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The effect of changes in hydrological services caused by effective watershed management measures on watershed health with the PSR approach in the Efin watershed, South Khorasan, Iran
  • Reza chamani,
  • Mehdi Vafakhah,
  • Seyed Hamidreza Sadeghi
Reza chamani
Tarbiat Modares University
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Mehdi Vafakhah
Tarbiat Modares University

Corresponding Author:[email protected]

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Seyed Hamidreza Sadeghi
no affiliation
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Abstract

Nowadays, the destruction of watersheds has increased under the influence of various human and natural factors, and the performance of watersheds and the provision of hydrological services have become a problem. Therefore, carrying out management measures, including watershed engineering and biological measures, is a human approach to deal with these threats and increase the expected hydrological services. Therefore, in this research, an attempt has been made to evaluate the impact of watershed management engineering and biological measures on the health of the Efin watershed in South Khorasan, Iran, with the conceptual approach of pressure-state-response (PSR). To do this, after determining the effective variables on the health and security of Efin watershed and removing the variables with co-linearity using Principal Component Analysis (PCA), the PSR indices were quantified and standardized and was used based on the behavioral data for determining the health and security of the watershed. In order to determine the role of watershed management operations on health and safety indicators, the variables related to watershed management measures including Normalized Difference Vegetation Index (NDVI), concentration time and Curve Number (CN) under three management scenarios of 50, 75 and 100% of the area of the measures Efin watershed was re-determined and the health index was calculated after implementing watershed measures and compared with the conditions before the operation. The results showed that the PSR indices were variable in the ranges of 0.35 to 0.73, 0.35 to 0.60 and 0.19 to 0.59, respectively. The health and security index of sub-watersheds also changed between 0.37 to 0.50 and 0.22 to 0.69, respectively. The research results showed that due to the non-change of the pressure variables, this index has not changed under the management scenarios. But on average, the status index in the first, second and third scenarios has increased by 7.38, 4.92 and 6.41%, respectively. This response index has increased in all three scenarios by 26.37, 18.95 and 14.65% respectively. In the first, second and third management scenarios, the health index has experienced an increase of 10.31, 7.32 and 6.50%, respectively. Finally, under the influence of the first, second and third management scenarios. The security index shows an increase of 35.32, 24.92 and 21.88%, respectively. As the results of the research show, the implementation of engineering and biological measures alone cannot increase the health of Efin watershed and ensure their security. Therefore, it is suggested to use comprehensive management approaches of watersheds in the direction of better and principled management of watersheds and help to improve their performance.