Storm Water Surface Run-off Model of Swat Express Way

Abstract

Surface water hydrology carries significant weightage in the study of various fields of engineering and sciences and nothing makes the study of hydrological parameters easier than GIS. In this project, a detailed hydrological study of Swat Expressway was carried out using GIS and HEC- HMS. The objective of this study was to define certain points on the Swat Expressway where surface run-off streams would intersect the highway, compute the peak flows under design storm and propose cross drainage mechanism(s) for effective drainage of storm water discharge. SCS Curve Number method was used to compute peak flows. HEC HMS takes Total Storm Precipitation, Time Series Precipitation, Curve Number Grid and Lagtime as inputs. The design storm was taken as 2010 flood for Peshawar and Saidu Sharif PMD precipitation gages; SCS Type II storm distribution curve was used to distribute the 24 hour maximum storm into 1 hour intervals. Curve number grid was generated by classifying Sentinel 2 satellite imagery into Landcover and then joining it with FAO soil data. CN lag method was used by HEC-Geo HMS for computing Lagtime. The final result generated recommended to provide 18 culverts and 10 bridges for effective storm water management under the first 57 RDs of swat Expresswa