazards. old and per 1000 persons  Percent of rain fed cultivated land  Estimated percent of cultivated land per pixel  Alternative means of transportation (secondary roads or other modes of transport)  Capacity and systems in place to identify and respond to disruptions from climate and geophysical hazards 5.3 Guidelines for Sustainable Roads in Rural Areas The guidelines for sustainable catchment management in Lesotho should include guidelines for developing sustainable roads in rural areas. Examples of such Guidelines for Integrated Catchment Management (ICM) are available for Malawi (MAIWD, 2015), Uganda (MWE, 2014), South Africa (Braid, 2019), Ethiopia (MoA, 2016) and other countries across Africa. The value of these guidelines is that they help to contextualise the community within the catchment and look at soil and water issues at a systems scale. At a systems scale, holistic, integrated management can assist in managing the collective impact of land, water, biodiversity and people (Figure 5-9). Sustainable land management is part of integrated catchment management, focusing on the land resource as a foundation for water, plants, animals and people. A problem tree analysis for key issues such as land degradation, soil erosion, climate change and overgrazing has been carried out for the use of these guidelines, identifying activities such as sustainable land management, erosion control, climate change adaptation and rangeland management implementation options (Figure 5-10). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 83 Figure 5-9: Issue identification for integrated catchment management (Braid, 2019) Figure 5-10: Example of a problem tree for land degradation from the South African Catchment Management Guidelines (Braid, 2019) The analysis indicates that a holistic consideration of all activities is critical as they are interrelated. Although the most significant impact will be on the soil and water when considering road construction and design, there is also a need to consider other guidelines such as soil fertility, water harvesting and storage and natural resources management. The Sustainable Land Management Guidelines focus on managing soil and water through rangeland management, erosion and runoff control measures, gully management, sediment trapping, and stream/river-bank management. Implementing these techniques and practices will minimise the loss of topsoil (through erosion) and reduce the erodibility of a catchment. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 84 The interventions identified under the sustainable land management section of the ICM Guidelines are shown in Figure 5-11 and indicate the issues addressed, complexity and indicative costs. An example of a sustainable land management activity is erosion management along roadsides. The activity will assist in managing gullies and sediment trapping, focusing on soil erosion, loss of soil fertility, sedimentation, water degradation and depletion, loss of crop yields/livestock forage, the risk to infrastructure and reduced standard of living. The activity will be preventative, may trigger legislation (in South Africa, to review applicability in Lesotho), be at the village scale, require many people for labour, be advanced to implement and have a medium cost. Implementation of this activity may require additional erosion measures and management of runoff. Figure 5-11: Sustainable land management implementation options (Braid, 2019) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 85 Figure 5-12: Erosion management along roadside part I (Braid, 2019) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 86 Figure 5-13: Erosion management along roadside part II (Braid, 2019) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 87 Figure 5-14: Erosion management along roadside part III (Braid, 2019) Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 88 6 Conclusions and Recommendations Climate change will undoubtedly impact future rainfall and temperature patterns in Lesotho, placing increasing strain on transport-related infrastructure. However, in most cases, implementing the current design standards (with adjustments for climate change) will help improve the climate resilience of critical transport infrastructure. Most of the current road-related challenges/hazards, as summarised in Table 6-1, are not caused by changing weather patterns but will be aggravated by climate change. However, Lesotho needs to address these issues to improve climate resilience. Table 6-1: Primary roads hazards, and the impacts of climate change on these Issue Primary road hazards/issues Impacts of climate change themes Unprotected side drains or Increased runoff and erosion riverbanks Increased flooding and Damage to bridge embankments overtopping Increased erosion due to flooding Eroding of the shoulder of the road and pavement heat deformation Limited Increased rainfall increasing protection Slope instability slope instability works Lack of downstream erosion Increased flooding and risk of protection for culverts, bridges and scouring drifts Sediment deposition or slope Increasing rainfall will further instability from unrehabilitated erode unrehabilitated slopes borrow pits More sediment/debris blocking Blocked/damaged culverts culverts More sediment/debris blocking Blocked/insufficient side drains Poor side drains maintenance/ Poorly built community roads will Insufficient drainage of unpaved condition deteriorate faster with increasing roads rainfall Lack of connection to main drainage Increasing runoff channels Damage to formal roads from rural Sediment deposition and runoff Informal access roads will increase roads Inadequate infrastructure for river More damage to infrastructure, crossings communities disconnected Increased erosion from Unsustainable land management unprotected farmlands or range practices Catchments lands Increase in meandering rivers Meandering Rivers and damage to infrastructure Based on these hazards, the report makes the following general recommendations regarding road infrastructure and maintenance in Lesotho:  Add paved shoulders to all major roads (A and B roads) to protect the road’s main section and improve connectivity with drainage structures and rivers, etc.  Increase design flood requirements for all new drainage structures by a minimum of 15%.  Apply a minimum of 900mm culverts to make it easier for maintenance and clearing.  Include considerations for climate change in all new road design and rehabilitation projects.  Reduce the threat posed by minor connecting roads by paving at least the first 25 m of a connection with a major road (A and B) and ensure the provision of adequate drainage. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 89  Undertake a review of the conditions of all major bridges to determine their ability to manage increased flood frequencies, including a review of the approaches and embankments, as these are particularly vulnerable.  Engage with local communities to support the clearing of culverts and identify priority interventions to reduce road risks as part of a catchment management plan (CMP). Based on this assessment, below is the summary of the initial recommendations for improving climate resilience and sustainability of roads:  It is recommended that this CRVA framework be used to identify national priority road infrastructure. This framework should be used in collaboration with existing frameworks for climate related planning. For the priority road segments, these additional frameworks could consider issues such as: i) cost to the economy of inaction; ii) distributional effects of different investments; iii) potential gains in different economic sectors from investing in catchment and flood management; and iv) funding and financing strategy behind a portfolio of interventions.  Undertake a study of the potential impacts of climate change on increasing road maintenance costs for Lesotho based on calibrated HDM4 model data. Lesotho can use it to determine likely climate change impacts by adjusting environmental input factors on overall maintenance costs (Figure 6-1).  Include priority road rehabilitation projects for rural access roads into CMPs for priority catchment areas.  Provide technical support (and incentives) for community-based road rehabilitation projects. For example, the UNCDF Local Climate Adaptive Living Facility 5 (LoCAL) funding model being trialled in Lesotho.  Increase investments in climate-proofing national and local government roads – pavement upgrades, improved drainage, paved shoulders, culvert replacement, protection of bridge embankments, paving connections to minor roads, etc.  Undertake a climate change risk assessment for planned infrastructure such as Hlotse to Butha-Buthe Road and consider the potential for additional aspects to be included that could improve the climate resilience of the new road.  Motivate for increased investments in improved catchment management upstream of critical/high-risk roads.  Raise awareness with local communities about the importance of clearing culverts and drainage channels. The recommended next steps for the Lesotho RD include the following:  RD to engage with LMS on readiness funding and developing proposals.  RD to consider reviewing policies and processes for incorporating climate change  Initiate critical studies to support updating the key aspects of the guidelines • Analysed observed rainfall and streamflow, temperature etc., to update guidelines (from 1980). Looking for climate change trends for road data. • Hydraulic study of impacts on flood peaks taking climate change into account. • Climate change impacts on the pavement (air temperature changes impact on asphalt temperature). • Climate change impacts on landslide risk and geotechnical design considerations (freeze- thaw, changing water table).  RD and MoLG to engage with ReNOKA on incorporating roads projects into the CMPs for priority sub-catchments (Hlotse and Makhalaleng) and identify a technical person at the district 5 LoCAL is promoting climate change–resilient communities and economies via increasing financing for and investment in climate change adaptation at the local level. LoCAL in Lesotho will directly contribute to one of the country’s development plan pillars – reversing environmental degradation and adapting to climate change. The objectives for LoCAL-Lesotho include: increased transfer of climate finance to local governments through national institutions and systems for building verifiable climate change adaptation and resilience; a standard and recognized country-based mechanism which supports direct access to international climate finance Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 90 level that will provide local assistance and be the key contact in the priority catchments (i.e. “roads extension office”)  RD to engage with ReNOKA to identify priority catchments for developing CMPs, based on critical road infrastructure, e.g. new bridge RD is building.  Review upcoming projects and consider opportunities for enhancing climate reliance (e.g. increasing drainage capacity, providing paved shoulders and lined drainage channels etc.), and develop a business case for additional climate change financing. Figure 6-1: Overview of approach for determine the impact of environmental conditions on road degradation which can then be used to determine overall maintenance costs and impacts of climate change. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 91 7 References ADB. (2011). Guidelines for Climate Proofing Investment in the Transport Sector Road Infrastructure Projects . Mandaluyong City. ADB. (2020). Climate change adjustments for detailed engineering design of roads experience from viet nam. Phillipines : ASIAN DEVELOPMENT BANK. AfDB. (2013). Climate Finance Tracking Manual- Transport Sector. Bles T, B. J. (2016). Climate change risk assessments and adaptation for roads – results of the ROADAPT project. Transportation Research Procedia , 58-67. Braid, S.G. 2019. WRC Green Village: Community-Based Catchment Management Guidelines. Report to the Water Research Commission, WRC Report TT 793/2/19 Burmeister H., Cochu A., Hausotter T. and Stahr C. Adaptation Briefings. 2019. Financing adaptation to climate change – an introduction. Chakela, Q. K. & Stocking, M. (1988). An improved methodology for erosion hazard mapping. Part II: Application to Lesotho. Geogr. Ann., 7QA, 181-189. Conway, D., Nicholls, R.J., Brown, S. et al. The need for bottom-up assessments of climate risks and adaptation in climate-sensitive regions. Nat. Clim. Chang. 9, 503–511 (2019). https://doi.org/10.1038/s41558-019-0502-0 Department of Transport (1994a). Technical Recommendations for Highways. Guidelines for the Hydraulic Design and Maintenance for River Crossings (TRH 25:1994). Department of Transport (DoT). Pretoria, South Africa. September 1994. Department of Transport (1994b). Technical Recommendations for Highways. Subsurface Drainage for Roads (TRH 15:1994). Department of Transport (DoT). Pretoria, South Africa. September 1994 Department of Transport (1996). Technical Recommendations for Highways. Structural Design of Flexible Pavements for Interurban and Rural Roads (TRH 4:1996). Department of Transport (DoT). Pretoria, South Africa. September 1994 Farrag-Thibault A. 2014. Climate Change: Implications for Transport. The Fifth Assessment Report from the Intergovernmental Panel on Climate Change. Cambridge: University of Cambridge. Filosa Gina, P. A. (2017). Vulnerability Assessment and Adaptation Framework. Washington DC: U.S. Department of Transportation. IPCC. (2007). Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change . Geneva. IPCC, 2014: Summary for policymakers. In: Climate Change 2014: Impacts,Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken,P.R. Mastrandrea, and L.L.White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1-32 LMS. (2018). Lesotho Extreme climate Indices: Historical and Future projections. Maseru. McCarthy, J. J., Canzlani, O. F., Leary, N. A., Dokken, D. J., and White, K. S., eds., 2001. Climate Change 2001: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press. Ministry of Public Works and Transport. 2012. Integrated Transport and Policies Development Study. Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 92 Ministry of Agriculture, Irrigation and Water Development (MAIWD) 2015. Malawi National Guidelines: Integrated Catchment Management and Rural Infrastructure. Volume II: Technical Guidelines. Ministry of Water and Environment (MWE). 2014. Uganda Catchment Management Planning Guidelines. Directorate of Water Resources Management. Ray, Patrick A., and Brown, Casey M.. 2015. Confronting Climate Uncertainty in Water Resources Planning and Project Design: The Decision Tree Framework. Washington, DC: World Bank. doi:10.1596/978-1-4648-0477-9. License: Creative Commons Attribution CC BY 3.0 IGO Roads Directorate. August 2022. LESOTHO ROADS MANAGEMENT SYSTEM (LRMS). Visual Road Condition Surveys 2021: Survey Results Report Sandink D, L. D. (2021). THE PIEVC PROTOCOL FOR ASSESSING PUBLIC INFRASTRUCTURE VULNERABILITY . Canada: Institute for Catastrophic Loss Reduction. SANRAL. 2013. South African Drainage Manual. Sixth Addition. Schweikert A, C. P. (2014). The infrastructure planning support system: Analyzing the impact of climate change on road infrastructure and development. Transport Policy, 146-153. Smit, B., Burton, I., Klein, R.J. et al. (2000). An Anatomy of Adaptation to Climate Change and Variability. Climatic Change 45, 223–251. Thibault, A. F. (2015). Key Findings from the Intergovernmental Panel on Climate Change Fifth Assessment Report. Cambridge: The University of Cambridge Institute for Sustainability Leadership (CISL). Wang, X. L., and Feng, Y., 2013, “Climate Research Division Atmospheric Science and Technology Directorate Science and Technology Branch, Environment Canada Toronto, Ontario, Canada,” Ontario, Canada, 17. Weinert H. H. (1980). The natural road construction materials of southern Africa. H & R Academica, Cape Town, South Africa, pp 298. WFP (World Food Programme). 2015. Lesotho Integrated Context Analysis (ICA). Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 93 In diversity there is beauty and there is strength. MAYA ANGELOU Document prepared by: Zutari (Pty) Ltd Reg No 1977/003711/07 1 Century City Drive Waterford Precinct Century City Cape Town South Africa PO Box 494 Cape Town 8000 Docex: DX 204 T +27 21 526 9400 E capetown@zutari.com Document number 1002246-0000-REP-NS-00001, Revision Final, Date 2023/02/28 94