Degasperi Curtis L, Berge Hans B, Whiting Kelly R, Burkey Jeff J, Cassin Jan L, Fuerstenberg Robert R
J Am Water Resour Assoc. 2009 Apr;45(2):512-533. doi: 10.1111/j.1752-1688.2009.00306.x.
We used a retrospective approach to identify hydrologic metrics with the greatest potential for ecological relevance for use as resource management tools (i.e., hydrologic indicators) in rapidly urbanizing basins of the Puget Lowland. We proposed four criteria for identifying useful hydrologic indicators: (1) sensitive to urbanization consistent with expected hydrologic response, (2) demonstrate statistically significant trends in urbanizing basins (and not in undeveloped basins), (3) be correlated with measures of biological response to urbanization, and (4) be relatively insensitive to potentially confounding variables like basin area. Data utilized in the analysis included gauged flow and benthic macroinvertebrate data collected at 16 locations in 11 King County stream basins. Fifteen hydrologic metrics were calculated from daily average flow data and the Pacific Northwest Benthic Index of Biological Integrity (B-IBI) was used to represent the gradient of response of stream macroinvertebrates to urbanization. Urbanization was represented by percent Total Impervious Area (%TIA) and percent urban land cover (%Urban). We found eight hydrologic metrics that were significantly correlated with B-IBI scores (Low Pulse Count and Duration; High Pulse Count, Duration, and Range; Flow Reversals, T(Qmean), and R-B Index). Although there appeared to be a great deal of redundancy among these metrics with respect to their response to urbanization, only two of the metrics tested - High Pulse Count and High Pulse Range - best met all four criteria we established for selecting hydrologic indicators. The increase in these high pulse metrics with respect to urbanization is the result of an increase in winter high pulses and the occurrence of high pulse events during summer (increasing the frequency and range of high pulses), when practically none would have occurred prior to development. We performed an initial evaluation of the usefulness of our hydrologic indicators by calculating and comparing hydrologic metrics derived from continuous hydrologic simulations of selected basin management alternatives for Miller Creek, one of the most highly urbanized basins used in our study. We found that the preferred basin management alternative appeared to be effective in restoring some flow metrics close to simulated fully forested conditions (e.g., T(Qmean)), but less effective in restoring other metrics such as High Pulse Count and Range. If future research continues to support our hypothesis that the flow regime, particularly High Pulse Count and Range, is an important control of biotic integrity in Puget Lowland streams, it would have significant implications for stormwater management.
我们采用回顾性方法，在普吉特低地快速城市化流域中，识别具有最大生态相关性潜力的水文指标，以用作资源管理工具（即水文指标）。我们提出了四项识别有用水文指标的标准：（1）对城市化敏感，符合预期的水文响应；（2）在城市化流域呈现出统计上显著的趋势（而在未开发流域则没有）；（3）与城市化生物响应的测量指标相关；（4）对诸如流域面积等潜在混杂变量相对不敏感。分析中使用的数据包括在金县11个溪流流域的16个地点收集的实测流量和底栖大型无脊椎动物数据。根据日平均流量数据计算了15个水文指标，并使用太平洋西北地区生物完整性底栖指数（B-IBI）来表示溪流大型无脊椎动物对城市化的响应梯度。城市化用总不透水面积百分比（%TIA）和城市土地覆盖百分比（%Urban）来表示。我们发现有8个水文指标与B-IBI得分显著相关（低脉冲计数和持续时间；高脉冲计数、持续时间和范围；流量逆转、T（Qmean）和R-B指数）。尽管这些指标在对城市化的响应方面似乎存在大量冗余，但测试的指标中只有两个——高脉冲计数和高脉冲范围——最符合我们为选择水文指标制定的所有四项标准。这些高脉冲指标随着城市化的增加是冬季高脉冲增加以及夏季出现高脉冲事件（增加高脉冲的频率和范围）的结果，而在开发之前实际上几乎不会出现这种情况。我们通过计算和比较从我们研究中使用的城市化程度最高的流域之一米勒溪的选定流域管理替代方案的连续水文模拟中得出的水文指标，对我们的水文指标的有用性进行了初步评估。我们发现，首选的流域管理替代方案似乎有效地恢复了一些流量指标，使其接近模拟的完全森林覆盖条件（例如，T（Qmean）），但在恢复其他指标（如高脉冲计数和范围）方面效果较差。如果未来的研究继续支持我们的假设，即水流状况，特别是高脉冲计数和范围，是普吉特低地溪流生物完整性的重要控制因素，那么这将对雨水管理产生重大影响。
