Hopkins Kristina G, Welles Jacqueline S, Pindilli Emily J, Noe Gregory B, Claggett Peter R, Ahmed Labeeb, Metes Marina J
U.S. Geological Survey, South Atlantic Water Science Center, Raleigh, NC, USA.
Contractor to the U.S. Geological Survey, Charleston, SC, USA.
J Environ Manage. 2023 Nov 1;345:118747. doi: 10.1016/j.jenvman.2023.118747. Epub 2023 Aug 19.
Floodplains provide critical ecosystem services to people by regulating floodwaters and retaining sediments and nutrients. Geospatial analyses, field data collection, and modeling were integrated to quantify a portfolio of services that floodplains provide to downstream communities within the Chesapeake Bay and Delaware River watersheds. The portfolio of services included floodplain sediment and nutrient retention and flood regulation. Sediment and nutrient retention were quantified and valued for all non-tidal wadable streams in the Chesapeake Bay and Delaware River watersheds. Predicted nitrogen fluxes from measurements of streambanks and floodplain geomorphic changes were summarized at various scales (river basin, state, and county) and valued using a benefits transfer approach. Floodplain flood regulation services were assessed through a pilot study focused on the Schuylkill River watershed in the Delaware River watershed. Geospatial analysis and published flood frequency estimates were used to assess baseline and counterfactual (i.e., floodplain storage removed) scenarios. Flood regulation was valued using the Federal Emergency Management Agency's Hazus model to compare differences in structural damage to private residences under baseline and counterfactual scenarios. The estimated value of floodplain sediment and nutrient retention was $223 million United States dollars (USD) per year in the Chesapeake Bay watershed and $38 million USD per year in the Delaware River watershed. Sediment and nutrient retention benefits were offset by a streambank erosion cost of $123 million and $14 million USD annually in the Chesapeake and Delaware watersheds, respectively. In the Schuylkill River watershed floodplain flood regulation was valued at $860,000 USD per year, with an additional $7.2 million USD annually provided through floodplain sediment and nutrient retention. Together this portfolio of floodplain ecosystem services indicates that floodplains provide substantial benefits to people by trapping nutrients and storing floodwaters.
洪泛平原通过调节洪水以及滞留沉积物和养分，为人类提供关键的生态系统服务。综合运用地理空间分析、实地数据收集和建模方法，对切萨皮克湾和特拉华河流域内洪泛平原为下游社区提供的一系列服务进行量化。这些服务包括洪泛平原沉积物和养分滞留以及洪水调节。对切萨皮克湾和特拉华河流域所有非潮汐可涉水溪流的沉积物和养分滞留情况进行了量化和估值。通过对河岸和洪泛平原地貌变化的测量得出的预测氮通量，在不同尺度（流域、州和县）上进行了汇总，并采用效益转移方法进行估值。通过一项针对特拉华河流域斯库尔基尔河流域的试点研究，对洪泛平原的洪水调节服务进行了评估。利用地理空间分析和已公布的洪水频率估计值，评估了基准情景和反事实情景（即去除洪泛平原蓄水功能的情景）。使用联邦紧急事务管理局的Hazus模型对洪水调节进行估值，以比较基准情景和反事实情景下私人住宅结构损坏的差异。切萨皮克湾流域洪泛平原沉积物和养分滞留的估计价值为每年2.23亿美元，特拉华河流域为每年3800万美元。切萨皮克和特拉华流域的河岸侵蚀成本分别为每年1.23亿美元和1400万美元，抵消了沉积物和养分滞留带来的效益。在斯库尔基尔河流域，洪泛平原洪水调节的价值为每年86万美元，通过洪泛平原沉积物和养分滞留每年还可额外提供720万美元。洪泛平原生态系统服务的这一系列价值表明，洪泛平原通过截留养分和储存洪水，为人类带来了巨大益处。
