20190248 Ver 1_More Info Received_20190723

Request for Additional Information Reply
DWR #19-0248
Received on 20 April 2019
Site Location: Phillips Residence
8652 Valley Brook Drive
Raleigh, N.C. 27613
Wake County
Subject: Reply to Request for Additional Information
Dear Mr. Bolich,
On April 20" 2019 I received your request for additional information concerning the proposed
retaining wall project at 8652 Valley Brook Drive. The request is divided into three part so I will
address them each in turn below.
1). Please provide more details regarding avoidance and minimization of buffer impact for the
retaining wall for this project. According to the plan, the retaining wall extends to the north 110
linear feet beyond the footprint of the house. Please describe in detail the necessity for this
extensive footprint.
Reply — The footprint of the homes vertical walls as observed from the front (or on its
dimensioned plan view) is only half of the equation here. There is a very substantial existing retaining
wall structure that supports the entire driveway along the left side of the drive. It is indicated on the plot
plan as a heavy black line running from the vertical structure on the left side to the right of way at C1
(curve 1). This retaining wall and the walkway attached to its back side are experiencing structural
issues at this time due to wasting/settling. A complicating factor with this "Driveway Retaining
Structure" is that it is located within 4 feet of the most steep terrain on the property.
I realize now that the "Heavy Black Line" representing the "Driveway Retaining Structure" is not
labeled as such and may have therefore led you to conclude the retaining wall was projecting further
north than was required.
Finally, the end of the paved asphalt cul-de-sac between the "Water Tank and the C 1 denotation" on
the plot plan provided is the only viable delivery point for the 1 ton retaining wall blocks and the
multiple tons of 57 washed stone that will be required for the back fill behind the proposed new
retaining wall. The most northern portion of the retaining wall (the portion which "ties back into the
hillside") and is mostly outside the buffer will be used to complete the containment of the stone as it is
dumped. It will form the support platform for the extended boom excavator which will be placed half
way up the hillside on the platform to deliver the 1 ton retaining wall blocks from the upper truck
delivery area down to the retaining wall building level.
In short, this northern retaining wall area is an indispensable portion of the project that is not only
integral to the viability of the project but will be the very best guard against silt or other soils entering
the zone 1 buffer.

DWR #19-0248
Request for Additional Information Reply Cont.
Page 2 of 2
2). On Page 3, Section D, Part I a of the Riparian Buffer Authorization Form it states that the
retaining wall will prevent impacts to Zone 1 of the buffer. In paragraph 1 of David Miller's
letter dated February 7, 2019 it states that the required 3:1 slope required to stabilized the bank
will enter Zone 1 of the buffer of Hare Snipe Creek. Please clarify if impacts to Zone 1 will
occur.
Reply — Zone 1 impacts will not occur.
The statement was attempting to differentiate a "no wall scenario" in which (a 3:1 slope would
enter the Zone 1 buffer and even the creek itself at some points) which is not at all the proposal.
Alternatively, with the use of the "Retaining Nall", which will be placed at a minimum of 31
feet from the top of the creek bank, and the retaining wall will not enter the Zone 1 buffer.
3). The site plan/ impact map should clearly label and show the Zone 1 and Zone 2 of the
Neuse Riparian Buffer and be measured from the top of the stream bank. These riparian
buffers parallel the stream pattern.
Reply — The retaining wall is proposed to be placed at a minimum of 31 feet from the top of
bank to remain outside the Zone 1 buffer at all times. An additional map is included (minus all
the other cluttering data on the original submission) so as to demonstrate the entire buffer and
the Zone I / Zone 2 delineation.
Please feel free to contact me at [phone] or by email at david.phillipsl358rcc.SmaiLcom
Sincerely,
David Phillips