HomeMy WebLinkAboutApplication Files_82693_pg0835 Stormwater Mounding
Analysis
Introduction
Stormwater management design for the Connecticut Studios Project was been based
on the "2004 Connecticut Stormwater Quality Manual." Under proposed conditions,
most stormwater runoff from the Site will be directed via closed piping network to
an underground Stormtech MC-3500 chamber infiltration system and an
interconnected surface infiltration basin. Due to the large size of the underground
system,a groundwater mounding analysis was performed to confirm proper
functioning of the system.
Analysis
Original Design(February 26,2010):
VHB conducted a mounding analysis of the infiltration system proposed on the Site
Plans submitted to the Town dated February 26,2010. VHB determined that the
groundwater mound created by the proposed layout was not ideal due to the dense
concentrated layout of the proposed chambers(see Figure 2).
Final Design(March 9,2010):
VHB has amended the design of the infiltration system by extending the system
linearly(northward) and laterally(creating greater separation between chambers). A
surface infiltration basin has also been added to the design and interconnected with.
the main chamber system(see Figure 3). The separation of chambers from a single
large block into a longer,more divided network does not require additional
chambers,but allows for the resulting groundwater mound to be lower due to a less
concentrated infiltrating surface.Mounding analysis of the final infiltration network
proves that the system will function for up to the 100-year storm event(included
herein). Revised HydroCAD analysis of the 100-year storm event has been included
herein.
' Revised water quality flow isolator row sizing)calculations were required for the
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amended Stormtech chamber layout,and have been included herein.Stormwater
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