Modeling the sediment retention and ecosystem provisioning services in the Kashmir valley, India, Western Himalayas

Sediment yield from mountainous alpine watersheds of the Himalayas affects flood vulnerability, clean drinking water supplies, and reservoir functioning of the region. The sediment retention provided by the natural vegetation in these regions, on the other hand, is of utmost importance, and the cost evaluation of this service in monetary terms is almost incomprehensible. The present study calculated the sediment export, and sediment retention and provisioning services, provided by the natural vegetation of the Kashmir valley, India, Western Himalayas. It was found that the sediment export values in the valley fall in the range 0.00-1778.3 tons/ha/year. The results indicated that 90.97% of the area of the Kashmir valley has sediment export estimates in the range 0.00-6.00 tons/ha/year, with 84.21% area contributing in the range 0.00-2.00 tons/ha/year alone. This indicated that most of the valley's landscape is low sediment yielding, despite having a large area under rugged topography. Among the 24 watersheds of the valley, the highest yielding watersheds include Pohru, with 239.71 sqkm of its area loading sediments in the highest range category 10.0-1778.9 tons/ha/year, followed by lower Jhelum and Arapal. At the same time, Wular II has the lowest area in this range of about 0.14 sqkm, followed by Anchar (0.33 sqkm) and Kuthar (4.16 sqkm) watersheds. Further, it was observed that the sediment retention capability of almost all watersheds is considerably higher than their sediment export capabilities. In addition to this, we also mapped areas that provide flood risk reduction services (FRRS) to the people and infrastructure of the Kashmir valley-a concept termed ecosystem service provisioning (ESP). FRRS provisioning was considered the service sediment retention provides to downstream villages to cope with the flood disaster. It was found that the lower Jhelum has the highest percentage of area under the high FRRS service provisioning zones, followed by Arin, Sind, Arapal, Bringi, Kuthar, Sandran, Anchar, and others. It was concluded that quantifiable ecosystem services, such as sediment retention, are inadequate for detecting and verifying the locations that deliver ecosystem service benefits to humans and infrastructure unless the demand aspect is incorporated into the analysis. Hence, it is essential to consider ESP while evaluating the services ecosystems provide. We also assessed the overlap between the FRRS zones and the protected area network of the valley. It was found that only 239.41 sqkm of FRRS zones are present out of a total area of 2289.63 sqkm of the protected areas in the valley, accounting for only 10.46%. Only 17 of the Kashmir valley's 32 protected areas contain FRRS zones, according to our findings. The Limber wildlife sanctuary has the highest area percentage of FRRS zones (68.71%; 12.74 sqkm), whereas Thajawas Baltal Wildlife Sanctuary has the lowest percentage (0.87%, 1.91 sqkm). The methods and results from this work shall be helpful to policy makers for making informed decisions regarding the developmental policy and management of natural resources in the Himalayan regions and the Kashmir valley in particular.

Automated summary

The sediment yield from mountainous alpine watersheds in the Himalayas impacts the region's flood vulnerability, clean drinking water supplies, and reservoir functioning. Natural vegetation plays a crucial role in sediment retention services, with most areas in the Kashmir valley having low sediment export values despite rugged topography. The study also highlights the importance of ecosystem service provisioning in flood risk reduction and emphasizes the need to consider ecosystem service benefits in policy decisions.