Low Flow Charecterzation of Satluj River

Abstract

The present study was envisaged to estimate low flow characterization of Satluj River. For the present study, Satluj river basin upto Kasol gauging site has been considered and the low flow charecterzation has been done at three locations viz. Rampur, Suni, and Kasol. The daily discharges of Satluj River at these sites for the years 1964-2011 were used for low flow characterization. These data have been aggregated to construct the average monthly, average 10-daily and average weekly discharge series. Flow duration curves for Satluj River at these three sites have been obtained by using the Weibull’s plotting method. For this purpose, average monthly discharge series has been used. Further, the flow characteristics related to low flow domain estimated in the present study were Mean Annual Runoff (MAR), Absolute Minimum Flow (AMF), Q20, Q50, Q90, Q20/Q90, Q50/Q90, and Q90/Q50, these parameters have been obtained by using the mean monthly flow series of Satluj River at these three sites. Mean annual runoff of Satluj river varies from 10,606.43 MCM (Rampur) to 13,192.72 MCM (Kasol); Absolute minimum flow from 44.18 cumecs (Rampur) to 73.05 cumecs (Kasol); Q20 from 625.75 cumecs (Rampur) to 826.55 cumecs (Kasol), Q50 from 167.25 cumecs (Rampur) to 206.14 cumecs (Kasol), Q90 from 84.60 cumecs (Rampur) to 98.34 cumecs (Kasol), Q20/Q90 from 7.39 (Rampur) to 8.41 (Kasol), Q50/Q90 from 1.98 (Rampur) to 2.10 (Kasol), and Q90/Q50 from 0.47 (Kasol) to 0.51 (Rampur) respectively.Further, Low Flow frequency curves have also been developed for average weekly and average 10 daily flows. The flow characteristics related to low frequency analysis estimated in the present study are mean of annual series of minimum 10-day average flow (MAM10), mean of annual series of minimum 7-day average flow (MAM 7), 10 day and 7 day minimum flows corresponding to 10 and 2 year return periods respectively (10Q10, 10Q2,7Q10, 7Q2).  These parameters have been obtained by using the average 10 daily and weekly flow series of Satluj River. Minimum 10-day average flow (MAM10) of Satluj River varies from 80.67 cumecs (Rampur) to 92.30 cumecs (Kasol); 10Q2 varies from 78.45 cumecs (Rampur) to 89.91 cumecs (Kasol) and 10Q10 varies from 102 cumecs (Rampur) to 112.46 cumecs (Kasol). Similarly, for average weekly flow, minimum 7-day average flow (MAM 7) varies from 79.02 cumecs (Rampur) to 91.10 cumecs (Kasol); 7Q2 varies from 78.05 cumecs (Rampur) to 89.11 cumecs (Kasol) and 7Q10 varies from100.1 cumecs (Rampur) to 109.63 cumecs (Kasol) respectively. All these values are a very good indicator of aquatic habitat for various species during different growth stages and environmental flows globally are used for recommending.

Keywords: Environmental Flow, Flow Duration Curve, Low flow characterization, Satluj River.