P. Beaudry and Associates Ltd. Integrated Watershed Management

P.Beaudry and Associates Ltd. Phone: (250) 563-8405

Survey of Small and Large Sediment Sources

Within the Moberly Watershed Dawson Creek Forest District

Prepared for: Chetwynd Forest Industries

A Division of West Fraser Mills Ltd. P.O. Box 330

Chetwynd, B.C. V0C 1J0

Prepared by: P. Beaudry and Associates Ltd.

Integrated Watershed Management 2274 S. Nicholson

Prince George, B.C. V2N 1V8

February 2003

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. ii February, 2003 Integrated Watershed Management

EXECUTIVE SUMMARY This project was initiated in 2002 by Chetywnd Forest Industries (CFI) in an effort to quantify and describe the nature of sediment sources within the Moberly watershed. The primary objective of this work was to better understand how forest activities may be impacting water quality. Both “large” and “small” sources of sediment were inventoried and described by this project. Large sources (greater than approx.0.05 ha) were inventoried using digital air-photos and a helicopter overflight of the Moberly watershed. Small sources were inventoried using a procedure called the Stream Crossing Quality Index (SCQI) survey, which was initially developed for Canfor’s forest certification programme. The SCQI value is obtained by surveying all of the stream crossings within a given watershed and qualitatively assessing the potential for erosion and the delivery of sediment to the stream at each crossing. The SCQI method focuses on evaluating the addition of fine sediment to streams at stream crossing locations. SCQI scores for individual crossings (referred to as “individual crossing scores”) range between 0 and 1, depending on the potential impact the crossing may have on water quality. A score of 1 indicates that the crossing has the potential for a substantial negative impact on water quality. As the potential impact is reduced, the score decreases until it eventually reaches 0. The SCQI for the watershed is calculated by adding the individual crossing scores and dividing this value by the watershed area. The resulting overall watershed SCQI score provides an index of the cumulative impact that the crossings are having on the introduction of sediments to the stream network at a watershed level. This score can then be translated into a Cumulative Watershed Effects Hazard Rating based on surface erosion and delivery potential, ranging from very low to very high. The SCQI is a refinement of the stream crossing density index (SCDI), an office based exercise that has traditionally been used to assess the potential impact that stream crossings have on water quality within a watershed. The individual crossings scores are a valuable tool in identifying specific areas where there may be localized negative impacts to water quality. Each crossing was assigned a Water Quality Concern Ratings (WQCR) of either None, Low, Medium, or High based on the individual crossing score. During the 2002 field season we surveyed a total of 419 stream crossings in the Moberly watershed. Slightly under half of these crossings had WQCRs of low or none. Approximately 29% of the crossings received medium WQCR’s and the remaining 24.5% of the crossings received high WQCR’s (Table 1). Most of these crossings with high WQCR’s were associated with small streams (i.e., less than 1.5 meters in width). Detailed maps are included in the report which provide the identification and the WQCR for each surveyed stream crossing. Many of the crossings surveyed in 2002 had high WQCRs and some common problems were identified. These include: 1) long ditchlines with exposed soil connected directly to streams, 2) sediment from the road surface directly entering streams at crossings and 3) poorly deactivated crossings. Most of the problems were associated with new roads, either recently constructed or recently deactivated, that had poorly implemented Erosion and Sediment Control (ESC) measures or none at all.

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. iii February, 2003 Integrated Watershed Management

Table 1 illustrates the key results found in each sub-basin or area surveyed in the 2002 season including the SCQI for the sub-basin, the SCQI Watershed Cumulative Effects Hazard Rating, and the percentage of crossings in the sub-basin with a high water quality concern rating. Table 1. Summary of SCQI Results for Sub-basins Surveyed in Moberly Watershed in 2002.

Sub-basin or area

identification

Size of sub-basin

(km2)

Number of crossings surveyed

Stream crossing

density index (number of

crossings/km2)

SCQI for sub-basin

(sum of individual crossing

scores/km2)

SCQI Watershed Cumulative

Effects Hazard Rating1

% of individual crossings surveyed

classified as High water

quality concern

Entire Moberly

Watershed 829.3 419 0.51 0.24 Low 24.58

Upper Moberly 130 44 0.34 0.10 Very Low 0

Shangweshi 45.46 80 1.76 1.04 Very High 38.75

Highrise 26.14 29 1.11 0.68 Very High 48.28

Hulcross 130.4 122 0.94 0.42 High 24.59

Dokie 54.33 33 0.61 0.18 Low 0

Lower Moberly Residual

442.97 109 N/A2 N/A2 N/A2 25.70

1 This hazard rating relates to the potential for negative impacts to water quality caused by watershed cumulative effects of erosion and sediment delivery to streams at road crossings. 2 The stream crossing density index (SCDI), stream crossing quality index (SCQI) and the SCQI Watershed Cumulative Effects Hazard Rating do not apply to Lower Moberly Residual since this area is not a stand-alone watershed such as the others listed in the table. An assessment of the large sediment sources in the watershed was also conducted for the entire Moberly watershed. The survey of large sediment sources was completed using digital air-photos and an overflight that was conducted in September 2002. These have been described and mapped and the results are provided in the report and the appendices. The large sediment source survey found many large natural sediment sources within the Moberly watershed, including large ravelling streambank terraces, extensive gravel bars, accelerated bank erosion and mass wasting which may be attributed to natural bank erosion, past forest fire activity, and the major flood of 2001. Mass wasting type sediment sources (e.g., slumps and debris avalanches) caused by riparian forest harvesting and roads were also depicted in the

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. iv February, 2003 Integrated Watershed Management

watershed. In addition, it was found that riparian agriculture, including the removal of riparian vegetation and livestock grazing, caused many large land-use related sediment sources (e.g., accelerated bank erosion) within the watershed. Overall, natural sediment sources encompassed 66% and land-use related sediment sources comprised 34% of the large sediment sources documented in the Moberly watershed. Of the large land-use related sediment sources, forestry related large sediment sources comprised 46% and riparian agriculture related sediment sources comprised 39%. The remaining 5% of the large land-use sediment sources were caused primarily by transmission lines in the Moberly watershed. Table 2 provides a summary of the density and number of large sediment sources, including both natural and land-use type sediment sources.

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. v February, 2003 Integrated Watershed Management

Table 2. Summary of Large Sediment Sources identified in the Moberly River Watershed in 2002.

Large Sediment Sources

Large natural sediment sources

Large natural sediment sources directly

connected to a stream

Large land-use related sediment sources

Large land-use related sediment sources directly

connected to a streamWatershed or

Sub-basin within

watershed number density

(#/km2) number density (#/km2) number density

(#/km2) number density (#/km2) number density

(#/km2)

Entire Moberly

Watershed 207 0.250 137 0.165 104 0.125 70 0.084 57 0.069

Upper Moberly 22 0.169 17 0.131 14 0.108 5 0.038 1 0.008

Shangweshi 21 0.462 15 0.330 11 0.242 6 0.132 2 0.044

Highrise 15 0.574 6 0.230 5 0.191 9 0.344 6 0.230

Hulcross 23 0.176 20 0.153 14 0.107 3 0.023 3 0.023

Dokie 17 0.313 17 0.313 15 0.276 0 N/A 0 N/A

Lower Moberly Residual

108

0.244

61

0.138

49

0.111

47

0.106

45

0.102

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. vi February, 2003 Integrated Watershed Management

ACKNOWLEDGMENTS We would like to thank Mr. Brian Pate, Forestry Supervisor at Chetwynd Forest Industries (CFI), for initiating the project and providing invaluable assistance throughout the project. We would like to thank Ray Huscroft, GIS coordinator at CFI, for his help in acquiring the necessary GIS data in a timely fashion. Mr. Bill Floyd, B.Sc., and Ms. Becky L’Hirondelle B.Sc. of P. Beaudry and Associates Ltd. (PBA) completed the stream crossing surveys. Ms. L’Hirondelle and Ms. Natalie Newman, R.P.Bio, of PBA, completed the data analysis and the reporting. Mr. Pierre Beaudry, M.Sc, R.P.F. also of PBA was the project manager, completed the aerial survey of the large sediment sources and provided technical guidance and quality assurance throughout the project. Funding for this project was provided by the B.C Forest Investment Account (FIA).

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. vii February, 2003 Integrated Watershed Management

Table of Contents

EXECUTIVE SUMMARY ............................................................................................................ ii

ACKNOWLEDGMENTS ............................................................................................................. vi

1.0 INTRODUCTION .................................................................................................................. 1

2.0 METHODOLOGY ................................................................................................................... 3

2.1 General Description of SCQI Survey ................................................................................... 3 2.1.1 2002 SCQI Sampling .................................................................................................... 5 2.1.2 Individual Crossing Scores and the SCQI .................................................................. 10 2.1.3 SCQI vs. SCDI............................................................................................................. 10 2.1.4 Hazard Rating Associated with Road Related Sediments .......................................... 11 2.1.5 Water Quality Concern Rating..................................................................................... 12

2.2 Survey of large sediment sources ...................................................................................... 12

3.0 RESULTS AND INTERPRETATIONS ................................................................................ 13

3.1 Entire Moberly Watershed.................................................................................................. 14 3.1.1 Stream Crossing Quality Index Survey................................................................. 14 3.1.2 Survey of Large Sediment Sources....................................................................... 15

3.2 Upper Moberly................................................................................................................... 17 3.2.1 Stream Crossing Quality Index Survey................................................................. 17 3.2.2 Survey of Large Sediment Sources....................................................................... 20

3.3 Shangweshi Creek.............................................................................................................. 22 3.3.1 Stream Crossing Quality Index Survey................................................................. 22 3.3.2 Survey of Large Sediment Sources....................................................................... 27

3.4 Highrise Creek ................................................................................................................... 29 3.4.1 Stream Crossing Quality Index Survey................................................................. 29 3.4.2 Survey of Large Sediment Sources....................................................................... 34

3.5 Hulcross Creek................................................................................................................... 36 3.5.1 Stream Crossing Quality Index Survey................................................................. 36 3.5.2 Survey of Large Sediment Sources....................................................................... 42

3.6 Dokie Creek ....................................................................................................................... 44 3.6.1 Stream Crossing Quality Index Survey................................................................. 44 3.6.2 Survey of Large Sediment Sources....................................................................... 47

3.7 Lower Moberly Residual ................................................................................................... 49 3.7.1 Water Quality Concern Rating.............................................................................. 49 3.7.2 Survey of Large Sediment Sources....................................................................... 56

4.0 SELECTED PHOTOGRAPHS FROM FIELD ASSESSMENTS........................................ 58

4.1 Selected Photographs of a High WQCR............................................................................. 58 5.2 Selected Photographs of a Medium WQCR ....................................................................... 70 5.3 Selected Photographs of a Low WQCR.............................................................................. 72 5.4 Selected Photographs of a None WQCR ............................................................................ 74

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. viii February, 2003 Integrated Watershed Management

5.5 Selected Photographs from the Overview Flight (Large Natural Sediment Sources) ........ 76 5.6 Selected Photographs from the Overview Flight (Large Land-Use Related Sediment Sources)..................................................................................................................................... 80

5.0 LITERATURE CITED ........................................................................................................... 83

APPENDIX 1. SCQI SCORING RATIONALE ......................................................................... 85

APPENDIX 2. EROSION, DRAINAGE AND SEDIMENT CONTROL TECHNIQUES........ 94

APPENDIX 3. POTENTIAL SCQI TARGETS........................................................................ 110

APPENDIX 4. OVERVIEW MAP OF ALL CROSSINGS SURVEYED IN THE MOBERLY WATERSHED............................................................................................................................ 112

APPENDIX 5. OVERVIEW MAP OF LARGE SEDIMENT SOURCES IDENTIFIED IN THE MOBERLY WATERSHED ....................................................................................................... 113

APPENDIX 6. DATABASE OF LARGE SEDIMENT SOURCES......................................... 114

APPENDIX 7. SCQI DATA SHEETS AND SCORE SHEET................................................. 121

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. 1 February, 2003 Integrated Watershed Management

Survey of Small and Large Sediment Sources within the Moberly Watershed

Moberly Watershed

Dawson Creek Forest District

1.0 INTRODUCTION The main objective of this project was to quantify and describe the nature of sediment sources within the Moberly watershed in an effort to understand how forest activities may be impacting water quality. Sediment sources can be divided into two broad categories. The first of these categories includes “large” sources that are clearly visible from air-photos and helicopter reconnaissance, e.g. landslides, slumps, large failing stream banks and avalanche tracks. The second category includes “small” sources that can only be detected and documented from the ground, e.g. eroding ditch lines, road running surfaces and cut and fill slopes. To document the large sources we completed a helicopter flight on the 9th of September 2002 and mapped all of the sources from digital ortho-photos. The small sediment sources were surveyed using the stream crossing quality index (SCQI) methodology which assesses the amount of erosion and sediment delivery that occurs in the vicinity of stream crossings. The SCQI survey was developed in 2000 for Canfor’s sustainable forest management plan and has been used throughout a number of areas in central B.C. (e.g., TFL #30, TFL#48, Fort St. John District, Horsefly Watershed, Bulkley District, Prince George T.S.A.). A decline in water quality can have major impacts on the water resources in an area. It is also widely accepted that improper forestry practices can have negative impacts on water quality (Government of BC 1995). Sediment generation from forestry practices comes from the following three main sources: roads, landslides and stream bank instability. Significant increases in sediment concentration in streams over natural levels can have a negative effect on fish and fish habitat (Slaney et al. 1977; Government of BC 1995; Hall et al. 1987; Hartman and Scrivener1990; Phillips 1971; Scrivener and Tripp 1998.). Sediment can also reduce the value of water for domestic, industrial and agricultural use (Government of BC 1995). In areas where rainfall precipitation is dominant and harvesting occurs on steep slopes, landslide processes can be a major contributor of sediment to streams. In areas such as the Moberly Watershed where the landscape is dominated primarily by rolling to moderately steep topography and wide valley bottoms, landslides are generally not a dominant sediment producing process (at least not compared to steep coastal watersheds). In watersheds such as the Moberly, the main source of forestry related accelerated erosion is generally associated with road building and road use. The scale of cumulative impacts at the watershed level is generally related to the density of stream crossings because this is where eroded material from roads has the potential to be delivered to the stream network. Sediment yields from logging and roads can show a 2 to 50 fold increase over historical levels (Reid 1993). The main point of road sediment delivery to streams is at crossings such as culverts and bridges (Brownlee et al. 1988; Government of BC 1995). While it is recognized that roads are not the only source of sediment related to forestry practices, they are considered to be the most significant causes of increased sedimentation (Beschta 1978; Brownlee et al. 1988; Government of BC 1995; Reid and Dunne 1984). Through the proper layout,

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd. 2 February, 2003 Integrated Watershed Management

construction, deactivation and use of erosion and sediment control (ESC) measures, the impact that roads have on water quality can be significantly reduced (Beaudry 1998; Government of BC 1995). The SCQI survey is based on the concept of the stream crossing density index (SCDI) used in the Watershed Assessment Procedure (WAP) (Government of BC 1999). The assumption in the WAP is that the risk to water quality increases as the density of stream crossings within a watershed increases. The stream crossing density index assumes that every crossing is a problem from the point of view of erosion and sediment delivery. Although this is a useful index to highlight potential for cumulative effects, it does not consider the actual quality of erosion and sediment control (ESC) or effective de-activation measures that may have been implemented at a particular stream crossing. Consequently, the numerical value of such an index will always increase with increasing activity within a watershed. Thus, such an index cannot evaluate progress towards the achievement of a specified goal, this being an explicit requirement of many forest management certification schemes (e.g. CSA). Consequently, it became necessary to develop an index that would document and evaluate problems as well as successes. The index must provide an incentive to improve practices by documenting those practices that achieve the desired goals. The SCQI method was designed to be such an index. The SCQI method is based on the concept that the impact of stream crossings on water quality can be reduced through effective erosion and sediment control practices, and that this can be evaluated and scored. As with the SCDI, each crossing within a watershed is, at priori, assumed to be having a negative impact on water quality. However, the theoretical negative impact of this stream crossing can be reduced if the crossing is evaluated in the field and does not show any signs of erosion and sediment transport to the stream. Using this method of evaluation a crossing that shows substantial problems receives an individual crossing score of one (1). As the quality of a crossing improves, the score is reduced, eventually reaching zero (0). This can effectively eliminate the crossing from the “erosion and sediment producing” inventory. As the scores for the individual crossings are reduced so is the SCQI for that watershed. This mechanism provides an incentive to implement good ESC measures. The SCQI method also provides valuable data that can be used to identify specific problem sites or areas. This enables the forest manager to implement proper ESC measures in areas where it is required. By addressing specific problems, the negative impact on water quality will be reduced and the overall SCQI score for that watershed will also be reduced. It also enables forest licensees to focus their resources to areas that will receive the greatest benefits. Specific problem crossings were identified in sub-basins with a high or very high SCQI and a summary of the problems were also provided in the report. In addition, the SCQI method provides a way to monitor progress in regards to water quality. The SCQI values calculated in this report could be used as a baseline to monitor the relative improvement of forest practices within the Moberly Watershed.

Chetwynd ForestIndustries

A Division of West Fraser Mills

Moberly Watershed

MoberlyWatershed

Williston Lake

M O B E R L Y L A K E

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Chetwynd

Legend

City

Roads maintained by Ministry of Transportation

Streams

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Lakes

Figure 1. Location map for the Moberly Watershed. 8

Base Map From Government of BCWatershed Atlas NAD83

February 2003

British Columbia

Moberly Watershed

6 0 6 12 18

Kilometers

Chetwynd ForestIndustries

A Division of West Fraser Mills

Moberly Watershed:Sub-basins

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Lower Moberly Residual

Shangweshi

Dokie

Highrise

Hulcross Upper Moberly

Legend

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Roads maintained by Ministry of Transportation

Streams

Watershed Boundary

Lakes

Figure 2. Sub-basins selected for the sediment source survey in 2002 9

Base Map From Government of BCWatershed Atlas NAD83

February 2003

4 0 4 8

Kilometers

Sediment Source Survey of the Moberly Watershed for: Chetwynd Forest Industries

P. Beaudry and Associates Ltd Integrated Watershed Management

SPECIAL NOTE The above information is an excerpt from the final report titled ‘Survey of Small and Large Sediment Sources within the Moberly Watershed’. A complete version of the final report is available with Mr. Brian Pate, Forestry Supervisor with Chetwynd Forest Products.