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
