Abstract
A model was developed for predicting the long term discharge of chemicals applied to golf links. The model consisted of two components. The hydrological component was based on a model with a series of non-linear tanks, and simulated flow through the basin with input of daily precipitation. The chemical component calculated the amount of chemicals discharged as a function of the amount of chemicals applied, the amount retained in the soil, and the discharge from the soil. It was assumed that chemicals that moved into runoff water were discharged into the regulating pondages and was partialy degraded before entering to the stream. Simazine [2-chloro-4, 6-bis(ethylamino)-1, 3, 5-triazine], which is one of the herbicides widely used in Japan was determined. The experimental basin included the golf links (D golf links) and the neighboring upstream forested basin. The daily discharges of Simazine calculated on a daily basis for two years, were consistent with the range of values determined by direct measurements. It was estimated that increasing of the capacity of regulating pondage was effective to reduce the discharge of the herbicide. Results from the simulations using precipitation data for 6 years suggest that the discharge of the herbicide was strongly affected by sequence, amount, and intensity of individual rainfall events and that the annual losses of the herbicide varied from 2.8% to 7.9%.
