Title: | Simulating land management options to reduce nitrate pollution in an agricultural watershed dominated by an alluvial aquifer |
Authors: | Cerro, I., I. Antiguedad, R. Srinavasan, S. Sauvage, M. Volk and J.M. Sanchez-Perez |
Year: | 2014 |
Journal: | Journal of Environmental Quality |
Volume (Issue): | 43(1) |
Pages: | 67-74 |
Article ID: | |
DOI: | 10.2134/jeq2011.0393 |
URL (non-DOI journals): | |
Model: | SWAT |
Broad Application Category: | hydrologic and pollutant |
Primary Application Category: | BMP and/or cropping system assessment |
Secondary Application Category: | nitrogen cycling/loss and transport |
Watershed Description: | 113 km^2 Alegria River, located in the Bosque region in northern Spain. |
Calibration Summary: | |
Validation Summary: | |
General Comments: | This article is part of the JEQ SWAT special section. |
Abstract: | The study area (Alegria watershed, Basque Country, Northern
Spain) considered here is influenced by an important alluvial aquifer
that plays a significant role in nitrate pollution from agricultural
land use and management practices. Nitrates are transported
primarily from the soil to the river through the alluvial aquifer. The
agricultural activity covers 75% of the watershed and is located in
a nitrate-vulnerable zone. The main objective of the study was to
find land management options for water pollution abatement by
using model systems. In a first step, the SWAT model was applied
to simulate discharge and nitrate load in stream flow at the outlet
of the catchment for the period between October 2009 and June
2011. The LOADEST program was used to estimate the daily
nitrate load from measured nitrate concentration. We achieved
satisfactory simulation results for discharge and nitrate loads at
monthly and daily time steps. The results revealed clear variations
in the seasons: higher nitrate loads were achieved for winter (20,000
kg mo−1 NO3–N), and lower nitrate loads were simulated for the
summer (<1000 kg mo-1 NO3–N) period. In a second step, the
calibrated model was used to evaluate the long-term effects of best
management practices (BMPs) for a 50-yr period by maintaining
actual agricultural practices, reducing fertilizer application by 20%,
splitting applications (same total N but applied over the growing
period), and reducing 20% of the applied fertilizer amount and
splitting the fertilizer doses. The BMPs were evaluated on the basis
of local experience and farmer interaction. Results showed that
reducing fertilizer amounts by 20% could lead to a reduction of
50% of the number of days exceeding the nitrate concentration limit
value (50 mg L-1) set by the European Water Framework Directive. |
Language: | English |
Keywords: | |