Effects of infiltration trenches and bio-retention ponds on stormwater runoff in Eldoret town

Abstract

The overall objective of the research was to evaluate the influence of low impact developments (LIDs) on the generated runoff in Eldoret town, Kenya. The specific LIDs investigated were the infiltration trenches and bio-retention ponds. On methodology, rainfall was measured using rain gauge while discharge was measured using the current meter. Simulation was done using Storm Water Management Model (SWMM) version 5. The results indicated a reduction of average runoff flow by 25% when infiltration trenches were used to an extent of 100% treatment of impervious area and a reduction in total runoff volume by 19.6%. In addition, bio-retention ponds reduced average runoff flow and volume by 1.6% and 4.4%, respectively. Therefore it was concluded that bio-retention cells and infiltration trenches have an effect of reducing flow and total volume in the study area and can be used to control flooding. Further study is recommended on effect of permeable pavements.