Data from: Investigation of Stormwater Runoff at the Sleepy Hollow Neighborhood, Fort Irwin, California

In arid and semi-arid region, low precipitation can lead to reliance on groundwater for our needs. A study was conducted in cooperation with the Environmental Protection Agency and the Agriculture Research Service (ARS) in Riverside, California in the residential area the Ft. Irwin Army base in southern California. The base only receives an average annual precipitation of 4 inches. An objective of the study was to see if enough runoff was generated in the residential neighborhood to enhance the recharge of groundwater. Rainfall, runoff, and characteristics of the watershed draining to a detention that in turn, drains into a dry well that is designed to enhance deep infiltration to groundwater. Three storm events with all instrumentation working properly were observed. The respective percentage of the rainfall that runoff was 9, 5 and 11 percent. These events were modeled with the uncalibrated ARS KINEROS2 watershed model using urban overland flow model elements. For EV1 and EV3 the precent difference between simulated and observed runoff was -9.7 and -14.1 percent, respectively. For EV2 the model overpredicted the observed runoff by 80.2 percent. However, EV2 was a very small runoff event where the measuring resolution of the rain gauges (0.25 mm) translated into 57% of the observed volume. To generate substantial volumes of runoff for groundwater recharge would require a much larger developed area than the one studied herein. In addition, a larger sample size of events, with all instruments in proper working order, would lend greater weight to overall character of rainfall-runoff processes at Ft. Irwin.

在干旱与半干旱地区，降水量（precipitation）匮乏会导致人们对地下水（groundwater）的依赖加剧，以满足日常需求。本研究由美国环境保护署（Environmental Protection Agency）与农业研究服务局（Agriculture Research Service, ARS）合作开展，研究区域位于加利福尼亚州河滨市及南加州欧文堡陆军基地（Ft. Irwin Army base）的住宅区。该基地年均降水量仅为4英寸。研究的核心目标是验证住宅区是否能产生足量径流（runoff），以促进地下水补给（groundwater recharge）。研究监测了降雨量、径流量，以及汇水区域（watershed）的特征——该区域的水流先汇入滞留池（detention basin），再经干井（dry well）排出，而干井的设计旨在促进水流向地下水的深层入渗（deep infiltration）。观测期间共记录到三次仪器运行正常的暴雨事件。这三次事件中，径流占降雨量的比例分别为9%、5%和11%。研究人员采用未校准的ARS KINEROS2流域模型，结合城市坡面流模型组件，对上述事件进行了模拟。对于事件EV1和EV3，模拟径流与观测径流的百分比差异分别为-9.7%和-14.1%；而事件EV2中，模型对观测径流的预测值偏高80.2%。然而，EV2是一次极小径流事件，雨量计（rain gauges）的测量分辨率（0.25毫米）导致其记录的径流量占观测总量的57%。若要产生足以补给地下水的大量径流，所需的开发区域面积需远大于本研究的观测范围。此外，扩大仪器运行正常的事件样本量，将能更准确地揭示欧文堡地区降雨-径流过程（rainfall-runoff processes）的整体特征。