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.

Study on multi-scale distributed modeling of flow, sediment, and transport processes for nitrogen and phosphorus in Lianshui basin, Jiangxi province

Abstract: Agricultural Non-point Sources Pollution is one of a leading cause of water quality problems in southeast of China. It is an effective approach for ANSP control that modeling nitrogen and phosphorus transfer in a basin system by using mathematic models based on geographic processes. In this paper, the multi-scale integrating distributed modeling frame was designed based on different spatial discretization units by using the (Soil and Water Assessment Tools) model and field-scale APEX (Agricultural Policy/Environmental eXtender) model. A large number basic geographic data were collected and parameterization in Lianshui basin, Xingguo County, Jiangxi province. The mutil-scale distributed computer simulation for water yield, sediment yield of 1991 to 2005 and the transport processes for nitrogen and phosphors of Oct, 2002 to Oct, 2004 were carried out in the study area of Lianshui basin. The average simulation accuracy, coefficient of efficiency (E NS ) and deterministic coefficient (R2) were 89.4%, 0.88 and 0.89 for annual water yield and 75.1%, 0.70 and 0.76 for annual sediment yield, respectively. The simulation results indicate that the integrating modeling has an acceptable performance in prediction of water yield and sediment loading in Lianshui basin. The predicted monthly nitrogen and phosphorus loading have larger amount difference than measured although both the predicted and measured have almost accordant trends. The reasons that caused bad accuracy for nutrient simulation should be further studied. The method of integration for multi-scale models can take the advantages effectively for each model which can be applied in quantitative study on the geographical processes in different levels.

A modelling study of the human impact on soil erosion processes within an agricultural watershed

Abstract: An increased emphasis has been placed on improving and maintaining the quality of terrestrial water resources in the last two decades. This is especially true in the case of agricultural watersheds for which many intensive studies are focused on the information relating to the effects of land use, management and conservation practices or in structures on the quality and quantity of water. In this context, the authors introduced some major improvements to a physically based hydrological and soil erosion model, namely ANSWERS (Areal Nonpoint Source Watershed Environment Response Simulation). The modifications takes into account some human effects such as structural entities (roads, hedgerows) and linear shapes (tillages) within the catchment. Moreover, this improved model has been completely incorporated in a raster Geographical Information System (GIS) for simplifying the use of remotely sensed data and auxiliary data (i.e., hydrological and physical properties of the soil surfaces). Simulations conducted on an experimental agricultural watershed in Springvale (USA) for different patterns of agricultural planning stressed the importance of human influences on dynamic hydrological processes.

Evaluating and monitoring method for Northeast intensive corn monoculture farmland non-point source pollution

Abstract: The invention relates to an evaluating and monitoring method for Northeast intensive corn monoculture farmland non-point source pollution The evaluating and monitoring indexes of farmland non-point source pollution are soil mass nitrate leaching amount and ammonia volatilization amount, and for the first time, the functional relation is set up between corn monoculture farmland soil residual nitrate nitrogen and soil nitrate leaching amount or soil ammonia volatilization amount on the scale of Northeast intensive agricultural areas through a model simulating method The evaluating and monitoring method for Northeast intensive corn monoculture farmland non-point source pollution is capable of comprehensively reflecting comprehensive effects such as annual rainfall, crop growth, soil nitrate leaching and soil ammonia volatilization, and compared with modern farmland monitoring technology of actually measuring soil leaching and ammonia volatilization, the method provides accurate and easy-to-measure parameters and algorithm which can comprehensively evaluate soil mass nitrate leaching amount and ammonia volatilization amount of Northeast intensive corn soil

Land use change detection with LANDSAT-2 data for monitoring and predicting regional water quality degradation

Abstract: The author has identified the following significant results. Comparison between LANDSAT 1 and 2 imagery of Arkansas provided evidence of significant land use changes during the 1972-75 time period. Analysis of Arkansas historical water quality information has shown conclusively that whereas point source pollution generally can be detected by use of water quality data collected by state and federal agencies, sampling methodologies for nonpoint source contamination attributable to surface runoff are totally inadequate. The expensive undertaking of monitoring all nonpoint sources for numerous watersheds can be lessened by implementing LANDSAT change detection analyses.