Influence of land use on nutrients transport using SWAT model: Study case of Ardila Watershed

Abstract

The impacts of agricultural activities in the environment are due to the lixiviation and soil erosion. Pollution of agricultural origin presents diffuse characteristics reaching the environment through surface runoff, lateral flow and groundwater flow. Models can contribute to understand the sources and the processes responsible for pollution, also identifying areas of concern. To evaluate the status of river water bodies is important to consider management options, being water quality models useful tools. The implementation of Ardila Subsistem primary irrigation network will change the actual land use (conversion of traditional olive grove to intensive irrigated systems) with important impacts in water quality. The objective of this study is to assess the effect of several land use changes, namely the nutrient loads of different crop management scenarios using the Soil and Water Assessment Tool (SWAT). For this purpose different simulation were done on Ardila Watershed, paying attention on the different nutrients loads coupled to water flows: surface, lateral and groundwater flow. This knowledge will contribute to understand the processes that can increase pollution by the change in vegetation cover. The results showed that in general the major contribution of phosporous (98%) is related to runoff and the major contribution of nitrogen (70%) is related to groundwater flow. Although, with implementation of Ardila Subsistem primary irrigation network the total Nitrogen load per year could increase 90%, with major contribution from runoff.