Model Library

Capabilities

• It can simulate sediment and nutrient load reductions by management practices;
• It is grid-based;
• It excels in identifying pollutant “hot spots”(Wong et al., 2008);
• It operates on an event-based framework, capable of forecasting runoff, as well as the movement of nitrogen, phosphorus, sediment, and chemical oxygen demand (COD) within small to medium-sized agricultural watersheds resulting from a single storm event (Borah et al., 2019).

Limitations

• The inability to predict peak flow accurately, even in an agricultural watershed (Najim et al., 2005);
• Inability to assess nutrient transformation and in-stream processes; thus, the model cannot simulate continuous modeling (Adu and Kumarasamy, 2018);
• Preparation of input data files and interpretation of simulation results may become overwhelming and time-consuming with increase in cell numbers (Tim and Jolly, 1994; Tim et al., 1995; Tim, 1996; Liao and Tim, 1997; Mankin et al., 2002);
• AGNPS model does not have the capability to predict runoff generating areas (Panjabi, 2019).

Inputs

Topography, LULC data, Soil data (layering, organic carbon, sand-silt-clay), Meteorological data, Storm-specific data, Hydrological data, Water quality data, Management data (tillage-fertilization, area-volume of water bodies, Point sources, Tillage drainage, Water source/demand).

Outputs

Simulation results of parameters: Surface flow, sediment, nutrients (N, P, COD, pesticides, and organic carbon).

References

Thilagam VK, Manivannan S, Khola OPS. Deriving land management practices for reduced nutrient movement from an agricultural watershed using the AGNPS model. Sustainability, 2023, 15:4001. https://doi.org/10.3390/su15054001

Zhang B, Shrestha NK, Rudra R, Shukla R, Daggupati P, Goel PK, Dickinson WT, Allataifeh N. Threshold storm approach for locating phosphorus problem areas: An application in three agricultural watersheds in the Canadian Lake Erie basin. Journal of Great Lakes Research, 2020, 46(1):132–143, ISSN 0380-1330. https://doi.org/10.1016/j.jglr.2019.12.003

Objectives

To assess the effect of nutrient management practices and the land-use system on nutrient enrichment in water resources of a hilly watershed using the AGNPS model.
To derive land management practices to reduce nutrient movement from the agricultural watershed using the AGNPS model.
To evaluate the impact of fertilizer application on the nutrient movement from agricultural lands through simulation scenarios with varying fertilizer doses.
The objectives of the study are to propose and define the concept of a threshold storm, evaluate this approach using models in three agricultural watersheds, and identify critical source areas of phosphorus to aid in designing cost-effective best management practices.