20200276 Ver 1_overlook 3 storm preliminary approval-02032020162513_20200219

Wake County Environmental Services Department
Water Quality Division, Watershed Management Section
336 Fayetteville St. • P.O. Box 550 • Raleigh, NC 27602
WAKETEL 919 856-7400 • FAX [phone]
COUNTY
N'th 1 II 1 4W 1 WA
TPR — TRC Plan Review Checklist (FALLS LAKE ONLY)
Project Name The Overlook at Mount Vernon Ph 3
Applicant
Project Existing
Acreage 30.10 Impervious SF
Planning
Number PLG-SU-001690-2019
Watershed Falls Lake
Proposed
Impervious 196,726 sf
Zoning R-40W
New or
Expansion
(N/E)? h,
Disturbed
Acreage 17.55
Preliminary
0
Special
❑
Variance ❑
Planned
Compliance ❑
General
❑
Rezoning
Ei
S/D
Use
Permit
Use
Request
RCb'Uldl — %AU.xc1 1w 1-11V1
Subdivision — Lot By Lot Open ❑ I Subdivision
Nonresidential ❑
Pre -Submittal Plan Comments Sent
7.
Review Status: All (Insert Checklist Item #'s) checked items must be addressed upon submittal of construction
plans.
1.27.20 Pre -Submittal Plan Not Approved
Items 6. must be addressed prior to pre -submittal plan approval.
Items ()must be addressed upon submittal of construction plans.
Submittal Package Requirements
Items marked with an "X" were noted as either insufficient or not provided. Watershed Manager comments are in
rovide the necessary requirements for either pre -construction or construction plan approval.
❑ FiT.Cover letter stating the purpose of the submission
❑ I 2. I One copy of the Hybrid Stormwater Tool (Site Data Sheet, Drainage Area Sheets, Site Summary Sheet, BMP
k I Sheets, and BMP Summary sheet) See the Wake County Stormwater Manual for guidance.
❑ 1 3, I Drainaee Area Maps with stormwater discharge points (existing/post construction/post BMP)
and
❑ a. I For Water Supply Watersheds: Provide drainage map showing drainage acres to the drainage features for
properties in the water supply watershed zoning districts
4' Copy of the USGS Quad Map (in color) with delineated project limits-
5 Copy of the Wake County Soil Survey map with delineated project limits from the 1970 manuscript.
❑ 1 6, 1 Proposed Site Plan:
I
PLGySU_001690_2019,Falls_TRC_4th.docx2_W M

Wake County Environmental Services Department
Water Quality Division, Watershed Management Section
�� 336 Fayetteville St. • P.O. Box 550 • Raleigh, NC 27602
COUNTY TEL [phone] • FAX [phone]
.at,.- P - x-. -..,
TPR — TRC Plan Review Checklist (FALLS LAKE ONLY)
El
a.
North arrow, graphic scale, drafting version date, and legend
❑
b.
Show all Riparian Buffers [Article 9-21]; (Neuse: [15A NCAC 02B.0233 & 0242]; Falls [15A NCAC
02B.0277(4)(h)]; Jordan: [15A NCAC 02B.0277(4)(h)]
❑
c.
Delineation of all existing and proposed impervious surfaces: roads, well lots, recreation sites, single family
residences, etc. (consistent with SNAP Tool inputs)
Delineation of Septic repair area and delineate setback to SCM
El
dl-
f.
Delineation of flood prone soil areas
Proposed drainage easements and widths (in Feet) Provide 20" width easements starting at 4oc
❑
g.
Q
h.
Location and type of all proposed stormwater management structures (grass swale, wet/dry detention
basin, filtering/infiltration basin, bioretention, etc.)
❑ i. Proposed easement access lanes and sediment disposal areas for future maintenance of stormwater
management facilities.
❑ j. A note should be added to the recorded plat distinguishing areas of disconnected impervious
77�Provide documentation of soil re -delineations (as needed) or include on site plan
Standards and Requirements ''Items marked with an "X" note relevant standards to be applied to the proposed
development. Notes in RED provide review comments and/or any required elements to comply with standard.
Wake County LIDO Article 8 — Subdivision Design and Improvements
Article 8-37 Streams or Drainageways - Easements for streams or drainageways must be provided and must
❑
8.
follow the existing course of such streams or drainageways. Easements for drainage of surface waters from 4
lots or less may cross lots only if the Planning Board or Planning Director determines that such location will not
pose a hazard to persons or property.
Article 8-42 Lakes and Dams - If a lake is proposed to be constructed or retained within a subdivision, the lake
and its dam must be constructed or structurally upgraded to accommodate the runoff from a 24-hour, 100-year
frequency storm. (note existing spillways appears to be severely eroding from visible head -cut via
topography) May also want to start PCNprocess as soon as possible to avoid delays with construction
I�
g
plan * offsite temporary construction easements will need to be looked into as well to repair spillway
channel
• Runoff computations must use [SCSI methods or other acceptable engineering standards
PLG SU_001690_2019 Falls_TRC-4th.docx2 VVM

Wake County Environmental Services Department
Water Quality Division, Watershed Management Section
_ 336 Fayetteville St. • P.O. Box 550 • Raleigh, NC 27602
WAKE
BOUNTY TEL [phone] • FAX [phone]
k W,1r 4P-11-.'4
0
1 10.
TPR — TRC Plan Review Checklist (FALLS LAKE ONLY)
Article 8-43 Standards - All subdivisions within the zoning districts R-40W, R-80W and overlay districts WSO-
2NC, WSO-3CA, WSO-3NC and WSO-4P must be designed and constructed so that all development directly
associated with the subdivision (e.g., roads, utilities, grading, drainage facilities) and all subsequent
development (e.g., buildings, driveways, yards, on -site utilities, grading, drainage facilities) on the subdivision's
lots and other parcels:
• minimizes impervious or partially pervious surface coverage;
• diffuses the flow of stormwater runoff, encourages sheet flow and avoids concentrated discharge of
stormwater into surface waters;
+ incorporates Best Management Practices (BMPs) to minimize adverse water quality impacts;
•. transports stormwater runoff from the development by vegetated conveyances; and
• avoids disturbance of vegetation within water suooly watershed buffers
Wake County UDO Article 9 - Stormwater Management Requirements
See Wake County's Stormwater Manual: Submittal and Design Guidance
Stormwater Review Required - All residential subdivision development must submit a plan to comply with
11. Article 9. Minor subdivisions have the option of limiting impervious to 15%. Office, institutional, commercial or
industrial development that disturbs greater than % acre is required to comply with the stormwater
management regulations of Article 9.
Stormwater Permit — is required for all development and redevelopment unless exempt pursuant to the LIDO. A
M 12. permit may only be issued subsequent to a properly submitted, reviewed and approved stormwater
management plan and permit application. [Article 9] Note: A permit may not be required if there are no post -
construction requirements (i.e. BMPs).
M 1 14.
Volume Management — is required for RESIDENTIAL regular subdivisions when the post development curve
number exceeds the pre development curve number using the Wake County Hybrid Stormwater Tool. Minor
subdivisions have the option of limiting impervious to 15%.
BMPs - For projects requiring stormwater treatment for quality and/or quantity control, the applicant must
comply with the NC BMP Manual, as well as Article 9 Stormwater Management, Part Completion and
Maintenance of Improvements prior to approval of the record plat.
Nutrient Management Strategies — Falls Lake Rules [15A NCAC 02B.0277] & [Article 9-21-2]
See Wake County's Stormwater Manual: Submittal and Design Guidance
Select all that apply.
® 3.5. 1 Peak Flow — new development shall not result in a net increase in peak flow leaving the site from the pre
development conditions for the 1 yr-24hr storm,
3
PLG_SU_001690_2019_FaIIs_TRC_4th.docx2 WM

Wake County Environmental Services Department
Water Quality Division, Watershed Management Section
336 Fayetteville St. • P.O. Box 550 • Raleigh, NC 27602
WAKETEL 919 856-7400 • FAX [phone]
COUNTY
TPR — TRC Plan Review Checklist (FALLS LAKE ONLY)
Nutrient Offset Option- Nitrogen and Phosphorus Loads contributed by the proposed new development activity
shall not exceed the unit area mass loading rate for nitrogen and phosphorus of : 2.2 N Ib/ac/yr and 0.33 P
Ib/ac/yr. [15A NCAC 02B.0277(4)(a)]
151 16.
Developers shall have the option of offsetting part of their nitrogen and phosphorus loads by implementing or
funding offset management measures. Before using the offsite offset option, a development shall implement
onsite structural controls that achieve one of the following levels of reduction. Select one of the following:
Proposed new development activity disturbing at least Y2 acre but less than 1 acre of land for single
0 �' family and duplex residential property & recreational facilities, shall achieve 30 % or more of the needed
load reduction in both nitrogen and phosphorus loading onsite.
Proposed new development activity disturbing at least 12,000 but less than 1 acre of land for
❑ #, commercial, industrial, institutional, multifamily residential, or local government property & other non-
residential property, shall achieve 30 % or more of the needed load reduction in both nitrogen and
phosphorus loading onsite;
Except as stated in (d) below, proposed new development activity that disturbs 1 acre of land or more
® c` shall achieve 50 % or more of the needed load reduction in both nitrogen and phosphorus loading
onsite. (SCM required from 19.j. may help meet this requirement)
Proposed development that would replace or expand structures or improvements that existed as of
❑ d, December 2006 and that increases impervious surface within a local government's designated
downtown area, regardless of area disturbed, shall achieve 30 % of the needed load reduction in both
nitrogen and phosphorus onsite.
Replacement or Expansion w/No Net Increase in BUA — proposed development that would replace or
expand structures or improvements that existed as of December 2006, and that would not result in a net
❑ increase in built -upon area shall not be required to meet nutrient loading targets or high -density
requirements except to the extent that the developer shall provide stormwater control at least equal to
the previous development.
Replacement or Expansion with Net Increase in BUA - proposed development that would replace or
f.
expand structures or improvements and that would result in a net increase in built -upon area shall have
the option either to achieve at least the % loading reduction objectives as applied to nitrogen (40%) and
phosphorous (77%) loading from the previous development for the entire project site, or to meet the
loading rate targets expressed in Ibs/ac/yr of nitrogen 2.2 and phosphorous 0.33.
Compliance Alternative/LID option - Developments that show volume matching using Storm-EZ shall be
considered as meeting nutrient export requirements without making offset payments provided the
following:
+ When analyzing a development site, the pre -development land cover shall be entered into
g. Storm-EZ as "Woods" for the entire project area.
■ The Wake Couty Hybrid Tool must be run to estimate the pre -development, and post -
development, post-BMP nutrient export rates for the site.
See NCDENR Memo on Coordination between LID & NSW Programs
Wake County UDO Article 10 - Erosion and Sedimentation Control Requirements
0 17. Erosion Control: This project will require a Land Disturbance Permit if it involves greater than one acre of
disturbance. See website for details,
PLG—SU_001690_2019_FaIIs_TRC_4th.docx2 WM

Wake County Environmental Services Department
Water Quality Division, Watershed Management Section
�C L 336 Fayetteville St. • P.O. Box 550 • Raleigh, NC 27602
TEL [phone] • FAX [phone]
COUNTY
TPR — TRC Plan Review Checklist (FALLS LAKE ONLY)
Wake County UDO Article 14 - Flood Hazard Area Requirements
I] 18 Flood Study Required [Article 14] A study of the potential changes in the base flood elevation caused by the
obstruction (fill), encroachment, alteration or relocation (including driveway or road crossings) of the following
areas (15a-f):
a FEMA mapped floodway
r�
a.
(Note: No new structures may be constructed or placed within a floodway or non -encroachment area
except as otherwise provided by subsection 14-19-2; AND No fill may be placed in a floodway or non -
encroachment area except as otherwise provided by subsection 14-19-2; [Article 14-19-3(A-B)])
i I
b.
a non -encroachment area (Article 14-19-3(A-8)], see note above
(�
C.
a FEMA mapped area of special flood hazard that has not previously been studied in detail
❑
d.
flood hazard soils areas with a total drainage area of more than 5 ac but no more than 25 ac
[Article 14-15-3] — or —
rl
e.
flood hazard soils areas with a total drainage area of more than 25 ac, but less than 100 ac
[Article 14-15-4] — or -
El f' flood hazard soils area with a total drainage area of 100 ac or more [Article 14-15-5]
Wake County UDO Article 11 - Environmental Standard Requirements
© 19. Water Supply Watershed Buffers (WSWB) Article 11, Part 2 Select all that apply.
Water Supply Impoundments with a drainage area of 25 acres or more [Article 11-21-21:
❑ a' WSWB required with a minimum width of 100' around all water supply impoundments
■ Buildin s must be setback at least 20 feet from the outer boundary of the required buffer area.
Water Supply Impoundments with a drainage area of 5 to 25 Acres [Article 11-21-3]:
El■
b.
WSWB required with a minimum width of 30' provided around all water impoundments
Buildings must be setback at least 20 feet from the outer boundary of the required buffer area.
Non -Water Supply Impoundments with a drainage area of 25 Acres or more [Article 11-21-4]:
7
c` WSWB required with minimum width of 50' around all non -water supply impoundments.
• Buildings must be setback at least 20 feet from the outer boundary of the required buffer area.
5
PLG,SUR001690_2019_Fa11s_TRC_4th,docx2 WM

Wake County Environmental Services Department
Water Quality Division, Watershed Management Section
336 Fayetteville St. • P.O. Box 550 • Raleigh, NC 27602
W KL TEL [phone] • FAX [phone]
COUNTY
.RlII 1.A �Ilw
TPR — TRC Plan Review Checklist (FALLS LAKE ONLY)
Perennial Streams [Article 11-21-5]:
■ WSWB required with a minimum width of 100' along each side of a stream shown as a perennial
stream on the most recent edition of U.S.G.S. 1:24,000 (7.5 minute) scale topographic maps.
d. + The area of the required buffer that begins at the stream bank and extends landward 50 feet is
subject to the Zone 1 standards of Sec. Section 11-22-1(A).
The area of the required buffer that begins at the outer edge of Zone 1 and extends landward 50
feet is subject to the Zone 2 standards of Sec. Section 11-22-1(B).
No minimum building setback from the required buffer.
Non -Perennial Watercourses [Article 11-21-6]
L. e. WSWB required with a minimum width of 50' along each side of non -perennial watercourses,
channels, ditches or similar physiographic features with a drainage area of 25 acres or more
Buildings must be setback at least 20 feet from the outer boundary of the required buffer area.
Watercourses and Channels, 5 to 25 Acres [Article 11-21-7]
WSWB required with a minimum width of 30' along each side of a watercourse, channel, ditch, or
similar physiographic feature with a drainage area of at least 5 acres, but less than 25 acres
■ Buildings must be setback at least 20 feet from the outer boundary of the required buffer area,
Activities Allowed within Buffers [Article 11-22-2]: Driveway crossings that access single-family
dwellings, provided:
• no alternative to their location in the buffer (including opportunity for shared driveways) exists;
buffer disturbance is no more than 60' wide;
• buffer disturbance is no more than 6,000 SF;
the driveway crosses the buffer at an angle close to 90 degrees and not less than 60 degrees;
+ side slopes do not exceed a 2:1 (horizontal to vertical) ratio (bridging and/or retaining walls may be
used to meet this and the disturbance width standard); and
M all culverts are designed and constructed for the 25-year storm event
Activities Allowed within Buffers [Article 11-22-2]: Road crossings (public or private roads), provided:
no alternative location in the buffer exists;
■ buffer disturbance does not extend beyond the required right-of-way or easement width, or in no
case is more than 90 feet wide;
• buffer disturbance is no more than 9,000 SF in area
• the road crosses the buffer at an angle close to 90 degrees and not less than 60 degrees;
• side slopes do not exceed a 2:1 horizontal: vertical ratio (bridging and/or retaining walls may be
used to meet this and the disturbance width standard); and
all culverts are designed and constructed for the 25-year storm (will need minimum culvert sizes to
pass 25 yr storm for driveways that will inevitably cross WSWSB) will also require 100 yr backwaters
on culverts draining 4 ac or more
Activities Allowed within Buffers [Article 11-22-2]: Stormwater management ponds, provided;
• no alternative to their location in the buffer exists; and
1 J. ■ a new vegetated water supply watershed buffer meeting the purpose and requirements
of this Paragraph is established around the new pond
5
PLG SU 001690 2019 Falls TRC 4th.docx2 WM

Wake County Environmental Services Department
Water Quality Division, Watershed Management Section
336 Fayetteville St. • P.O. Box 550 • Raleigh, NC 27602
WAKE TEL [phone] • FAX [phone]
COUNTY
TPR — TRC Plan Review Checklist (FALLS LAKE ONLY)
Activities Allowed within Buffers (Article 11-22-2]: Drainage ditches, roadside ditches, and stormwater
outfalls, provided:
], • no alternative to their location in the buffer exists; and
a stormwater management facility is installed to control nitrogen and attenuate flow before the
conveyance discharges through the buffer
recommendations/ notes
Recommend starting PCN process for stream crossing
—4.12 ac is max assumption of wooded area on lots for this plan without tree preservation area on
ii. construction plan and record plat, currently shows 9.99 ac and will need to delineate area on construction
plan(see Wake County Stormwater Design Manual sec 5.1.1) Will be required on Construction Plan
® I iii. I Is the Drainage easement between lots 1&2 going to be the maintenance and access easement as well for
SCM1? If not delineate on plan
® I iv. May want to discuss piped drainage easements with onsite as well to ensure setbacks aren't prohibitive
Wake County PE: " ; 14 4-' y Contact Info:
Shawn Springer, PE,CFM
[e-mail]
919-369-6135
7
PLG Stl 001690 2019 Falls TRC 4th.docx2 WPA