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Home My WebLink About20140762 Ver 4_RE_ R-2915 B_ Station 165 request to swap PSH with a dissaptor pad_20200312 Wanucha, Dave From:Hining, Kevin J Sent:Wednesday, March 11, 2020 11:23 AM To:Wanucha, Dave; Beckwith, Loretta A CIV USARMY CESAW (USA) Subject:RE: R-2915 B, Station 165 request to swap PSH with a dissaptor pad Attachments:pipe outlet without ditch.pdf Hey Lori and Dave, Hoping to answer your questions with one email, but let me know if you need more information. Both the planned PSH and proposed dissipator pad location will be a good distance from the stream. Probably 30+ feet away. So, no impacts to the creek are planned with either the PSH or proposed dissipator pad. Also, the dissipator pad will be smaller than the PSH. That’s really our only reason for making this request - to have a smaller footprint than the PSH. Also, the change will require the contractor to tear up less ground and vegetation. The PSH at station 165 was scheduled to have a footprint (rock and matting combined) of approx. 16’ x 12’. The proposed dissipator pad would be trapezoid shaped, and composed of class B rip rap over geotextile (see attachment above for standard design). Since the pipe is 15”, our proposed dissipator pad would be 30” wide at the pipe outlet, extending 60” out from the pipe, and widening out to 60” . So, much smaller footprint than the PSH, and we could literally build it by hand without the need of ripping out existing trees and shrubs (which would be required in order to install the PSH). There is very little flow during storms (none when it’s not raining). So it would just be a way to prevent a scour hole from forming. It’s a flat area, so the flow would probably rarely make it to the creek. My assumption is it would just soak into the sandy soil that is in the area. To back this claim up, the pipe system has been in place for a couple of years and there is no defined channel currently from the pipe outlet to the stream. Dave – hopefully my interpretation of the site was similar to yours, but let me know if not. Regarding your question about what changed - I do not know what changed, or why there was a PSH originally planned at the location. The drainage area is primarily private property, so possibly a private driveway pipe or spring box was altered outside of our RW. I’m not sure. When asked about the proposed PSH, the NCDOT hydraulic engineer I spoke to said “the site is at the outlet of a 15” RCP which drains the roadway coming to two 2GI’s. There is very little runoff being discharged at this location. A rip rap pad should function more than adequately.“ So, that makes me think that possibly nothing changed, and the request for a PSH was not necessary in the first place. That’s all I have to go on. All of this said, we’ve paid the contractor to put in a PSH, so we are fine going forward with that approach. I just thought this alternative might be more environmentally friendly since the area is vegetated and in good shape. But, not sure what all is involved to make the change. Thanks, Kevin Kevin Hining Division 11 Environmental Officer North Carolina Department of Transportation 336 903 9129 office 1 828-386-7202 cell kjhining@ncdot.gov 801 Statesville Rd. PO Box 250 North Wilkesboro, NC 28659 Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties. _____________________________________________________________ From: Wanucha, Dave <dave.wanucha@ncdenr.gov> Sent: Tuesday, March 10, 2020 3:41 PM To: Beckwith, Loretta A CIV USARMY CESAW (USA) <Loretta.A.Beckwith@usace.army.mil> Cc: Hining, Kevin J <kjhining@ncdot.gov> Subject: Re: \[External\] RE: R-2915 B, Station 165 request to swap PSH with a dissaptor pad I’m wondering what changed from the original upstream drainage? Is there less stormflow than when originally designed? If so, why? Need more explanation. Dave Wanucha Division of Water Resources 401 & Buffer Transportation Permitting NC Department of Environmental Quality 336-776-9703 office 336-403-5655 mobile Dave.Wanucha@ncdenr.gov NC DEQ Winston Salem Regional Office 450 West Hanes Mill Road, Suite 300 Winston Salem, NC 27105 Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties. On Mar 10, 2020, at 3:17 PM, Beckwith, Loretta A CIV USARMY CESAW (USA) <Loretta.A.Beckwith@usace.army.mil> wrote: 2 CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to report.spam@nc.gov Kevin – what would the footprint of the dissipator pad be compared to the footprint of the PSH? For example, the PSH would have extended 10 lf in the stream, and the dissipator pad will extend 20 lf… Dave – do you have any objections to this? Thanks, Lori From: Hining, Kevin J <kjhining@ncdot.gov> Sent: Tuesday, March 10, 2020 12:09 PM To: Wanucha, Dave <dave.wanucha@ncdenr.gov>; Beckwith, Loretta A CIV USARMY CESAW (USA) <Loretta.A.Beckwith@usace.army.mil> Subject: \[Non-DoD Source\] R-2915 B, Station 165 request to swap PSH with a dissaptor pad Hey Dave and Lori, I have a modification I would like to seek your approval on, regarding a proposed pre-formed scour hole (PSH) at the outlet of a stormwater pipe on R-2915 B, at Station 165 (Ashe County). Dave visited the site with us last month. I’ve attached a photo above, and the plan sheet as well, for reference. The contractor has yet to install the PSH, and currently the pipe outlet is over sand. Despite this, it has only caused a small depression in the ground, suggesting the pipe carries very little stormwater. Since the surrounding area is vegetated, we were hoping to replace the proposed PSH with just a dissipator pad. We could do the latter by placing rock from above the pipe, without having to disturb much of the surrounding vegetation. Both our roadside environmental engineer and hydraulics staff in Raleigh were fine with the modification. In their view, the proposed PSH was not necessary given the minimal amount of stormwater the pipe carries. So, I’m writing to see what you might need from me in order to swap out the PSH at this location with a dissipator pad. Also, you will noticed the pipe needs to be shortened. We plan to remove the excess length of pipe, and not sure why that wasn’t done in the first place. If this email is all that is needed to make the modification, then great, but just let me know if you need more information. Or, if this level of documentation is overkill, then let me know that as well:) Thanks, Kevin Kevin Hining Division 11 Environmental Officer North Carolina Department of Transportation 336 903 9129 office 828-386-7202 cell kjhining@ncdot.gov 3 801 Statesville Rd. PO Box 250 North Wilkesboro, NC 28659 <image001.png> Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties. _____________________________________________________________ Email correspondence to and from this sender is subject to the N.C. Public Records Law and may be disclosed to third parties. 4