HomeMy WebLinkAboutApplication Files_82693_pg0036 10.Why is there a LID outlet from Collection Basin 1 and a CB outlet from Collection
Basin 2? 1 suggest both these outlets be CB outlets for ease of maintenance.
The outlet from Collection Basin 1 should be moved to the east end to better align
with the other pipe flows in and out of DMH-3.
11.The 36 D entering DMH 9 from the north is at such an angle that over time it will
likely create a backwater condition in the pipes increasing the need to properly
maintain the system relative to sediments.
12. Label the undeveloped area south of Biofiltration Basin 1.
13.The grass swales and possibly the water quality swales should be lined with
erosion control matting prior to turf establishment to prevent erosion.
14.The drainage discharge from the water quality swale along Ellington Road needs
to be better defined with more contours and spot grades to insure no adverse
effects along Ellington Road or 1-291.
15. The utilities are very close together along Studio Buildings 2, 3 and the entrance
from Ellington Road south of the Guard House. In a 10 foot wide section there is
underground water, electric, telephone, data,fire,water and possibly other
utilities. These utilities will be difficult to construct and maintain. I suggest they
be spread out more.
16. Change all the 4"sewer laterals to 6" laterals outside the buildings per Town
standards.
17. Provide estimated flows for the 3"sewer force main for future development.
18.Label the sanitary sewer pipe slopes on the plans.
19. Show a;profile of the utility pipes including sewer, storm drainage,water and
others to insure there are no conflicts where these utilities cross.
20. There two trees shown near the electrical switchgear manhole that look like they
should be relocated to avoid conflicts.
- 21.Provide pipe flow analysis and headwater calculations for the 100 year storm.
Show the rainfall intensity and time of concentration in flow calculations for both
the 10 year and 100 year storms. Clearly label all tables.
22. The 10 year stomwater flows exceed the full flow capacity for some of the pipes,
according to the calculation tables in the stormwater Management Report. This
will cause stormwater to surcharge in catch basins and manholes. The pipe
slopes and/or sizes should to be increased to remedy this condition. 1 strongly
suggest all stormwater pipes be installed at a slope of 0.5%or greater. It is
extremely difficult to install plastic pipes flatter than this and not end up with flat
areas and bellies in the pipes.
23. Still awaiting the mounding Analysis. Our concerns are with potential outbreaks
and impacts to the slope along the railroad tracks/ROW as a potentially high
volume of water moves through the soil horizon.
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