Integrated Rainwater Management Strategies: Hydrology and Hydrological Modeling

1. Rainwater management for resilient livelihoods • Rationale For Integrated Rainwater Management Strategies (RMS) want to know: what works, where and why? This requires basic biophysical understanding: • how much rain falls & where does the water go? • how much water is “used” in different • components of the landscape? • what changes will different interventions make? • what are the on-site and downstream impacts • of scaling-up the interventions? Integrated Rainwater Management Strategies: Hydrology and Hydrological Modeling Planned Monitoring • Project Activities • Hydro-Meteorological instruments installed in three watersheds to: • measure rainfall, flow, climate variables, soil • moisture & water table • provide insights into hydrological fluxes, • processes and water budget • Hydrological modeling to determine: • Rainfall –Runoff relationships • Soil/Vegetation/Livestock water interactions • Water balance and catchment yield • Understanding of flow regime necessary for • design of RWH structures • Possible biophysical impacts of scaling-up • interventions • Possible biophysical implications of climate • change (Dapo) (Mizewa) (Mieja) Birhanu Zemadim, Matthew McCartney, Bharat Sharma and Seleshi Bekele Location of 3 study watersheds • Outputs • Guidance on suitable RMS for the Ethiopian • Highlands • Systems for increasing agricultural production • using RMS, including a range of water storage • options • RMS that maximizes water productivity and • ecosystem services Contact: b.zemadim@cgiar.org CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies

2. Integrated Rainwater Management Strategies: HydrometricMonitoring Mizewa Watershed in FogeraWoreda Rainwater management for resilient livelihoods • Description • Located in the north-east of the Abbay basin, • to the east of Lake Tana • Tributary to Ribb river • Rainfall: 1,000 – 1,500 mm • Large flat floodplain in the vicinity of the lake • and hilly catchments to the east • Traditional diversions and increasingly small • pumps used for irrigation Area 27.0 km2 • Interventions • 18 trapezoidal RWH ponds (129m3) lined with • geo-membranes have been constructed • Soil conservation practices: terracing, zai pits, • hydro-basins afforestation & protected areas • 67 new RWH to be constructed by Ag. Bureau Trapezoidal pond Rice cultivation • Challenges • Flooding and water logging • Drying-up of streams in the dry season and • hence water scarcity • Conflicts between upstream and downstream • water users • Constructed rain water harvesting ponds • failing for a variety of reasons Water logging of Maize Proposed location for flow monitoring CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies

3. Integrated Rainwater Management Strategies: HydrometricMonitoring Dapo Watershed in DigaWoreda Rainwater management for resilient livelihoods • Description • Located in the south-west of the Abbay basin • Tributary to the Didessa River • Rainfall: 1,400 – 2,000 mm • High potential for irrigation • Currently less than 8% developed by • traditional irrigation Typical view of the Midland • Interventions • Some farmers have built small ponds and • reservoirs, but currently there is seemingly • little real interest in rain water management • In some places, Bone, a traditional practice of • cultivating in wetland areas using residual • moisture, is being undertaken • There are plans for a 40-60 ha irrigation • scheme to commence later this year in the • lowlands on the Jirma River • Feasibility studies are presently being • conducted for the establishment of a large • irrigation scheme in the lowlands (Didessa River) View of the catchment Bridge proposed for flow monitoring • Challenges • Scarcity of water during the dry season • Long distance (>2 km) to fetch water • Increasing problems of erosion and loss • of soil fertility • Deforestation and over grazing • Problems of soil compaction and acidity • (on the old Didesa state farm) CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies

4. Integrated Rainwater Management Strategies: HydrometricMonitoring Meja Watershed in JelduWoreda Rainwater management for resilient livelihoods • Description • Located in the south of the Abbay basin • to the north-east of Ambo town • Tributary to the Guder river • Rainfall: 1,400 – 2,000 mm • The headwaters are in a flat wide valley, • which is heavily utilized by livestock • Downstream, the catchment comprises • deeply incised mountain streams • Slopes of up to 80o are being cultivated • Plantations of eucalyptus occupy • approximately 10-15% of the landscape Middle catchment Upper catchment Gully with eucalyptus Drainage Traditional bridge • Challenges • Seasonal water scarcity • Heavily deforested in the last 10-20 years • Slope slumping and gullying are common • phenomena • Productivity has “halved” in recent years • (according to local farmer) • Interventions • Some traditional diversions for irrigating • potatoes, maize and onions • Drainage furrows to remove water from fields in • the wet season • Planting of euclayptus to halt gullying and • erosion CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies