N. LaJan Barnes, Thomas E. Durborow, Stuart Z. Cohen, Amelia J. Svrjcek, Michael J. O'Connor "Proceedings of the Focus Conference on Eastern Regional Ground Water Issues. NGWA, 1993. Ground Water Management Book 16 of the Series.
The State of Vermont has comprehensive regulations controlling pesticide use on golf courses. The regulations apply to every golf course in the State -- new and old -- and require the submission of a proposed turf management program that includes, among other things, a pesticide application schedule. Ground water and surface water dilution analyses are required for the pesticides not included on a "prescreened list." These conservative dilution calculations are less resource intensive than computer simulation modeling.
Data on pesticide mobility, persistence, human toxicity, and aquatic toxicity are collected and evaluated. Health Advisory Levels (HALs) and water quality criteria usually must be calculated due to lack of government standards.
Parallel to these activities, local hydrogeology and surface hydrology are characterized to an extent slightly more intensive than the reconnaissance level. Staff walk the site, sample the soils, observe surface drainage patterns, and look for surface features that would be indicative of subsurface geology. The soils are analyzed for drainage and pesticide retention characteristics. Well logs are obtained and evaluated. Regional hydrogeology reports are reviewed. This information is combined with rainfall and irrigation data to estimate annual recharge rates as well as to describe the hydrogeologic setting. In addition, low flow exceedance data are obtained or estimated for adjacent streams.
At this screening level of assessment, pesticide losses are conservatively estimated based on a literature review and without explicit consideration of site-specific attenuation processes. A fraction of the pesticide -- typically 10% -- is "mixed" into the top 10 ft of the aquifer. Predicted concentrations are compared with HALs. A different fraction -- typically 5% -- is "washed off" in a 10-yr return, 24-hr storm event. Runoff volumes are calculated using the runoff curve number method. Runoff is "diluted" into receiving streams and compared with water quality criteria.
This approach has been applied successfully to four Vermont golf courses. Mitigation measures requiring selective pesticide limitations were required to at least some extent for each golf course.