Symmetree Consulting Group Ltd.
|
Symmetree Consulting Group Ltd. |
Watershed Restoration Program
Site Assessment for The Willow River and Selected Drainages
For
Weldwood of Canada Ltd.
March 16, 1998
Watershed Restoration Program
Site Assessments for:
Slough Creek, Upper Willow River, Big Valley, Rebman, Sugar Rucheon and Tregillus Creeks
Submitted by
LGL Limited
Prepared by
B.G. Bancroft and K. Zielke
Symmetree Consulting Group Ltd.
6301 Rodolph Rd.
Victoria, B.C.
V8Z 5V9
Acknowledgments
Completion of this project would not have been possible without input from various contributors. Thanks go to Northwest Hydraulics for coordination of the project, LGL: Limited for their role in providing maps, photographs and identification of riparian segments to visit. Special thanks go to Bob Bocking of LGL for administering the project and to Sergei Yazvenko of LGL for his photo interpretation work. Thanks also go to Marnie Cuthill (Weldwood of Canada Ltd) who is the contact person and provided valuable field and data collection assistance. We would also like to thank Michael Parker (Ministry of Environment, Lands and Parks) for managing the project for Forest Renewal British Columbia (FRBC).
Executive Summary
A number of stream reaches were assessed for possible silviculture rehabilitation work in the upper Willow River drainage. Each area had been identified as having possible opportunities for rehabilitation within the Watershed Level Assessment (LGL 1997, in prep.). Summary tables were created and identified stream reaches were visited to determine possible options.
Logging began in this area in the 1950’s when intermediate utilization (IU) standards were in place. Intermediate utilization meant that trees less than approximately 28 cm in diameter at breast height (DBH) were not considered as merchantable and were left post harvest. This left many stands with a mix of smaller stems, some damaged, some not. It was the intent of the field visits to assess whether the remaining stands provide the attributes desired for effective riparian function.
Intermediate utilization was replaced by close utilization in the mid 1960’s and early 1970’s, resulting in clearcutting to the edge and across stream reaches. Stream reaches in areas clearcut harvested after 1970 were visited to assess possible actions to provide for riparian functioning.
A reconnaissance assessment was done for all identified accessible riparian segments. Initial field comments were provided to address the restoration concerns identified through photo interpretation (comments are provided in the issues section). Riparian function was assessed based on the present and future riparian structure. Recommendations are provided by riparian segment.
Overall the IU stands, while possibly not providing maximum timber increment, were providing a rich mixture of stem sizes from dominants to seedlings. Overstory stems were often growing well and showed little signs of internal rot. The streamside structure often provided a good mix of all the required riparian functions. We found no need to treat these segments unless further activity that will change their structure is contemplated.
In the newer blocks (post 1970) while clearcutting often occurred to the stream edge, reforestation efforts have left the blocks stocked with conifers (500-1500 per ha). Natural willow and alder growth is present in all areas providing shading and nutrient inputs.
Where roads are within the Riparian Management Zone, established vegetation is providing for erosion control and limited shading. No treatment was identified at this time.
Due to the good shrub growth, stocking in newer blocks and structure of the IU stands our overall recommendation is that no vegetation management actions be taken unless there is an instream or related engineering activity that requires rapid vegetation reestablishment. In our estimation, for all of the reaches assessed, the natural or planted vegetation will provide the fastest route to repairing limited riparian or maintenance of established functions. Where there is a need for LWD, in the short term, it is recommended to use instream placement.
Table of Contents
Acknowledgments i
Executive Summary iii
Methodology 1
Introduction 1
Project Background 1
Objectives: 1
Methodology 1
Identified Riparian Segments 2
Site Assessment - Slough Creek 4
Site Assessment - Big Valley Creek
Site Assessment - Sugar Creek
Site Assessment - Rebman Creek
Site Assessment - Willow River
Site Assessment - Tregillus Creek
Site Assessment - Rucheon Creek
Summary of Proposed Actions 18References 21
Appendix 1 - Area Map 23
Appendix 2 - Photographs 25
Appendix 3 - Riparian overview and visitation priorities 51
Appendix 4 - Field notes 61
Introduction
This project is a portion of watershed restoration contracts awarded to Weldwood of Canada Ltd. by Forest Renewal B.C. (FRBC). The intent of the project is to conduct watershed and site level assessments of selected drainages within the Willow River Drainage (see Appendix 1 for an overview map that provides field site locations). Symmetree Consulting Group Ltd., in association with LGL Limited of Sidney, B.C., were retained by Northwest Hydraulics to conduct the assessments to determine, what, if any vegetation management is needed to meet riparian objectives.
An Interim Stream Overview Assessment for the Willow River (LGL, Sept 1997) was created and provided guidance for Riparian Site Level Assessments. The site level assessments focused on areas where historical logging practices (late 1950’s, 1960’s and 1970’s) may have negatively affected riparian function.
The objectives for this contract are as follows::
From table 4 in the Willow River WRP Stream and Riparian Overview Interim Report, a total of 57 riparian segments were identified as having a high (H) priority for riparian management review or prescriptions. Ground reconnaissance was done to assess what if any riparian functions were compromised, and what, if any, management actions were available to ameliorate the function, if found to be lacking.
The methodology provided in the new Riparian Assessment and Prescription Procedures Field Guide suggests the following steps:
Step 1. Prepare a Watershed Level Assessment - its components are to:
This step was the basis of the Stream and Riparian Overview (LGL 1997, in prep.) and provided the riparian segments outlined below.
Identified Riparian Segments
The following reaches and riparian segments were identified as being possible candidates for riparian work.
This document summarizes the site assessment for vegetation management options for the stream reaches identified above.
Step 2. Perform site level assessments.
Details of the vegetation structure found and recommendations to improve the loss or impairment of a riparian function are provided in this report.
Riparian Overview
We performed an overview assessment of the study area using air photos of each stream and riparian area to assess LGL’s initial recommendations.
On-the-ground evaluations were done to achieve the following objectives set out in the Riparian Assessment and Prescription Procedures:
The areas viewed were photographed and data pertinent to impairment was collected (see Appendix 4 for field notes). Measurement plots were not established unless there appeared to be an opportunity for management or rehabilitation. Photographs are provided as Appendix 2.
The following decision key provided in Oikos and Johnson (1996) was used for each riparian segment to evaluate the need for additional data collection.
Assessment of Riparian Function |
Yes or No |
areas have exposed mineral soil where surface erosion is eroding sediments directly into the stream (loss of surface filtering function) |
|
frequent rutting or soil disturbance so that the ability to establish vegetation is impaired |
|
stream lacks shrub cover and re-establishment of stream shade is the highest priority? |
|
stream lacks large conifers and increasing the stocking of conifers (future LWD) is a high priority |
|
stream lacks shrub cover and establishment of shrubs for SOD or stream shade is a high priority? |
|
If an impairment was identified options were provided by segment.
Stream Reach Assessments
Slough Creek - Reach 3 A and B
Slough Creek, reach 3 riparian segments A &B were assessed for riparian impairment on September 22, 1997. From the aerial photographs it was noted that a road is within the area that would constitute the Riparian Management Zone. As well, there are some open deposits near the creek in riparian segment B. The reach is found within a block that was logged under Intermediate Utilization Standards in 1959.
Reach 3A was found to have a mix of 20 to 40 year old lodgepole pine (Pl) that range in height from 7 to 18 m. There is abundant shrub cover of willow (Salix) species along the banks (90% cover approximately 2 m tall) a minor amount (<5%) of alder (Alnus viridis) and cottonwood (Populus balsamifera ssp. trichocharpa). Small spruce (Sx - hybrid) and true fir species (Bl) are found in patches amongst the shrubs. The structural stage is PSc/SHRts with less than 20% of the trees as deciduous (note table 8 showed PSm).
Reach 3 segment B had similar vegetation to 3A but is slightly older (YFc/SHRts) with scattered Pl and more tree size spruce. Willow is still the dominant shrub cover to the creek edge with minor alder. Along one portion of 3B a beaver dam has affected the water table killing some of the established Pl. While there are some moderate sized conifers (30 cm plus) along the bank, most trees are relatively young small, thrifty and will not presently provide long term LWD. However, in time, this site will provide LWD.
The stream has had deposition from a mine approximately 1 km upstream. Presently the road is not impairing vegetation recolonization in the riparian zone. The vegetation found on site is fitted to the environment and in proportions suited to this site. We could not improve upon it. See plates 1 and 2 Appendix 2.
Recommendation:
If instream LWD is an objective as found by the Level 1 stream assessment, we suggest LWD placement in the stream as required. The stands in place will provide replacement LWD within the next 30 to 70 years depending upon the size of LWD desired.
Big Valley Creek - Reaches 1, 8 and 11
Site Assessment
Five riparian segments were identified for viewing from three stream reaches. Each will be described separately.
R 1 - D
Stream reach 1 segment D was logged in 1973. It was identified for viewing due to a road in the RMA and a bridge within the reach. The structural stage of MFc/SHRts is what is present within the reach. The stand is made up of 30 m plus spruce with abundant willow along the stream edge. No riparian functions were found to be impaired. See plate 3, Appendix 2.
Recommendation:
Leave as is.
R 8 - C
Reach number 8 riparian segment C is found within an unlogged portion of the stream reach. It was identified for viewing due to a road crossing and a slide. The present situation is the glacial fluvial parent material is being undercut by a meander in the creek. Most, if not all, of the material that was deposited at the base of the slide has been transported downstream. Raveling on the slope is ongoing.
There is also a portion of R 8-C where the road meets the stream and at that point the stream is diverted from its mainstem and instead follows the road as a creekbed. The mature conifer forest (OFc) is intact around the creek and will not require modification if the creek is relocated back to the original channel. See plates 4 - 6 Appendix 2.
Recommendation:
Slide area: Due to the active nature of the slide, re-vegetation would not be practical. If fisheries values were considered high enough, there are engineering options available to reduce the potential for additional sedimentation. It may be possible to stabilize the lower bank with wood, rip rap, gabions, or interlocking blocks. Due to its location it may be more feasible to re-channel the stream to take out the meander. All of this depends on the risk to fish habitat.
Road crossing: Some engineering structures could be used to divert the creek into the main channel. Depending upon fish values this may be desirable.
R 8 - E
Reach 8 riparian segment E is found within an unlogged portion of the stream reach. It was identified for viewing based on the potential for eroding banks. It was not visited on the ground due to the road problem identified in reach C. From adjacent reaches and aerial photographs the YFd structure chosen through air photo interpretation appears accurate. This also concurs with the vegetation in adjacent reaches.
Recommendation:
No action is necessary.
R 11 - C
Reach 11 riparian segment C is found within an unlogged portion of the stream reach. It was identified for viewing due to an industrial area near a road crossing. The area in question has been excavated either for gravel or for exploration purposes. Approximately 100m of the riparian segment is SHRls/INIT the remainder is mature conifer (MFc). There is no impairment of riparian function identified for this segment. See plate 7, Appendix 2.
Recommendation:
No action is required.
R 11 - F
Reach 11 riparian segment F is found across from segment C also within an unlogged portion of the stream reach. It was identified for viewing as the road travels close to the stream through this segment. Mature spruce and Bl are the dominant structural stage within this segment (MFc). While logging was not noted on the map there are old stumps in the area. Spruce budworm has reduced some of the Bl understory but is not seriously impairing any riparian functions. See plate 8, Appendix 2.
Recommendation:
No action is needed in this segment.
Sugar Creek - Reaches 4, 5, 6 and 9
Site Assessment
Nine riparian segments were identified for viewing from four stream reaches. Each will be described separately.
R 4 - B & D
Stream reach 4 segments B and D are located alongside Sugar Creek, north of the active placer mine. The riparian segments were identified for viewing due to a large unstable riparian area identified through photo interpretation. This area is downstream of an active placer mining claim. The structure of 4B is MFc/Shr and MFc/Shr/Yd for 4D. Timber harvesting has not affected this reach.
Recommendation:
Presently there is no forest related riparian impairment within this reach. Leave as is.
R 5 - A
Sugar Creek reach 5 segment A is found on the west side of Sugar Creek, north of the active placer mine. There is a road running alongside the creek and a bridge crossing the creek within the segment. The present vegetation is SHRts/PSd along the road edge between the stream and the road (approximately 5 - 10 m wide). The vegetation is well established. There is a lack of future LWD in the segment. The bridge is not resulting in riparian impairment. See plate 9, Appendix 2.
Recommendation:
Because of its road edge location, and relatively short length of the segment no action to promote the creation of LWD is recommended. Leave as is. If LWD is desired it should be placed directly in the stream.
R 5 - C
Sugar Creek reach 5 segment C is found on the eastern edge of the creek upstream of the crossing. Riparian segment C has been modified through mining and is presently made up of settling ponds and exposed gravel along with an area recently harvested to provide access to more materials. The area was being actively mined while we were on site. The recently logged area has abundant willow, alder and cottonwood (INIT/SHRls/PSd). See plate 10, Appendix 2.
Recommendation:
The disturbance is mining related and is therefore outside of the mandate of the project. Because of the active nature of the mining, restoration at this time is not warranted and should be a responsibility of the mine owner.
R 6 - B
Sugar Creek reach 6 segment B is found on the northeastern side of Sugar Creek. The area was identified as having a high site visitation priority due to a road in the entire RMA. The riparian segment is an undisturbed shrub young mixed conifer/deciduous complex (SHRts/YFm) relatively undisturbed by the road. The road is away from the creek and therefore the major influence here was from the opening adjacent to the road where cover was removed.
Recommendation:
The reach is evolving naturally and has no impairment of functions within the segment, save a short term reduction in LWD. No action is required. If further LWD is needed in the short term, it should be placed directly in the stream.
R 9 - C and D
Sugar Creek reach 9 segments C and D are found to the southwest of the active mining area. The stream reach is in an area that has not been harvested according to the map. Some stumps were seen in segment 9C. There is a road adjacent to the stream within both segments C and D. Based on the amount of flagging along the road some form of road upgrading is likely in the works. Some flooding has occurred in wetland portion of segment D resulting in death of isolated spruce. Overall no riparian functions were found to be impaired at the time of observation (OFc/SHRts for segments C and D. See plates 11 and 12 Appendix 2.
Recommendation:
The reach is evolving naturally and has no impairment of functions within the segment. No action is required at this time. New road construction could result in modified conditions and should be monitored.
R 11 - A and C
Sugar Creek reach 11 segment A is found on the southern edge of a tributary to Sugar Creek and forms the block boundary of a block harvested in 1991. Because the block boundary is the creek edge there is a reduction in cover for the riparian segment. The area has since been planted with Sx at 1200 stems per ha (INIT/SHRls). There is abundant low shrub cover of Lonicera involucrata, and Salix species. However the other side of the stream (segment C) remains unharvested and contains abundant large (Sx 80%, Pl 20%). Low shrubs and herbs are found up to the stream edge (MFc/SHRls). See plates 13 and 14, Appendix 2.
Recommendation:
The reach has been harvested along one side. The block has been planted with spruce up to the stream edge. Shrubs remain intact since harvesting and erosion is not a threat. Source LWD is abundant in segment C on the south facing edge. While there has been a reduction in shading the planting done to date will result in increased shading over time (not likely a limiting condition at this elevation and latitude). No further action required.
Rebman Creek - Reaches 2, 3, 4, 5, 6, 7, 8 and 9
Site Assessment
Four stream reaches with a total of 8 riparian segments were visited to assess riparian impairment. Each riparian segment will be described separately to provide site specific information.
R 1 - A and B
Rebman reach 1 sections A and B are located at the junction of Rebman Creek and the Willow River. This portion of the stream has significant aggradation of cobbles. Section A is on the south side of the creek within a block harvested in 1977. The vegetation in stream section A is composed of a mosaic of spruce saplings at approximately 1000 stems per ha (sph) of what appear to be planted spruce with a mix of willow and black twinberry (Lonicera involucrata) PSc/SHRts.
Stream section B is to the north of the stream in a block logged in 1969. Within this section are clumps of larger (10 to 15 m) tall spruce where the clumps are spaced approximately 15 m apart. There are abundant (600 sph plus) smaller sapling sized Sx as well as abundant willow and other shrub species (PSc/SHRts). Isolated cottonwood are present. See plates 15 and 16, Appendix 2.
Recommendation:
There are no impaired riparian functions that require attention within either of these two riparian segments. If LWD is needed over the short term it should be placed instream. Locally grown LWD will be 20 m tall and 30 cm in diameter in approximately 60 to 100 years.
R 3 A and B (includes R 2 A and B)
Both Rebman reach 3 stream sections A and B are found in a block harvested in the mid 1980s. Stream section A is on the south side of the creek, section B is on the north side (south facing) of Rebman Creek. Both are now regenerated with planted Sx along with abundant alder, willow, black twinberry and fireweed. While LWD creation has been interrupted by harvesting, the regenerated stand is presently moving toward LWD creation as fast as naturally possible. The planted spruce (600 - 1000 sph) are 1.2 m tall on average and growing 15 to 50 cm per year. There are also patches of advance Bl (5 - 10 m tall) that range from 4 to 10 m tall (approximately 50 sph). Established cottonwood are found in all segments at approximately 40 to 50 sph at 9 to 10 m tall (SHRts). See plates 17 and 18, Appendix 2.
There is old LWD in the streambed. The streambed is well shaded with no exposed soils.
Recommendation:
There are no impaired riparian functions that require attention within either of these two riparian segments. If LWD is needed over the short term it should be placed instream.
R 4 A and C
Rebman reach 4 stream section A is found on the southwest side of the stream in a block that was harvested in the mid 1980s. Riparian segment C is found on the northeast side of the reach in the same block. Harvesting was done to the stream edge with some patches of advance regeneration left standing. It is now regenerated with planted Sx along with abundant alder, willow and black twinberry. Along the reach there are approximately 50 sph of trees 20 to 25 cm dbh and 8 to 10 m tall (some up to 20 m). Most of these stems are within 5 m of the stream edge. There are approximately 400 sph of Sx and Bl between 1 and 1.3 m tall (70% Sx, 30% Bl), with about 100 sph of 1.3 to 2.2 m spruce and subalpine fir with the same ratio. Approximately 25% of the area is covered with two to three meter tall willow with patches of alder (one to two meters) and dispersed cottonwood, along with an understory of oak fern (Gymnocarpium dryopteris), bluejoint (Calamagrostis Canadensis), cow parsnip (Heracleum sphondylium) and Indian hellebore (Veratrum viride) (SHRts). There are small 8 - 10 m portions of the reach with limited shading. See plates 19 and 20, Appendix 2.
Recommendation:
At this time the stand structure in place is providing all but input of LWD. If LWD is needed over the short term it should be placed instream.
Willow River - Reaches 2, 3, 4, 5, 6, 7, 8 and 9
Site Assessment
Eight stream reaches with a total of 27 riparian segments were visited to assess riparian impairment. Each riparian segment will be described separately to provide site specific information.
R 1, B and R 2 - E
Willow reaches 1 B and 2, E are located north of the confluence with Rebman Creek. The riparian segments are within IU logging. These reaches were not visited due to logistical constraints (road closed due to flooding from beaver dam). From viewing similar areas no treatment is anticipated.
R 2 - B and C
Willow reach 2 segments B and C are located west of reach G, north of the confluence with Rebman Creek. The area was IU logged in 1965. The structure is now MFc with abundant willow along the river edge.
Recommendation:
Leave as is.
R 2 - G
Willow reach 2 segment G is located to the east of an oxbow north of the confluence with Rebman Creek. Partial harvesting was done in the adjacent stand but was done at such low levels the stand remains essentially intact (MFc). There is a significant log jam at the southeastern corner of the oxbow that is a result of trees falling into the river upstream and transported to this bottleneck. The mature timber patch adjacent to the reach has approximately 35 to 40 m2/ ha of basal area and is approximately 25 to 30 m wide. See plate 21, Appendix 2.
Recommendation:
Vegetation is a mature forest that should be maintained unless there is a fear of bank erosion created when future large trees enter the river. This will not likely be a concern here.
R 3 - F
Willow reach 3 segment F is located in a block logged in 1983. The reach was not visited due to an impassable road.
R 4 - C
Willow reach 4 segment C has a road in the riparian management zone, located approximately 2 to 10 meters from the river edge. The vegetation growing on the bank is patchy with clumps of mountain alder 2 to 4 m tall along with regenerating spruce 1 to 3 m tall. The south bank is unharvested and offers shading and a source of LWD. The structural stage on the north bank (segment C) is SHRts/INIT. See plate 22, Appendix 2.
Recommendation:
Leave the established vegetation to mature naturally.
R 5 - H and J
Willow reach 5 segments H and J are found adjacent to a main haulroad east of the mainstem. The segments are vegetated with grass and shrubs (SHRh/Urb). The riparian area between the stream and the road is approximately 5 to 10 m wide. This area does not provide shade or will it contribute LWD. However, due to its location along a main haulroad it is remained unforested to maintain visibility. See plate 23, Appendix 2.
Recommendation:
Unless fish values were identified that require additional shading from the east we recommend no action.
R 7 - A
Willow reach 7 segment A was partially harvested in 1963 The vegetation complex found is a mosaic of shrubs on the floodplain with conifers on upland positions. The tall shrubs are mainly willow (85%) and mountain alder at 15% with isolated cottonwood. The structure is SHRts/MFc. See Plate 24, Appendix 2.
Recommendation:
This riparian segment has a mix of shrubs, mature conifers and no observable riparian deficiencies. Leave to mature as it is.
R 7 - B
Willow reach 7 segment B was partially harvested in 1963. The resultant stand structure is an uneven-age mix of mature spruce, 2 to 5 m tall saplings and abundant willow in the floodplain. There are also isolated cottonwood. A damaged spruce was drilled to assess release. The diameter growth responded approximately 26 years ago, eight years after harvest. The damaged tree had a linear scar 2 m long on the bole but showed only minor center rot. The structure is MFc/SHRls. See plates 25 - 27, Appendix 2.
Recommendation:
This band of vegetation is working well at providing nutrient inputs, shade and is a LWD source. It should be left as is.
R 7 - C
Willow reach 7 segment C was partially harvested in 1963. The structure in the segment is predominantly young conifers with patches of mature conifers along with a shrub understory (YFc/SHRls). The issue identified for this segment is the road placement. It is too close to the river as there is constant erosion. The bank has been grass seeded but due to undercutting ravels yearly. See plate 28, Appendix 2.
Recommendation:
This riparian segment should be looked at for reduction in sediments by the engineering staff. If structures are created the bank could be planted to a range of native shrubs, e.g., willow, alder. Grass presently excludes seeding-in from natural seed sources in areas that have not yet slumped.
R 7 - D
Willow reach 7 segment D was harvested in 1972 using a road within what would now be the 50 m riparian management zone (see appendix 3 for RMA classes and Riparian zone widths). There is some bank instability on the upper slopes (on the side away from the river). They have been grass-seeded and barriers have been placed at the toe of the slope to minimize ditch filling. The present stand structure is made up of a good, uneven aged structure of Sx and Bl. There is a high mature component just east of the bridge. The structure is MFc/SHRls.
Recommendation:
This reach provides a possible sediment source. It should be looked at from an engineering perspective to look at stabilization options. Once assessed by engineering staff bank stabilization using shrubs such as red-osier dogwood (Cornus stolonifera), black twinberry, willow and alder could be used to augment any engineered structures.
R 7 - E
Willow reach 7 segment E was harvested in 1972 leaving only scattered large spruce near the river. This segment is relatively flat resulting in a wider deciduous band in the floodplain. The floodplain is dominated by willow patches that are 3 to 4 m tall and in some cases provide 100% cover. In the same area are spruce saplings approximately 4 to 5 m tall. Some of the stems have been attacked by terminal weevil (Pissodes strobi). The mature Sx that were left are isolated (30 to 50 m between clumps) and stand approximately 25 m. There are localized stunted Pl in the wetter areas. On the sandy banks of the river are short willow and willow herb. The present stand structure is PSm. See plate 29, Appendix 2.
Recommendation:
Leave as is. While the conifer stocking is variable it is due to the seasonally shifting water table and will reestablish over time. The present vegetation offers shading, nutrient input and where there are islands of older stems, a source of LWD.
R 7 - G
Willow reach 7 segment G is within an area that was partially harvested under intermediate utilization standards in 1963 (MFc). What remains is an intact stand with a residual basal area of approximately 25 m2/ha. See plate plates 30 and 31, Appendix 2.
Recommendation:
Leave as is. The vegetation is a mix of herbs, shrubs and various sizes of conifers. Spruce and subalpine fir range in size from 15 to 40 cm DBH. There are also young Sx and Bl in layers 3 and 4 (1.3 m - 7.5 cm and < 1.3 m respectively). The present structure lends itself to shading and recruitment of LWD.
R 7 - H and I
Willow reach 7 segments H and I have portions of unharvested forest as well as being within areas partially harvested in 1962-63 (present condition - YFc/MFc). Much of the riparian area is steep (>50%) with instability where the river undercuts the bank. This steep sandy site has low productivity (estimated site index of 12-14 m BHA 50). There are abundant saplings between the larger more established Sx and Bl. The basal area ranges from 15 to 20 m2/ha. The vegetation on the slope is well established, but is moving down-slope in areas due to soil creep. See plates 32 and 33, Appendix 2.
Recommendation:
Leave as is. Even where there are trees with large established root systems the soil creep is taking the trees with it. The steep noncohesive soils and undercutting of the bank contributes to the gravitational movement of the sidehill and established vegetation. Spacing of the smaller stems would do very little to improve tree root growth, and as mentioned, even large root systems are being moved by the creep.
R 7 - K
Willow reach 7 segment K is found within a partial cut area harvested in 1963. The riparian area is dominated by mountain alder (Alnus incana ssp tenuifolia) with willow and interspersed spruce and subalpine fir below (PSm). The conifers range in height from 1.3 to 3 m. There are patches of 20 to 25 m mature spruce approximately 15 to 20 m from the stream edge. This riparian segment experiences high water fluctuations limiting conifer growth along the stream edge. See plate 34, Appendix 2.
Recommendation:
Leave as is. The structure is suited to the shifting watertable. If additional LWD is needed for the short term it is recommended to use instream placements.
R 7 - L
Willow reach 7 segment L is located on the north bank opposite riparian segment E in the same 1972 opening. The riparian zone is a mosaic of tall willow patches, mature unharvested Sx and young Sx and Bl. The structure provides cover, current supply of LWD and a future supply of LWD. It is presently PSm/MFc. See plate 35, Appendix 2.
Recommendation:
Leave as is. The structure is suited to the shifting watertable. If additional LWD is needed for the short term it is recommended to use instream placements. The large failures noted on the air photo are the result of bank undercutting and would require engineered structures prior to any type of re-vegetation.
R 7 - N
Willow reach 7 segment N is within an unharvested area adjacent to partial cutting that took place in 1963. The present structure is MFc. The riparian segment was identified for viewing due to an unvegetated slope failure. The bank along the segment has eroded causing the forest above to slump towards the river. The slumped material has partially dammed the river resulting in the creation of a pool. The bank is made up of bands of glacial fluvial sands, gravel with lens of silt. The non-cohesive soil and active raveling from the continued undercutting make re-vegetation problematic. See plates 36 and 37, Appendix 2.
Recommendation:
Leave as is. To modify the input of soil and forest debris will require engineered structures to divert the flow. If this were a priority, some form of terracing (e.g., wattle) could be used to re-vegetate the stabilized bank. Without active stabilization, re-vegetation is not advisable.
R 7 - O
Willow reach 7 segment O is within a partial cutting block that was logged in 1963. The present structure is uneven-aged with all layers represented in both Sx and Bl. The structural stage is presently MFc with shade tolerant individuals growing in understory positions. The stand is growing well with spruce up to 45 cm in diameter. See plate 38, Appendix 2.
Recommendation:
Leave as is. This structure lends itself to the long term creation of LWD.
R 8 - B, G,
Reach 8 riparian segments B and G were not viewed due to access problems.
R 8 - I
Reach 8 riparian segment I is within a block that was partially harvested in 1956. The vegetation along this riparian segment is dominated by mature spruce and Bl with a herb and moss understory (MFc). There has been a spruce budworm (Choristoneura spp.) infestation in the area recently, killing some of the understory Bl and reducing the vigor of others. There is approximately 30 to 40% crown closure along the reach. A 27 m tall, 41 cm diameter dominant spruce was determined to be 212 years old within the stand. See plates 39 - 41, Appendix 2.
While spruce budworm has reduced the total density of Bl, no riparian functions were deemed to be impaired at this time. The partial logging appeared to remove a minor proportion of the stand (less than 10% of the basal area). Diameter increment release was found in the co-dominant Bl, where a large diameter increase began about 40 years ago. This would indicate logging occurred prior to that marked on the map (65 logging indicated). As a point of interest, there was little scarring on the leave trees, while 60 cm stumps remain indicating careful logging. A subalpine fir that released was only 13 cm in diameter and over 100 years old when it did release. This indicates overstory removal can increase diameter increment significantly even on old suppressed understory Bl when they are left undamaged.
While the stand has extensive ladder fuels, fire periodicity is low indicating a low hazard overall.
Recommendation:
Leave as is. The structure in place lends itself to large stem replacement. Do not harvest from within the Riparian Zone at next harvest to maintain vegetative benefits in place. What this does indicate is that with careful harvesting volume can be removed from what would be considered the riparian reserve zone without compromising the function of the zone.
Tregillus Creek - Reaches 1, 2 and 5
Site Assessment
Three riparian segments were slated to be visited on Tregillus Creek to assess riparian impairment.
R 1 - A
Tregillus Creek reach 1 section A has a road in the RMA. The segment has not been logged. It has a OFc/SHRls structural stage. See plate 42, Appendix 2.
Recommendation:
The vegetation is well adapted to the site and should be left as is.
R 2 - C
Tregillus Creek reach 2 section C is located in an unharvested area at the end of a spur road. Numerous trees have died, apparently from an elevated water table or from mining spoil. The remaining vegetation is a mix of tall willow and young conifers on higher ground. There are abundant snags along the reach. The present structural stage is SHRts/INIT. The stream itself looks unhealthy with red sediments and green algal growth on the bottom (from mining waste?). See plate 43, Appendix 2.
Recommendation:
Assess for fish values and potential impact on downstream reaches in the Willow system. If engineering is done to mitigate downstream effects the segment should be reevaluated for re-vegetation options.
R 5 - A
Tregillus Creek reach 5 section A is located behind a locked gate with a do not enter sign due to active mining. This reach was not viewed due to the sign. From a distance it appeared to be a mature Sx forest with mining activity in the vicinity.
Recommendation:
Not available due to access constraint.
Rucheon Creek - Reach 9
Site Assessment
Reach 9E was identified for a site visit on Rucheon Creek to assess the road within the RMA.
R 9 - E
Rucheon Creek reach 9 section E has not been logged but has been severely affected by mining activity upstream. The stream channel transports sediment from the mine above. One cottonwood on the bank shows rooting over a meter up from the original ground interface. This creek appears to have an active influence from the upstream mining. The structural stage is SHRts/MFc. See plates 44 and 45, Appendix 2.
Recommendation:
Mining is affecting the stream channel significantly. Monitor for fish habitat integrity.
Summary of Proposed Actions:
The original assumption, from air photo interpretation, of possible interventions to promote riparian functions proved to be overly conservative. Most of the stream segments were found to be maturing naturally, resulting in fully stocked conifer stands or well established shrub complexes. The areas that were harvested under IU regulation were found to have a good mix of stem sizes providing for present and future LWD along with abundant shrubs and herbs.
More modern logging left stream reaches without LWD for the next 50 to 100 years. These riparian segments were primarily stocked with planted conifers growing within a compliment of local shrub species. The conifers will, over time, provide for LWD. In the short term, where LWD is deemed necessary for habitat, it is recommended that LWD be placed instream.
Other riparian functions such as filtration, shade, small organic debris and impaired vegetation establishment were not seen as problems for this area based on the sites visited.
From our observations we have the following specific recommendations:
Slough Creek
Willow River
Big Valley Creek
Sugar Creek
Rebman Creek
Rucheon Creek
Tregillus Creek
Reach 2- C appears to have been affected by mining spoils. Engineering structures of some sort may be needed to mitigate downstream effects. If engineering structures are installed re-assess for re-vegetation options.
References
LGL 1997 (in press) Willow River WRP Stream and Riparian Overview Interim Report.
Oikos, Johnson. 1996. Riparian Assessment and Prescription Procedures: Watershed Restoration Program - Field Guide - Draft 3 A, June 1996.
Appendix 1
Area Map
Map 1 - Area Overview
Appendix 2 - Photographs
Plate 1 Slough creek looking west. Note the progression from rushes to shrubs to conifers along the bank. The lodgepole pine are approximately 22 years old in the foreground. Over time the resultant structure should provide for all riparian functions.
Plate 2 Slough Creek reach 3B note the transported gravel in the foreground. The adjacent stand has mature and immature components.
Plate 3. Big Valley Creek reach 1 - D. Note the abundance of both large willow and conifers up to the stream bank. No riparian functions are compromised here.
Plate 4. At this point in Big Valley Creek the creek channel splits resulting in the mainstream following the roadbed. Some form of engineered structure is needed to rechannel the creek back to its former position
Plates 5 & 6 Big Valley Creek reach 8C. Note the steep glacial fluvial bank has been undercut resulting in a rotation slump and subsequent ravelling. There is an option to cut out the meander to minimize further erosion. A more likely option is to accept intermitant inputs. Note the accumulation at the base.
Plate 7. Active mining area in Big Valley Creek reach 11 C. Note the exposed soil and low shrub in the foreground.
Plate 8 Big Valley reach 11-F. The area was harvested but is not identified as such on the map. Spruce budworm has reduced some of the Bl understory but is not seriously impairing any riparian functions at this time.
Plate 9. Mining activity in reach 5C of Sugar Creek. The bridge crossing Sugar Creek can be seen on the left. The settling ponds are part of an active placer mine.
Plate 10. Looking south down Sugar Creek reach 5-C. The creek is just to the right of the road in the timber. Note the piles of dirt along the road edge from the placer mining operation.
Plate 11. Wetland along Reach 9-D of the Sugar Creek. A fluctuating watertable has resulted in some conifer mortality.
Plate 12. The road along the edge of reach 9 of the Sugar has been heavily flagged indicating future activity.
Plate 13 Sugar Creek reach 11 sits adjacent to a recent cutblock where the block boundary is the stream. Some trees and original shrub vegetation were left undisturbed. The block has been planted with spruce that are doing well.
Plate 14 Planted spruce along-side Sugar riparian segment 11A. Note the gravel deposits in the draw. These appear to be of natural origin, however there has been active mining in the area and possible historical logging.
Plate 15 Note the patches of mature conifers in Rebman riparian segment 1B on the right. This is the result of IU logging in the late 1960s. Reach 1A was clearcut in 1977 and has abundant sapling size regeneration.
Plate 16 The young mixed forest found in the lower reach of Rebman Creek appears to provide for all riparian functions.
Plate 17 Further up Rebman Creek in reach 3 recent 1980s harvesting has resulted in the lack of present LWD sources. However, as the photograph attests the planted spruce are growing well and will provide LWD over time.
Plate 18 Large woody debris found in Rebman reach 3 A and B.
Plate 19 Overview of the vegetation mosaic found in reach 4 of Rebman Creek. Note the heavy shrub accumulations near the creek. The planted spruce are doing well.
Plate 20 Good shading is found within the shrub dominated vegetation adjacent to Rebman reach 4. There are some remaining mature stems in the riparian area along with abundant willow, alder and planted spruce.
Plate 21 Log jam at the bend of Willow River reach number 2. The intact forest on the right of the photo is riparian segment G. The stand is approximately 30 m wide.
Plate 22 Reach 4 on the Willow River has the road within 1 to 5 m of the water. This narrow band between the road and river has seen some minor erosion but is now vegetated with patches of willow and spruce.
Plate 23 The main road lays adjacent to Willow River reach 5 - H. For visability the low shrub cover is preferred over conifers. The bank vegetation appears stable.
Plate 24 Willow reach 7 segment A is in a relatively flat segment of the river that floods yearly. The tall shrub vegetation on the flats gredates to conifers as one moves upland. The vegetation is well established with young conifers growing to replace those falling into the river.
Plate 25 Uneven-aged structure as a result of IU logging in Willow reach 7 B. The scarred Sx in the center of the photograph was drilled to assess diameter release. The photograph below shows the release point.
Plate 26 Release 26 years ago, 8 years after the overstory was removed by partial harvesting.
Plate 27 Abundant structure found along Willow River reach 7 - B. The 1960s partial harvest resulted in an uneven-aged distribution. Willow and mountain alder form the tall shrub component.
Plate 28 The erosion along the roadedge in Willow River reach 7 - C is not being controlled by the grass seeding. The adjacent shrubs provide greater bank stability.
Plate 29 The relatively flat topography along the Willow River reach 7 - E results in a willow dominated floodplain. Conifers are found in the shrub strata on elevated microsites.
Plate 30 Willow River reach 7 - G had a low level harvest leaving a mature conifer stand.
Plate 31 The streamedge along Willow reach 7 - G has abundant shrubs and mature conifers after a light IU cut from the 1960s.
Plate 32 Small slump found in Willow reach 7 - H. The bank is being undercut resulting in soil creep leading to a rotational slump.
Plate 33 The steep (70% +) slopes found in Willow reach 7 - H are on unstable glacial fluvial parent materials. The slope is moving even when vegetated. The photograph shows angled stems characteristic of soil creep.
Plate 34 A progression of shrub (willow), small deciduous trees (mountain alder) gredating into conifers is the vegetation structure along Willow reach 7 - K. Regenerating conifers are found growing through the shrub and deciduous band. Flooding has likely affected conifer performance near the streambed.
Plate 35 Willow reach 7 - L shows a mix of mature Sx on the riveredge along with abundant mountain alder and willow. This is a typical structure resulting from diameter limit logging (IU) practiced in the 1950’s and 60’s.
Plate 36 Striated soil profiles in the glacial fluvial bed of the Willow River (reach 7 - N). The bank is being undercut resulting in erosion and deposition of slope materials and trees from the stand above.
Plate 37 View of Willow River reach 7 - N from the water level. Note the pool in the foreground formed by the partial dam created by the slump.
Plate 38 Well balanced uneven-aged distribution along Willow reach 7 - O. The large woody debris in this reach are oriented parallel to the river due to its strength and width.
Plate 39 Partially harvested stand along reach 8 I on the Willow River. The stump being written on is 60 cm in diameter. The subalpine fir in the foreground is growing rapidly as the core sample below shows. Little harvesting damage was noted.
Plate 40 Increment core from the above Bl. Note the good growth for the last 40 plus years (the tree is about 160 years old). The additional growth started prior to the date of harvest (1962). This may have been due to natural causes or unrecorded harvesting. The stand is growing well and needs no intervention.
Plate 41 Uneven-aged structure to the edge of Willow River reach 8 I. The IU logging done in the 1960s left a relatively intact stand that has responded with additional growth and revived vigour.
Plate 42 Tregillus Creek near the mouth where it enters the Willow River. The slow moving stream has abundant structure on both sides.
Plate 43 Dead and dying conifers line Tregillus reach 2 - C. The cause may be flooding but may also be due to mine spoils as the stream has reddish accumulations and algal growth, not observed on any of the other streams or reachs assessed. As a note an oxbow lake off of the Willow A was bright orange in a 1991 air photo.
Plate 44 Severe stream deposition and scouring along Rucheon Creek reach 9 E.
Plate 45 Note the cottonwood in the center of the photograph. The original soil interface is near the present position. A deposition event resulted in adventitious roots forming from the bole of the tree. The most recent scouring exposed the old bole and new roots. The tree is now dead.
Appendix 3
Overview riparian assessment and visitation priorities for the Upper River Willow watershed
Appendix 4
Field notes