Janke Benjamin D, Finlay Jacques C, Taguchi Vinicius J, Gulliver John S
Dept. of Ecology, Evolution, and Behavior, University of Minnesota, 1986 Upper Buford Circle, St. Paul 55108, MN, USA; St. Anthony Falls Laboratory, Dept. of Civil, Environmental, and Geo-Engineering, University of Minnesota, 2 Third Ave SE, Minneapolis 55414, MN, USA.
Dept. of Ecology, Evolution, and Behavior, University of Minnesota, 1986 Upper Buford Circle, St. Paul 55108, MN, USA; St. Anthony Falls Laboratory, Dept. of Civil, Environmental, and Geo-Engineering, University of Minnesota, 2 Third Ave SE, Minneapolis 55414, MN, USA.
Sci Total Environ. 2022 Jun 1;823:153722. doi: 10.1016/j.scitotenv.2022.153722. Epub 2022 Feb 9.
Managed stormwater ponds are abundant in urban landscapes in much of the world, performing vital but under-studied functions for attenuation of urban runoff and nutrient pollution. Water quality improvements are widely assumed to arise from settling of nutrients and other contaminants bound to particulates, with less consideration of hydrological and biogeochemical processes. To inform improved management of ponds for nutrient retention, we studied three mature urban detention ponds in the Twin Cities, MN, USA using continuous monitoring of pond hydrology and concentrations of nitrogen and phosphorus, coupled with periodic measurement of physiochemical conditions in the ponds. Across the three sites, annual nutrient retention was high for both nitrogen (>58%) and phosphorus (>48%) despite expectations of poor performance for phosphorus due to old age and internal loading linked to hypolimnetic anoxia. Both annual and event-scale analyses suggested strong hydrologic controls on nutrient retention, with retention for individual storm events strongly regulated by antecedent pond storage capacity. Events with net nutrient export occurred primarily due to low volume retention rather than relatively high outflow concentrations. Together these results suggest that understanding and improving pond hydrologic function is crucial to improving managed stormwater pond performance for meeting downstream water quality goals.
在世界上许多地方的城市景观中，人工管理的雨水塘随处可见，它们在减少城市径流和营养物污染方面发挥着至关重要但却研究不足的作用。人们普遍认为水质的改善源于与颗粒物结合的营养物和其他污染物的沉降，而对水文和生物地球化学过程的考虑较少。为了为改善池塘营养物截留管理提供依据，我们对美国明尼苏达州双子城的三个成熟城市滞洪塘进行了研究，连续监测池塘水文以及氮和磷的浓度，并定期测量池塘中的理化条件。在这三个地点，尽管由于池塘老化和与下层滞水缺氧相关的内部负荷，预计磷的截留效果不佳，但氮（>58%）和磷（>48%）的年营养物截留率都很高。年度和事件尺度的分析都表明，水文对营养物截留有很强的控制作用，单个暴雨事件的截留受前期池塘蓄水量的强烈调节。营养物净输出的事件主要是由于蓄水量低，而不是流出浓度相对较高。这些结果共同表明，了解和改善池塘水文功能对于提高人工管理雨水塘实现下游水质目标的性能至关重要。
