Topic
Nonpoint source pollution
About: Nonpoint source pollution is a research topic. Over the lifetime, 5706 publications have been published within this topic receiving 117043 citations.
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01 Jan 1982
397 citations
TL;DR: In this article, a general model for estimating monthly nitrogen and phosphorus fluxes in stream flow is proposed, with a simple mathematical structure, describing a wide range of rural and urban nonpoint sources, and couple surface runoff and ground water discharge.
Abstract: Loading functions are proposed as a general model for estimating monthly nitrogen and phosphorus fluxes in stream flow The functions have a simple mathematical structure, describe a wide range of rural and urban nonpoint sources, and couple surface runoff and ground water discharge Rural runoff loads are computed from daily runoff and erosion and monthly sediment yield calculations Urban runoff loads are based on daily nutrient accumulation rates and exponential wash off functions Ground water discharge is determined by lumped parameter unsaturated and saturated zone soil moisture balances Default values for model chemical parameters were estimated from literature values Validation studies over a three-year period for an 850 km2 watershed showed that the loading functions explained at least 90 percent of the observed monthly variation in dissolved and total nitrogen and phosphorus fluxes in stream flow Errors in model predictions of mean monthly fluxes were: dissolved phosphorus - 4 percent; total phosphorus - 2 percent; dissolved nitrogen - 18 percent; and total nitrogen - 28 percent These results were obtained without model calibration
390 citations
TL;DR: In this paper, a nutrient flu assessment for phosphorus and nitrogen is conducted through an extensive literature review of nutrient export studies, and the coefficients are screened according to sampling design criteria and compiled according to land use.
Abstract: Lake and watershed management strategies and recent environmental legislation dictate that nonpoht nutrient sources associated with storm water runoff must be assessed. Accordingly, a nutrient flu assessment for phosphorus and nitrogen is conducted through an extensive literature review of nutrient export studies. These studies are reevaluated. The nutrient export coefficients are screened according to sampling design criteria and compiled according to land use. The ecological mechanisms within each land use influencing the magnitude of nutrient flux are also discussed
381 citations
TL;DR: In this article, a first-order model was fitted to the data giving an average removal constant, k, of 214 m per year, which increased with increasing hydraulic load due to the simultaneous increase particle settling velocity.
379 citations
TL;DR: In this article, a basin-scale water quality model, SWAT (Soil and Water Assessment Tool), was integrated with a GIS to extract input data for modeling a basin, which was applied to simulated a 114 sq. km upper portion of the Seco Creek Basin by subdividing it into 37 subbasins.
Abstract: Geographic Information Systems (GIS) have been successfully integrated with distributed parameter, single-event, water quality models such as AGNPS (AGricultural NonPoint Source) and ANSWERS (Areal Nonpoint Source Watershed Environmental Response Simulation). These linkages proved to be an effective way to collect, manipulate, visualize, and analyze the input and output date of water quality models. However, for continuous-time, basin large-scale water quality models, collecting and manipulating the input data are more time-consuming and cumbersome due to the method of disaggregation (subdivisions are based on topographic boundaries). SWAT (Soil and Water Assessment Tool), a basin-scale water quality model, was integrated with a GIS to extract input data for modeling a basin. This paper discusses the detailed development of the integration of the SWAT water quality model with GRASS (Geographic Resources Analysis Support System) GIS, along with an application and advantages. The integrated system was applied to simulated a 114 sq. km upper portion of the Seco Creek Basin by subdividing it into 37 subbasins. The average monthly predicted streamflw is in agreement with measured monthly streamflw values.
361 citations