By Chad Ingram

 

The
Coalition of Haliburton County Property Owners’ Association is
encouraging any property owners who are undertaking paving projects on
their properties to consider the use of permeable paving. 

 

“In
the Lake Simcoe area, permeable paving is becoming almost mandatory,”
CHA board chairman Paul MacInnes told county councillors during a recent
meeting. 

Permeable paving is a method
of paving that allows for the infiltration of liquids. In this way, the
pavement reduces runoff and actually acts as a filter of contaminants
such as phosphorous. 

 

Phosphorous
is public enemy No. 1 when it comes to lake health in Haliburton County
and is the culprit behind algae blooms. When large enough, algae blooms
not only make lakes unsafe for swimming, but also, in severe cases,
render them effectively dead. There was one confirmed algae bloom in
Haliburton County last summer, and eight reported. 

 

Credit
Valley Conservation conducted a case study on the benefits of permeable
paving, with a report published in 2018. One of the test sites used was
the parking lot of an IMAX office in the Sheridan Business Park in
Mississauga. 

 

“The
parking lot was expanded and retrofitted with a combination of
traditional asphalt and permeable pavement,” the report reads. “The
asphalt runoff drains to one of three bioretention units. The permeable
pavement section is divided into three catchments with differing
subsurface materials. The parking lot runoff is collected, absorbed and
filtered by these LID [low impact development] practices before entering
a wetland adjacent to the parking lot.” 

 

The
data shows a substantial load reduction in contaminant levels from the
portion of the parking lot done with permeable paving. The test sites
showed up to a 99 per cent reduction in suspended solids (small
particles suspended in water); 98 per cent reduction in phosphorous; 98
per cent reduction in Kjeldahl nitrogen (total concentration of organic
nitrogen and ammonia); 94 per cent reduction in nitrates; 98 per cent
reduction in copper; and up to a 99 per cent reduction in zinc. 

 

“As
part of adaptive management, stormwater management has evolved over
time from flood control requirements, to water quality and erosion
requirements, to water balance requirements,” the report reads. “The
cost and complexity of these engineered system has increased. In light
of the current spotlight on climate change and aging infrastructure
there is growing awareness that stormwater management has become more
than just treating a storm event, it’s also about maintaining stream
flows during dry weather periods for wastewater assimilation, fisheries,
and water takings. 

 

“Results
from IMAX and other similar performance studies will provide private
land owners and municipalities with the knowledge they need to make
informed decisions on the role of green infrastructure for stormwater
management. They are essential to gain insights into preferred designs
and advancements which may be needed to meet stormwater management and
other objectives cost-effectively. This data can help inform the
planning and implementation processes required for green infrastructure,
such as informing the credit application process for the City of
Mississauga’s stormwater charge. Studies such as IMAX are also providing
the local, long-term performance data needed to conduct the integrated
life-cycle analysis required for asset management, including tracking
operations and maintenance activity need, frequency and cost.” 

 

While
permeable paving is currently more expensive than regular paving,
MacInnes also noted that along with its environmental benefits, it is
not subject to the heaving and cracking that comes along with regular
paving, and is therefore more durable as well. The only contaminant that
permeable paving does not seem to filter out is road salt.