United Slates Environmental Protection Agency Office of Water (WH 550G) EPA 570/9-91-036N January 1992 Best Management Practices For Protecting Ground Water Facilities Using Special Drainage Wells (Class ¥ Well BMP Fact Sheet Number 5) EPA recognizes that drainage wall disposal practices may pose a threat of contamination to Underground Sources of Drinking Water. These wells, while necessary, may need additional attention to minimize their impact on ground water resources. For mors information, contact the person names below. • Filter and treat pool water regularly to remove microbial and chemical contaminants • Line well bottoms with filter fabric where practical • Ensure that well outlets are at least two feet above high-water level to allow for adequate natural filtration • Use appropriate cleaners (e.g., biodegradable) ° Ensure that the above-ground portion of the overflow system is totally enclosed to prevent airborne and surface contamination Landslide Control Drainage Wells • Test routinely for contaminants • Extend vertical wells so that they drain into trenches or horizontal wells « Treat water at horizontal well outlets (direct water from multiple well outlets to centralized treatment such as a settling pond) Closure of Landslide Control Drainage Wells and ' Alternative Landslide Prevention Techniques All Special Drainage Wells • Apply for a permit to continue injecting if so directed Wells PMaMeWaler Tank Overflow Wells ¦ Install retaining walls around landslide area • Unload material from top of landslide area • Buttress bottom of landslide area by adding material • Fill with grouting and cap well ------- Municipal DewaterlnaWells • Check land uses in area before dewatering to help identity contaminants that may be in extracted ground water • Treat extracted water before reinjecting where necessary; for example, install a treatment device at dewatering well openings Note: These BMPs are adapted from a May 1991 EPA report titled, "Class V Well BMP Guidance - Phase I and Phase II," and have been modified in response to comments by EPA Regions, For a copy of the EPA report, please contact the Underground Injection Control Branch ot the Office of Ground Water and Drinking Water, U S EPA. For further information contact: ------- |