Effects of irrigation withdrawals on streamflows in a karst environment: lower Flint River Basin, Georgia, USA
Effects of irrigation withdrawals on streamflows in a karst environment: lower Flint River Basin, Georgia, USA
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喀斯特环境中灌溉撤水对水流的影响：美国佐治亚州弗林特河流域下游
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发表时间：
2012
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影响因子：
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通讯作者：
J. Dowd
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作者：
K. Rugel;C. Jackson;J. Romeis;S. Golladay;D. Hicks;J. Dowd
1970年至1980年，美国格鲁吉亚西南部的弗林特河流域（FRB）下游广泛采用了中心枢纽灌溉系统。该岩溶系统中的地下水与区域河流直接水力连接，其中许多河流通过覆盖层切入下层石灰岩。我们使用长期的美国地质调查局测量站数据来评估FRB下游两条支流（Ichawaynochaway Creek和Spring Creek）的多个流量指标，以确定自灌溉实践加强以来河流行为的变化程度。我们比较了灌溉前后的流量持续时间曲线，1天，7天和14天的最小流量，以及8天（季节性）和年基流衰退斜率，此外还评估了区域气候数据，以确定灌溉前后是否存在显著差异。我们的结果表明，两种压力计的灌溉后记录中低流量持续时间发生了显著变化，包括Spring Creek的98%无水流量减少了一个数量级。两种压力计均显示1、7和14天低流量显著降低。八天基流衰退曲线（初夏月份内）和年基流衰退曲线在Ichawaynochaway河灌溉后的时期变得明显陡峭。我们还发现，一个显着的关系存在于冬季和夏季之间的最小流量在两条河流在灌溉前的时期，这是在灌溉后的几年中断。研究期间的区域气候数据显示，降雨总量或干旱频率没有显著变化;但是，有证据表明季节性降雨模式发生了变化。版权所有© 2011约翰威利父子有限公司.
Extensive implementation of centre pivot irrigation systems occurred between 1970 and 1980 in the lower Flint River Basin (FRB) of southwestern Georgia, USA. Groundwater within this karstic system is in direct hydraulic connection with regional streams, many of which are incised through the overburden into underlying limestone. We used long‐term U.S. Geological Survey gaging station data to evaluate multiple flow metrics of two tributaries (Ichawaynochaway Creek and Spring Creek) in the lower FRB to determine the extent of changes in stream behaviour since irrigation practices intensified. We compared pre‐ and post‐irrigation flow duration curves, 1‐, 7‐, and 14‐day minimum flows, and 8‐day (seasonal) and annual baseflow recession slopes, in addition to evaluating regional climate data to determine whether significant differences existed between the pre‐ and post‐irrigation periods. Our results showed significant changes in low‐flow durations in the post‐irrigation record for both gages, including a decrease by an order of magnitude for 98% exceedance flows at Spring Creek. Both gages indicated significant reductions in 1‐, 7‐, and 14‐day low flows. Eight‐day baseflow recession curves (within early summer months) and annual baseflow recession curves became significantly steeper during the post‐irrigation period for Ichawaynochaway Creek. We also found that a significant relationship existed between winter and summer minimum flows in both streams in the pre‐irrigation period which was disrupted in post‐irrigation years. Regional climate data for the study period revealed no significant changes in rainfall totals or frequency of drought; however, there was evidence for a shift in seasonal rainfall patterns. Copyright © 2011 John Wiley & Sons, Ltd.