Characteristics of groundwater recharge of small watershed in hilly and gully region of the Loess Plateau
MA Jian-ye;SUN Bao-yang;XIAO Jun-bo;WANG Shan-shan;MA Bo;LI Zhan-bin;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Northwest A&F University;Shannxi Provincial Land Engineering Construotion Group Co.,Ltd.,Key Laboratory of Degraded and Unused Land Consolidation Engineering,the Ministry of Land and Resources;Guangxi Institute of Water Resource Research;
It has serious water resources shortage and soil erosion in hilly and gully region of the Loess Plateau,China. The groundwater has become an important water source for vegetation breeding and human life as well as the production in the arid and semi-arid areas. Groundwater recharge refers to the process that the aquifers obtain water from the outside,reflecting the renewable capacity of aquifers. It is one of the key parameters in groundwater resource management,development and utilization. It is of significance to study quantitatively the correlation between groundwater recharge and precipitation,recharge and base flow,and explore the characteristics of temporal and spatial variation of groundwater recharge in small watershed of the loess hilly region. This paper was based on the observation data of daily precipitation and runoff from three hydrologic stations in the period from 1959 to 1969. These stations are located in the upper,mid and downstream of the Chabagou Watershed,respectively. The groundwater recharge was estimated by the method of recession curve method. The results showed that the average annual precipitation and runoff were 489. 00 mm and 75. 17 m3·s~(-1),respectively. The base flow and base flow recharging index were 13. 09 mm and 0. 89,respectively. The groundwater recharge and recharging index were 11. 45 mm and 0. 03,respectively,and the residence time was 124 d. The groundwater recharge had been gradually and significantly increased from upstream to downstream( P 0. 05). But there weren't significant difference between the upstream and the midstream,the midstream and downstream( P 0. 05). The base flow recharging index has been decreased gradually from upstream to downstream,which has significant difference between different catchments. There was linearly positive correlation between groundwater recharge and precipitation( R2 0. 40),and the Pearson correlation coefficient was 0. 69. And the amplitude of increase of groundwater recharge with precipitation in downstream catchment was the largest. The base flow and precipitation were also positively correlated( R2 0. 77),and the Pearson coefficient was above 0. 80. More than 80% of the base flow in main stream is derived from the transformation of precipitation. The groundwater recharge process can be divided into two main stages in May,namely the"first recharge"and the "second recharge". The supplementary amount of the "first recharge"and the "second recharge"of each catchment in the Chabagou Watershed were as follows: upstream( 3. 02,5. 58 mm) midstream( 3. 76,8. 84 mm) downstream( 4. 75,11. 54 mm). They accounted for about 30% and 70% of the annual total recharge,respectively. And the "second recharge"is the main stage of the groundwater recharge causing difference in each catchment. This study could provide reference for the groundwater resources evaluation in the small watershed without recorded data.
【Fund】： 国家自然科学基金(41330858);; 西北农林科技大学博士科研启动基金(2452015345)
【CateGory Index】： P641
【CateGory Index】： P641