Increased sedimentation, reduced water quality, and ecosystem degradation have been a major environmental threat to the catchment areas of Lake Baringo and Lake Bogoria. All these issues have been brought about by soil erosion in the upper sections of the two lakes where the source rivers feeding the two lakes originate. The use of space technology such as remotely sensed satellite imagery and other geographic information system (GIS) methods to assess and analyse soil erosion patterns in these two catchment areas will be able to develop solutions that will help to quantify the rate of sedimentation and come up with policies and targeted interventions to enhance soil and water conservation measures in these areas. Soil erosion in the catchment areas enhances sediment deposition into the two lakes, reducing storage capacity in terms of volume and also affects livelihoods that depend on these water sources.

Has this problem been acknowledged in the past?

The problem of soil erosion in the Lake Baringo and Lake Bogoria catchment areas has been of much concern to the Kenyan government and various NGOs, such as ChemiChemi Foundation, who are champions of water quality access for the women and marginalised communities in the counties of Baringo and Nakuru in Kenya. The conservation partners at the Lake Bogoria area have highlighted the problem of soil erosion, and siltation in the lake as a major conservation issue. There has also been involvement by the United Nations Development Programme (UNDP) to launch projects aimed at addressing land degradation in the Lake Baringo area. United Nations Educational, Scientific and Cultural Organization (UNESCO) in collaboration with the Kenyan government has also been in the ground to initiate projects aimed at addressing deforestation, land degradation and effective water management practices. The World Wildlife Fund (WWF) is active in Kenya and also promotes integrated river basin management to conserve freshwater resources in the country. Government agencies such as Directorate of Resource Surveys and Remote Sensing (DRSRS), Kenya, have also conducted field research in the two catchment areas, developed reports and strategic plans, and given recommendations to government for policy formulation and decision-making.

Can this challenge be solved using space technologies and data?

Space technology will be a vital component in this water challenge. Firstly, satellite imagery like Sentinel at 10m resolution will be used for Land Use and Land Cover (LULC) classification, conducting Normalized Difference Vegetation Index (NDVI) monitoring that will detect bare soils as one of the outputs of the LULC and NDVI analysis. For historical imagery analysis for mapping vegetation and land use trends, Landsat imagery at 30m resolution will be used. Sentinel-2 will be used for surface water quality analysis. The initial idea was to also monitor flooding/flooding extent using Sentinel-1 imagery. Lower resolution imagery from platforms such as Planet will be used to track seasonal variations of vegetation and also water quality. Planet data has resolutions from 3m and below, which is high resolution. Planet's and Norway’s International Climate and Forest Initiative (NICFI) has now restricted the access to high resolution imagery, and we will require more resources to access the licenses for the same. Digital elevation models (DEMs) at 15m resolution will be used for slope analysis, watershed and basin delineation and as inputs for soil erosion modelling. Soil Moisture Active Passive (SMAP) will be used to monitor soil moisture conditions and also conduct flood mapping.

We have an existing wetlands map developed by DRSRS and other collaborating agencies that needs to be updated, so in terms of datasets we could try to find an area of focus for validation purposes. The output has a reasonable resolution for interpretation.

Expected timeframe to develop a solution

• Planning and data collection will be a short-term task taking between 0 to 6 months. Here, stakeholder engagement and needs assessment will happen between month 1 to 2. Meetings, workshops and surveys will be conducted to understand the needs and challenges of stakeholders. We shall also define the project scope, set objectives and expected outcomes. The collection and preprocessing of satellite datasets will take place between month 2 and 4. Maps for land cover and soil erosion risk will be generated between month 4 and 6. Ground validation sites will be visited within this timeframe if need be.
• The second phase on solution development and implementation will take between month 6 and 2 years. Month 6 to 12 will be used for soil erosion modelling, where we shall integrate the RUSLE model to estimate the annual soil loss. The model will be used to predict soil loss and monitor future trends. We shall also use the same to identify areas needed for rehabilitation. Month 12 to 18 will be used to build a GIS-based decision support tool for monitoring of soil erosion on a continuous basis. The other plan will be to integrate remote sensing data with a real-time weather monitoring system. A mobile and web-based platform will be developed to aid in data access for the community members and decision-makers. Field validation and piloting of the various interventions like erosion control structures and reforestation efforts will be done between month 18 to 24. The local communities will also get expert training on matters conservation and data collection techniques for reporting purposes.
• The third phase will involve scale up measures. It will happen between year 2 and 4. The aims will be to expand monitoring coverage to additional existing watersheds in the counties. We shall also aim to strengthen partnerships with national and regional conservation programs, promote data sharing with policymakers, researchers and local authorities. Between year 3 and 5, we shall use our research findings to influence policy on watershed conservation and land use management. In addition, we shall develop guidelines for sustainable land use practices, advocate for increased government funding for space-based environment monitoring. Year 4 and 5 will be used in establishing long-term soil erosion and sedimentation monitoring programs. We shall then publish our research findings and best practices for replication in other counties in the Republic of Kenya.

Potential consequences if no action happens

If no intervention measures are made to address the issue of soil erosion and sedimentation in the two lakes, there shall be environmental consequences as the unchecked soil erosion will lead to more siltation which will lead to a decrease in the depth and water-holding capacity of Lake Baringo and Lake Bogoria. An increase in turbidity levels will also affect water quality. The women and marginalised in those localities will need to go to far distances to access clean water for use. High surface runoff in the bare areas will cause flash floods that will subsequently increase soil loss and result in infertile soils. Productive land will turn into barren landscapes, affecting the agricultural activities in that area. Crop yields will decrease as a result. This will in turn affect income, and issues of food security will also arise. Habitat destruction on the lake areas will reduce fish stocks, and fishermen will suffer. Lake Baringo is a UNESCO World Heritage Site, and it could lose this status if the ecosystem is disrupted.

What are additional physical requirements for a solution?

Field infrastructure will be required. Terracing and contour farming on steep slopes will be needed to reduce surface runoff. Check dams and gabions will need to be set up. We shall also need to establish reforestation and agroforestry programs to stabilise soils. Rainwater harvesting systems will need to be set up to improve soil moisture and reduce surface runoff. Riparian buffer zones will be set up to reduce direct erosion and pollution. Satellite data and ground equipment will be significant. Global positioning devices will be used for ground validation. They are capable of picking precise ground coordinates. Drones will be required for the acquisition of high-resolution aerial photography and terrain mapping. Soil sampling kits will be used by soil experts to establish soil depth and soil composition. In collaboration with the weather agencies in Kenya, we shall require the setting up of more weather stations to collect real-time climate data on rainfall, windspeed and temperature. Powerful computers with efficient processing capacity will be needed for satellite data analysis. Data servers will be required for storing large datasets.