Drainage SummaryABD Engineers, LLP Proposed Garage
December 22, 2020 18 Dark Bay Lane
DRAINAGE SUMMARY
FOR
PROPOSED GARAGE
18 Dark Bay Lane
Town of Queensbury
Warren County, New York
The existing 4.7± acre site at 18 Dark Bay Lane is currently developed as a single-family
residence. The Applicant is proposing to construct a detached garage with a new driveway off of
Dark Bay Lane. The existing home and driveway will remain. An additional drainage culvert is
proposed across the new driveway to continue the conveyance of runoff down the existing ditch.
According to the Town of Queensbury regulations, all water from newly created
impervious areas shall be directed to an infiltration device sized to provide 1.5 gallons of storage
for every square foot of impervious area. Two stone diaphragms are proposed for stormwater
control, one adjacent to the driveway at the front of the site and one along the perimeter of the
new garage. Sizing calculations are as follows:
πΉππππ ππππποΏ½βππ:
π ποΏ½βππππππ¦ πΌππππποΏ½βπππ π΄πππ=1,600 ππ2
π ππποΏ½βπππ π ππππππ=(1,600 ππ2 )(1.5 πππ)=2,400 πππ=320 ππ3
π ππππ π ππππππ πππποΏ½βπππ=(400 ππ2 )(2β²πππποΏ½)(40% πποΏ½βππ)=320 ππ3
π πππ ππππποΏ½βππ:
π ποΏ½βππππππ¦ πΌππππποΏ½βπππ π΄πππ=5,881 ππ2
π ππποΏ½βπππ π ππππππ=(5,881 ππ2 )(1.5 πππ)=8,822 πππ=1,179 ππ3
π ππππ π ππππππ πππποΏ½βπππ=(1,525 ππ2 )(2β²πππποΏ½)(40% πποΏ½βππ)=1,220 ππ3
The total storage volume provided within the stone infiltration areas exceeds the required
quantities per the Town of Queensbury regulations.