At the request of Slocan Forest Products Ltd. on behalf of the Ministry of Forests (MOF), Quesnel District, and the Watershed Restoration Program of Forest Renewal British Columbia (FRBC), Carmanah Research Ltd. has conducted a Sediment Source Survey (SSS) of the Nazko River watershed. This document presents the findings of the SSS, which is a component of an Integrated Watershed Restoration Plan also being undertaken as part of the same contract.

As one of the procedures in the Watershed Restoration Program (WRP), the main objective of the SSS, as specified in the contract, is to identify overview level deficiencies and problems of existing roads, landslides and gullies, and to determine sites that require prescriptions for rehabilitation or restoration works.

The scope of the SSS is the overview examination of the condition status of roads, landslides and gullies through a combination of aerial imagery analysis, aerial reconnaissance, and limited, semi-quantitative field visits in order to confirm the nature, locations and severity of impacts. The results of the SSS will be used to determine sites requiring prescriptions for rehabilitation or restoration works and indicate areas of concern that may be dealt with through restoration projects.

The Nazko River watershed (Figure 1) is located in the Interior Plateau of central British Columbia. The Nazko River is a fifth order stream with a drainage basin area of 415,000 ha. The Nazko River mainstem is 157 km in length. Major tributaries of the Nazko River include: (in order of confluence with the mainstem upstream from the mouth) Snaking River, Redwater Creek, Michelle Creek, Clisbako River, Canyon Creek, Wentworth Creek, Tautri Creek, Brown Creek, Aneko Creek, Goering Creek, and Ross Creek. Udy Creek is a major tributary of Snaking River. Nazko Lakes Provincial Park encompasses the upper portion of the Nazko River mainstem and the lower reaches of Goering Creek, and includes Tchusiniltil, Tzazati, Nastachi, Tanilkul, and Nazko lakes. Settlements within the watershed include the community of Nazko located near the confluence of the Nazko River and Redwater Creek, and the Nazko Indian Reserve at the confluence of the mainstem and Michelle Creek. Quesnel is the nearest city to the watershed, and is situated approximately 90 km east of Nazko.

The Nazko River watershed lies within the physiographic regions of the Chilcotin and Nechako Pleauteaux. The topography is made up of gently rolling, undissected uplands interspersed with numerous small lakes and wetland areas. The bedrock geology is of volcanic origin, consisting of gently dipping, Miocene/Pliocene olivine basalt flows. The surficial materials are mainly unconsolidated glacial deposits. Fluvial and glaciofluvial deposits dominate the mainstems of the Nazko and Clisbako rivers, while the remainder of the basin is overlain by basal and ablation morainal deposits of till (Lord and Walmsley, 1988).

The biogeoclimatic zones of the study area fall within the Sub-Boreal Pine-Spruce, Sub-Boreal Spruce and Montane Spruce zones (Figure 2). The Sub-Boreal Pine-Spruce zone is dominated by lodgepole pine with some minor white spruce in regenerated areas. Hybrid engelmann-white spruce and subalpine fir are the major species in the Sub-Boreal Spruce zone, with lodgepole pine present in drier regions. The Montane Spruce zone is mainly composed of engelmann and hybrid spruce with some subalpine fir (MOF, 1992).

The climate of the study area is characteristically dry. Average annual temperature is approximately 2° C, with average summer highs in July-August of 14° C and January winter lows averaging -13° C. Average annual precipitation is approximately 440 mm, with an estimated 40% falling as snow. The majority of rainfall occurs in June, July and August.

The Water Survey of Canada gauging station, Nazko River above Michelle Creek (No. 08KF001), has a flow record going back to 1965. Mean annual flow over the period of record is 4.61 m3s-1. To estimate the mean annual flow for the Nazko River at the mouth, a conversion of the measured discharge by a ratio of the total watershed area (415,000 ha) over the gauged watershed area (324,000 ha) gives a discharge of 5.9 m3s-1. Average maximum and minimum monthly discharges take place in May and January-February respectively. Summer and winter 7 day low flows calculated by Rood and Hamilton (1995) using records from 1981 to 1990 are 1.27 m3s-1 and 0.96 m3s-1 respectively.

The major land use activities within the watershed are agriculture and forestry. Some mineral exploration also take place in the Michelle Creek and upper Clisbako River sub-basins. Farming is predominant on the mainstem downstream of the Nazko reserve. Surface and groundwater extraction for irrigation, stock watering and domestic use impact the hydrological regime of the watershed mainly in the summer. Furthermore, bank erosion, stream sedimentation and fording impacts from cattle are of a high level of concern in certain areas (Rowland and MacDonald, 1996, p.313). At the present time, Michelle Creek is designated a community watershed. However, the sub-basin is in the process of being removed from that designation as it is no longer used as a domestic water source for the Nazko Indian Reserve (T. Gale, pers.comm.).

The watershed falls within the boundaries of the Quesnel (61), Chilcotin (65) and Williams Lake (62) Forest Districts of the Cariboo Forest Region. Of the 415,000 ha of the Nazko River watershed, 90% of the area is forested. Harvesting in the study area began in the mid-1960’s, the majority taking place over the past 15 years. Forest licensees operating in the watershed include Slocan Forest Products Ltd., Lignum Ltd., Riverside Forest Products Ltd., Tolko Industries Ltd., Weldwood of Canada Ltd., and West Fraser Mills Ltd.; in addition to the MOF Small Business Forest Enterprise Program (SBFEP). From 1982 to 1997, logged and areas proposed for logging is estimated at 6.3% of the watershed; less than 2% of the area was logged prior to 1982. Within the Nazko watershed, the lower portion of the Snaking River has been identified as areas of concern with regard to potential logging impacts of fisheries habitat (Rood and Hamilton, 1995).

The predominant salmonid fish species in the Nazko River watershed is chinook salmon. Resident rainbow trout are also prevalent, mainly in tributary sub-basins. Kokanee and mountain whitefish have also been documented in some mainstem lakes (FISS, 1994; Imhof and Sutherland, 1996). Salmonid spawning density is highest from the mouth of the Clisbako River downstream to Marmot Lake (Quigley, 1998, fax corr.). The distribution of salmonid presence has been updated during a Fish Passage Culvert Inspection Procedure carried out during July and August, 1997 (Carmanah Research Ltd., in progress) and where applicable, those results have been included in this report.

The methods used in this SSS followed those outlined in the Technical Specifications for the Integrated Watershed Restoration Plan, Section 9.0. The synopsis below presents a summary of the steps in the SSS methodology.

The office review of existing information entailed the collection of available reports, maps and aerial photographs. Reports included the WRP overview assessment reports, the Interior Watershed Assessment Procedure (Carmanah Research Ltd., 1997), Overview Fish Habitat Assessment Procedure (Chew, 1997) and Fish Habitat Inventory (Imhof and Sutherland, 1996). Maps reviewed included the digital (provided by MOF under this contract) and hardcopy 1:20,000 Terrain Resources Inventory Maps (TRIM), forest cover maps, 5-Year consolidated development plans, and Co-ordinated Access Management Plans (for Chilcotin and Williams Lake Forest Districts only). Additional road, recreation and physiographic information was provided on the Quesnel T.S.A. Nazko Road Users map, Quesnel District forest road atlas, Cariboo Forest Region (West) Recreation map, and geology, soils and biogeoclimatic classification maps. 1:15,000 scale aerial photograph coverage from 1996, 1995, 1993, 1992 and 1991 was also reviewed. With the information gathered, preliminary base maps were prepared showing the road inventory, and the location and origin (natural or harvesting-related) of landslide tracks and surface erosion. No gullies were present in the watershed. Recreational sites and the community watershed of Michelle Creek were also included on the maps.

Based on the review of information collected, a field schedule was prepared outlining the areas and road networks to be ground-truthed in the field. Due to the large size of the watershed and the relatively low relief and potential for sediment source problems, it was determined by MOF that the amount of roads to be assessed in the field would be 15-20% of the entire road network. Consequently, the role of the office review of information was very significant in defining those areas to be field checked under the objectives of the SSS and WRP.

Upon receipt of written approval by the Ministry Representative, the field work commenced in May 1997. Two helicopter reconnaissance overview flights took place on May 16th and 22nd. The flights were scheduled during high flow to ensure that problem sites could be easily identified. A limited number of impacted sites requiring field checking which were not already included in the original field scheduled were added at this point.

The main focus of the field work centered around road sediment source problems due to the absence of harvesting-related landslides and gullies in the watershed. The field work methodology was based on the guidelines for conducting overview field inspections of existing road conditions from the Resource Road Rehabilitation Handbook: Planning and Implementation Guidelines (Interim Methods) (Moore, 1994). Field data sheets and photographs were utilized to document the road-related sediment source problems observed in the field, and their locations were mapped. An overview risk assessment and preliminary work priority was assigned for sediment source problem sites. In addition, impacted sites were classified as to whether or not there was a requirement for detailed assessment, and those requiring the involvement of a professional (P.Eng. or P.Geo.) were designated as such.

During the field assessment, if a sediment source problem was perceived to be a threat to an area along a road corridor containing domestic dwellings, rural or industrial development, highways, public utilities, water supplies or fisheries habitat, the Ministry Representative was immediately notified. These sediment source sites were mapped as areas of immediate attention.

Preliminary access management strategies were proposed for roads potentially eligible for FRBC funding under WRP. The considerations for determining access strategies included the existing condition status of the roads and slopes, potential risks to environmental, social and economic values, and the future access needs within the watershed. The criteria used to identify access needs and develop preliminary access strategies were based on those outlined in the Resource Road Rehabilitation Handbook: Planning and Implementation Guidelines (Interim Methods), (Moore, 1994) and the Forest Road Deactivation (RRET 0410) Course Manual (BCIT, 1995).

The following are the three possible access management strategies:

Maintained roads generally included all Forest Service Roads, active roads under permit (includes road permit, road use permit, special use permit and cutting permit), or roads required for harvesting under the MOF SBFEP.

Deactivation can be proposed to one of three different levels depending on current and long term access needs, type of vehicle access require, the present condition of the road, and funding availability for period inspections.

All of the sediment source survey and road inventory information collected both in the field and the office, in addition to the proposed preliminary access strategies were compiled into Table 1: Road Inventory and Recommended Access Strategies. Photodocumentation of impacted sites accompany the tables, and the sediment source problems were summarized for each road network in the watershed.

The general findings of the SSS are that due to the physiography and climate of the Nazko watershed, there are no major sediment sources attributable to forest harvesting. The low relief and precipitation present a low potential for mass wasting and gully problems; consequently, surface erosion is the only significant mode of sediment production. Each road-related sediment source problem in the watershed is documented in Appendix A.

Road fill erosion at culvert outfalls was one of the most common occurrences throughout the watershed. The lack of fillslope armouring at the outlet was especially noted as a problem in steeper areas where the culvert outlet drop was as high as 1.5m. These sites were noted in the table and should be addressed. However, they do not require a detailed assessment before repair. Cutslope and fillslope erosion was also observed in the field. Ravelling and rill erosion was prevalent on unvegetated, erodible glacio-fluvial soils, particularly on the Clisbako Mouth FSR where the road cuts into the incised valley of the Clibako River. Hydroseeding and bioengineering are possible rehabilitation alternatives at these sites. Road surface erosion was observed on some inactive roads in the watershed. In some cases, the roads have self-armoured having already washed away the fine material on the surface. However, other roads built of sandy or silty erodible materials of low cohesion continue to be a sediment source.

Poor bridge design and failing bridges in the watershed were also noted as sediment sources (Figure 10). While these sites are less common than those discussed above, they are significant sediment concerns due to their direct stream connectivity and potential for major erosion.

Both the erosion of road surface material and fillslopes at culvert outfalls are primary reasons to deactivate roads. The installation of structures such as cross ditches and water bars controls drainage and stabilizes the road prism to reduce road surface erosion, and the removal of culverts and installing fords eliminates the potential for the blockage of unmaintained culverts which can lead to washouts. However, in some cases where culverts have been removed on fish-bearing streams, fords have not been built to the standards of the Draft Stream Crossing Guidebook for Fish Streams (Poulin and Argent, 1997), and therefore need to be upgraded.

The only landslides in the watershed are a series of large natural bank failures contributing sediment to the lower Snaking River (Figures 3 to 8). There is no forest harvesting, mining or agriculture activity in the area which can be attributed to the slides. At the time of writing this report, a Level 1 FHAP assessment has not been undertaken in the river to ascertain the impacts of the sediment sources to the chinook and rainbow populations documented in the reach.

There were two impacted sites in the watershed which required immediate attention resulting in notification of the Ministry Representative. The collapse of the road prism around a culvert at the crossing of 52B Road at Udy Creek was observed on May 23, 1997 (Figure 9). The presence of rainbow trout in the creek at that site was confirmed during the Fish Passage Inspection Procedure in July (J. Horchik, pers.comm.). The Ministry Representative was also notified of a washout at 5.7 km on the Nazko Falls FSR (8000 Road) on June 18, 1997 (Figure 11). Although there is no active hauling in the area, the road leads to Bishop Lake and is subject to regular use for recreation.

The SSS is a vital overview component of an Integrated Watershed Restoration Plan, and many examples of sediment source problems were identified during the assessment. However, it is readily apparent that the majority of problems sites documented in Table 1 are on roads that were driven during the field checking phase. Major sediment sources such as significant surface erosion and large tension cracks were visible during the helicopter flight. Sediment sources assessed from the aerial photographs were primarily erosion at stream crossings, although major surface erosion was also sometimes visible. Therefore, it is highly likely that other sediment source problems exist in the 80-85% of the watershed that were not observed on the ground. As stated in the methodology, environmental risk is not the only factor in the proposed access management strategies; future access is also a component and plays a major role in the process. Any agency intending to carry out road deactivation in the watershed should do an inspection of the road under due diligence, and may find additional sediment sources not identified in this assessment. As a result, an alternative access strategy may be more appropriate and those proposed in this report could possibly change.

The purpose of this overview is to identify sediment sources primarily in relation to past forest harvesting activities in the context of risk to environmental, social and economic values in the Nazko River watershed. Given the large size of the study area, a relatively small number of impacted sites were identified as requiring further assessment as a potential restoration opportunity. In no cases were the sediment sources a threat to human life. The primary risks in the watershed relate to the impacts of sedimentation on fisheries habitat. Therefore, preliminary recommendations for rehabilitation and future restoration works revolve around the repair of impacted culvert sites and the deactivation of roads, particularly those located on or having high sediment delivery potential to fish-bearing streams. The development of watershed-level and component project objectives in the Integrated Watershed Restoration Plan will specify the areas where rehabilitation is recommended and prioritize the work sequence for restoration works in the watershed.

British Columbia Institute of Technology (1995). Forest Road Deactivation RRET 0410.

Burnaby, British Columbia: B.C. Institute of Technology.

B.C. Ministry of Forests, Research Branch. Biogeoclimatic Zones of British Columbia Map,

1992.

B.C. Ministry of Forests (1997). Co-ordinated Access Management Plan, Chilcotin District and

Williams Lake District.

Carmanah Research Ltd. (1997). Interior Watershed Assessment Procedure of the Nazko River.

Chew, L.C. (1997). Overview Report: Fish Habitat Assessment Procedure of the Nazko River

Study Area. Carmanah Research Ltd.

Department of Fisheries and Oceans and Ministry of Environment, Lands and Parks. Fisheries

Inventory Summary System Maps. NTS 1:50,000 scale maps, 1994.

Forest Renewal B.C. (1997). Land-based Programs Handbook 1997/98. Victoria, British

Columbia: Forest Renewal B.C.

Gale, T. Personal communication. Technician, Water Management, Ministry of Environment,

Lands and Parks, Williams Lake, 1996.

Imhof, D. and D.R. Sutherland (1996). Fish Habitat Inventory of the Nazko River Watershed

1995. Regional Fisheries Report No. CA963.

Horchik, J. Personal communication. Fisheries Biologist, Carmanah Research Ltd., 1997.

Lord, T.M. and M. Walmsley (1988). Soils of the Nazko Area, British Columbia. British

Columbia Soil Survey, Research Branch, Agriculture Canada. Report No. 38.

Moore, G.D. (1994). Resource Road Rehabilitation Handbook: Planning and Implementation

Guidelines (Interim Methods). Watershed Restoration Technical Circular No. 3, July

1994. Victoria, British Columbia: B.C. Ministry of Environment, Lands and Parks and

B.C. Ministry of Forests.

Poulin, V.A. and H.W. Argent (1997). Stream Crossing Guidebook for Fish Streams: A

Working Draft for 1997/1998. Victoria, British Columbia: B.C. Ministry of Forests,

B.C. Ministry of Employment and Investment, B.C. Ministry of Environment, Lands

and Parks, Department of Fisheries and Oceans, British Columbia.

Quigley, J. (1998). Faxed correspondence with map. Department of Fisheries and Oceans, Prince

George.

Rood, K.M. and R.E. Hamilton (1995). Hydrology and Water Use for Salmon Streams in the

West Road Habitat Management Area, British Columbia. Can. Manuscr. Rep. Fish.

Aquat. Sci. 2295.

Rowland, D.E. and L.B. MacDonald (1996). Salmon Watershed Planning Profiles for the Fraser

River Basin within the Cariboo-Chilcotin Land Use Plan (CCLUP) Area. Victoria,

The following is the rationale used in filling out Table 1 - Road Inventory and Recommended Access Strategies. Included is an explanation of the abbreviations used in the table.

The road identification reference numbering system is based around road networks branching off of Forest Service Roads (FSRs) or public roads (ie. Nazko Highway, Honolulu Road and Baezaeko Road). Secondary or branch roads leading off of FSRs are named based on the nearest 0.1 kilometre distance mark. Spur roads off of the secondary or branch roads are named based on their distance from the start of the road to the nearest 0.1 kilometre. The resulting road i.d.’s are a hierarchical set of numbers separated by hyphens beginning with the FSR number, followed by one or more of a series of road numbers which correspond to the distance from the start of the road. Wherever possible, existing road names/numbers were incorporated into the identification system.

For permitted roads, the year that the road permit was applied for was put into the table. For non-status roads and roads under a cutting permit, the year that logging has taken place was used.

Y - Yes

Y (P.Geo.) - Yes, Profession Geoscientist/Professional Engineer Required

N - No

H - #### - Harvesting – Year of proposed harvest based on 1997 Consolidated Forest

Development Plan and discussion with forest licensees

Sil - Silviculture

Rec - Recreation

Res - Residential

Min - Mineral prospecting

Fire - Fire Protection

Grz - Grazing based on active grazing permit

None - None

Ind - Industrial (logging truck, lowbed)

2WD - Two wheel drive

4WD - Four wheel drive

ATV - All terrain vehicle

HT - Hiking Trail

None - None

M - Maintain

M(PRB) - Maintain but permit required by one of the following forest licensees:

- R - Riverside Forest Products Ltd.

- S - Slocan Forest Products Ltd.

- T - Tolko Industries Ltd.

- WF - West Fraser Mills Ltd.

- WW - Weldwood of Canada Ltd.

T - Temporary Deactivation

SP - Semi-permanent Deactivation

P - Permanent Deactivation

LA - Leave Alone

UC - Unclassified (includes public and private roads, and trails which were not

assessed under this contract)