Cycle 1 (2011 Deadline)
Reducing soil loss through effective soil and water conservation practices using hydrologic considerations and farmers’ participation in the Blue Nile Basin
PI: Seifu Tilahun, Bahir Dar University
US Partner: Christopher Barrett, Cornell University
Project Dates: May 2012 - April 2015
Project Overview
Soil erosion decreases food production and hampers poverty reduction efforts in the highlands of eastern Africa. Although intensive efforts have been underway both to reduce sediment production and to halt land degradation since the 1980s, erosion continues unabated and the already low crop yields are deceasing even further. Shallow soils are becoming shallower and are often abandoned, and gullies are swallowing up productive cropland. Finally, some of the lost soil fills up reservoirs and silts up downstream irrigation canals. Current measures to reduce soil loss are ineffective, and new approaches that both consider the hydrology of the whole landscape (instead of the current plot based erosion research) and use traditional farmer’s knowledge for locating erosion control practices are required. The goal of the proposed research is to develop appropriate watershed and farmer-based erosion control practices for the Ethiopian highlands in order to replace the well minded imported and inappropriate technologies from foreign donors.
Dr. Seifu Tilahun with community farmers and a USAID representative during the October 2012 site visit. |
Ali Yassin, 4th year undergrad student, building a weir (a structure used as a measuring place for runoff and sediment concentration in the river). |
Team members (Hiwot, Ali and Christian) conducting a group walk and discussion with local community women on erosion in Debre Mawi watershed. |
These researchers will instrument the Debre Mawi (5.27km2) and Bir (64km2) watersheds in the headwaters of Blue Nile and to continue monitoring another instrumented by the International Water Management Institute (IWMI), the Mizewa watershed (27km2). Their efforts will be aimed at identifying erosion hotspots by measuring spatially distributed runoff and soil loss (from periodically saturated areas in the valley bottoms and areas with exposed subsoil that are severely degraded) and by participatory watershed methods approach and sediment tracers. They will also study the relationship between nutrient loss and soil loss by measuring soil nutrients (N, P, K, Mg, and Ca). Perched water table levels will be measured in the Bir watershed (~64km2) to identify saturated areas. Gullies will be monitored through areal and satellite images in addition to field measurement in the Bir and Debre Mawi watersheds. By locating the hotspot areas within the watershed, they will propose effective conservation practices. A simple physically-based hydrology model will be applied to locate the practices on the vulnerable areas. Their predictions will be compared with farmers’ knowledge including the location of the traditional practices. Finally, practices will be designed with the participation of farmers. Within the project period and beyond, some of the proposed practices will be installed with the farmers’ help in the Debre Mawi and monitored after the project. This research project will be carried out by the School of Civil and Water Resource Engineering as part of the newly implemented PhD program and an existing master’s graduate program on hydrology in close cooperation with faculty and students of a NSF IGERT program at Cornell. Most importantly, the international partnership will train future scientists and managers for managing the soil and water resources in Ethiopia.
Summary of Recent Activities
After first-semester training, the PhD students on the project commenced their field work during the first quarter of 2013. One student, Getaneh Kebede, started on his watershed (named Enchilala) in the Birr watershed. He constructed two masonry weirs and installed two rain gauges. In addition, he finished setting up a pipe that forms part of the device measuring the water level at the outlet of the watershed. Finally, he identified gullies that will be rehabilitated in cooperation with the community. The overall objective of his project is to conduct an effective measure of gully erosion. In addition, the PhD students were assigned to write a paper on improving the rating curve of sediment concentration developed by the Ministry of Water and Energy. They were able to improve the equation and the resulting paper was submitted and accepted to the International Conference on Science and Technology being held at Bahir Dar University in May 2013.
The students and faculty visit a model farmer in soil and water conservation. |
Students work to install rain gauge in the Enchilala watershed. |
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