NO COMMITMENT TO BEST MANAGEMENT
PRACTICES FOR STORMWATER AT SAUNDERS LAKE
Dear editor,
When researching the effects of having an industrial park next to Saunders Lake it became evident that the discharge of stormwater runoff into the Lake would be a problem for wildlife.
Articles on stormwater management commonly refer to a "flushing" action during a rain event, where roof runoff, joins with paved area runoff, gathering volume and speed, collecting pollutants and debris while heading towards an outfall into a river or lake.
The word "flushing" drew a visual image of a toilet bowl for me, with its impervious sides, carrying unwanted human waste, waiting to be efficiently transported to another location to be dealt with by others.
It just happens that the outfalls planned for the Northwest Saunders Lake Industrial Park are at a location where my wife and I observed flocks of North American Pelicans last year.
The shallow waters of Saunders Lake are ideal for many shore birds, but are vulnerable to any accumulation of concentrated pollutants and disturbance from stormwater outfalls. Why the stormwater outfall could not be located in the Blackmud Creek drainage ditch is beyond my understanding, it is after all, located at the north end of the development.
In the revised Northwest Saunders Lake Area Structure Plan dated Feb. 10, the consultant has included descriptions of bioswales and constructed wetlands that could be used in the development. These applications would be a huge step forward from grass ditches and storm retention ponds, as they allow downward infiltration, increased exposure to natural UV light, temperature moderation and with slower movement - increased transpiration and filtering.
Typically storm retention ponds drain down over 24 hours, although best practices recommend a minimum of 48 hours and grassed ditches are graded to expedite the movement of stormwater, usually with a clay base.
The focus of good stormwater management is to reduce runoff in the first place, at source. This can be accomplished by simple measures such as roof rainwater storage in cisterns for later use in onsite irrigation, increasing drainage below landscaped and grassed areas, and by dense tree planting in water pooling areas.
The rainwater absorption rate in a forested area is 67 times faster than hardened grassed areas, not only is evapotranspiration increased, but the shaded forest floor does not bake to a solid crust in the sun and becomes home to burrowing and tunneling wildlife.
The Province of Alberta makes it clear in their publications that they encourage the reduction of stormwater at source, and have even funded research to prove that these solutions provide cost savings for tax payers.
Is it up to our elected officials to mandate these requirements or are we to rely on the social conscience of the developer?
Vic Moran
Leduc County, AB
No comments:
Post a Comment