西北地区地下水水量-水位双控指标确定研究——以民勤盆地为例

地下水是西北内陆河流域干旱半干旱地区重要的供水水源、生态因子和环境因子。当前缺乏针对西北干旱半干旱地区特点的地下水水量和水位双控管理指标确定方法研究，无法为西北地区开展流域水资源管理生态保护提供技术支撑。本研究基于地下水可持续利用和生态保护的原则，提出了一套确定西北地区地下水水量-水位双控指标的技术方案。采用“以位定量”的思路，依据指标监测井代表的不同地下水功能区的地下水管理水位，确定水位指标区间值；将通过天然植被排泄的地下水量作为不可袭夺的排泄项，以数值模拟方法预报求解满足水位指标约束的地下水开采量，计算水量指标区间值。以民勤盆地为研究区开展示例研究，依据技术方案计算得到水位指标的下限阈值为埋深5.00～49.37 m，上限阈值为埋深0.00～5.00 m，水量指标上限为6 000×104 m3/a，下限为10 000×104 m3/a。采用2012—2016年区内实际开采量和监测水位变化趋势进行验证，当开采量在水量指标区间内运行时，水位也基本在水位指标区间内变化。该技术方法可以为西北地区开展双控管理提供一定的技术支撑。

A study of the determination of indicators of dual control of groundwater abstraction amount and water table in northwest China: a case study of the Minqin Basin

Groundwater plays an important role in water supply, ecological factors and environmental factors in the arid and semi-arid inland river basins of Northwest China. At present, there is short of research on the determination methods of indicators of dual control of groundwater abstraction amount and water table fitting to the characteristics of the arid and semi-arid areas in northwest China. There is not enough technical support for water resource management and ecological protection in northwest China. In this study a technical scheme is set up for determining groundwater dual control management indicators in Northwest Chinato meet the demand of sustainable utilization and ecological protection of groundwater.This system design include the following steps: (1) Observation wells in the management region are divided into 3 types according to groundwater functional zone, each type of well has its upper and lower threshold, and the water level management index is composed of the selected observation wells and their thresholds. (2)Groundwater discharge by natural vegetation can be regarded as an irresistible discharge term. Based on the corrected groundwater numerical simulation model, forecast simulations under different abstraction scenarios are programmed. The abstraction scenarios that meet the water table index constraint is picked out and the extremum amounts are defined as the threshold of water amount index. The technical scheme is employed to the Minqin Basin in the lower parts of the Shiyang River for the example verification. Water level index are emerged at 26 observation wells with the upper threshold of 5.00～0.00 m and the lower threshold of 49.37～5.00 m. The calculations of 18 abstraction scenarios show that the groundwater amount index was 6 000×104 m3/a as lower threshold and 10 000×104 m3/a as the upper threshold. The actual exploitation and water table during 2012 to 2016 show that the water level index and water amount index are matching, indicating that the technical scheme is reasonable. This technical scheme can provide certain technical support for the development of dual-control management in northwest China.