20151021 Ver 1_B4792_Polk Bridge No. 4_404 REVISED Culvert Avoid and Min_20151112

[ li�,ll��'�l�' North Carolina D�partment of Transpmrtation �
���7r�z����ci1!�r ]iighway Storrsirvater Program �/'�
STQRMWATER MAFiAGEMEN7 PLA�I ��=�i
(Venian 2.01; Rcleased Oecomber 2014) FOit NCDQT PRb,tECTS
WBS Element: 3&5fi2.1.7 71P No.; 8-4792 Coun ies : Polk Pa e 3 oF 3
Bridge to GuEve�^t Auaidance and Mireimizatian
Pro osed Struttur� Surroma
Sheet No. & 5tation Sheet h1o.: 4 Station: 12+�1.63 hJumber of Culverts: Z
Draina e Area ac or s mi : 2.a9 S. E�fles Culvert WidthlDiameter ft: 11
Surface Watcr Bod : ;1)Fork Creek Culvert Hei ht ft: 6
Culvert T e: Reinforce4 Concrete Box Culvert Culvert Len th ft 48.57
Avpidanee and M�nimizatian Efforts: Have made attempts ro avoid impacts to streams and wetlands to the greatest extent practicable in the design of the preferred altemative. Design
(8ridge ta Gulve�rt) Standards in Sensrstive Watersheds was followed during khe project design due to NCWRC designatian of trout waters.
Stream Slo o Fish andlor A uatiC Li e assa a
Existin Avera e Stream Slo e%: __ 3.$0 °/a __ Existing Low Flow ChanRel Dimensions Low flow dimensions were about 24'. No
Pro osed Gulvert Sfo e%: 4.00 % in the Stream: natural defin�tiv� low flow Ch�nnel.
Gul ert Burial
Pro osed Culvert Burial De th ft: 1
Existing Streambed Material: Alluvial sand, gravel, cobbdes and boulders Proposed Low Flow Dimensions Proposed low flpw dimensipns are both barrels
Tiirough the Culv€rt: of the culvert (22'}
Proposed SillslBaffles: 1 ft. sill across both barrels in inlet and outlet.
Existing �.ow Flow Welacities in the g,g ips
Stream €Us ; '
ropose ow ow e oc�ties roug
thc Gu�vert ft!s ; $.9 fps
AEternating Low Flaw SillslBaffles: 1 fr. sill acrflss both barrels in inlet and outlet.
Culvert slope �2%.
Cuiuortl5tream Ali nment
Stream Pattems U�astream and Downsteeam None noted.
of the Culvert that Cvuld AfFect Fish
Passage and Bank Stability:
Bcd Form$ Impacted by CulverC (rifffes, Stream is on 4% grade, no pools nr gfides exist.
pools, g[ides, etc.):
Low Flow Floodplain Bench Required7 No
(provide justificationy
Sharp Bends at Inlet+0utlet? No
(d�SCribe tulvert dli nment with stream)
S4ream Reafignment Necessary? {provide �o
justificatior�}
Bank Stabiiiiation: 13A37 tons of Class I rip-rap used for approximacely 25 feet along stream on each bank. boYh at the inlet and the outl�t of the culuert.
pukfet Vetocities
Natural Stream Ghannel 2- r Veloci ft!s : N!A �latural Stream Channel 't0- r V�[oci dffls : 7.1
Pra osed Gulver[ 2- r dutlet Veloci ftls : N!A Pro osed CulverY 10- r Outlet Veloci ft!s : 4.36
Roadwa Geometric Considerations
EualuatelDescripe Roadwa Gcometric Cortstraints:
Phased construCtian to be used during bridga removal and Cui�eR installatian.