Bluescaping – Green Infrastructure to Protect the Water Table

After last year’s drought, local conservation authorities are introducing new tools to minimize the impact of development on local hydrology. 

Most construction projects inevitably affect water drainage by increasing water runoff and reducing the natural absorption process of rain and snowmelt.  Problems arising from stormwater runoff can be significantly reduced by incorporating some design features that anticipate these unintended consequences; techniques that are designed to “let the rain drain”.   Conservation Authorities and many municipalities are introducing stormwater management practices help to reduce the opportunity for polluted runoff to flow into lakes and streams, and curb the strain that stormwater places on municipal infrastructure.

Called Stormwater landscaping or Stormwater Low Impact Development (LID), these tools address runoff which occurs when rain or snowmelt flows off hard surfaces rather than being absorbed by vegetation and soils. Stormwater running off asphalt surfaces, driveways, sidewalks and roofs drains quickly, and in urban areas is routed through underground pipes, eventually flowing into stormwater ponds, local creeks or Lake Ontario.

When stormwater enters creeks at a rapid pace, there can be a sharp and sudden increase the volume and flow of water.  Not only does this create a public safety hazard, it can also result in creek bank erosion, sediment accumulation and the alteration or destruction of fish habitat. Water quality is also affected as contaminants (gas, heavy metals, salt, bacteria, and sediments) from roads, driveways and parking lots end up in the water.

New development projects can incorporate some simple ideas to reduce water runoff caused by changes to the landscape.  These techniques can boost natural water absorption from precipitation to as high as 50%, and reduce run-off from 55% to only 10% of the water volume.  For example, raising the depth of topsoil levels surrounding new developments from a depth of 6” to at least 10” increases the soil’s ability to absorb rainwater and reduces the runoff flow through storm drains.  Establishing rain gardens with significant layers of sand and gravel to disperse rain water prevents flooding from large downspouts or large asphalt areas by facilitating water absorption and preventing water accumulation in low lying areas.

At the January Cavan Monaghan Council meeting, Kawartha Conservation Stewardship Outreach Technician Greg Bunker outlined some of the tools his organization is promoting and identified some of their pilot projects.  One of their main areas of concern is Lake Scuggog, where sedimentation and erosion problems are changing the face of this important natural landscape feature.  Two of their pilot projects include the installation of a bio-retention feature in the public parking lot near the boat launch, and a rain garden to collect water from downspouts in Victoria Park in Lindsay planned for this spring.  They are also offering workshops and guides for landowners to take the initiative on private property.

The Ganaraska Regional Conservation Authority (GRCA) is also promoting new water conservation techniques.  They recently hosted a lunch and learn seminar on porous concrete systems attended by more than 30 engineers, architects, municipal staff and contractors.  One of many porous surface materials, this water conservation product helps rain and snowmelt drain into the soil instead of running off over its surface.  It increases groundwater recharge, reduces surface runoff rates and volumes, reduces water contamination through natural filtration, and reduces flash flooding by increasing the drainage capacity of the immediate area.

To learn more about low impact design systems contact Gbunker@KawarthaConservation.com or call 705-328-2271 x242 or the GRCA at stewardship@grca.on.ca. KG

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