Ghimire Santosh R, Schumacher Brian, Swanson Sherman, Hall Robert, Hall Eric S, Zambrana José, Johnston John M
U.S. Environmental Protection Agency, Office of Research and Development, 960 College Station Rd., Athens, GA, 30605, USA.
University of Nevada, Reno, Cooperative Extension and Department of Agriculture, Veterinary and Rangeland Sciences, 1664 N. Virginia Street, Reno, NV, 89557, USA.
J Environ Manage. 2025 Feb;375:124154. doi: 10.1016/j.jenvman.2025.124154. Epub 2025 Jan 23.
Riparian functioning condition refers to a rating and description of the current ecological status of a reach of a riparian ecosystem in consideration of its potential hydrology, vegetation, and geomorphology. Reach rating options are Proper Functioning Condition (PFC), Functional-At-Risk (FAR), Non-Functional, and apparent or monitored trends. We assessed the functioning condition of flowing riverbank areas of Back Creek located in Virginia (USA) following a PFC protocol developed by the U.S. Department of the Interior and the U.S. Department of Agriculture. The PFC protocol involves 17 qualitative assessment items that address three categories of attributes (hydrology, vegetation, and geomorphology); each is answered as "yes", "no," or "not applicable" with an explanation. We discussed key PFC items driving stream water quality contextualizing the previously modeled riparian buffer zones and ecosystem services tradeoffs in the Back Creek watershed published by U.S. Environmental Protection Agency. Using the remote sensing data in the Geographic Information System, we delineated and characterized 26 Back Creek reaches of 41.1 km length. We also analyzed the 38-year (1981-2018) daily datasets of the precipitation, surface runoff, temperature, soil moisture pattern, and vegetation types for the watershed. Then, we conducted the PFC assessments using field reconnaissance of 10 reaches, 19.3 km of the Back Creek. The field assessments concluded that 52% of the assessed length of Back Creek was in PFC, attributed to diverse vegetation, maintained channel characteristics, floodplain accessibility (where appropriate), and balanced water and sediment loading supplied by individual headwater streams to the Back Creek. 48% of the assessed length was in FAR condition due to land use changes and urban road network. This study provides an exemplar of nonpoint source (diffused pollution generated by land runoff) methodology for identifying key riparian functioning issues and assessing effectiveness of the non-point source best management practice programs.
河岸功能状况是指对河岸生态系统某一河段当前生态状况的评级和描述，需考虑其潜在的水文、植被和地貌情况。河段评级选项包括正常功能状况（PFC）、功能受胁（FAR）、无功能以及明显或监测到的趋势。我们按照美国内政部和美国农业部制定的PFC协议，评估了位于美国弗吉尼亚州的巴克溪流动河岸区域的功能状况。PFC协议涉及17个定性评估项目，涵盖三类属性（水文、植被和地貌）；每个项目的回答为“是”“否”或“不适用”并附解释。我们讨论了驱动溪流水质的关键PFC项目，将其与美国环境保护局发布的巴克溪流域先前建模的河岸缓冲带和生态系统服务权衡情况相结合。利用地理信息系统中的遥感数据，我们划定并描述了巴克溪26个河段，总长41.1公里。我们还分析了该流域38年（1981 - 2018年）的降水、地表径流、温度、土壤湿度模式和植被类型每日数据集。然后，我们对巴克溪10个河段（19.3公里）进行实地勘查，开展PFC评估。实地评估得出结论，巴克溪评估长度的52%处于PFC状态，这归因于多样的植被、保持的河道特征、洪泛区可达性（如适用）以及各源头溪流为巴克溪提供的平衡的水和泥沙负荷。由于土地利用变化和城市道路网络，评估长度的48%处于FAR状态。本研究提供了一个非点源（由土地径流产生的分散污染）方法的范例，用于识别关键河岸功能问题并评估非点源最佳管理实践方案的有效性。
