| Autor: |
Tarafdar, Soukhin, Dutta, Subhashis |
| Zdroj: |
Journal of Earth System Science; Sep2023, Vol. 132 Issue 3, p1-22, 22p |
| Abstrakt: |
This paper is an attempt to study the cause and effect of the reported widespread decline in spring-flow from a catchment in the middle Himalaya in the Garhwal region. A range of statistical tests to the long rainfall data series is applied to the two gauge-based interpolated gridded data. A decline in annual and seasonal rainfall with a rising frequency of moderate to severe drought in the subseries (1961–2018) is observed compared to the first half of the 20th century. A sudden shift of declining trend is observed in IMD4 gridded data in the early to mid-sixties. Prolonged post-monsoon and winter recession characteristics are analysed through a single nonlinear model and a power-law model. The nonlinear model and event-based power-law recession analysis showed nonlinearity (B≠1) in a storage–discharge relationship at the spring catchment scale as well as the intercept (A) highlights a very fast-draining aquifer with a very short recession timescale. The log-transformed fitted single nonlinear modelled recession data revealed control of antecedent storage over the rate of outflow as parallel offset was observed in interannual prolonged recession curve in –dQ/dtvs. Q plot. Groundwater reservoir contributing to Ayal springflow is very vulnerable to reservoir storage changes. Research highlights: In recent time, threat to water sustainability in middle Himalaya is widely reported. However, a clear understanding of the cause is not being investigated in a systematic manner. The present study highlights that deficient monsoon years as well as dry winter months, are causing multi-year drought in middle Himalaya basins. Higher frequency of moderate drought is observed in the long-term rainfall data after the early to mid-sixties and may have caused the decline in springflow. Recession characteristics of springflow showed nonlinearity in storage–discharge relationship as well as very short recession time scale and springflow are extremely vulnerable to aquifer storage change. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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