Groundwater is one of British Columbia’s most vital water resources. Stored beneath the earth’s surface (in saturated, permeable geological formations called aquifers), it has an important role in sustaining aquatic ecosystems and salmon habitat. Often directly under streams and along valley bottoms, aquifers can be shallow or deep and ensure streams flow year round. Streams are constantly exchanging water with the ground, and these exchanges can either augment the stream’s flow, or recharge the aquifer below. An important feature of these exchanges is they can very seasonally, allowing groundwater to keep streams flowing during the warm summer months and to keep water temperatures cool enough for salmon to survive. Without groundwater to augment stream base flows during the summer months, when rainfall is scarce and the spring snow melt has finished, many streams, especially in the warm BC Interior regions that provide vital spawning habitat would have potentially lethal temperature and flow conditions.
Groundwater also absorbs minerals during its underground journey, giving it a different chemical make up than surface water that supplies nutrients to streams, supporting the food web that feeds fish.
|The importance of groundwater to fish|
|Base flows||Maintains free-flowing water, channels, and habitat through winter low flows||Maintains base flows through dry periods|
|Stream temperature||Prevents/delays ice formation and influences thickness and break-up; provides areas with above-freezing water temperatures||Reduces daily stream temperature fluctuations, delays cooling in the fall|
|Water quality||Supplies dissolved oxygen and nutrients to stream; buffers water quality changes through groundwater – surface water exchanges||Helps maintain stream productivity through nutrient inputs; stimulates macrophyte growth; and buffers water quality changes through groundwater –surface water exchanges|
|Habitat||Determines size/quality of winter refugia; affects winter mortality and carrying capacity||Provides protection from lethal temperatures|
 Adapted from Power, G., R.S. Brown and J.G. Imhof. 1999. Groundwater and fish – insights from northern North America. Hydrological Process 13:401 – 422.
Climate change impacts will likely have multiple effects, but British Columbia has already experienced higher temperatures, precipitation pattern changes, and drought like conditions in parts of the Interior. These situations are likely to increase, placing increased importance on groundwater to mitigate impacts on instream flow and temperature.
Groundwater also has uses beyond its ecosystem functions: In BC one-quarter of all households get their drinking water from wells. Groundwater is essential in situations where access to surface water is not possible, or where piped municipal water is not available. The agricultural sector also uses groundwater extensively, often during the spring and summer growing season when groundwater is needed most.
Unfortunately British Columbia is the sole jurisdiction in Canada that has no general permitting requirements for groundwater extraction, despite the fact that we extract one-quarter of all the groundwater used in Canada. After the contaminated drinking water tragedy in Walkerton, Ontario, BC developed the “Groundwater Protection Regulation” that deals with water quality to ensure new wells are properly constructed, all wells are properly capped and old wells are sealed. This regulation is limited and does not address how much groundwater is extracted. Another groundwater regulatory issue in BC is we have no reliable way of measuring exactly how much groundwater is used (currently wells are only reported voluntarily) throughout the province. This lack of monitoring is something that needs to be addressed, especially if any changes are to be made to allocation systems in the future.
Watershed Watch has addressed the need for better regulation of groundwater in numerous publications. Fish out of Water: Tools to Protect British Columbia’s Groundwater and wild salmon examined how First Nations rights and title could be applied to protect groundwater within traditional territories. Review of British Columbia’s Groundwater Regulatory Regime: Current Practices and Options produced by environmental lawyer Randy Christensen considers various regulations (both provincial and federal) and how they can be applied to protect groundwater and also presents recommendations for moving regulations forward, many that have been incorporated into the Water Act Modernization process.
Besides looking at groundwater from a regulatory perspective, Watershed Watch has also released key publications on the importance of groundwater to salmon and ecosystems through a technical report (Review of Groundwater-Salmon Interactions in British Columbia) and an outreach brochure (Groundwater and Healthy Salmon Streams: It’s all Connected). We also teamed up with Simon Fraser University and the Speaking for the Salmon Series to host a groundwater and salmon meeting that focused on groundwater regulations, the importance of groundwater in areas with increasingly high water temperatures and presented two case studies in water use planning that incorporated groundwater: Langley and the Nicola watershed.
The need to protect groundwater becomes even more important when its vital ecosystem services are considered in the face of increasing pressures from climate change. The Water Act Modernization process has included principles related to groundwater regulation throughout the entire process, though the recent policy proposal still does not give adequate details on exactly how the regulations will be enforced and how comprehensive they will be. The WAM process could allow BC to show just how vital groundwater will be in the future through a comprehensive set of regulations and stringent monitoring program.
You can learn more about salmon and water issues using Watershed Watch’s Fraser Basin LiveMap: An Interactive Salmon and Water Atlas. This web-based tool allows users to explore Fraser waterways and salmon populations, the threats they face, and their current status and future prospects. The LiveMap includes official government data sets on historic water flows, salmon returns, water temperature, and other important factors that affect the aquatic ecosystems that make up the Fraser River watershed.