Evaluation of the sand-trap structures of the Wonji-Shoa sugar estate irrigation scheme, Ethiopia |
| |
Authors: | T Paulos S Yilma T Ketema |
| |
Institution: | (1) Melkassa Agricultural Research Center, Nazareth, Ethiopia;(2) Civil Engineering Department, Addis Ababa University, Addis Ababa, Ethiopia;(3) Alemaya University, Alemaya, P.O.Box 45, Ethiopia |
| |
Abstract: | A study was undertaken to evaluate the performance of sand-traps at Wonji-Shoa Sugar Estate, Ethiopia. Inflow and outflow samples from the sand-traps and deposited sediment samples from the sand-traps, main canal, and reservoirs were taken. The samples were analyzed for sediment concentration and particle size distribution. During the study period, the sand-traps were performing satisfactorily in removing a good portion of suspended sediment (as high as 63% in case of sand-trap A and 54% in case of sand-trap B) in the week after flushing and they were performing poor (as low as −40% in case of sand-trap A and 6% in case of sand-trap B) when the sand-trap was running without flushing for about two months. Sediment particle size analyses of the samples indicated that the sand-traps retained almost all the sand fractions (90–95%) greater than 0.15 mm. Fifty to sixty percent of the sediment particles passing the sand-traps into the main canal was smaller than 0.002 mm. Sieve analyses of the bed materials taken from the sand-traps showed that particles up to medium gravel size (6.3–13.2mm) were entering the sand-traps and almost all were trapped. This result shows that performance of the sand-traps under the existing sediment load of Awash River was found to be satisfactory. However, it was observed that performance level of the sand-traps was very much dependent on the flushing interval of deposited sediment. |
| |
Keywords: | irrigation sand-trap sediment flushing trap efficiency |
本文献已被 SpringerLink 等数据库收录! |
|