Environmental assessment – Springbank Off-stream Reservoir

Overview

An environmental assessment is a process to identify, predict and evaluate the potential environmental effects of a proposed project. This process happens before decisions about a proposed project are made.

An environmental assessment supports planning and decision-making. Through the environmental assessment process, the potential adverse environmental effects of a project are identified.

Fish

The Springbank Reservoir has been designed to allow fish to pass unimpeded through the diversion structure when the reservoir is not in operation. Fish caught in the Springbank Reservoir during operation will be safely returned to the Elbow River.

The has not resulted in the loss of significant fish. The environmental assessment indicated bull trout habitat is primarily upstream of the Springbank Reservoir and would be less affected by the project.

Wildlife

Wildlife will pass freely when the Springbank Reservoir is empty. The diversion channel will include sections of vegetated slopes, with a 33% gradient to facilitate wildlife movement. Wildlife-friendly fencing was installed along the project perimeter for wildlife to jump over or move under. The areas where Highway 22 crosses the diversion channel are designed to allow wildlife passage.

The Springbank Reservoir resulted in a partial loss of wildlife habitat; however, the land is primarily very low to moderately suitability habitat for Grizzly bears and ungulates. Higher suitability Grizzly bear habitat is located west of the project and was not be impacted.

Debris management

In response to concerns raised during stakeholder engagement, about debris entering the reservoir, a debris deflector was added to promote the passage of debris down river and prevent it from entering the diversion channel.

The debris deflector will help keep much of the larger debris in the Elbow River out of the Springbank Reservoir, while also helping to mitigate accumulation of debris:

• on the diversion inlet gate bays that could affect operation
• in the diversion channel that may reduce its capacity
• on the dam’s emergency spillway
• at the low-level outlet that may affect post-flood operations

Air quality, post-flood sediment

Sediment deposited in the reservoir during a flood event could potentially be a dust source if the sediment dries out and windy conditions occur. Air quality modelling has shown that under these conditions, airborne dust (suspended particulate matter) in the immediate vicinity of the Project Development Area (PDA) could exceed air quality objectives.

Although not expected to be a frequent occurrence, it is most likely to occur along the east reservoir's boundary. Should this occur, air quality models predict the potential to exceed air quality objectives for up to 4 days in a year following a significant flood.

After the reservoir is drained, mitigation for dust will include revegetation with native grasses and, if necessary, the use of tackifiers (a commonly used sprayable product that bonds with the soil surface and creates a porous and absorbent erosion-resistant blanket that lasts up to 12 months).

Groundwater

In response to feedback from stakeholders and Indigenous groups, groundwater modelling examining more than 4,000 well records in the area was completed. Results indicate that overall, the effects on groundwater quantity and quality are not significant and limited to local areas around project infrastructure.

Surface water

While the estimated methylmercury concentrations in all floods are below the Canadian Council of Ministers of the Environment Canadian Water Quality Guideline for the Protection of Aquatic Life, there is the potential for methylmercury to be retained in water that is released back into Elbow River. This is because mercury methylation is a chemical process that occurs in soil that is inundated by water. The reservoir area is not anticipated to continue to produce or release methylmercury after it is drained.

The concentration of sediment in the water will be higher for a short time at the end of release from the reservoir back to the Elbow River. However, the reservoir will reduce the total amount of suspended sediment and associated elements (for example, metals, nutrients) downstream to the Glenmore Reservoir because much of the sediment will settle out in the reservoir. Water quality modelling has shown water that will be released is not anticipated to cause negative effects to drinking water or the environment downstream. Water quality in the reservoir will be monitored for temperature, pH and potential contaminants. A draft surface water monitoring program is also being developed.

Traditional land and resource use

The environmental assessment predicts that the residual effects of the Springbank Reservoir on traditional land and resource use will not be significant. Consultation and the engagement process has heard concerns about:

• historical resources and cultural sites
• fish and fish habitat
• wildlife and wildlife habitat
• medicinal and ceremonial plants
• groundwater and water quality
• monitoring and employment opportunities
• dam safety
• future land use and access
• treaty rights and traditional uses
• project alternatives

We sought feedback on the traditional land and resource use section of the environmental assessment, as well as proposed mitigation measures, and continues to engage with Indigenous groups.

Archaeological and heritage sites

We recognize that information regarding traditional land and resource use, including archaeological and heritage sites, are best identified by Indigenous groups. The Indigenous groups with which we have engaged have identified potential effects and mitigation measures that will be addressed throughout various stages of the project.

We will meet those requirements and make several additional commitments, including:

• limiting disturbance, to the extent possible and practical, of cultural and spiritual sites and subsurface impacts
• developing a protocol for recovery, collection, reporting on, and possible repatriation of artifacts found in consultation with Indigenous groups, which could include flagging, fencing, or providing signage of sites to prevent disturbance during construction
• notifying Indigenous groups regarding project activities and schedules
• maintaining access to identified current use sites located outside of the designated construction and project site limits during construction and operations, to allow for hunting and fishing
• providing opportunities for harvesting or relocating medicinal and ceremonial plants prior to construction

We are committed to Indigenous participation in the project, including training, employment, and contracting opportunities.

Land use

Stakeholders, including Indigenous groups, have advised that they wish to access the reservoir lands in the future. We continue to engage with these groups regarding potential future land use, given the unique opportunity of converting private land to Crown land.

Future land use decisions will be guided by principles, including:

• the primary use of the land will be for flood mitigation – no secondary use will conflict with this
• public safety is an overriding factor in land use decisions
• uses and activities must have minimal impact on the land – in general, First Nations’ traditional activities will be allowed

Dam safety requirements

Because the Springbank Reservoir will temporality hold water until it can be safely released back to the Elbow River, regulatory requirements for dam safety apply. These requirements, established by the Canadian Dam Association (CDA), are based on possible downstream consequences of a potential failure that could result in loss of life, loss of environment and cultural values, or loss of infrastructure and economics.

The dam structure component of the Springbank Reservoir will meet requirements for an ‘extreme’ consequence structure under the CDA Guidelines. This is the highest maximum standard for dam safety. The reservoir will only hold an amount of water that the dam is designed to hold.

The diversion structure will also meet requirements for a ‘high’ consequence structure under the Canadian Dam Safety Guidelines. The dam structure component of the reservoir will only handle a magnitude of water that it designed to hold.

Contact

Connect with the Springbank Off-stream Reservoir Project:
Email: [email protected]