Water Quality

Protecting our Water Quality

Clean water is essential. We need it for drinking, fish health, farming, businesses, and to sustain the overall health of our environment.  

Urbanization, population growth, and land use have largely impacted water quality in much of our region, particularly on our east coast. Major inputs of pollutants are widely distributed in the region. They include urban development, poorly maintained and/or located septic tank systems, logging operations, agricultural operations, and recreation, among other activities. 

Our goal is to take an approach to water quality that goes beyond a traditional focus on large facilities. We aim to approach water quality by science-supported monitoring, and shared stewardship, to protect the health of the environment, residents, and economy.

  1. Protecting Surface Water
  2. Protecting Groundwater

What is surface water?

Surface water refers to the water found on the earth's surface. This can be rivers, lakes, streams, or any other above ground water source. In the Cowichan Valley, surface water is a crucial source of water for drinking, biodiversity and habitat, agriculture, business, recreation, and more.


What are we doing to protect Cowichan's surface water quality?

The CVRD's Drinking Water and Watershed Protection program aims to protect water resources in the Cowichan Valley and promote sustainable water use by focusing on watershed science and information, watercentric planning, and watershed stewardship and outreach.2025-04-24 Somenos Lk Galen and Ellery prepping bottles

The Regional Hydrometric and Climatic Monitoring Strategy (2021), CVRD Watershed Risk Analysis (2019), and Surface Water Monitoring Strategy (2020) are resources that were developed to inform decision making that prioritizes surface water quality and supply that supports Cowichan Valley residents, and ecosystem function.

The collection and analysis of surface water data is essential to the Drinking Water and Watershed Protection plan. Guided by our Surface Water Monitoring Strategy, the Environmental Services Team samples over 30 different stream and lake sites 3 times a year (in the spring, summer, and fall). 

The main objectives of our sampling program is to assess the impacts of land use on water quality, identify surface water bodies where water quality problems are occurring, understand threats to aquatic ecosystem health, ecosystem services, and drinking water, and enable the identification of water quality management actions.

What are we measuring and sampling?

We take several on-site (in-situ) measurements with probes. These include: water temperature, pH, conductivity, turbidity and dissolved oxygen. These parameters can indicate to us whether or not the water is healthy enough to support aquatic ecosystems, or if they are experiencing problems. 

We also take a number of water quality samples in bottles, vials, and tubes, and send these to be tested at a lab. We test for the following: 2025-04-22 Shawn Cr DSSIA YSI screen shot

  • Coliform, E. Coli, and Fecal Coliform
  • Ammonia
  • Biochemical Oxygen Demand (BOD)
  • Alkalinity, CO3, Bicarbonate (HCO3), Hydroxide (OH), Chloride/Sulphate, Nitrate+Nitrite (N)
  • Mercury (Total) and Mercury (Dissolved)
  • Hardness (calculated as CaCO3)
  • Sodium (Na), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S), (dissolved)
  • Sodium (Na), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S), (total)
  • Total Nitrogen
  • Total Phosphorus
  • Total metals
  • Dissolved metals
  • BTEX (select sites).

Learn more about what these parameters tell us by visiting the Province's Water Quality Parameters page.

All data we collect is added to the BC Environmental Monitoring System, where data is made publicly available. To find data at a sampling site near you, check out the Surface Water Quality Monitoring Sites Interactive Map. 


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What do we do with this data?

Once we have learned more about Cowichan's watershed science and information, we can use this science and knowledge to inform policy, land use decisions, and operational activities that affect drinking water quality and watershed health. This includes developing coordinated policy frameworks, informing planning and decision making, and informing operational decision making with the aim of protecting surface water. 

Resources: