Transient effects of groundwater pumping and surface‐water‐irrigation returns on streamflow
Transient effects of groundwater pumping and surface‐water‐irrigation returns on streamflow
复制标题
地下水抽取和地表水灌溉回灌对径流的瞬态影响
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Bredehoeft
中科院分区：
文献类型：
--
作者：
Eloise Kendy;J. Bredehoeft
在地表水灌溉的西部河谷，过量灌溉的地下水排放维持了冬季超过自然流量的径流量。这种不自然的状况已经持续了很长时间，以至于水文学家、水资源管理者和用水者都认为这是正常的。不断变化的土地利用和灌溉方式使管理地下水排放的努力复杂化，进而保护河流径流。我们研究了(1)在距加拉丁河不同距离的季节性地下水抽水和(2)提高蒙大拿州加拉廷河谷灌溉效率对径流的影响。结果表明，季节性抽水井到溪流的距离越大，溪流枯竭的季节性波动越小，非灌溉季节的年枯竭比例越大。此外，我们还表明，提高灌溉效率的意义不仅仅在于减少分流。灌溉效率的提高将秋季和冬季的流量减少到一个更低但更自然的条件，而不是我们已经习惯的人为高条件。然而，现有的用水者和水生生态系统可能依赖效率低下的灌溉系统的回流。通过在一个流域内对人工补给进行战略性的计时和定位，地下水和地表水可以同时进行管理，以帮助在土地利用和灌溉方式发生变化时保持理想的径流条件。
In surface‐water‐irrigated western valleys, groundwater discharge from excess irrigation sustains winter streamflow at levels that exceed natural flows. This unnatural condition has persisted for so long that hydrologists, water managers, and water users consider it to be normal. Changing land uses and irrigation practices complicate efforts to manage groundwater discharge and, in turn, to protect instream flows. We examined the impacts on streamflow of (1) seasonal groundwater pumping at various distances from the Gallatin River and (2) improving irrigation efficiency in the Gallatin Valley, Montana. We show that the greater the distance from a seasonally pumping well to a stream, the less the stream depletion fluctuates seasonally and the greater the proportion of annual depletion occurs during the nonirrigation season. Furthermore, we show that increasing irrigation efficiency has implications beyond simply reducing diversions. Improving irrigation efficiency reduces fall and winter flows to a lower, but more natural condition than the artificially high conditions to which we have become accustomed. However, existing water users and aquatic ecosystems may rely upon return flows from inefficient irrigation systems. By strategically timing and locating artificial recharge within a basin, groundwater and surface water may be managed conjunctively to help maintain desirable streamflow conditions as land uses and irrigation practices change.