Imbalance in the modern hydrologic budget of topographic catchments along the western slope of the Andes (21–25°S): implications for groundwater recharge assessment
Imbalance in the modern hydrologic budget of topographic catchments along the western slope of the Andes (21–25°S): implications for groundwater recharge assessment
复制标题
安第斯山脉西坡（21-25°S）沿线地形流域的现代水文收支失衡：对地下水补给评估的影响
作者：
D. Boutt;L. Corenthal;L. Munk;S. Hynek
在干旱的集水区，现代排水量往往超过地下水补给量。流域内这种明显的质量不平衡可以通过地形排水之间的地下水流动和/或排干洪水期间补给的储存地下水来调和。这项研究调查了智利北部安第斯山脉西侧(21-25°S)流域现代水文收支的差异，重点是内陆型萨拉德阿塔卡马盆地及其邻近盆地。给出了现代补给率的不确定性估计，这并没有接近于平衡地形集水区内观测到的现代地下水流量。利用简化的二维地下水模型，探讨了排放到萨拉德阿塔卡马的水文地质集水区的两种概念化。模型的结果支持这样的解释，即为了平衡高原边缘的水量平衡，需要地下跨流域流动和从蓄水中瞬时排出地下水。模型进一步检验了该系统是否仍在响应来自雨水期的气候强迫(在古气候时间尺度上)，并强调了类似高原边缘系统的一般特征，包括：(1)高原边缘的水位变化对高原长期(100-1000年)补给的变化高度敏感；(2)地下水位变化的范围和幅度由边缘的渗透系数分布控制；(3)低海拔集水区的贡献区域本身是动态的，与地形边界不一致。
Modern rates of water discharge often exceed groundwater recharge in arid catchments. This apparent mass imbalance within a catchment may be reconciled through either groundwater flow between topographic drainages and/or the draining of stored groundwater recharged during pluvial periods. This study investigates discrepancies in the modern hydrologic budget of catchments along the west flank of the Andes in northern Chile (21–25° S), focusing on the endorheic Salar de Atacama basin and adjacent basins. Uncertainty-bounded estimates of modern recharge rates are presented, which do not come close to balancing observed modern groundwater discharge within topographic catchments. Two conceptualizations of hydrogeologic catchments discharging to Salar de Atacama were explored with a simplified two-dimensional groundwater model. Results from the models support the interpretation that subsurface interbasin flow and transient drainage of groundwater from storage are required to balance water budgets along the plateau margin. The models further examine whether this system is still responding to climatic forcing (on paleoclimatic time scales) from pluvial periods and highlight general characteristics for similar plateau margin systems including: (1) water level changes at the plateau margin that are highly sensitive to long-term (100–1,000 years) changes in recharge on the plateau, (2) extent and magnitude of the changes in water table, which are controlled by the distribution of hydraulic conductivity at the margin, and (3) the contributing area to the lower-elevation catchment, which is itself dynamic and not coincident with the topographic boundary.
影响因子：
5.8
作者：
Perez-Fodich, Alida;Reich, Martin;Fehn, Udo
通讯作者：
Fehn, Udo