Deterministic Lake and Stream Temperature Modelling: Maintaining Optimal Water Temperatures for Kokanee and Rainbow Trout through Informed Design

Author: Alana Shewan, Anna Akkerman, Violeta Martin
Conference: CSCE Annual Conference 2017 / 23rd Canadian Hydrotechnical Conference
Date: May 31-June 3, 2017

Stream temperature is an important indicator of habitat quality for fish of all life stages. However, stream temperature is often overlooked when designing mitigation systems, with the focus being on the effects of development on stream flow, depth and velocity. A number of simple deterministic water temperature models exist for lakes, channels, and pipelines that can be utilized to optimize key design parameters for mitigation systems.

Knight Piésold Ltd. (KP) used water temperature modelling to support the preliminary design of a water supply system for a proposed mine in BC. The water supply system will augment flows to an existing stream to support kokanee and rainbow trout populations. The proposed water supply system includes an intake in a nearby lake, a pump and pipeline conveyance system, and a small reservoir with low level and surface outlets.

KP modelled the water temperatures throughout the supply system and in the receiving stream using three models: a one-dimensional Fresh Water Lake model (FLake), a heat transfer pipeline model, and the Stream Segment Temperature model (SSTEMP). Baseline models of the existing lake and stream were completed to assess model suitability and to calibrate model parameters. Operation models were then developed using long-term site specific climate inputs for the project. The models were run with various design considerations to maintain stream temperatures within optimal ranges to support various life stages of the kokanee and rainbow trout populations. Modelling identified those periods in which conditions similar to baseline could not be fully achieved and additional mitigation measures were required.


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