Langford Lake Outlet Creek Enhancement hand in water'

The Veins of Life
Watershed Society




In August and September 2002, the Veins of Life Watershed Society was involved in a project to enhance the Langford Lake outlet creek in a section adjacent to the Trans-Canada Highway, near Sooke Lake Road. The creek was to be deepened and widened to allow for extra flow during periods of extreme rainfall. The goal of the enhancement project was to increase the flood-levels of the outlet so that Langford Lake would not flood the surrounding residential properties during future winter storms. A series of pools and cutbanks were designed, to allow enough standing water to remain for fish habitat during normal flow periods.


The project was managed by the District of Langford and R. Irwin Consulting Ltd.; Earth Tech created the blue-prints, the excavation was done by Don Mann Excavating Ltd., and the environmental restoration work was done by Veins of Life.

Figure 1: The blue star indicates the location of the enhancement site along the Langford Lake outlet (Map adapted from Natural Areas Atlas, Capital Regional District)

Figure 2: Orthographic photo of the enhancement area.
(Photo adapted from Natural Areas Atlas, Capital Regional District)


A.     Planning

Plans were drawn up by Earth-Tech and the environmental monitor, Chris Morley, assigning the locations of the cut-banks and pools that would be constructed for fish habitat. Supplies were gathered together and the Stream Restoration Supervisor and the Stream Restoration Technician set a game plan for the work that lay ahead.

Taryn McCaffrey, photo

Figures 3 & 4: View of east end of stream before excavation.

Taryn McCaffrey, photo

B.     Equipment Used

Cedar logs, boulders, gravel, 3/8" steel cable and clamps, 1/2" ogger (drill), gas powered generator and water pump, sandbags, erosion-control fabric (from Nilex), grass seed, hay bales, shovels, rakes, wheelbarrows.

Taryn McCaffrey, photo
Figure 5: View of west end of stream before excavation.

C.     Stream Enhancement

Site Preparation

The stream was sandbagged at the south end of the culvert that passes under the highway, in order to keep the stream-bed dry while we were working. An excavator began widening and deepening the stream on August 13, 2002. The machine work started at the east end of the stream, working towards the culvert. The operator put some ferns and other vegetation asside as he excavated the banks, so that we could transplant them later. An arborist came in to cut down 4 maples that would be replaced at the end of the stream/bank work.Once the first 2 pools were completed and the banks were widened, we were able to begin our work restoring the banks and stream to a natural state.

Taryn McCaffrey, photo
Figure 6: Four maples along the stream bank had to be removed during the widening process. Each maple that was cut down would be replaced with four new maples.

Bank Work

Once the excavator had finished digging out the first pool, we began our work along the banks; creating cutbanks and stabilizing the disturbed banks with erosion control material.

Taryn McCaffrey, photo
Figure 7: After widening the stream, the banks were very unstable.

1. Cutbanks

To create the cutbanks or "fish-condos", the excavator cut a notch in the side of the bank and then placed some large boulders roughly two metres apart. We then placed three cedar logs on top of the boulders and laced 3/8" steel cable through our pre-drilled holes to bind the logs together. The excavator then placed more boulders on top of the logs, as well as gravel and finally soil, to cover the logs completely, essentially making them part of the existing bank. Erosion-control mattress was placed over the soil above the cutbank and seeded with fall-rye so that the soil would not be flushed back into the stream during the rainy season. The result is a small covered area at the side of the stream (cutbank), which will retain standing water and provide a place for fish to rest during their journey upstream.

Bob Truelson , photos
Figures 8-9: A double-cutbank or, "fish-condo" created to allow sheltered, standing water for fish to rest or spawn.

2. Erosion Control

After the excavator widened the stream, most of the banks were left in a very unstable condition. To remedy this, we placed erosion control mattress over the steep areas and staked it with live stakes. This mattress was then seeded with a combination of a fast-growing rye/wheat/vetch seed mix, and a native seed mix that would fill in later. The combination of mattress and grass will keep the banks from eroding until other plants have a chance to establish themselves.

Bob Truelson , photo

Taryn McCaffrey, photo

Taryn McCaffrey, photo

Taryn McCaffrey, photo
Figures 10 - 13: Erosion-control mattress (top & middle) was used on the steep areas of the disturbed banks. Live stakes were used to attatch the erosion-control mattress to the bank. The banks were seeded after the mattress was placed.

3. Rip-Wrap

In some areas, there were large trees in close proximity to the bank. To protect their roots from erosion, "rip-wrap" (a collection of large boulders) was added to the bank at the base of the trees. This rip-wrap essentially adds a protective barrier over the roots, minimizing erosional damage.

Bob Truelson , photos
Figures 14 -15: Rip-wrap (collection of large boulders) was placed along the bank, at the base of any large trees.

In-Stream Work

1. Low-Flow Channels

After the excavator finished digging an area, and he was satisfied with the grade, he laid-down some river gravel along the bottom. He left a fairly flat surface which resembled a ditch more than a stream. To make it look and work more like a stream, we hand-dug a small, 2-3 ft. wide channel along the center. This would mimic the natural water course in this stream by creating a "low-flow channel" for the water to follow.

Taryn McCaffrey, photos
Figure 16 - 17: Above, the excavator digs out one of the pools and places a layer of gravel on the bottom. Below, a low-flow channel to direct the flow of the stream during low periods.

2. Boulder Placement in pools

After the pools were completed, and the cutbanks were constructed, some large boulders were "strategically" placed in the pool to create more fish habitat. (See below):

Bob Truelson , photo
Figure 18: Large rocks were added to pools for fish habitat.

3. Digging, Digging and More Digging!

The last section of stream closest to the culvert had to be dug-out by hand because the area was too tight for the excavator to get into. A few hundred wheel-barrows of dirt and gravel later (plus a few well-deserved slurpy breaks)....

Taryn McCaffrey, photo
Figure 19: A small area was hand-dug by the mighty restoration crew!

4. Washing the Stream

Once all the gravel had been laid-out by the excavator, the stream needed to be washed. There was a lot of excess sediment in the gravel that could potentially flush into Goldstream River during the first heavy rain. We did not want this to happen.

A truck came in and sprayed the entire length of the stream. Much of the sediment washed off the top and settled at the bottom, where it would cement itself. In particularly dirty areas, we washed the water into the nearest pool, and filled the pool so we could pump out the silty water. This process was very successful in removing the majority of the unwanted sediment.

Taryn McCaffrey, photo
Figure 20: A few sections of stream were pumped to remove sediment.

Clean-up of Access Points

The excavator left a few access points in his travels that we had to clean up and cover so that the dirt would not erode into the stream. The areas were covered with hay and then seeded with grass seed to create some stability in sloping areas which could potentially drain into the stream. The areas will then be planted (up to 15m from the bank) to fill in these bear spots and essentially make them "dissappear."

Bob Truelson , photo

Taryn McCaffrey , photo
Figures 21 & 22: The access points left by the excavator needed to be covered with straw and seeded with grass so they would not erode into the stream.


All of the disturbed areas including banks and access points were replanted with a variety of native plants suitable for a riparian (stream-side) environment. Species included: Broadleaf Maple, Red Alder, Salal, Salmonberry, Ocean Spray, Red Elderberry, Red Huckleberry, Snowberry, Pacific Ninebark, Indian Plum, and Sward Fern. A total of 245 plants were placed in the ground.

Taryn McCaffrey , photos
Figures 23 & 24: Potted plants ready and waiting!

Taryn McCaffrey , photos
Figures 25-27: Planting in progress along disturbed access points and banks.

Plants were placed 2 metres apart along the disturbed areas. Holes were cut into the erosion-control mattress in order to put plants into the side of the banks.

Bob Truelson , photo
Figure 28: Planting, planting... more planting!

The fall leaves provided a natural cover over the banks, meshing in with the grass and erosion-control mattress to stabilize the disturbed areas.
Taryn McCaffrey, photo
Figure 29: The cutbank is barely visible now, with fallen leaves and grass covering the top.

All plants were labeled for future monitoring purposes.
Taryn McCaffrey, photo
Figure 30:Plant label, "VOLWS Oct 02"


The Crew


© 2009 Veins of Life Watershed Society / All Rights Reserved / if you wish to use any info for commercial or non commercial usage you must obtain permissions from The Veins of Life Watershed Society