SWAT-A Semi-empirical Model to Predict Concentrations of Pesticides Entering Surface Waters from Agricultural Land
✍ Scribed by Brown, Colin D.; Hollis, John M.
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 846 KB
- Volume
- 47
- Category
- Article
- ISSN
- 1526-498X
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✦ Synopsis
A semi-empirical model called SWAT has been developed to predict concentrations of agriculturally applied pesticides moving to surface waters, an aspect which is not well described by current models for pesticide fate. The model is based upon a direct hydrological link established between soil type and the amount of water moving rapidly to streams in response to rainfall. Attenuation factors describe the decrease in concentrations of pesticide between field application and loss in water moving from the site into surface waters. Evaluation of model predictions against available field data from three sites and four soil types in England shows that SWAT is capable of predicting the transient peak concentrations of a wide range of pesticides during rapid water movement to streams in response to rainfall. Predicted concentrations were too great when rainfall initiated water movement to streams very soon after pesticide application, particularly for the more mobile pesticides, and some predictions for pesticides sorbed very strongly to soil were relatively poor. Almost all of the predicted concentrations were within one order of magnitude of measured values.