Phillips River Watershed. Bank Protection Prescription for Bend B on the Phillips River, February 2006

Transcription

1 Phillips River Watershed Bank Protection Prescription for Bend B on the Phillips River, 2006 February 2006 Prepared for: Cascadia Forest Products 65 Front Street, Nanaimo, BC V9r 4H9 Submitted by: M. C. Wright and Associates 2231 Neil Drive Nanaimo, BC V9R 6T5 Phone/Fax: (250) mcw-assoc@shaw.ca And Fisheries and Oceans Canada Habitat and Enhancement Branch 4166 Departure Bay Road Nanaimo, BC V9T 4B7 Phone: (250) DoucetRu@pac.dfo-mpo.gc.ca M.C. Wright and Associates Prescription Series Phillips River Groynes

2 1.0 Introduction Phillips River is located approximately 250 km northwest of Vancouver British Columbia. Phillips River flows southwest through the Pacific Range of Coast Mountains and drains into the head of Phillips Arm. It drains an area of approximately 450 km 2 and has a length of 38.9 km. (Hatfield Consultants Ltd. 2001) (Figure 1 and Drawing Phillips 10). Phillips River supports five Pacific salmon species; Coho, Chinook, Sockeye, Chum and Pinks. Of the five species pink salmon escapements are the largest with even year runs averaging 186,400 between 1985 and 1994 (Hatfield Consultants Ltd.). The Phillips River was assessed by M. Miles and Associates Ltd. (2000) to determine what remedial actions could be taken to stop erosion problems along the left bank of the Phillips River. In 2005 M.C. Wright and Associates and representatives of DFO inspected Bend B to determine the extent of erosion since it was last measured in 2001 and to determine what works would be required to protect Bend B from further erosion. 2.0 Location The closest communities are Campbell River (70 km southwest on Vancouver Island) and Powell River (95 km south on the Sunshine Coast). The work site is adjacent to Clearwater Creek. 3.0 Objectives 1. Collect the necessary information required to develop a prescription to protect the left bank of the Phillips River at Bend B using rock groynes. The information required was longitudinal and cross-sectional profiles of the Philips River mainstem at Bend B. 2. Create engineered drawings for the construction of 17 rock groynes. 4.0 Rationale Between 1991 and 1999, >210 m of bank erosion occurred at Bend B (the site of interest for this prescription) (Miles 2000). Miles (2000) has identified that bank erosion at Bend B could impact the mainline road and Bend A if nothing is done. Silt generated as the result of bank erosion at Bank B has likely caused aggrading of spawning and rearing habitat downstream as well as reduced incubation success at downstream spawning habitat. Between 2000 and 2005 the Phillips River has continued to under go bank erosion at an average annual rate of approximately 5.8 meters. Since last measured in 2000, an additional 29 M.C. Wright and Associates Prescription Series Phillips River Groynes

3 m of bank has eroded. As of June 7, 2005, 62m of riparian forest is left between the Phillips River mainline and the Phillips River. If this situation is allowed to continue the chances of loosing the Phillips mainline logging road from erosion at Bend B is high. The continued erosion of the river bank at Bend B combined with the potential loss of the mainline logging road would severely impact the already declining wild salmon populations by destroying spawning and rearing habitat. In the Taylor River Watershed on Vancouver Island a similar situation occurred along the Taylor River Mainline logging road. At that time M.C. Wright and Associates in collaboration with the Department of Fisheries and Oceans developed a strategy to install rock groynes along the right bank of the river to alleviate or reduce the hydraulic stress at critical locations along the river bank. Installing the rock groynes reduced the hydraulic forces where bank materials were erosive improving bank stability. Monitoring has shown that erosion has been eliminated along the bend and has started to train the thelwag of the river away from the Taylor River mainline. 5.0 Assessment Works On June 7, 2005, Mike Wright, M.C. Wright and Associates and, Russ Doucet and Rick Senger from DFO conducted a field assessment of Bend B to determine how much of the remaining bank has been lost since At the time of the survey the Phillips River had eroded the left bank to within 65 meters of the Phillips River mainline logging road. On September 30 th, 2005, M.C. Wright and Associates personnel and Greg Keel of Parallel-Geo Services surveyed Bend B using RTK- GPS technology. Representative photographs of work site are presented in Plates 1 through 11. Details for the proposed works are presented in Table 1 and Drawings Phillips 10, 20 and Prescription The primary objective of the project is to construct 17 groynes to reduce the hydraulic forces along Bend B to increase bank stability and reduce sediment transport to downstream spawning and rearing habitat 6.1 Accessing the Work Site Access to the work site will be via barge for the equipment. Personnel will be moved by boat, floatplane or helicopter to the Phillips River Camp which is owned and operated by Cascadia Forest Products. From the camp, equipment and personnel can access the work site through the current network of logging roads. The access from the mainline to the work site will require upgrading old spur roads (Drawing Phillips 20). M.C. Wright and Associates Prescription Series Phillips River Groynes

4 6.2 Creating Access Old spur roads will be rehabilitated to allow equipment access to the work site. The location of the temporary road is indicated on the plan view drawings Phillips 10 and 20. Spoil from the work site will be transported to a designated spoil site to be determined in advance of commencement of the project. 6.3 Isolating the Site It is not practical to isolate the work site. As with other groyne installations an agreement with DFO to install the groynes in the wet will be required. The Taylor River groynes were installed in the wet because it was virtually impossible to isolate the work site. Silt is generated when keying any groyne into the riverbed. The operator will be required to excavate for a set period of time, stop and allow for the area to clear before resuming excavation. Water quality will be monitored to ensure sediment load is kept within acceptable limits. Turbidity levels will be set by DFO. Once the groyne is keyed in and construction is above the water line siltation is minimal. 6.4 Groyne Construction The bank stabilization plans call for the installation of 17 rock groynes spaced at 25 m intervals along the left bank of Bend B (Table 1 and Drawings Phillips 10, 20 and 30). The first groyne will be constructed at Groyne locations lengths and rock quantities are presented in Table 1. Rock to construct the groynes will be evenly graded from 600mm to 1000mm nominal diameter. Once the groynes are installed the excavator(s) will scalp the gravel bar along the right side of the channel and side cast the material against the left bank between each groyne to cover the fine textured sediments and gravels which will increase stability between the groynes. The gravels placed on the banks should be placed to a thickness of approximately 300mm. A plan view drawing and cross sections of the work site are presented in drawing Phillips 20. Groyne plan and sections are presented in Phillips Environmental measures All areas disturbed during construction will be seeded with West Coast Hemlock Mix. The seed mixture is comprised of: 5.0% Canadian Bluegrass 20.0% Alsike Clover M.C. Wright and Associates Prescription Series Phillips River Groynes

5 5.0% Azay Sheeps Fescue 30.0% Creeping Red Fescue #1 5.0% Orchard Grass 10.0% Red Top Bentgrass 15.0% Timothy 10.0% Birdsfoot Terfoil Because spawning salmon are known to enter this system as early as late August this prescription should be done during the low flow period between late July and September 1. Excavators and trucks will be in good repair and will have to be power washed prior to working at the site. A 20 m oil containment boom will have to be on-site at all times. The oil containment boom will be deployed at all times. Spill kits for the excavators will be required at all times. A supply of oil absorbent pads will also be necessary. All fuelling of equipment will be done on the logging road away from the channel. Supplies to be on-site to contain silt if necessary are; 1. 2 x 4 inch trash pumps and 600 ft of discharge hose per pump 2. tarps, rope and a roll of polyethylene 3. sandbags. 7.0 Recommendations: It should be specified in the bid package that excavator operators have experience with stream restoration. The operator s qualifications should be provided with the bid. The contractor will not be allowed to substitute operators unless approved by the site manager. Monitoring of the groynes should occur after the area has experienced a number of flood events (winter of 2007). If funding is not sufficient to complete the project in 2007 then consideration should be given to completing the project in It is critical that the first 11 groynes are built in M.C. Wright and Associates Prescription Series Phillips River Groynes

6 8.0 Costing: A breakdown of costs associated with installing the rock groynes are provided in Table References Hatfield Consultants Ltd Reconnaissance (1:20,000) Fish and Fish Habitat Inventory of Phillips River Watershed WSC: Volume 1 of 2. Prepared for Ministry of Environment, Lands and Parks Lower Mainland Region, Surrey BC. M. Miles and Associates Ltd Phillips River Mainline Bank Erosion Opposite Clearwater River. Prepared for Stillwater Timberlands, Weyerhaeuser Company Ltd. M.C. Wright and Associates Prescription Series Phillips River Groynes

7 Plate 1. This photograph shows the location of cross section 1. Plate 2. This photograph shows the location of Plate 3. This photograph shows the location of Cross section #2. Cross section #3.. Plate 4. This photograph shows the location of Cross section #4. Plate 5. Thid photograph shows the location of Plate 6. Thid photograph shows the location of Cross section # 5. Cross section # 6.

8 Plate 7. Shows the location of Cross Section #7. Plate 8. Shows one of the braids at Cross Section #7. \ Plate 9. Shows all of the braids in the Phillips River located at Cross Section #7.

9 Plate 10. This photograph shows the control station for the survey and subsequent surveys Plate 11. This photograph shows the GPS equipment used to survey the Phillips River.

10 Phillips River Bank Erosion Bend B Table 1. Rock Quantities needed to Construct 17 Groynes at Bend B in the Phillips River. m 3 m 3 m 3 Length of Groyne Number Section Quantity Key Plus 20% Groyne at the Centerline Total Amount of Rock Required Plus 20% Contingency m 3

11 Table 2. Estimated costs for the Phillips River Groyne Project at Bend B, Unit Expanded Item # Construction Item Description Qty Unit Cost Cost 1 Mob/Demob lump sum barging 2 units $ 5,000 $10, site transport pick-up trucks 2 trucks 20 day $ 200 $4, minor purchases and equipment rentals pumps, fabric, netting,culvert. 3 week $ 1,500 $4, Prep quary for blasting 1-30 ton track excavator 8 hr $ 160 $1, Rock quarry riprap development 2300 cu.m riprap at approx 10 km from site 2300 cu.m $ 12 $27, prepare access from the mainline to groyne locations 1-20 tonne and 1-30 tonne track excavators 30 hr $ 300 $9, Hauling rock to the construction site 2 rock trucks 115 hr $ 200 $23, rock structures at approx 175 cu.m 1-20 tonne and 1-30 tonne track excavators (one loading and one placing) 9 units $ 3,795 $34, rock structures at approx 90 cu.m 1-20 tonne and 1-30 tonne track excavators (one loading and one placing) 8 units $ 2,760 $22, approx 750 cu.m river rock/gravel between groynes 1-20 tonne and 1-30 tonne track excavators 50 hr $ 300 $15, approx 750 cu.m river rock/gravel between groynes trucking 45 hr $ 200 $9, river bar reshaping 1-20 tonne and 1-30 tonne track excavators 35 hr $ 300 $10, LWD complexing-procurement and installations 1-20 and 1-30 tonne track excavators and 2 trucks 30 hr $ 500 $15, site cleanup/deactivation 1-20 tonne and 1-30 tonne track excavators 25 hr $ 300 $7, room and board for 4 crew, 1 supervisor,1 other camp 20 day $ 600 $12, Supervisor Project supervisor 24 day $ 500 $12, Technician/Laborer Survey Tech/General Labour/Biological Tech. 24 day $ 350 $8, Construction subtotal: $225, Post construction 1 project report As built survey and reporting 10 day $ 400 $4, monitoring Project supervisor, technician, helicopter, equipment and report 1 day est $3, Post-construction subtotal: $7, Total (Excluding Taxes): $232,015.00

12 Source Hatfield Consultants Limited.

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