Author(s): Urvashi Malani; Sanjaykumar M. Yadav

Linked Author(s):

Keywords: Discharge; Middle tapi basin; Sediment load; Trend analysis

Abstract: Discharge in a river is a major carrier of sediment load. Changes in the discharge and sediment load are occurring due to climatic changes and rise in anthropogenic activities. To understand the variation in sediment load over the course of time, variation in discharge is also to be taken in consideration. In present study, Sarangkheda gauging Station (G. S. ) is considered to find out the trend in Suspended Sediment Load (SSL) and Discharge (Q) of Middle Tapi Basin (MTB), India. To determine the temporal variation, data from 1985- 2020 (36 years) is taken from Central water Commission (CWC). Innovative Trend Analysis (ITA) method is adopted in present study to find the trend of SSL and Q. ITA is used to find the hidden trend in the time series. It is a graphical method which helps to determine the monotonic or non-monotonic trend in the series. Data length of 36 years is split into 2 parts (1985-2002,2003-2020) and then those two parts are again split into 2 parts individually to determine detailed hidden trend in the series. 1985-2002 is divided into 1985-1993 and 1994-2002.2003-2020 is divided into 2003-2011 and 2012 to 2020. Decreasing trend was obtained for discharge and sediment load. Trend slope for each time block was determined and it was found that slope of discharge is much lesser than that of sediment load. This indicates that variability in sediment load is greater than discharge in the river. It was found that maximum decreasing trend was found during 2003-2011 where SSL has shown a decreasing slope of -24.03 MT/day/year while for the same time block discharge has shown decreasing slope of -0.068 m3/s/year. The minimum slope for SSL was obtained during 1985-2020 as magnitude of -2.88 MT/day/year. The flood event of 2006 in Tapi River has maximum discharge and sediment load from 1985-2020. Hence, time block 2003-2011 has shown maximum decreasing slope because event of 2006 lies in the first half of the time series. Time block 2003-2011 has shown maximum deviation in sediment load and discharge. Incorporating results of trend in sediment load and discharge can be useful for water management. Both climatic and human activities appear to be responsible for alteration in flow pattern in the river.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0146-cd

Year: 2023