Determination of Different Lining Materials for Reducing Seepage Loss in Water Harvesting Structures at Arsi Zone, Ethiopia

Abstract

Water harvesting has been practiced for many years in several regions globally and is mainly used for domestic and agricultural purposes. Seepage losses through soils have a great influence on the performance of water harvesting structures. The experiment was conducted at Kulumsa Agricultural Research Center to identify the best efficient lining material for a water harvesting pond. The experiment was conducted for two consecutive years during the off-season. Four treatments (mortar, ash, compaction alone, and bentonite) were used in a randomized complete block design (RCBD) with four replications. The overall analysis of the data showed a highly significant difference among the treatments. The overall findings of the study indicated that the use of various lining materials had a significant impact on seepage loss control (P 0.05). The maximum seepage rate of 19.50 cm/day was observed at T1 (compaction alone treatment), and the lowest seepage rate of 11.13 cm/day was found at treatment using T4 (bentonite). The seepage rate observed at T4 (bentonite) was 42.92% lower than the highest seepage rate at T1 (compaction alone). The physical seepage rate analysis shows that bentonite was the best lining material to control water loss from water harvesting structures and store water for a longer period than other treatments. As a result, bentonite was recommended to control water loss from water harvesting structures in similar soil types based on the lowest seepage rate.