20131013 Ver 1_More Info Received_20131011

Strickland, Bev
From: Devane, Boyd
Sent: Tuesday, November 12, 2013 3:47 PM
To: Strickland, Bev
Subject: FW: Tom Allen Driveway # 13 -1013
This is the first of many emails for this project.
From: Kevin Varnell [ mai Ito: kvarnell (a)stocksenaineerina.com]
Sent: Friday, October 11, 2013 7:57 AM
To: Devane, Boyd
Cc: Jeff Harbour (aharbour(a)nc.rr.com)
Subject: Tom Allen Driveway
Boyd,
See my responses below to your comments for the Tom Allen Driveway.
1. Show on a drawing what the final elevations and slope of the road will be so I will know what flows are going
across the buffers at the crossing and what flows are diffused across the landscape
The single family residential driveway will be constructed at grade. So the proposed contours will match the
existing for the centerline of the road except for the stream crossing where the contours are shown. The fill side
of the road will not have a ditch. The water will simply sheet flow off the road and down the hill. For the cut
side of the road, which is on the left prior to getting to the creek crossing, the ditch is created by the fill and
therefore will go straight into the stream.
2. Show on a drawing if swales or ditches will line the road or if runoff from the road will flow in a diffuse manner
across the landscape.
See comment above.
3. Show on a drawing the drainage area that is contributing stormwater to the buffer area.
There should have been calculations with a Runoff Map submitted. If you do not have the calculations or the
Runoff Map, let me know and I will email one to you.
4. Calculation of velocity of stormwater going across the buffer and how the Diffuse Flow Requirement of the Tar -
Pamlico buffer rules will be met. The Tar - Pamlico buffer rules can be found at this link. DOC
The Runoff Map may be useful for you here as the largest drainage area I have is 2.33 Acres. For a non - erosive
flow ( <2 ft /s), it only has to spread out 10 feet. For the cut areas the ditch created by the fill slope will go
straight into the stream with the drainage area being 7% impervious. I don't really have many other options
here as the driveway has to go over the culvert.
If you have any other questions, do not hesitate to let me know.
Sincerely,
Stocks Engineering, PA

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J. Kevin Varnell