Catchment Landuse Change Impact on Runoff and Sediment Inflow to a Reservoir in Shivalik Foot-hills
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Date
2020
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Punjab Agricultural University, Ludhiana
Abstract
Landuse change in a catchment modifies the hydrologic processes and affects the capacity
and life of water storage and conveyance structures in the downstream areas. In the present
study, the impact of catchment landuse change on runoff and sediment inflow to Saleran
reservoir located in Shivalik foothills of Punjab has been assessed using RS, GIS and SWAT
model. The analysis of landuse maps generated in ArcGIS using Landsat satellite imageries
for the years 1999, 2009 and 2019 indicated significant changes in landuse of Saleran
catchment during the period of 20 years (1999-2019). Degraded land is the most expanded
landuse that increased by 55.28% (78.71 ha) and mixed forests decreased by 12.48%
(68.9 ha). The SWAT model was calibrated and validated on an adjacent training watershed
(40.28 ha) before its application on the study catchment. The average annual catchment runoff
and sediment inflow to the reservoir was simulated to be 14.2 mm and 3.1 Mg/ha
(1995-1999), 13.2 mm and 2.9 Mg/ha (2000-2009), and 11.8 mm and 3.37 Mg/ha
(2010-2019) per 100 mm of rainfall under the landuse 1999, 2009 and 2019, respectively. The
Saleran reservoir filled to its full capacity for 60%, 50% and 40% of the years under landuse
1999, 2009 and 2019, respectively. The mean sediment inflow rate (1995-2019) was
35.55 Mg/ha/yr, which reduced the gross storage capacity of Saleran reservoir by 1.77%,
annually. At this rate of sedimentation, the useful life of the dam/reservoir is estimated to be
45 years. The dead storage of the reservoir (29.88 ha-m) completely silted up by the year
2009 and thereafter sediment inflow is occupying and reducing the live storage capacity. The
sedimentation has already reduced the live storage of the reservoir by 19.41% (17.49 ha-m)
up to the year 2019, leaving only 72.63 ha-m (80.59%) of capacity for storing rainwater. The
results of the study indicate that changing landuse have negative impact on the reservoir
storage capacity and hence require urgent planning and execution of soil conservation
measures in the Saleran catchment.
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Citation
Prasad, Vishnu (2020). Catchment Landuse Change Impact on Runoff and Sediment Inflow to a Reservoir in Shivalik Foot-hills(Unpublished M.Tech. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.