AGNPS: A nonpoint-source pollution model for evaluating agricultural watersheds

TLDR

The study presents a computer model for analyzing nonpoint‑source pollution and prioritizing water‑quality issues in rural watersheds. The model is event‑based, using 0.4–16 ha geographic cells to represent upland and channel conditions, simulating runoff, sediment, nutrients, and COD transport, and routing them to the watershed outlet. The model enables examination of flow throughout the watershed and identifies and prioritizes upland sources that could be targeted for efficient water‑quality improvement.

Abstract

ABSTRACT: A computer model to analyze nonprofit-source pollution and to prioritize potential water quality problems in rural areas is described. The event-based model uses geographic cells of data units at resolutions of 0.4 to 16 ha to represent upland and channel conditions. Within the framework of the cells, runoff characteristics and transport processes of sediment, nutrients, and chemical oxygen demand are simulated for each cell and routed to the outlet. This permits the flow at any point in the watershed to be examined. Upland sources contributing to a potential problem can be identified and prioritized where remedial measures could be initiated to improve water quality most efficiently.