Impact of resource conservation interventions on water and sediment yield in a watershed of Shivalik
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Date
2015
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Publisher
PAU
Abstract
Soil and water are considered as one of the world‟s limited and non-renewable resource. Soil erosion by water is being increasingly recognized as a problem across the world. The objective of this study was to assess the impact of resource conservation interventions on water and sediment yield in a watershed. Morphometric analysis of Sukhna Lake watershed covering Chandigarh, Punjab and Haryana was carried out by using GIS technique. This analysis shows that the basin has a dendritic pattern with fifth order stream. Bifurcation ratio, drainage density, drainage texture, elongation ratio and relief ratio value of the watershed confirm that the geologic structures do not distort the drainage pattern. The area
was impermeable subsurface having sparse vegetation, hilly relief and steep slop es with very fine texture cause prone to soil erosion. Impact analysis for six scenarios have indicated that in the initial period (1958-70) rainfall was less but runoff percentage was 22% of rainfall, no soil conservation measures were present due to which heavy soil loss of 150 ton/ha/yr, where as in 2013 rainfall was high but runoff percentage significantly decreased to 7.8% of rainfall due to increased number of structures over 190 as a result the sediment yield also decreased to 5 ton/ha/yr. This study shows that an adequate soil conservation measure exists, as result creations of new strictures are not required. In order to retain the sediment yield, the structures need regular maintenance. High evaporation rate in the region causes drying of the lake as the capacity has reduced from 10.74 million cubic meter (MCM) initially to 5.24
(MCM) at present, almost 50% of the lake‟s capacity reducing the depth of lake. In case of afforestation preference should be given to drought resistant species and deep rooted plantation. However the sediment yield has reduced to 5 ton/ha/yr but from the catchment of 4284 ha it is a huge amount settling down in the lake and reducing its capacity. In such case periodic desilting has to be taken up once in 2-3 years. To maintain the required water level in Sukhna Lake on a sustainable basis throughout the year, strategies must be made to divert the water from the other adjacent catchments.
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Keywords
precipitation, land resources, irrigation, soil degradation, area, land management, sediment, runoff, yields, surface water