SW3230803_Response To Comments_20231219

RESPONSE MEMORANDUM
Date: December 15th, 2023
To: Jim Farkas
From: James McGivern (for Hy Nguyen) design
Proj: 19076 McCoy Farm
master planning . civil engineering
Re: 1st Review Comments Response urban design.landscape architecture
The following is an enumeration of responses to plan review comments dated November 15th, 2023:
• 1. Please correct the following issues with the Sand Filter Designs:
DPR: la:Noted. We were not able to have more SCMs. 1b: The design volumes were adjusted so each
has at least half of the WO design volume.
• 2 a: Section IV, 1 —Please revise the treatment summary for consistency with the proposed design as
both "one" and "(2)" SCMs are indicated as being provided.
DPR: Text was updated; Only 2 SCMs are being use.
• 2 b: Section IV, 8—Please recalculate the percent BUA for the project.
DPR: BUA was correct.
• 2 c: Section IV, 9 & 10—SCM 1 B does not appear to be required in order to meet State post-
construction permitting requirements.
DPR: SCM 1B was removed from the EZ Supp and the Application. In the Calculation binder, it
stipulates that SCM 18 is included for Reference Only.
• 2 d: Section IV, 10—See later comment with regard to inconsistencies in the drainage area information
shown on this form and as shown in the Supplement-EZ Form.
DPR: Noted.
• 2 e: Section IX—Since the Applicant is also the Property Owner, this section of the Application should not
be filled out.With your permission, I can revise the hard copy of the form that I have, however, you will
need to revise the electronic version of the Application.
DPR: The form was correct.
• 3a,
• i: Line 2—Please exclude the surface water area from the project area (This value should correspond
to the value shown in Section IV, 7 of the Application). DPR: Done.
• ii. Lines 7-9—Please answer these items. These items refer to the vegetated setback required from
surface waters in accordance with 15A NCAC 02H .1017(10). DPR: Done.
• iii. Line 22—See earlier comment with regard to SCM 1 B. DPR: Noted.
• 3b:, i. Line 2—See earlier comment with regard to SCM 1 B.
• ii. Entire Site Column:
• 1. Lines 5-7—The"drainage area"for the entire site column is equal to the project area (as shown in
Section IV, 7 of the Application), this value is not a summation of the values from the other columns.
DPR DESIGN • 919 Berryhill Road,Suite. 101,Charlotte,NC 28208 • PH 704.332.1204 • www.dpr.design 1

• 2. Line 8—Similar to the above comment, this value is not a summation of the other column values,
but rather corresponds to the total amount of BUA that is located within the project area. It includes
all of the on-site BUA(whether or not it drains to an SCM) and does not include off-site BUA.
• 3. Line 9—Per the deed restriction document, the 43 lots are each allocated 10,000 sf of BUA for a
total of 430,000 sf of BUA allocated to the individual lots (43 lots* 10,000 sf/lot= 430,000 sf). The
value on this form should correspond to this value obtained from the deed restriction document.
• 4. Line 11 —See earlier comment with regard to off-site areas for the entire site column. This value is
not a summation of the values from the other columns.
• 5. Line 17—Please ensure that any existing BUA that is to be removed is accounted for here (so you
can get credit for it).
DPR: All updated and Done.
• 3 b iii: There appears to be inconsistencies in the drainage area information shown on this form and
as shown in the Application. One such example is that the New BUA on subdivided lots for SCM 1A
in the Supplement-EZ Form (348,321 sf) does not match the On-site Buildings/Lots value for SCM
1A in the Application (348,081 sf). The issue also appears for the "Other" BUA type and for values in
SCM 2. Please revise either the Application and/or the Supplement-EZ Form as needed.
DPR: Noted and Done.
• 3 c:
• i. Line 10—This item is required per General MDC 7. If this item is not applicable, please use "N/a".
• ii. Line 19, SCM 2—Please indicate that this is a closed bottomed SCM (due to the impermeable
liner) and elaborate in the additional information section (Line 43) if Lines 20 &21 cannot be
answered for this SCM configuration.
• iii. Line 23—This value refers to the volume that can be stored in the sediment chamber between the
bottom of the sediment chamber(Line 25) and the invert of the bypass device (Line 35). The
provided values (40,300 cf for SCM 1A&3675 cf for SCM 2) appear to be too high, per the stage-
storage table. Please revise as needed.
• iv. Line 25, SCM 1 A—This value refers to the excavated bottom elevation of the sediment chamber.
Per the provided grading plans, the provided value (595.0') appears lower than the actual bottom
elevation of the sediment chamber. Please revise as needed.
• v. Lines 27 &28—The depth of the sediment chamber is the distance from the bottom of the
sediment chamber(Line 25) to the invert of the bypass device (Line 35). For sand filters with a
permanent pool in the sediment chamber, these values differ, but for a sand filter without a
permanent pool, these values are the same. Please revise as needed.
• vi. Line 32—This item refers to the cross-sectional area of the sand chamber at the elevation of the
top of the sand layer(Line 31). The provided values (10,000 sf for SCM 1A&8,200 sf for SCM 2)
appear to be too high, per the stage-storage table. Please revise as needed.
• vii. Line 35, SCM 2—This value (614.5') does not correspond to the invert of the lowest bypass
device as shown in the plans (2.5"orifice @ 612.5').
• viii. Line 36, SCM 2—Please indicate that the bypass device is an orifice, not a weir.
• ix. Line 39—This value refers to the depth of sand that is provided above the underdrain lines (per
Sand Filter MDC 7, this value must be at least 12"). Please revise as needed.
DPR: Thanks for explaining the how the values are based! Updated and Done.
• 3 d: Dry Pond Page—See earlier comment with regard to SCM 1 B.
DPR: SCM was removed from these forms.
• 4: O&M Agreement Form—See earlier comment with regard to SCM 1 B.
DPR: The O&M Agreement was updated.
DPR DESIGN • 919 Berryhill Road,Suite. 101,Charlotte,NC 28208 • PH 704.332.1204 • www.dpr.design 2

• 5: Upload PDFs and main in Hard copies.
DPR: Done.
DPR DESIGN • 919 Berryhill Road,Suite. 101,Charlotte,NC 28208 • PH 704.332.1204 • www.dpr.design 3