Your search found 2 records
1 Yilak, D. L.; Tilahun, S. A.; Schmitter, Petra; Nakawuka, Prossie; Enku, T.; Kassawmar, N. T.; Steenhuis, T. S. 2015. Determining the groundwater potential for agricultural use in Ethiopian Highlands [Abstract only] Paper presented at the 10th Alexander von Humboldt Conference 2015 on Water-Food-Energy River and Society in the Tropics. EGU Topical Conference Series, Addis Ababa, Ethiopia, 18-20 November 2015. 2p.
Agriculture ; Groundwater irrigation ; Groundwater recharge ; Water levels ; Water use ; Highlands ; Irrigation water ; Water levels ; Watersheds ; Sustainability ; Case studies / Ethiopia / Ethiopian Highlands / Robit-Bata watershed / Lake Tana
(Location: IWMI HQ Call no: e-copy only Record No: H047278)
(0.01 MB)
The Ethiopian government has declared the Lake Tana - Beles region to be a growth corridor and irrigation development is one of the priorities. Since the dry season river flow is limited, groundwater has the greatest potential for increasing irrigation in the near future. The main drawback is lack of information on sustainable groundwater use and specifically the ground water potential. Therefore the objective of this research is to calculate the annual groundwater recharge. The study was conducted in Robit-Bata, an experimental watershed of 911 ha, located at the south-eastern edge of Lake Tana. Farmers have excavated more than 300 hand dug wells for irrigation use from which, we used 50 wells for water table fluctuation observations for one year starting from April, 2014. Daily Precipitation was recorded for the same period. The annual recharge was estimated using the water – level fluctuation method. Specific yield was defined as the difference of porosity and field capacity of the subsurface formation. The annual average areal groundwater recharge was 640 mm/year, which is 41% of the rainfall and ranged from 50mm to 390mm per week for the various locations in the watershed. The greatest recharge amounts were found in the plains at the foot of the hills and river course areas consisting mostly weathered basalt rock. At those locations the groundwater rose steadily during the rainy monsoon phase. Smaller amount of recharge occurred both near the top of the hills with tough rock formation and in the, flat areas near to stream with sandy and clay deposits and groundwater at, shallow well depth. Our study indicates that the current use of the groundwater seems sustainable. Further research is required for optimized utilization of the limited groundwater resources for irrigation development to meet the food security of the community.
2 Yilak, D. L.; Tilahun, S. A.; Schmitter, Petra; Nakawuka, Prossie; Haile, Alemseged Tamiru; Kassawmar, N. T.; Guzman, C. D.; Steenhuis, T. S. 2015. Adaptation of the SCS [Soil Conservation Service] runoff equation for a (Sub) humid monsoon climate. Paper presented at the 3rd OpenWater Symposium, Addis Ababa, Ethiopia, 16-17 September 2015. 19p.
Climate change ; Monsoon climate ; Humid climate ; Runoff ; Adaptation ; Soil conservation ; Soil moisture ; Watersheds ; Water shortage ; Water balance ; Hydrology ; Models ; Highlands ; River basins ; Rain ; Runoff / Ethiopia / Ethiopian Highland / Maybar Watershed / Anjeni Watershed / Blue Nile Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047279)
(0.01 MB)
The Soil Conservation Service Runoff equation was developed and tested for the temperate climate in the United States. Application to the monsoon climates has been only partially successful. The objective to adapt the SCS equation to a monsoon climate equation is to predict watershed runoff. The adaptation is based on the fact that in many humid areas the main mechanism for direct runoff is saturation excess and in monsoon climates the contributing area expands as a function of the cumulative effective rainfall ( Pe). This then translate in smaller watershed storage (S) in the equation. When estimating runoff contributing area within a watershed and assessing the runoff mechanisms, we have used the original concept of SCS-CN approach in a 113 ha Anjeni and 113ha Maybar Watersheds in the headwaters of the Blue Nile Basin, North Ethiopian highland. Analysis was done at daily, weekly and biweekly base using nine years of hydrological data (1988-97) by classifying the rainfall seasons in to six based on the seasonal cumulative of effective rainfall (Pe). The initial abstraction (Ia) was taken to be equal to the evapotranspiration loss (E) computed by Thornthwaite-Mather water balance method in replacement of the 20% of the potential storage (S). Effective rainfall (Pe) is the difference of total rainfall and Ia. The model performed more as the seasonal cumulative Pe is increased indicating that runoff responses occurred as the watershed saturated. The proportion of runoff contributing area (Af) increased linearly until the cumulative Pe up to nearly 500mm and then the watershed reaches in equilibrium for addition increase of Pe, which is in line with the concept of partial source area hydrology.
Powered by DB/Text WebPublisher, from
