Impact of forest degradation on streamflow regime and runoff response to rainfall in the Garhwal Himalaya,Northwest India |
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| Authors: | Nuzhat Q. Qazi L. Adrian Bruijnzeel Shive Prakash Rai Chandra P. Ghimire |
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| Affiliation: | 1. Water Resources Systems Division, National Institute of Hydrology, Roorkee, Uttarakhand, India;2. Department of Geography (Visiting Senior Research Fellow), King’s College London, London, UK;3. Hydrological Investigations Division, National Institute of Hydrology, Roorkee, Uttarakhand, India;4. Faculty of Geo-Information and Earth Observation (ITC), University of Twente, Enschede, The Netherlands |
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| Abstract: | Baseflows have declined for decades in the Lesser Himalaya but the causes are still debated. This paper compares variations in streamflow response over three years for two similar headwater catchments in northwest India with largely undisturbed (Arnigad) and highly degraded (Bansigad) oak forest. Hydrograph analysis suggested no catchment leakage, thereby allowing meaningful comparisons. The mean annual runoff coefficient for Arnigad was 54% (range 44–61%) against 62% (53–69%) at Bansigad. Despite greater total runoff Qt (by 250 mm year–1), baseflow at Bansigad ceased by March, but was perennial at Arnigad (making up 90% of Qt vs. 51% at Bansigad). Arnigad storm flows, Qs, were modest (8–11% of Qt) and occurred mostly during monsoons (78–98%), while Qs at Bansigad was 49% of Qt and occurred also during post-monsoon seasons. Our results underscore the importance of maintaining soil water retention capacity after forest removal to maintain baseflow levels. EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR D. Gerten |
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| Keywords: | baseflow forest disturbance forest hydrology headwater hydrology land degradation soil water retention storm flow |
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