Spatiotemporal modeling of watershed nutrient transport dynamics: implications for eutrophication abatement
Yükleniyor...
Tarih
2016
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Bv
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The main objective of this study was to quantify nutrient transport dynamics of a previously ungauged, temperate watershed (145 km(2)) surrounding a shallow eutrophic lake and discern lake response to external nutrient loading, based on soil water assessment tool (SWAT) and the Organization of Economic Cooperation and Development (OECD) empirical lake models, respectively. A SWAT model was used to simulate baseline nutrient dynamics after its calibration and validation against daily tributary flow, total dissolved phosphorus (TDP), total phosphorus (TP), and nitrate (NO3) loads. On the watershed scale, median annual TDP, TP, and NO3 losses were 0.4, 1.1, and 2.0 kg ha(-1), respectively. The highest median annual TP and NO3 losses were estimated at 3.7 and 7.7 kg ha(-1) for pastureland and 1.7 and 3.8 kg ha(-1) for cropland and mixed forests, respectively. Baseflow was the major nutrient transport pathway over a wide range of precipitation events (450 to 900 mm yr(-1)). Erosion was the predominant surface process exporting P across the watershed. Critical source areas (CSAs) of TP and NO3 comprised 17% and 4% of the watershed, respectively. Annual mean TP, and mean and maximum chlorophyll content indicated a hyper-eutrophication risk for the lake. An external P load reduction by excess of 80% could be necessary to restore mesotrophy in the lake. Our results suggested that subsurface P transport should not be overlooked a priori when groundwater-dependent and extensively farmed watersheds are managed for eutrophication abatement. (C) 2016 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
Critical Source Areas, Empirical Lake Model, Phosphorus, Nitrate, Transport Pathways
Kaynak
Ecological Informatics
WoS Q Değeri
Q2
Scopus Q Değeri
Q1
Cilt
34
