HomeMy WebLinkAboutKate Roosa_RE_ Town of Barnstable DPW - 725 Main Street - Stormwater QuestionFrom: Kate Roosa <klr@envpartners.com>
Sent: Tuesday, January 10, 2023 11:56 AM
To: Karle, Darcy
Cc: Francesca Barilla; Ziad F. Kary; Cavanaugh, Kimberly; Beaudoin, Griffin
Subject: RE: Town of Barnstable DPW - 725 Main Street - Stormwater Ques on
A achments: 725MainSt_PostDevelopment_Atlas14.pdf
Good morning Darcy,
To answer the Chair ’s ques on: Yes, we can and we did re-run the HydroCAD model using the provided NOAA Atlas 14
precipita on events. A ached is a PDF of the revised HydroCAD Report. The table below summarizes that post-
development peak flows do not exceed pre-development condi ons.
Table 3A – Post-Development Peak Flows using NOAA Atlas 14 Storm Events
Design
Points
NOAA Atlas 14 2-Year (3.39")
NOAA Atlas 14 10-Year (4.95")
NOAA Atlas 14 25-Year (5.92")
NOAA Atlas 14 100-Year (7.41")
4L 0.00 cfs 0.00 cfs 0.00 cfs 0.00 cfs
9L*0.00 cfs (0.08 cfs)0.00 cfs (0.14 cfs)0.00 cfs (0.18 cfs)0.00 cfs (0.24 cfs)
*Reach 9L estimates about 0.50 cfs of infiltration capacity. Therefore, the number shown is the difference between the estimated
capacity and the runoff from the design storm. The design storm runoff value in parenthesis represents the inflow to the infiltration
strips.
Please pass this along and let me know if there are any other ques ons I can help answer.
Thanks, Kate
Kathryn L. Roosa, PE Senior Project Engineer She/Her O: 617.657.0986 Environmental Partners envpartners.com
From: Karle, Darcy <Darcy.Karle@town.barnstable.ma.us> Sent: Tuesday, January 10, 2023 9:59 AM To: Kate Roosa <klr@envpartners.com> Cc: Francesca Barilla <