School of Geographic and Environmental Sciences, Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin, 300387, China.
Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, 74078, USA.
Environ Manage. 2018 Jun;61(6):954-967. doi: 10.1007/s00267-018-1019-4. Epub 2018 Mar 9.
Nutrient discharge into peri-urban streams and reservoirs constitutes a significant pressure on environmental management, but quantitative assessment of non-point source pollution under climate variability in fast changing peri-urban watersheds is challenging. Soil and Water Assessment Tool (SWAT) was used to simulate water budget and nutrient loads for landscape patterns representing a 30-year progression of urbanization in a peri-urban watershed near Tianjin metropolis, China. A suite of landscape pattern indices was related to nitrogen (N) and phosphorous (P) loads under dry and wet climate using CANOCO redundancy analysis. The calibrated SWAT model was adequate to simulate runoff and nutrient loads for this peri-urban watershed, with Nash-Sutcliffe coefficient (NSE) and coefficient of determination (R) > 0.70 and percentage bias (PBIAS) between -7 and +18 for calibration and validation periods. With the progression of urbanization, forest remained the main "sink" landscape while cultivated and urban lands remained the main "source" landscapes with the role of orchard and grassland being uncertain and changing with time. Compared to 1984, the landscape use pattern in 2013 increased nutrient discharge by 10%. Nutrient loads modelled under wet climate were 3-4 times higher than that under dry climate for the same landscape pattern. Results indicate that climate change could impose a far greater impact on runoff and nutrient discharge in a peri-urban watershed than landscape pattern change.
营养物质排入城市周边溪流和水库对环境管理构成了重大压力，但在快速变化的城市周边流域中，定量评估气候变异性下的非点源污染具有挑战性。本研究使用土壤和水评估工具（SWAT）模拟了代表中国天津大都市周边流域 30 年城市化进程的景观格局的水预算和养分负荷。使用 CANOCO 冗余分析，将一系列景观格局指数与氮（N）和磷（P）负荷相关联，以干湿气候条件为基础。校准后的 SWAT 模型能够很好地模拟该城市周边流域的径流量和养分负荷，校准和验证期的纳什-苏特克里夫系数（NSE）和决定系数（R）均大于 0.70，百分比偏差（PBIAS）在-7 到+18 之间。随着城市化的发展，森林仍然是主要的“汇”景观，而耕地和城市土地仍然是主要的“源”景观，果园和草地的作用不确定，并且随着时间的推移而变化。与 1984 年相比，2013 年的景观利用格局增加了 10%的养分排放量。对于相同的景观格局，湿润气候下模拟的养分负荷是干旱气候下的 3-4 倍。结果表明，气候变化对城市周边流域的径流量和养分排放的影响可能比景观格局变化大得多。
