B.C. Lake Monitoring Network

Osoyoos Lake

Lakes are complex ecosystems that are sensitive to a wide range of stressors that operate at provincial, regional, and local scales. Lakes are sentinels of environmental change, and long-term monitoring of water quality trends in B.C. Lakes allows for inter-annual variation to be distinguished from directional change. Understanding these trends can provide insights into the causes of change, and support effective watershed management.

The B.C. Lake Monitoring Network provides a strategic and co-ordinated approach to monitoring water quality in lakes across B.C.

The goals of the network are to:

  1. Monitor, assess, and report on current water quality conditions of B.C. lakes;
  2. Assess and report on how B.C. lake water quality is changing over time;
  3. Develop an understanding of how human activities are influencing B.C. lake water quality;
  4. Determine how B.C. lake water quality is responding to climate change;
  5. Provide accessible, accurate, timely and scientifically defensible water quality data for network lakes to inform government decision makers, industry, research institutions, Indigenous Peoples and the public

Physical, chemical, and biological information is obtained biannually from a wide variety of B.C. lakes to determine current water quality status and to understand long-term trends. Currently, 53 lakes (74 lake sites) are sampled, which cover various ecoprovinces and span wide gradients of area, depth, and trophic status.

Explore these sites in the interactive map below or view a list in a searchable table format.

Interactive map

View map in full-screen

Sampling Strategy

Lake sampling technique and effort has been standardized to provide a consistent province-wide approach.

Lake Sampling Strategy Diagram

Sampling is conducted  biannually

  • Late-winter/spring (mixed conditions): February to May, depending on location and ice melt
  • Late-summer/fall (stratified conditions): August to September

Water chemistry samples are collected from multiple depths

  • Shallow lakes (<10 m) = 1 surface discrete grab sample (1 m below water surface) + bottom discrete grab sample (1 m above sediment surface)
  • Deep lakes (>10 m) = 1 epilimnion composite + 1 hypolimnion composite

Vertical profiles are obtained using multi-parameter sondes (temperature, dissolved oxygen, specific conductance, pH)

  • For shallower sites, measurements are taken every 1 m until the bottom
  • For deeper sites, measurements are taken every 1 m until 20 m, and then every 5 m until 50 m.

Water Clarity

  • Measured as Secchi depth


  • Phytoplankton: 1 x 1 L sample
    • Shallow lakes = discrete surface
    • Deep lakes = epilimnetic composite
  • Zooplankton: 1 x 30 m vertical net haul (or 1 m off bottom for shallower lakes)
  • Invasive zebra/quagga mussel veliger sampling (Late-summer/fall sampling only)


Provincial ambient water quality monitoring