Endako Weir Project

The UFFCA and partners T’sil Kaz Koh and Stellat’en First Nations are taking steps to improve critical Chinook spawning habitat. The Endako Weir will help increase and stabilize the flow of the Endako River during the salmon spawning season and egg incubation period to improve survival for the next generation of salmon, and will benefit the habitat of all fish that call the Endako home.

Out on the boat in Burns Lake.

Ashley and Rebecca working on the real-time water monitoring station on the Endako River.

Low flow conditions on the Endako River in August 2023.

Saikuz monitor James Thomas measuring the water level in Burns Lake east.

Endako Chinook need our help

Climate change, as well as reduced forest cover, have led to seasonal reductions in water levels and an increase in water temperature in streams and rivers in BC. This makes for challenging conditions for migrating salmon, and poor conditions for eggs that are incubating in these waterways. The effect in the Endako is lower August and September flows during periods that are key for Chinook and kokanee migration and spawning.

The graph to the left shows the sharp decline in Endako Chinook spawner escapement since the year 2000.

 

Fluctuating flows in the Endako River

Water flow in the Endako has become erratic through the late summer months, which is critical spawning time for Chinook.  Unpredictable flows often mean that the fish do not arrive at their spawning beds and are left struggling to swim in a river that has become a trickle of water. It also means kokanee are often not able to use the Endako River to spawn due to dewatered spawning habitat.

The graph to the left shows flow levels before (orange) and after (blue) installation of the weir. The orange line shows how flows are unpredictable without the weir in place; the blue line shows higher and more stable flows after installation of the proposed weir. 

The Endako Weir: Stabilizing water flow in the Endako River

Water Survey Canada and the Upper Fraser Fisheries Conservation Alliance (UFFCA) have been monitoring the Endako for over 20 years. The UFFCA has now come to an elegant solution to the issue of lower water flow: build a weir where Burns Lake flows into the Endako River.

A weir is a structure used to manage the flow of a river. The proposed Endako Weir is very simple in its design: rocks will be placed across the Endako River where it flows from Burns Lake, with a fishway channel on the side to allow year-round flow and fish passage. Flow augmentation in the Endako River is is achieved by storing water in Burns Lake and Decker Lake during the spring and summer. These increased flows will improve the spawning and incubation habitat for Endako River Chinook and kokanee and improve habitat for all resident fish that utilize the Endako.

The weir will include a fishway to allow kokanee fry to migrate from spawning areas below the weir back into Burns Lake. The nature-like fishway will also allow rainbow trout and other fish to move freely between the lake and the river.

How will the weir affect water levels in Burns Lake?

The weir’s construction will not significantly change Burns Lake water levels. High water levels will not change at all, and average levels during the year will increase by approximately 33 cm, or about 1 foot.

The graph on the left illustrates the effect of the weir on Burns Lake water levels. The red line shows the water level during a sample year before the weir construction. The blue line is a model showing water levels in the lake after installation of the weir.

What happens if the weir fails?

According to the hydrological engineering report commissioned as part of project planning, the weir is very safe. Even if the weir totally fails, the infrastructure and economic losses will be limited to the weir itself, and the weir’s owners. A breach of the weir, even at maximum water levels in Burns Lake, would be extremely unlikely to impact environmental or cultural values.

How will we know the weir is working?

Measuring the effectiveness of the weir will be the job of UFFCA biologists and technical staff, who have installed water monitoring stations on the Endako River and in Burns Lake. These will be able to tell if the weir is successfully increasing water flows in the Endako where fish spawn.

The UFFCA’s partner the Carrier Sekani Tribal Council also counts spawning Chinook in the Endako system, which will provide another way to understand the effectiveness of the weir. Of course water flows are only one factor in the decline of salmon in BC, but we are hopeful that with the weir installed, as well as the release of Chinook fry reared in enhancement facilities such as the Spruce City Wildlife Association Hatchery in Prince George, that the Endako Chinook will recover and once again be plentiful.

In collaboration with the Carrier Sekani Tribal Council, Ts’il Kaz Koh and municipal, provincial and federal levels of government, the UFFCA will also have teams regularly maintaining the weir to ensure it continues to do its job and complies with provincial safety regulations.

Studies and Monitoring

Studies

  • A hydrological study of the weir’s potential impact on Burns Lake water levels
  • Erosion assessment including:
    • shoreline assessment by boat to determine which areas are currently at high risk of erosion;
    • a LiDAR (light detection and ranging) flight over Burns and Decker lakes to establish current shoreline condition;
    • a desktop erosion assessment, which defined areas of very high, high, moderate and low risk of erosion along the shoreline of Burns Lake and Decker Lake.
  • Assessment of groundwater interface with municipal wastewater. using pressure transducers in existing groundwater wells to confirm the relationship between lake water levels and groundwater levels.
  • Preliminary wave monitoring data collection.
  • Water quality assessment including literature review on potential impacts of weirs to water quality, summary of available water quality baseline data, and recommendations for additional monitoring.

Monitoring:

  • Installation of 16 erosion monitoring locations in Burns Lake and Decker Lake (see map below)

  • In person data-collection of turbidity, nutrient, temperature, and dissolved oxygen levels at various depths (2022-present, see map below).

  • Installation of a turbidity monitor at the outflow of Burns
  • Geotechnical assessment at the weir site, which informed weir design.

Engagement

The UFFCA team conducted extensive engagement with Ts’il Kaz Koh First Nation (a member of the UFFCA) and residents of Burns Lake. Due to COVID restrictions, much of this engagement was online – but we were able to include some in-person meetings in June and July as restrictions relaxed. You can access a report on the engagement here.

Permitting

Archaeological Impact Assessment – complete

Archaeological Site Alteration Permit – received

DFO Authorization – received

BC Section 11 under Water Sustainability Act – under review

BC License of Occupation – received pending Section 11 permit

 

The schematics below show the weir at high flow and low flow, respectively.