Monday, August 18, 2014

Brydon Lagoon

Earlier this month, around 500 to 1,000 fish died in Brydon Lagoon. As reported in the local news, and according to information from the City of Langley, the deaths were likely the results of low oxygen levels in the water due to the significant green algae blooms in the pond, combined with the extremely warm temperatures.

The City of Langley commissioned a Pond Management Strategy which was finish back in March 2013. The Strategy focused on Brydon Lagoon, the ponds at Sendall Gardens, and the pond just beside the Langley Seniors Resource and Recreation Centre.

The City of Langley Parks and Environment Advisory Committee, which I am a member of, provided input into the Pond Management Strategy. Based on the report, I wanted to highlight some facts about Brydon Lagoon.

Brydon Lagoon was built in 1963 to serve as a primary sewage treatment facilities for the City of Langley. As it was designed to be a sewage treatment facility, the lagoon needed to be shallow. Today it has a maximum depth of 1.25 metres.

In 1975, the lagoon was decommissioned as a primary sewage treatment facility and turned into a storm water management pond (see image in the post.) The lagoon was meant to help regulate the flow of water from storm water drains and reduce the sediment that would be deposited into the Nicomekl River, when it rains.

Brydon Lagoon - Existing drainage features and location. Source: Pond Management Study. Select image to enlarge.

In 1985, the lagoon and its surrounding area was designated as a wildlife sanctuary and public green space. The two aeration fountains in the lagoon today were installed in 2003 in an attempt to improve water circulation and increase the oxygen levels in the lagoon.

As the lagoon is only feed by storm water, during the summer month, the lagoon water essentially becomes stagnant.

The lagoon has become home to both invasive vegetation and aquatic animals. The dominant plant life consists of Reed canary grass and Himalayan blackberry. The grass at the edge of the lagoon is slowly causing an infilling of the lagoon.

Right now the lagoon is home to invasive fish species introduced by humans. While the lagoon does connect to the Nicomekl River, due to the current design of the lagoon’s outflow, indigenous fish from the Nicomekl River could not enter the lagoon.

So what could be done to improve Brydon Lagoon?

Dillon Consulting recommended that the lagoon would be most useful as a natural/park area. As such, they recommended keeping up with the current maintenance of the aeration fountains, perimeter path, and vegetation control along the path. In addition, they recommended that the City:

  • Install additional signage and lighting to improve the public realm
  • Replace the wooden outlet culvert with a new structure that would also allow fish to pass between the lagoon and the Nicomekl River
  • Install sediment catchers on the storm water inflow pipes
  • Stabilize the south bank of the lagoon to reduce infill
  • Widen the perimeter gravel path to 2m and build a viewing platform.

If the City implemented all the recommendation in the report, it would cost $218,025 and add $6,000 to the City’s operating budget.

To me this is well worth the cost as it would enhance the Nicomekl Floodplain Park System.

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