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Home My WebLink AboutNCG530079_correspondence_20230622mcgdf TO: FROM DATE: RE: Shaping Communities Together MEMORANDUM G. Landon Davidson, P.G, CPM — NCDEQ Regional Supervisor Kyle Seaman, P.E. — Project Manager June 16, 2023 �_ C�) Proposed Setzer Fish Hatchery Heavy Sediment Removal System Sand Disposal Alternatives The Bobby N. Setzer (Setzer) Fish Hatchery is located in Pisgah National Forest about 12 miles from Brevard and 37 miles from Asheville, North Carolina. Setzer is a cold -water rearing facility which produces rainbow, brook and brown trout. The facility is supplied with water from the Davidson River, and Grogan Creek. The facility has several water supply issues that impact production. Sediment accumulation following storm events is one of them. This naturally occurring material is mostly inorganic sedimentary bed load from the influent streams that become suspended in the water column during storm events. This sediment load, which is comprised mostly of sand and silt, passes into the hatchery system since it is not removed by the coarse screens at the intake. As the flow velocities decrease in the various rearing tanks in the hatchery this sand/silt settles out of suspension and then must be manually removed by Hatchery staff to prevent flow restrictions and or stoppages. The potential for loss of flow, even for a short period of time, can cause massive fish loss and requires several hours of hatchery staff time to correct. The proposed Setzer Improvements project intends to remove this sand/silt well before it enters the hatchery process. This will help prevent the sand/silt from causing flow stoppages and will also prevent it from settling in the rearing units where it has the potential to mix with uneaten fish food and fish waste. As seen in the attached drawings, a vortex separation system which uses centrifugal force to separate the sand/slit from suspension in the water will be utilized for this purpose and will be located adjacent to the two intakes. It is assumed that a majority of the material that will be removed by the proposed system will be sand as silt is much finer and is carried through the system to be discharged back to the river through the facilities outfall without settling out of suspension. Once captured the sand is fluidized using the clean water at the discharge and pumped out of the unit utilizing a submersible wastewater pump capable of pumping sand and solids. There are several alternatives for dealing with this sand once pumped out of the unit. Land application, hauling the material off -site for disposal or return the sand and river/creek water back to the bodies of water they came from. As seen in the attached drawing a majority of the site is used for the hatchery process. In the portions of the site not used for the hatchery process a large amount of the area is in 100-year floodplain and trout buffer which would not be suitable for loose fill material. Additionally, stabilizing the loose material to prevent erosion and potential release to surface waters would create an ongoing maintenance issue. G. Landon Davidson June 16, 2023 Page 2 of 2 These restrictions severely limit the areas for land application, especially in the volumes anticipated. Accordingly, land application is deemed unfeasible due to site limitations. Hauling material off -site would require further dewatering to make this alternative feasible. This would increase the capital cost of the project marginally but more significantly would increase O&M costs for Setzer due to hauling and proper disposal fees. Due to the increased O&M costs this alternative was deemed unfeasible. The pumping of naturally occurring sand back to the bodies of water they came from is a common practice at Water Treatment Plants as a way to deal with sand and silt that accumulates at their screened raw water intakes. The site has enough space for these technologies to be located near the intakes. The O&M and capital costs are the least of the three alternatives evaluated. Further by returning the sand and silt back to the river prior to the rearing tanks, the impact of the hatchery process on the natural sediment transport of the Davidson River and Grogan Creek is minimized while also removing the potential of introducing accumulated solids produced by the facility to the surface waters. For these reasons returning the sand and silt removed by the vortex separation system was deemed the most feasible alternative for this project. MCGILL ASSOCIATES 55 BROAD STREET, ASHEVILLE, NC 28801 / 828.252.0575 / MCGILLASSOCIATES.COM 25' TROUT STREAM BUFFER (TYP) II? \ \ AVEL GR- PLAN P FORES � s n PROPOSED PRODUCTION RACEWAYS EXISTING PARKING LOT TO BE RENOVATED AND COVER STRUCTURE / DAVIDSON RIVER - — — I I I I PROPOSED ASPHALT ROAD DAVIDSON RIVER DAM AND INTAKE r �� 1 --- R — — — R — — — R _ _ _ R _ PROPOSED EQ BASIN , I U-105 R DAVIDSON RIVER PROPOSED HEAVY SEDIMENT I — — — FE—1 03 REMOVAL SYSTEM I o / I r / L -102 El _ �DAVIDSON- / I -EXISTING BUILDINGS TO REMAIN, i ' X—X__+ _ _ I EXISTING RESIDENCES TO REMAIN 1. Elmw�� ..eee.•.i.2. ► .r ZONE A FLOOD BOUNDARY (TYP), APPROX 100—YR FLOODPLAIN DAVlDSON RI=,a . C-106 I � X—X C x PROPOSED BROODSTOCK RACEWAYS PROPOSED 2" MILL AND OVERLAY AND COVER STRUCTURE (TYP), SF 9.5C ASPHALT R 55 Broad Street �� v Asheville, NC 28801 828.252.0575 NC Firm License # C-0459 mcgil lassociates.com PROPOSED STORAGE BUILDING PROPOSED HEAVY SEDIMENT REMOVAL SYSTEM RIN \ EXISTING RESIDENCES I REMAIN — a, � � ,(I \' �...OREEK �� PROPOSED STORMWATER � \� GROGA" WET POND PROPOSED HATCHERY BUILDING�\ PROPOSED PUBLIC RESTROOM EXISTING BUILDING TO REMAIN j I PROPOSED CONCRETE PAD FOR EFFLUENT WASTE TREATMENT / -sly--- I � \ �1 I� 1 I SPRING I�j I I tj /i / C-102 / / // / ati /RpG P� / i' GROGAN CREEK DAM AND INTAKE BOBBY N. SETZER STATE FISH HATCHERY RENOVATION SCO PROJECT # 19-20324-02A NC WILDLIFE RESOURCES COMMISSION I I TRANSYLVANIA COUNTY, NORTH CAROLINA NO. DATE I BY I DESCRIPTION 120 0 60 120 240 GRAPHIC SCALE DIVISION VALUE = 120 FEET OFFICE MANAGER DESIGNER M. CATHEY N. CROOM PROJECT MANAGER REVIEWER K. SEAMAN B. CATHEY OVERALL SITE PLAN AND SITE SHEET INDEX PLAN DATE PROJECT # FUNDING # J U LY 2022 19.00124 SHEET C=1 01 PROPOSED SLIDE GATE W/ S-6" x 5'-0" CLEAR OPENING 24" PLUG VALVE PLAN >-18" PLUG VALVE 30" PLUG VALVE 30"x30"x18" TEE BOBBY N. SETZER 4' 0 2' 4' 8' SHEET STATE FISH HATCHERY RENOVATION DAVIDSON RIVER INTAKE 55 Broad Street ' c PROJECT 1 -2 24- 2A GRAPHIC SCALE DIVISION VALUE: 1/4" = V-0° IMPROVEMENTS ® J��,y SCO# 9 03 0 PLAN AND SECTION C=501 Asheville, NC 28801 OFFICE MANAGER DESIGNER 828.252.0575 �� NC WILDLIFE RESOURCES COMMISSION M. CATHEY NC Firm License # C-0459 0 PROJECT MANAGER REVIEWER DATE PROJECT # FUNDING # C9 mcgillassociates.com TRANSYLVANIA COUNTY, NORTH CAROLINA NO. DATE BY DESCRIPTION K. SEAMAN JULY 2022 19.00124 SECTION A -A ON: 2385.0' 2372.34' BASE ELEVATION: 2370.92' FOR REVIEW ONLY BOBBY N. SETZER 3' 0 2' 5. SHEET STATE FISH HATCHERY RENOVATION I = = = = = GROGAN CREEK INTAKE 55 Broad Street <*> PROJECT 1 -2 24- 2A GRAPHIC SCALE DIVISION VALUE: 3/8" = V-0° IMPROVEMENTS ® SCO# 9 03 0 PLAN AND SECTION_Asheville, NC 28801 OFFICE MANAGER DESIGNERMcg 828.252.0575 NC WILDLIFE RESOURCES COMMISSION M.CATHEY NC Firm License # C-0459 PROJECT MANAGER REVIEWER DATE PROJECT # FUNDING # mcgillassociates.com TRANSYLVANIA COUNTY, NORTH CAROLINA NO. DATE BY DESCRIPTION K. SEAMAN JULY 2022 19.00124