Bouchie Lake

Bouchie Lake Stewardship Society

Background Information

The Bouchie Lake Stewardship Committee (BLSC) was formed several years ago by local residents concerned about the state of Bouchie Lake and the surrounding area.  In 2008, there was a severe fish-kill (see photos below) in the lake due to an algal bloom and lake turn-over resulting in oxygen depletion.  This created new motivation for the BLSC and residents to work together with provincial and local government as well as other stakeholders to prevent this from happening again.

The BLSC began formally working with Baker Creek Enhancement Society (BCES) in 2009.  A series of community meetings with government, residents and stakeholders were held to address the issues in the watershed and possible solutions.  The Watershed Management Plan was developed to address the issues and solutions in the Bouchie-Milburn Watershed.

clear_day.jpg       fish_kill_at_public_access.jpg     Fish_kill.jpg

Photos above  left -Clear day on Bouchie Lake, centre – Algae blooms, right – fish kill

Bouchie Lake

Some facts concerning Bouchie Lake water quality:

  • Bouchie Lake is not “dying”, but has become more biologically productive as a result of land and residential development
  • The decomposition of the algae & other plant material depletes oxygen in the lake bottom waters
  • There was a dramatic decline in water quality in the 1950s
  • Fish kills are the result of the lake turning over and mixing this low oxygen water at the same time as algal bloom.
  • Fish kills may become more frequent in the future as the climate warms because the lake will turn over more often – these will be worse if something is not done to address sources of phosphorus 

The Science

Phosphorus is the primary nutrient of concern contributing to the algal growth that is resulting in poor water quality.  Large algae blooms, excessive aquatic plant growth, and decreased water clarity have all been identified as concerns to residents.  Two studies were conducted prior to 2007 looking at phosphorus inputs to the watershed.

The Bouchie-Milburn Watershed encompasses the west side of Milburn Mountain, Mit Lake, Milburn Lake, Bouchie Lake, and all associated creeks.  There is a sub-surface water connection between the outlet of Milburn Lake and the inlet of Bouchie Lake.  The main water bodies in the watershed are Milburn Lake and Bouchie Lake.  Both lakes have development on the lakeshore to varying degrees.

An analysis was completed in 2002 by J.S. Hart and Associates to examine the phosphorus sources in the Bouchie-Milburn watershed.  Annual phosphorus input to Bouchie Lake from the watershed is broken down as follows.

Phosphorus source                                         Annual phosphorus input to

                                                                         Bouchie Lake from the watershed                                                                                                                Amount (kg)                            % of total

Agriculture land (including hobby farms)                          190.2                                      42.2

Lakeshore sewage disposal systems                                     70.0                                      15.5

Livestock wintering areas                                                     60.2                                      13.4

Crown land (excluding lakes and ponds)                             37.6                                        8.3

Lakeshore residential land                                                   36.0                                        8.0

Rural residential land                                                           28.2                                        6.3

Atmospheric contributions to lakes and ponds                     28.2                                        6.3

Total                                                                                  450.3                                    100.0

 

The above table represents inputs from lakeshore and upland sources only.  Hart estimates an increase of 3.9% input from lakeshore sewage systems (to 91.6 kg/year) by 2027 assuming no further development and no upgrades to sewage systems.

For a more complete synopsis of septic system impacts on the Bouchie-Milburn watershed, please see this document prepared by Chris Swan with the BC Ministry of Environment.

Internal phosphorus loading is also a significant source of nutrients to Bouchie Lake.   Internal phosphorus loading is estimated to be 52% of the entire annual phosphorus load (C. Perrin 2005).  This internal loading is a result of build-up of lakeshore and upland sources over time and was estimated using sediment core samples of the lake bottom.

Ongoing Activities

In addition to community and stakeholder meetings and planning with provincial and local government, BLSS and BCES have done a lot of work on the ground.

One of the areas of concern is Purser Creek Road.  Along a portion of the road is a bank that has been eroding into the creek.  The sediment being released carries a high nutrient load that is being deposited in Bouchie Lake.  In October of 2009, Bouchie Lake Elementary students walked (!) to Purser Creek Road to help harvest plant material and begin building a wattle fence to combat the erosion on the bank.  BCES staff, BLSC volunteers, Quesnel River Environmental Restoration Services, and students harvested willow and cottonwood trees from the nearby area and started work on the living wattle fence.  The next day, volunteers from the community, including members of the Bouchie Lake Volunteer Fire Department, completed a section of the fencing and planted native vegetation.  They also planted native vegetation on three lakeshore properties to improve riparian habitat.