HomeMy WebLinkAboutSP-20-023 - Supplemental - 1200 Airport Drive (26)
Project Narrative
Burlington International Airport Construct Overnight Apron (Phase 7)
Project Description
BTV needs to construct a Remain Overnight (RON) aircraft parking apron. Due to growth at the airport, there is not enough room at its terminal to park all the aircraft that “remain
over night”. BTV proposes to redevelop an area within the current airport boundary as shown on the plans provided to construct an approximately 14,100 SY aircraft parking apron south
of the terminal apron, adjacent to the north hangar. The project will result in the construction of approximately 62,568 sq ft of new impervious surface.
The area of redevelopment is located within the boundary of BTV, which is an active public-use commercial airport located at 1200 Airport Drive, South Burlington, VT. Construction is
expected to occur over two years and will be phased to minimize impacts to aircraft operations during construction.
Existing Condition
The existing site consists of an impervious pavement aircraft apron with several grass islands within the overall airport layout. The soil consists entirely of Adams and Windsor loamy
sands, 0 to 5 percent slopes, hydrologic soil group A. The quantity of existing impervious surface is approximately 2.38 acres/103,800 square feet. The approximate proposed quantity
of impervious surface will be 3.82 acres/166,400 square feet due to the paving of the grass islands, which will add approximately 1.44 acres/62,600 square feet of impervious pavement.
Existing Stormwater System
The site has an existing stormwater system in place that consists of approximately 9 catch basins capturing runoff from approximately 2.38 acres of impervious and 1.44 acres of pervious
area and outlets at Outfall 7.
Proposed Stormwater System:
The proposed stormwater system consists of 14 catch basins capturing runoff from approximately 3.82 acres of impervious surfaces, of this 1.44 acres is pervious surface to be converted
to impervious surface. A storage chamber will be installed to satisfy required peak flow requirements and an underground sand filter system will be installed to satisfy water quality
standards.
The project will make the site 100% impervious surface, intended for the movement and parking of aircraft. FAA rules do not allow above ground objects within these areas or open standing
water bodies that could attract wildlife and pose a safety hazard to operating aircraft.
Because of these constraints only an underground stormwater control system is viable. Furthermore, aircraft re-fueling may take place on the site. This creates a “hot spot” and per
the VSMM no groundwater infiltration is allowed. Therefore, the selected water quality practice is a lined underground sand filter. Additionally, since the project site is on an airport
and the amount of sediment and trash potentially getting into the system will be minimal. FAA does not allow the use of sand on paved surfaces for traction and they have strict rules
on “FOD”, foreign object debris, and its prompt removal when encountered. Both rules are for the protection and safety of operating aircraft, but also act as “pre-treatment” for the
stormwater system.
Pre and Post Development Runoff:
Storm
Pre-development Q
Post Development Q
0.9”
0.89 cfs
1.66 cfs
1-year
4.37 cfs
2.58 cfs
10-year
7.85 cfs
6.77 cfs
25-year
8.11 cfs
7.48 cfs
100-year
8.42 cfs
8.40 cfs