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Rithet's Bog LogoRithet's Bog - Looking Good!

BARA Bugle (Broadmead Area Residents Association Newsletter),
Spring 2003 - Sharon Hartwell

Hectares of open water, flocks of ducks, muskrats swimming in the ditches, and a lot less willows! It's a pleasure walking at Rithet's Bog these days. Our long-anticipated restoration project is well underway, and it shows.

What has been done so far?

Last fall, Ducks Unlimited completed several hydrological engineering tasks to combat the low, fluctuating water levels that were slowing but surely destroying Rithet's Bog. First, an adjustable wood and concrete weir was installed at the outlet culvert under Chatterton Way. This weir has been designed to raise the water level to the ground surface in the central bog during the winter, and maintain it within 50 centimeters of that surface over the summer and fall. If this critical water level is maintained, water can then be released from the bog as needed to supplement low water flow in the salmon bearing Colquitz Creek during the summer.

Next, the pattern of water flowing into the bog was altered, to improve water quality. An earthen plug was created to block the FirTree Glen end of the drainage ditch that transects the bog, in order to divert the nutrient rich waters of Gabo Creek away from the central bog and into the surrounding wetlands.

Lastly, heavy equipment was used to cut 4 hectares of willows in the old agricultural fields along Chatterton Way. These willows were causing enormous evapo-transpirational loss of water, and had also invaded and eliminated what were formerly large expanses of open water providing excellent waterfowl habitat.

Ducks Unlimited staff tells us that this project, a partnership with Saanich Parks, the Rithet's Bog Conservation Society and Fisheries and Oceans Canada, was one of the best they have ever worked on. Cooperation between parties was excellent, as was support from the general public. BC Hydro even donated a day's work by one of its crews to handle the temporary disconnection of two power poles!

And the commitment is ongoing. Saanich has signed a 30 year conservation agreement with Ducks Unlimited, guaranteeing ongoing maintenance of the weir, and continued liaison with Duck Unlimited and DFO in developing a water level management plan for the bog.

The results to date

Changes to the Rithet’s Bog environment have been dramatic. The weir immediately raised water levels throughout the park, and they have been at maximum height since early December, when the weir first began to overflow. Open water is standing along Chatterton Way, where the willows were removed, and has also accumulated in the old fields parallel to Dalewood Lane. Up to 300 waterfowl have been observed on a given day, and the number of species has also become more diverse. The ubiquitous mallards have been joined by American wigeon, shovellers, pintails, green-winged teal, Canada geese, trumpeter swans and American coots.

Colquitz Creek has also benefited. The surges of sediment-laden water that usually flushed out of the bog after heavy rains have been prevented by the weir. Now, a slow, steady flow of clean water feeds the creek.

How and why results are being monitored

Environmental monitoring is necessary to provide the information needed to develop a long term strategy for managing water levels in the bog. Our goal is to protect and enhance both the ecological function of the bog, and the downstream water quality in Colquitz Creek. To do this, we need to know how water levels and quality have changed, and what effect this is having on the vegetation and wildlife.

Over the winter, we have been monitoring water levels at the weir, water flow into Colquitz Creek, and the number and variety of waterfowl at the bog. This spring and summer, additional monitoring will include water quality in the bog and Colquitz Creek (oxygen content, pH, dissolved oxygen and turbidity), mapping the size and composition of the plant communities in the wetlands, and assessing the extent and health of the rare Sphagnum bog community in the central forest. This baseline information will be used as a reference point for information collected in the years to come.

What next?

More work will be taking place this summer and fall.

  • Saanich Parks will replace the snow fencing near the weir with a permanent fence, and finish resurfacing the walking trail along Chatterton Way.
  • Ducks Unlimited contractors will return to mow any regrowth from the stumps of the cut willows. (These repeated cycles of winter submersion and summer cutting should kill the majority of the willows within 5 years).
  • RBCS will coordinate volunteers to manually remove slashed willow debris from the Chatterton field. If this is not done, the larger pieces may sprout and produce new growth, the decomposing wood will become malodorous, and large amounts of dissolved tannin will be added to the water. Many volunteers will be needed!
  • A willow cutting party will also be held in late summer for people who wish to cut willow switches for basket making, streamside restoration planting or creating living willow fences.
  • Our display case at the Dalewood corner will be updated with new information on natural and human history. The first display will be all about the ducks and other waterfowl at the bog.

 

Help us Celebrate - Sign Unveiling April 26

Please join us for a sign unveiling ceremony on Saturday, April 26. Ducks Unlimited has produced a series of interpretive signs explaining bog ecology, describing how human activity has altered Rithet's Bog, and how the restoration project will benefit the Colquitz watershed. We hope you can join us at the unveiling and help celebrate this successful project. Watch for details in the Saanich News and on the information kiosk at Dalewood corner.

Many thanks to all who wrote, emailed or phoned Saanich Council over the years in support of our efforts!

Sharon Hartwell, Rithet's Bog Conservation Society

 

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