EVALUATION OF THE HYDROLOGICAL MODELLING USING CLIMATIC STATION DATA: (A CASE STUDY OF SAROBI SMALL DAM)

Abstract

In this paper an effort has been made to carry out the hydrological modelling using the available rainfall
data. Hydrology plays the key role in the design of any hydraulic structure. If the discharge data is available for a
certain place, then the frequency analysis is carried out using this discharge data. However if the discharge data is
missing then the peak design flood is estimated from the rainfall data. Sarobi Small Dam located at North Waziristan
KP, Pakistan was selected as the case study and the SCS-Curve number method was used to estimate the direct runoff
because this model is simple and many researchers prefer this model for small watersheds [1]. The Gumble Extreme
Value-I distribution was selected for the frequency analysis of rainfall in order to generate the peak rainfall for different
return periods. The SCS type-2 distribution of rainfall was used for generating the peak storm hyetograph. The design
rainfall for 10 & 200 years return period was found to be 4.06 and 6.99 inches. The design Hydrograph for different
return periods was estimated using HEC-HMS software. The design hydrograph for the 10 & 200 years return period
was found to be 83.4 and 191.5 cumecs respectively.