HomeMy WebLinkAbout20200270 Tait Lane Reserve Supplemental Information Comment 33: A wet pond detail sections should be added to the plans and closely follow the outlined
requirements per the Design Manual Section 6; for example, the following should be included
in plan and detaii:
a) The required drawdown drain with gate valve per the Design Manual Section 6.1.6;
b) The location and detail of a fixed vertical sediment depth marker including typical
installation and marking to indicate when accumulated sediment is to be cleaned out;
c) Since the proposed project utilizes a wet pond warning signs for the wet pond should be
added to the plans as per Design Manual Section 6.1.6; and
d) The location of all stormwater management signs should be indicated on the plans.
Response 33: a)Per Section 6.1.6 of tlie Design Manual,pond drain are not required where local
slopes prohibit the ability to drain the pond. The permanent pool of the pond is below
the elevation of the surrounding area and therefore cannot be drained.
b)A sediment depth marker will be added to the site plan and details.
c)The project proposes a fence restrict access to the wet pond to maintenance
personnel only.
d) Stormwater management practice signs wi11 be added to the site plans.
Comment 34: Stormwater management sign details should be provided that include and follow the
requirements stated in the Design Manual Section 3.5 Page 3-12. Sign locations and details
are required to be shown on the plans (Sheets L-3.1 through L-3.3 and Sheet L-7.1). Special
attention should be applied to signage as needed to protect porous asphalt parking lots from
winter sanding and other unsuitable activities (Sheet L-2.0).
Response 34: Stormwater management practice sign details will be added to the site plans.
Comment 35: The detail for the V-notch weir is incorrectly labeled as"Stone Overflow Weir"and should be
revised to indicate the V-notch weir(Sheet L-7,4).
Response 35: The detail will be updated.
Comment 36: Insufficient weir dimensions are provided in plan and detail. Provide the dimension used in
the stormwater analysis on the plans and details (Sheets L-3.2, L-7.3, and L-7.4).
Response 36: Additional dimensions will be added to the V-notch weir detail.
Comment 37: The stormwater analysis should be re-run to include prior comments and a starting surface
water elevation for the pond equal to the elevation of the bottom of the"V"in the v-notch weir.
Response 37: Based on the test pits perFormed in the area of the proposed wet pond,the
groundwater elevation was observed at elevation 319.50.The starting elevation was
set at that elevation to most accurately model the pond under normal conditions.
Comment 38: The SWPPP should be revised to show the apparent seasonal high groundwater elevation for
any infiltration area, including but not limited to porous pavement areas. The"Porous Asphalt
PavemenY'detail should include a note that requires 2'minimum separation between the
bottom infiltration layer and seasonal high groundwater elevation (Sheet L-7.0/Sheet L-7.1).
Response 38: The site plans and details wi11 be updated to include this information.