Abstract:
Wadecha-Belbela reservoir system is located in Oromia Region, East Shoa
zone, Adaa Liben woreda serving as a water source of 1600ha irrigation
projects. The irrigation system under the reservoir system is increasing
progressively during the past decades. The expansion of irrigation development
without the knowledge of the water source will have the outcome of agricultural
yield reduction and water stress. Inadequate knowledge on operation of the
reservoir has been leading to inefficient usage of stored water.
This study focuses mainly on the description and assessment of water
resources of the woreda based on climate, land and water information,
estimation of irrigation water requirements of the reservoir system irrigation
projects, and operational analysis of the reservoir system by the application of
reservoir system simulation model (HEC-ResSim). Nine years of meteorological data were used to simulate the Wadecha-Belbela
reservoir system. The main input data to the model were the reservoirs physical
characteristics, the irrigation water diversion estimated by CROPWAT 4
windows software, potential evaporation (mm), daily surface inflow (m3
/sec) to
the reservoirs system. The outputs of the model were the release (m3
/sec),
storage (rrr'), reservoir level (m), and inflow-outflow relations of the reservoir 4.63Mm3
remained in the reservoirs system. Therefore, if the releases of water
from the reservoir systems are followed according to the monthly irrigation
water requirement, this can sufficiently serve as the operating rule of the
reservoirs.
The study also provides an operation rule curve using the application of HEC
ResSim
