SW6210801_Final Comments_20220919

As indicated in the 4/13/22 Request for Additional Information Letter for project
SW6210801, this is the final review. The following comments from the 4/13/22 request for
additional information were not addressed with the 6/21/22 resubmission:
Original Comment 5 — "Please submit a completed Deed Restrictions and Protective
Covenants form... [15A NCAC 02H .1017(8)]" An original, signed and notarized deed
restriction document was not provided in this resubmission. It is noted in the response to
comments letter that this form would be provided prior to approval.
2. Original Comment 6 — "Please submit a maintenance plan, maintenance agreement,
and supplemental forms... [15A NCAC 02H .1017(6)]" No original signed & notarized
hard copy of the O&M Agreement Form was provided. The provided hard copy of the
Supplement-EZ Form is missing the wet pond information page and no electronic copy of
this document was provided.
3. Prior Comment 4a — "Delineate the drainage areas to the proposed SCMs... " The
drainage areas to the SCMs were not delineated in the main set of plans.
4. Prior Comment 6.c —"Wet Pond MDC 5b... "Wet Pond 3 (plan sheet C-426) does not
appear to have both an entrance and exit elevation for the forebay, only a bottom
elevation of 293.0 ft is provided.
5. Prior Comment 6.d — "General MDC 1... " Wet Ponds 3 is shown to have a 12" bypass
orifice with an invert elevation of 298.0' which is at a lower elevation than the temporary
pool surface elevation (298.7').
6. Prior Comment 6.e — "General MDCs 8 & 9... " The stormwater maintenance accesses
and easements was not provided in the main set of plans.
7. Prior Comment 7.e — "Section X [of the Application]... " An original signature was not
provided for Section X of the Application.
8. Prior Comment 8.b.ii.1— "The `drainage area' for the entire site column should
correspond to the project area (114.51 ac) and the BUA breakdown for the entire site
column should be only for the BUA located within the project area. " The information
shown in the Entire Site Column appears to just be a sum of the information in wet pond
drainage are columns, but it should be an accounting of the entire project site (a sum of
the on -site portions of the drainage areas and the on -site areas that bypass the SCMs).
9. Prior Comments 8.c.i-x — "Please provide a hard copy of this [wet pond] page of the
form... " Neither a hard copy nor an electronic copy of the Wet Pond Page of the
Supplement-EZ form were provided so it was not possible to determine if these
comments were addressed or not.
10. Prior Comment 9a — "Provide PDFs of all revisions... " Electronic files for the
6/21/2022 resubmission were not provided.

The following comments were also noted during review:
Wet Pond MDC 3 — Wet Pond 1 shows a sediment storage top elevation (256.5') that is at
a lower elevation than both the forebay entrance (256.9') and forebay exit (257.0' ).
Please revise as needed.
2. Wet Pond MDC 1 lb — Wet Pond 1 does not appear to have a sufficient plant density for
the vegetated shelf. The cross -sectional area of the pond at the top of the vegetated shelf
(elevation 261.0') is shown in the stage -storage table as 19,774 sf and the cross -sectional
area of the combined pond at the bottom of the vegetated shelf (elevation 260') is 13,186
sf. Subtracting these two values results in a vegetated shelf area of 6,588 sf (since this
value was not provided) with a total number of plans shown as 1,151
(172+117+220+173+176+293). This results in a plant density of only 34.9 plants per 200
sf (a minimum of 50 plants per 200 sf is required). Please revise as needed.
3. There appears to be an issue with the surface area information provided for Wet Pond 1.
The calculations show that the combined surface area (main pool & forebay) for the pond
at the permanent pool surface elevation is 14,919 sf and the stage -storage table shows the
cross -sectional area of the pond at the permanent pool surface elevation as 17,887 sf.
Some discrepancy between these two values can be expected if the top of the berm
separating the forebay from the main pool is not accounted for in the "combined surface
area (main pool & forebay)" for the pond, however, this discrepancy is significantly
larger than the surface area of the top of the berm. Please revise as needed.
4. There appears to be an issue with the forebay volume calculation for Wet Pond 3. Per the
information in the calculations, the cross -sectional area of the combined permanent pool
at the permanent pool surface elevation (2975) is shown as 5,965 sf and the surface area
of the main pool only at this elevation is shown as 4,297 sf. Subtracting these two values
results in a forebay surface area at this elevation of 1,668 sf (this information was not
provided so it had to be calculated based on provided information). Assuming that the
cross -sectional area of the forebay at the top of the sediment storage zone (293.5') is zero
(this value was not provided (but it is most likely larger than zero) and making this
assumption allows for the smallest possible volume of the forebay based on the provided
information) would result in a forebay volume of approximately 3,336 sf, which is larger
than the volume of 2,293 cf shown in the calculations (i.e., something is not right but it is
unclear where the issue is since stage -storage tables for the portions of the ponds below
the permanent pool surfaces are not provided). Wet Pond 5 appears to have a similar
issue. Please revise as needed.
Please be aware that, due to the size of the submitted items, only the Application, Supplemental
Forms, and other smaller documents will be returned by mail. The larger items (plan sets and
calculation booklets) will need to be picked up from our office before close of business on
9/23/2022 if you would like them back, otherwise they will be recycled.
-Jim Farkas