WorldWide Drilling Resource®

Environmental Monitoring by Thomas Kwader, Ph.D., P.G. WorldWide Drilling Resource ® Hydrogeologist Maintaining Stormwater Ponds - An Important Task for the Protection of Our Groundwater We have seen the routine; a developer wants to build a residential or commercial project, but must retain all the stormwater on-site since the present stormwater system cannot handle any more “new development” stormwater run-off. Stormwater ponds generally: 1) Require a proportionally large footprint of land, usually 5-20% of the project area. 2) Water runs downhill and ponds need to be located at lower elevations of the project unless pumps are utilized to move water at a sufficient rate to prevent flooding. Pumps require constant maintenance - gravity is usually the preferred choice. 3) Ponds create a wet environment which favors dense growth of plants that, if left alone, will cause the ponds to hydro- logically fail, thus requiring constant cleaning and maintenance. If neglected, vegetation will plug the horizontal and vertical flow of water, rendering the pond useless and requiring significant rehabilitation and restoration. 4) Require an annual budget to maintain the effectiveness and operation of the pond. Ponds can provide a significant source of beneficial groundwater recharge to the local underlying aquifers as long as the permeability of the pond is routinely maintained. It is recommended that sediments are scraped clean to the design depth, as needed. The volume removed and the frequency of cleaning depend on the sediment load entering the pond. Paper and plastic trash should be collected in a screen upgradient of the pond and not allowed to enter the pond. Unwanted surface water run-off must be prevented from entering the pond. Any harmful liquids that could impact local groundwater must be monitored. Some of the more common compounds include - oil, grease, fuels, pesticides, herbicides, fertilizers, etc. These compounds, once in the aquifer, would be very difficult, if not impossible, to clean up to drinking water standards. It is recommended to place monitor wells downgradient of the pond to provide assurance our aquifers remain clean. Tom Tom Kwader may be contacted via e-mail to 7 WorldWide Drilling Resource ® JUNE 2020 ENV