Water during storms should remain on-site to absorb and infiltrate where it lands. This is not always possible, especially during storms. Best practices seek to reduce the volume and velocity of storm water that flows off land (roofs, streets, driveways, compacted earth) into public storm water systems.
Best practices don’t prevent run off, they can reduce it significantly by limiting land disturbance, reducing impervious surfaces, integrating a sites natural vegetation, and keeping trees with stabilizing roots on site.
Our creeks and streams can be restored to healthful use, if urban pollution is stopped, slowed, and filtered on-site, absorbed through soil and earth to replenish and clean our groundwater. It is imperative to capture water onsite so it doesn’t drain pollution downstream through historic streams and tributaries (residential streets and hills) and into Sligo Creek.
Below is an example of problems and better methods to reduce runoff.
Location: 600 Block of Ellsworth Drive, (Chelsea Heights New Development )
Time: 8:30 am
Event: Storm and flash flooding
One photo shows this “waterfall” and exposed soil, at the former Chelsea School (Chelsea Heights) is a channel, created by water forces in nature and enlarged by man, over a few years time drop by drop, storm by storm to drain water off-site (a 5 acre site) from a large parking lot (at top of ‘waterfall’ unseen). The water spilling offsite was worsened by the recent removal of trees and stabilizing roots that had naturally helped absorb storm water. The ‘waterfall’ adversely drains on-site water into off-site public storm water systems, streams and creeks.
One photo shows that sandbags, rather than gutter guards, were erroneously installed. They prevented the storm water from entering the public systems (which prevent flooding streets and homes downstream.) Gutter guards would have been better: they are like a sieve, they prevent soil, sediment and debris from entering the Creek. (Gutter guards must be cleaned routinely.). Solution: The sandbags belong above the ‘waterfall’, at the top of the hill along the parking lots edge, to hold and filter storm water on-site.
By blocking the storm drain system uphill vast amounts of the streets dirty water flooded down Ellsworth Drive to Bennington and entered cracks and crevices along road edges, spilling into the creek, as one photo shows. (5 blocks and 124 feet downhill from Springvale Road and Chelsea Heights is Sligo Creek)
The added force and volume of free flowing storm water flooding the street and systems created an explosive force of water into Sligo Creek. This force and volume of storm water degrades stream banks. In 8 years of almost daily monitoring the Sligo-Bennington tributary outfall (through many storms, including the Derecho) This day was a record breaker, it was the loudest and most violent “Niagra falls’ force of water to date.
As of October 9, 2013
Improvement: Developer moved sandbags to hill top, keeping parking lot storm water onsite, and limiting storm water from draining off-site and into Sligo Creek. Hay was also added to the exposed soils and disturbed earth to hold soil in place and reduce runoff. (Shown in photo)