Optimal Ecological Management Practices for Controlling Sediment Yield and Peak Discharge from Hilly Urban Areas

Abstract

Sustainable mitigation of soil erosion and peak discharge from hilly urban watersheds in an ecologically and economically sound manner is a formidable challenge. This paper applies a linear programming optimization model for determining the best combination of ecological management practices that control sediment and peak discharge within permissible limits at a minimum cost. The linear programming model equations were solved with simplex method using a computer program. The model was applied to a hilly watershed of a rapidly developing city located in the northeastern part of India. The sediment yield and peak discharge were determined by well known equations. A mapping program was employed for extracting topographic parameters of the watershed. The best combination of three possible ecological management practices—grass, garden, and detention pond—was then established. Sensitivity analysis was performed for the assessment of physical parameters. While the sensitivity to rainfall intensity was observed to be high, the sensitivity to rainfall erodibility factor, soil erodibility factor, slope length factor, and runoff coefficient were each found to be moderate.