Lawn Irrigation Contributions to Semi-Arid Urban Baseflow Based on Water-Stable Isotopes
Lawn Irrigation Contributions to Semi-Arid Urban Baseflow Based on Water-Stable Isotopes
复制标题
DOI：
10.1029/2020wr028777
复制
发表时间：
2021-08-01
影响因子：
5.4
通讯作者：
Jefferson, Anne J.
中科院分区：
文献类型：
--
作者：
Fillo, Noelle K.;Bhaskar, Aditi S.;Jefferson, Anne J.
在半干旱城市，城市化可导致夏季基流升高。额外水的一个潜在来源是草坪灌溉。我们试图量化草坪灌溉的贡献，夏季基流在丹佛，科罗拉多，美国使用水稳定同位素（δ O-18和δ H-2）分析地表水，自来水和降水。如果草坪灌溉显着贡献基流，我们预测丹佛的城市溪流的同位素组成将更接近当地自来水比降水或径流从附近的草原流域。由于当地供水商从高海拔地区进口水源水，我们预计自来水将与众不同。13条城市溪流和2条草地溪流被选中进行采样。这些溪流都没有高海拔的水源或废水排放，草地溪流也没有得到灌溉。从五个供水服务区采集自来水样品。2019年夏季，草原溪流的流量为60%，而城市溪流的流量为90%-100%。同位素混合分析使用自来水和降水端元在两个星期的前期估计，自来水贡献65% +/- 10%-93% +/- 3%，平均80%的城市基流在夏末的特定日子。在考虑基础设施渗漏的贡献后，我们估计草坪灌溉回流占分析基流的32% +/- 10%-82% +/- 21%。量化草坪灌溉对城市基流的贡献为了解草坪灌溉效率的变化如何影响丹佛大都市区的产水量提供了基础。
In semi-arid cities, urbanization can lead to elevated baseflow during summer months. One potential source for additional water is lawn irrigation. We sought to quantify lawn irrigation contributions to summertime baseflow in Denver, Colorado, USA using water-stable isotope (delta O-18 and delta H-2) analysis of surface water, tap water, and precipitation. If lawn irrigation contributed significantly to baseflow, we predicted the isotopic composition of Denver's urban streams would more closely resemble local tap water than precipitation or streamflow from nearby grassland watersheds. We expected tap water to be distinctive due to local water providers importing source water from high elevations. Thirteen urban streams and two grassland streams were selected for sampling. None of the streams had high-elevation headwaters or wastewater effluent, and the grassland streams did not receive irrigation. Tap water was sampled from five water service areas. The grassland streams flowed for 60% of summer 2019 while urban streams flowed for 90%-100% of the summer. An isotope mixing analysis using tap and precipitation end-members over a two week antecedent period estimated that tap water contributed 65% +/- 10%-93% +/- 3% with a mean of 80% of urban baseflow on specific days in late summer. After taking contributions from infrastructure leakage into account, we estimated that lawn irrigation return flows made up 32% +/- 10%-82% +/- 21% of analyzed baseflow. Quantifying lawn irrigation contributions to urban baseflow provides a basis for understanding how changes to lawn irrigation efficiency would affect water yield in the Denver metropolitan area.