Volunteer Lake-Monitoring Program (VLMP)
(Réseau de surveillance volontaire des lacs - RSVL)
Together with its partners, the Volunteer Lake-Monitoring Program pursues
the following objectives:
Acquire data to determine the trophic level of a large number lakes
and monitor their evolution over time;
Identify lakes showing signs of eutrophication and degradation;
awareness, support and inform lake associations and other participants;
Provide an overview of the state of Québec’s recreational lakes.
Sharing of responsibilities
Ministère’s VLMP team
||Lake association or participating organization
Coordinates and supervises the Program
Supports lake association members
Analyzes the data and communicates the results
Develops supporting tools and documents
Teams with local
partners to support lake association members
- Collects water samples
- Makes measurements and observations in the field using the
For optimal results, participants who register a lake should
commit to a long-term monitoring effort.
- Water quality is monitored by:
measuring water transparency (Secchi disk depth);
collecting water samples for laboratory measurements of
phosphorus, dissolved organic carbon and chlorophyll a. All water
analyses are performed by the Ministère’s laboratory, the Centre
d’expertise en analyse environnementale du Québec (CEAEQ).
Transparency measurements and water samples are taken at a
station generally located in the deepest part of the lake. For a very
large lake, more than one station may be needed.
- In addition to water quality measurements procedures, participants
are also provided with protocols to assess state of the riparian strip
and littoral zone.
Water quality monitoring: What is involved?
Using a Secchi disk, water transparency should be measured every two
weeks, from the beginning of June to the beginning of October, on an
Water transparency is an easy and inexpensive measure that can reveal
long-term changes in water quality and the general state of the lake.
The basic water monitoring program was modified in 2010. The program
now involves sampling for two or three consecutive years, in
June, July and August. A pause of four years is taken before
For example, if the last sampling took place in 2010, sampling would
resume in 2015 after a four-year break.
This monitoring plan is designed to achieve greater precision in
estimating average concentrations of the water quality variables used to
evaluate the lake’s trophic level.
The approach taken by the VLMP is to evaluate the precision obtained for
each lake after a two-year monitoring period. Depending on the results, an
optional third year of sampling may be suggested to the participants to
improve precision. However, a participant may choose right from the start to
sample for two or three consecutive years. After each additional year of
sampling, precision of the mean concentration estimates will be
recalculated. For lakes displaying a high variability, VLMP specialists
could recommend that the number of samples taken annually be increased to
Laboratory analysis costs $372 per station per year. In addition to the
cost of analyzing three samples per station, the total includes accompanying
documentation, delivery and taxes. In addition, $52 is added to the cost for
the acquisition of a Secchi Disk for each new station added to the network.
No charges are incurred for years when participants only monitor water
The VLMP program is getting better with time
Analyses of the data collected since 2004 have revealed that
in order to account for normal variations in water quality over the
course of a summer and from year to year, the best monitoring
strategy for the VLMP is to sample over several consecutive years.
This allows obtaining enough data for average concentrations to be
calculated with acceptable precision, while holding down the expense
of laboratory analyses.
How many years of monitoring are required to obtain
sufficient precision? This varies from lake to lake and from one
water quality variable to another. Without being a stringent
constraint, the total phosphorus parameter objective is to achieve a
margin of error of within 20% of average value.
Protocols and support documents
Guide for the assessment of lake bacteriological water quality
(French, PDF, 1,4 MB)
- Periphyton monitoring protocol
(French, PDF, 2,4 MB)
monitoring protocol for blue-green algae blooms (French, PDF, 2 MB)
Water quality sampling protocol
PDF, 1 MB)
English versions available
Planning inventories (riparian strips and littoral zones)
(French, PDF, 539 kb)
Riparian strip characterization protocol
(French, PDF, 2,2 MB)
Support document for the riparian strip characterization protocol
(French, PDF, 3,9 MB)
- Tool for compiling data and presenting results from the riparian strip
transparency measuring protocol (French, PDF,
English versions available