Integrated Rainwater Management Strategies: Hydrology and Hydrological Modeling Birhanu Zemadim, Matthew McCartney, Bharat Sharma and Seleshi Bekele CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies 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? 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) 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 Location of 3 study watersheds Planned Monitoring Rainwater management for resilient livelihoods Contact:

Area 27.0 km 2 Rice cultivation Trapezoidal pond Water logging of Maize Proposed location for flow monitoring Integrated Rainwater Management Strategies: Hydrometric Monitoring Mizewa Watershed in Fogera Woreda 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 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 Interventions  18 trapezoidal RWH ponds (129m 3 ) 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 CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies Rainwater management for resilient livelihoods

Integrated Rainwater Management Strategies: Hydrometric Monitoring Dapo Watershed in Diga Woreda 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 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) 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 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) CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies Typical view of the Midland Bridge proposed for flow monitoring View of the catchment Rainwater management for resilient livelihoods

Integrated Rainwater Management Strategies: Hydrometric Monitoring Meja Watershed in Jeldu Woreda 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 80 o are being cultivated  Plantations of eucalyptus occupy approximately 10-15% of the landscape Challenges  Seasonal water scarcity  Heavily deforested in the last 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 CPWF Nile Project 2: Integrated rainwater management strategies – technologies, institutions and policies Gully with eucalyptus Middle catchment Upper catchment DrainageTraditional bridge Rainwater management for resilient livelihoods