Thursday, March 13, 2014
The Pawleys Island Planning Commission unanimously voted to oppose French drainage systems on the island.
In October, a north end property owner requested a variance to allow installation of a conventional, impervious concrete driveway coupled with a French drainage system.
Currently, the Town only sanctions pervious concrete, rock or slag for paving.
According to an engineer working with the homeowner, pervious concrete is more expensive and more difficult to maintain. A French drainage system was proposed instead.
A French drain is a trench filled with gravel and/or rock or a perforated pipe surrounded by gravel and/or rock, to redirect surface water away from an area – in this case, away from the proposed impervious concrete driveway.
The homeowner’s engineer explained it as an “underground infiltration/exfiltration storm water disposal system.”
At the commission’s February meeting, commissioner Rocky Holliday was asked to research the concept and present details at the March meeting.
After extensive contact with a number of experts, Holliday presented five pages of data concerning French drains versus pervious pavement. Critical details included these expert opinions:
When developing a property:
The primary goal should be to mimic the site’s original hydrology by maximizing infiltration and limiting run-off into the island’s creeks and into the ocean.
French drains alter original hydrology by moving water from one location to another; infiltration is a secondary function. The drains are often clogged by silt and sand, and would require intermittent checks to assure proper function.
Policing the proper installation of French drains, if they were approved, would be prohibitively labor intensive.
Pervious pavement is easier to maintain and provides superior pollution reduction by distributing water over a larger amount of square footage.
All these details noted, existing island sanctions allowing properly installed pervious concrete and paver systems, gravel, shell, crushed rock were decided to be both smart and sufficient. Slag was removed from the list of approved materials.property owners who have questions about ordinances relative to pervious and impervious paving should contact Jim McCants, chairman of the Planning Commission, at firstname.lastname@example.org.
In other business
Commissioners continued a discussion about Widows Walks.
Current regulations require Widows Walks not to exceed 100 square feet with the longest dimension not longer than 10 feet and height not exceeding 4 feet above the peak of the roof.
After some discussion, a decision was made not to entertain change to existing regulations.
Commissioners also continued a discussion about swimming pools on the Island.
New pools are consistently being installed, and chemically-maintained pools are under question. Salt water pools are more environmentally friendly. Chlorinated pools cannot be drained easily because of groundwater pollution.
Other issues include aesthetics of above-ground versus below-ground pools. It was agreed to research ordinances from similar East Coast communities and re-visit the topic next month.