202308997 Ver 1_Canterbury Estates Erosion Control_20230620

Canterbury Estates Fe and Mn Removal Filters
Erosion Control
The project site is a well lot containing 46,023 square feet. The project involves the construction of an 8'
X 10' extension onto the existing building to house the new filters. The new filters will backwash into
two 5000 gallon tanks which will sit on a 12' X 24' concrete slab. The disturbed area consists of 1206 sf
with a total of 375 additional square feet of impervious area.
The area draining the project area consists of 3650 sf of which 904 sf of roof and gravel drive and having
a C value of 0.95. The remaining area is wooded with a C value of 0.25 for a compiled C value of 0.43.
Adding 375 feet of concrete slab and roof brings the impervious area to 1279 sf and a combined C value
to 0.49.
Using the rational method Q=CIA where "I" is 1" per hour, a drainage area "A" of 0.084 acres and a pre -
construction "C" value of 0.43 the flow off the site is 0.036 cubic feet per second (cfs).
The post construction runoff is equal to 0.49 (1")(0.084ac) = 0.041cfs, a minimal increase of 0.005 cfs.
Install Silt fence down slope of Construction. Use silt fence to level out any concentrated flow. The
period of construction is 60 days. Once construction is completed all disturbed areas shall be seeded an
mulched

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