MATHEMATICAL MODEL STUDIES FOR FLOOD PROTECTION MEASURES OF RIVER SWAN, HIMACHAL PRADESH

Abstract

Floods and flash floods are common water related natural disasters in the state of Himachal Pradesh. The flooding mostly occurs in summer season due to snow melt in the upper regions and coupled with heavy rainfall leads to heavy flooding in the lower regions. The other form of flooding is flash flood, which principally occurs due to cloud burst in the catchment area. The duration of flash flood is short but the damage caused by it is extensive. In Himachal Pradesh, the agriculture is practiced mostly on the flood plains of rivers. During flood, water spreads over the flood plains and causes damage to the agricultural fields. The river Swan experiences this kind of flooding every year. To protect the precious agricultural lands adjacent to the River Swan, IPH Department of HP proposed to construct flood protection measures along the banks of River Swan in the form of levees. One dimensional mathematical model HEC-RAS was used to study the location, alignment and various design parameters of the proposed embankments. The top level of the embankments were decided using the predicted maximum water levels with suitable free board. Based on the velocity of the flow computed, suitable protection measures were also suggested along with geo-fabric filter. Based on the model studies, adequately planned, well aligned and properly designed embankments have been recommended for Swan river.