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Home My WebLink About20230552 Ver 1_ColdSpringsCrk_StrmRehab_2023_Project Description_PERMIT_20230417 twhW9/ 59{/wLtLhb {ǒĬƒźƷƷĻķ ĬǤʹ .ƩğķǤ 5ƚķķͲ bCƭb/ IǤķƩƚƌƚŭźƭƷͲ WğƓǒğƩǤ ЍͲ ЋЉЋЌ Current Condition: Cold Springs Creek is a major headwater tributary to the Pigeon River in the French Broad River Basin (Figure 1). Cold Springs Creek drains a forested landscape managed by the US Forest Service and is classified by the state as Class C, occupied by and managed for trout. A road and trail network accesses the drainage, and the area is managed for timber and is used heavily by recreationists. Figure 1. Location of the Cold Springs Creek Stream Rehabilitation project. Cold Springs Creek The Cold Springs Creek stream channel and floodplain/terraces appear to have been modified by past human management within these project stream reaches. This reach has evidence of historic logging, farming, development and subsequent channel relocation and damage. The channel is slightly entrenched, and there are sections of excessive streambank instability and erosion (photo 1). The most upstream section of this reach is adjacent to the picnic area where the floodplain has Cold Springs Creek Stream Rehabilitation Project 1 | Page been leveled and the channel confined (photo 2). Downstream the channel is entrenched, and the frequency of floodplain access has decreased from natural, resulting in lateral channel adjustment and bank erosion. These conditions exist downstream to the beaver ponds, a reach of about 0.35 miles. The current elevated rates of erosion will likely continue unless stream rehabilitation work is conducted. PHOTO 1 PHOTO 2 Cold Springs Creek Stream Rehabilitation Project 2 | Page Fall Branch Fall Branch is a tributary to Cold Springs Creek. The Fall Branch stream channel has been disturbed and channelized by past management in the area. The channel is mostly stable, but there are several sections of elevated channel instability and erosion in this 0.31-mile reach. Additionally, there is an old road crossing of timbers covered with soil that has plugged (photo 3) and is a high risk of failure and a resulting large source of sediment to the downstream channel. PHOTO 3 Proposed Action: Within these stream reaches of Flat Branch and Cold Springs Creek work is proposed to meet the following goals: restore floodplain connectivity, stabilize erosion and sources of sedimentation, would be maintained or reestablished in the construction reaches using reference data (Appendix A) to establish a more stable stream channel with high quality aquatic habitat. Natural channel design techniques will be central to the rehabilitation of these channels. Table 1 summarizes the proposed activities. Work would involve the construction of instream structures within the existing stream channel, such as log vanes and debris jams (see Appendix B Structure Typicals). In addition, work would restore floodplain access and old logging damage to meet project goals. Logs and woody debris will come from the surrounding area, harvested by the tracked excavator, and disturbed ground will be sown with native seed, mulched, and planted with woody species of native vegetation during the plant dormancy. Disturbed streambanks will be seeded, covered with Coir matting, and planted with live stakes. Additionally, aquatic organism passage (AOP) will be restored at two stream crossing by replacing culverts with natural-bottomed fords on the Forest Service Road #3526. The existing gate will need to be moved closer to the horse camp to close off these crossings from frequent Cold Springs Creek Stream Rehabilitation Project 3 | Page use. Table 1 summarizes the proposed work and Figure 1 gives general site locations on the topographic map of the Cold Springs Creek Stream Rehabilitation project reaches. Table 1. Summary of proposed structures for the Cold Springs Creek Stream Rehabilitation Project. See also Figure 1. Site Current Condition Proposed Treatment Fall Branch Fall Br Remove culvert and replace with a natural-bottom ford to pass Culvert forming an aquatic barrier AOP aquatics Little Remove culvert and replace with a natural-bottom ford to pass Fall Br Culvert forming an aquatic barrier aquatics AOP Divert channel into adjacent relic channel with construction of 20 feet FB-1 Channeled stream reach & eroded bank of new channel FB-2 Stable Place Debris Jam to enhance habitat FB-3 Impeded floodplain Remove 25 feet of streamside berm to restore floodplain access FB-4 Eroded streambank Place Debris Jam to enhance habitat FB-5 Channeled reach & eroded bank Construct Log Vane structure to divert energy from bank FB-6 Channeled reach & eroded bank Construct Log Vane structure to divert energy from bank Old log bridge w/ earth plugged and Remove earth bridge and sediment wedge and reconstruct stream FB-7 eroding into stream channel FB-8 Stable Construct Log Vane for habitat enhancement FB-9 Impeded floodplain Remove 20 feet of streamside berm to restore floodplain access Cold Springs Creek Construct Log Vane structure to stabilize bank and enhance habitat CS-1 Eroded streambank diversity Construct Log Vane structure to stabilize bank and enhance habitat CS-2 Eroded streambank diversity Construct Log Vane structure to stabilize bank and enhance habitat CS-3 Eroded streambank diversity Construct Log Vane structure to stabilize bank and enhance habitat CS-4 Eroded streambank diversity CS-5 Mostly stable Place Debris Jam to enhance habitat Construct Log Vane structure to stabilize bank and enhance habitat CS-6 Eroded streambank diversity Construct Log Vane structure to stabilize bank and enhance habitat CS-7 Eroded streambank diversity CS-8 Mostly stable Place Debris Jam to enhance habitat Construct Log Vane structure to stabilize bank and enhance habitat CS-9 Eroded streambank diversity CS-10 Stable Add to existing Debris Jam to enhance habitat Erosion control measures will be taken on all soil disturbed by the proposed work, including seed, mulch, and General Coir matting on stream banks Cold Springs Creek Stream Rehabilitation Project 4 | Page Figure 2. Locations of proposed stream rehabilitation work in Cold Springs Creek and its tributary Flat Branch. Cold Springs Creek Stream Rehabilitation Project 5 | Page APPENDIX A Design Features using Regional Curve Relationships and USGS Equations Cold Springs Creek REGIONAL CURVES: 0.682 Bankfull Cross-Sectional Area vs. Drainage Area: y = 21.61x = 46.3 ft 0.76 Bankfull Discharge vs. Drainage Area: y = 100.64x = 236.0 cfs 0.37 Bankfull Width vs. Drainage Area: y = 19.05x = 28.8 ft 0.31 Bankfull Mean Depth vs. Drainage Area: y = 1.11x = 1.57 ft Ϋ ǞŷĻƩĻ ǣ ў ķƩğźƓğŭĻ ğƩĻğ ƚŅ Ќ͵ЉА ƭƨǒğƩĻ ƒźƌĻƭ USGS STREAM STATS: Bankfull Cross-Sectional Area (Range) = 31.3 - 45 ft2 Bankfull Width (Range) = 18.4 27.8 ft Bankfull Mean Depth (Range) = 1.53 1.56 ft Flat Branch REGIONAL CURVES: 0.682 Bankfull Cross-Sectional Area vs. Drainage Area: y = 21.61x = 14.2 ft 0.76 Bankfull Discharge vs. Drainage Area: y = 100.64x = 63.0 cfs 0.37 Bankfull Width vs. Drainage Area: y = 19.05x = 15.2 ft 0.31 Bankfull Mean Depth vs. Drainage Area: y = 1.11x = 0.92 ft Ϋ ǞŷĻƩĻ ǣ ў ķƩğźƓğŭĻ ğƩĻğ ƚŅ Љ͵ЎЍ ƭƨǒğƩĻ ƒźƌĻƭ USGS STREAM STATS: Bankfull Cross-Sectional Area (Range) = 11.2 13.3 ft2 Bankfull Width (Range) = 9.97 14.1 ft Bankfull Mean Depth (Range) = 0.91 1.06 ft Cold Springs Creek Stream Rehabilitation Project 6 | Page APPENDIX B STRUCTURE TYPICALS Figure 3. Typical detail and photo of a completed Debris Jam (Big Creek, Uwharrie RD, 2022). Cold Springs Creek Stream Rehabilitation Project 7 | Page Figure 4. Typical detail and photo of a completed log vane (Cantrell Creek, Pisgah RD, 2019). Cold Springs Creek Stream Rehabilitation Project 8 | Page APPENDIX C PROPOSED CHANGES IN CROSS SECTION AND LONGITUDINAL PROFILE AT TYPICAL CONSTRUCTION SITES Cold Springs Creek Stream Rehabilitation Project 9 | Page Cold Springs Creek Stream Rehabilitation Project 10 | Page Cold Springs Creek Stream Rehabilitation Project 11 | Page