Categories
Community Remediation

Mount Polley built and managed an on-site fish hatchery in 2018

After the spill, a population monitoring program on Polley Lake indicated there had probably been a reduction in the age class of the population of Rainbow Trout (as upper Hazeltine Creek was the main spawning area for these trout). There was spawning observed in Frypan Creek at the north end of Polley Lake, however it was noted to be a much smaller habitat. The Mount Polley Environmental Team (MPET) recognized it was important to allow the fish to spawn in Hazeltine Creek, but the Habitat Remediation Working Group (HRWG) had concerns whether the spawn in the reconstructed Hazeltine Creek would be successful.

The MPET developed a backup plan. With guidance provided by Minnow Environmental and David Petkovich (Aqua-culturist), over 11,000 Rainbow Trout fry were raised in an on-site fish hatchery in spring 2018. Eggs were harvested and fertilized from some of the local Rainbow Trout that had returned to upper Hazeltine Creek to spawn.

The fertilized eggs were incubated in trays so temperature, flow and dissolved oxygen levels could be regularly monitored. Water intake was sourced from below the thermocline in Polley Lake in order to maintain cooler water temperatures.

Egg trays in Mount Polley on-site Rainbow Trout hatchery [2018]
Egg trays in Mount Polley on-site Rainbow Trout hatchery [2018]

Within two months, the eggs hatched into alevins (yolk-sac fry) and within another two weeks the yolk sacs were completely absorbed.  Throughout the incubation stage the eggs were counted, and unfertilized eggs removed.

Fish tray showing Rainbow Trout eggs hatching [June 2018]
Fish tray showing Rainbow Trout eggs hatching [June 2018]
Rainbow Trout fry in shallow ponding tanks [early July 2018]
Rainbow Trout fry in shallow ponding tanks [early July 2018]

The fry were then transferred from the incubation trays to shallow rearing tanks. When the fish reached their target biomass, they were transferred into deeper rearing tanks, and from there released into the Polley Lake watershed.

Mount Polley hatchery rearing tanks. [summer 2018]
Mount Polley hatchery rearing tanks. [summer 2018]

The MPET and Minnow Environmental released over 11,100 Rainbow trout fry from the hatchery into Polley Lake on September 25 and 26, 2018. The adipose fins from each fry were clipped as a means of tagging (identification). On the second day, students, parents and a teacher from Columneetza Middle School’s Greenologists / Enviro Club based in Williams Lake assisted with the Rainbow Trout fry release

Mount Polley strongly encourages Polley Lake fishers to report if they catch fish with a clipped adipose fin to gabe.holmes@mountpolley.com. This will help the MPET determine how successfully the hatchery trout are surviving. Thank you!

Categories
Remediation

Rainbow trout return to Hazeltine Creek

In 2018 a milestone was celebrated by the Mount Polley Environmental Team (MPET) when the efforts of the remediation work rebuilding Hazeltine Creek witnessed the return of Rainbow Trout, Redside Shiners and Long Nose Suckers to the rebuilt part of the creek.

After the August 2014 tailings spill, fish from Polley Lake were prevented from entering Hazeltine Creek by fish fences above the Polley Lake Weir, while the habitat underwent reconstruction. During the winter of 2014-2015, the creek channel was cleaned up, tailings and debris removed, and a new Hazeltine Creek channel was built and rocked-in.

Fish fences blocking passage from Polley Lake (top left) into upper Hazeltine Creek [2015]
Fish fences blocking passage from Polley Lake (top left) into upper Hazeltine Creek [2015]

In April 2015, the Habitat Remediation Working Group (HRWG*), including the T’exelc First Nation (Williams Lake First Nation) and Xatśūll First Nation (Soda Creek Indian Band) and their consultants, and Mount Polley Mining Corporation (MPMC) representatives and their consultants (Envirowest and Golder), began discussing options for constructing new fish habitat in upper Hazeltine Creek, and requirements MPMC would need to meet in order for fish to be allowed to return to the creek.

*HRWG also includes representatives of the federal Department of Fisheries and Oceans, the provincial Ministry of Environment, and the provincial Ministry of Forest Lands and Natural Resource Operations, both water stewardship and fisheries sections.

Mount Polley employees, consultants, contractors, First Nations and community partners began ecological remediation work on Hazeltine Creek in 2015. By May 2015 the water in Hazeltine was running clear, and the bugs (invertebrates that provide food for fish) were starting to grow in the creek, so it was decided that the installation of new fish habitat could begin and this work started in 2016.

HRWG members looked at historical records to determine what the local conditions were before the spill, and remediation planning was based on that information. The planning was also constrained by the configuration of the constructed rocked-in channel. The group agreed to a field fit approach for the remediation. Conceptual designs were developed by Mount Polley and their consultants, and the plans were reviewed by the HRWG.  

The design approach was to naturalize the rocked-in channel by adding sinuosity (curves and bends), building a sequence of pools, riffles and weirs, and installing boulders, large woody debris and gravel at the bottom of the creek, to provide appropriate spawning and rearing habitat for the fish known to have used upper Hazeltine Creek before the spill, particularly Rainbow Trout, an important species in Polley Lake.

Abundant Rainbow Trout observed upstream of fish fences, looking to transit into Hazeltine Creek from Polley Lake to spawn. [May 2017]
Abundant Rainbow Trout observed upstream of fish fences, looking to transit into Hazeltine Creek from Polley Lake to spawn. [May 2017]

After two years of habitat construction (2016-2017) approximately 2.5 km of spawning and rearing habitat was completed in the upper part of Hazeltine creek from the outlet of Polley Lake to the Gavin Lake Road Bridge. In late 2017, the MPET believed conditions were right to let the fish back into the creek. There was habitat, flowing water, and food, and the water quality met aquatic guidelines.

In December 2017, the HRWG began detailed discussions on the approach to allowing the Rainbow Trout back into Hazeltine Creek. Discussion included requirements for fish monitoring, water quality, sediment quality, habitat quality and quantity, Polley Lake access and egress etc, and the permits and licenses that Mount Polley would have to apply for and comply with from the Ministry of Forests, Lands, Natural Resource Operations and Rural Development Water Stewardship Group.

In March 2018, new fish fences were installed in Hazeltine Creek approximately 2.6 km from the outlet of Polley Lake to prevent fish from going further downstream than the area where habitat reconstruction have been completed. On April 26, 2018, the fish fences at the outlet of Polley Lake to Hazeltine Creek were removed and the Rainbow Trout once again had access to the first 2.6 km of upper Hazeltine Creek.

Note:  the lower part of Hazeltine Creek includes a steep rock canyon that is a natural barrier preventing Quesnel Lake fish from entering middle and upper Hazeltine Creek and Polley Lake. However, in the natural creek system, fish from Polley Lake can be swept down the creek into Quesnel Lake once all the fish habitat reconstruction is completed and fish fences are removed.

In addition to ingress into Hazeltine Creek, the fish also needed to be able to return to Polley Lake. This required that a fishway (ladder) be built for the fish to bypass the Polley Lake Weir water control structure. An engineered fishway was installed by Mount Polley maintenance staff at the Polley Lake weir and the flows are monitored to properly maintain water levels for fish passage.  The fishway was designed so the flow can be adapted to seasonal changes.

Mount Polley fishway ladder
Mount Polley fishway ladder

Fish monitoring was intense in 2018.  MPET worked with Minnow Environmental conducting weekly surveys of the fish populations to track the 2018 spawn and fish activity. The surveys included counting fish at established monitoring stations and pools, and observing how the fish used the creek (i.e. seeking shelter under woody debris or behind boulders). Temperature data and dissolved oxygen levels were also monitored in Hazeltine Creek.

Results of the 2018 Hazeltine Creek fish re-introduction were very impressive. Fish monitors estimated almost 5,000 Rainbow Trout accessed the creek to spawn in spring 2018.  The spawn was successful. A spawning survey in July 2018 observed over 18,600 Rainbow Trout in upper Hazeltine Creek, the majority being from the 2018 spawn.

Spawning rainbow trout in Hazeltine Creek. [late May 2018]
Spawning rainbow trout in Hazeltine Creek. [late May 2018]
Categories
Remediation

Major milestones of Mount Polley’s environmental remediation efforts to date

The remediation effort at Mount Polley is ongoing; however, we are very proud of the major milestones that have been completed to-date.

  1. Repair of lower Edney Creek, re-establishment of link to Quesnel Lake and installation of new fish habitat for spawners from Quesnel Lake, completed in spring 2015, with evidence of successful spawning by Interior Coho, Kokanee and Sockeye Salmon.
  2. Completion of construction of a new Hazeltine Creek channel in May 2015, to control erosion and provide base for remediation of the creek itself and the creek valley.
  3. Ongoing planting of native trees and shrubs in the riparian and upland areas along the creek, now totally more than 600,000 trees and shrubs planted.
  4. Installation of over 6 kilometres of new fish spawning and rearing habitat in upper to middle Hazeltine Creek. Evidence of successful 2018 and 2019 Rainbow trout spawning in upper Hazeltine Creek.
  5. Clean-up and repair of 400 metres of Quesnel Lake shoreline, including placement of new fish spawning gravels.
  6. Re-establishment of wetlands in the Polley Flats area adjacent to the repaired TSF.
Hazeltine Creek aerial view
Hazeltine Creek recovery work. An aerial view of the environmental remediation efforts captured by a drone.
Categories
Remediation

The Mount Polley Team: Maintaining a Healthy Environment

Mout Polley continues to restore the environment during its current care and maintenance phase.

With 14 staff members working at the Mount Polley site, as well as several contractors, the remediation team at Mount Polley continues to work diligently to restore habitats, ecosystem and the environment at Mount Polley and affected sites.

The Mount Polley team includes environmental staff ensuring environmental recovery.  DWB Consulting Services Ltd. is also on site to provide quality control and assurance.

Some monitoring activities taking place during Mount Polley’s continued remediation include water sampling, water treatment plant sampling, plankton sampling, fish population monitoring, Hazeltine Creek monitoring and fish surveys.

Sockeye salmon in Edney Creek as a result of Mount Polley remediation
Salmon and trout are repopulating Edney Creek during Mount Polley remediation efforts.

Our efforts have proved successful to-date! Several sockeye salmon were observed in Edney Creek. Furthermore, Rainbow Trout, Coho Salmon, Lon Nose Dace and Burbot have also been identified.