IDP 2020-Environment

This set of graphics includes historical data on the environment of the Sylvan Lake watershed and surrounding Central Alberta. The quality and quantity of water in the watershed are critical factors that determine watershed value. Dissolved and suspended minerals and organics from the land are transported in surface and underground water into the lake and change the composition of it. In the worst case, excess nutrients in the water-body can cause eutrophication which in turn can affect the value of private property. The quantity of water in Sylvan Lake varies from year to year in Central Alberta as the components of the water cycle determine the balance between incoming precipitation and outgoing evaporation and transpiration. A small fraction of precipitation infiltrates into the soil and becomes part of the groundwater inventory that is critical for domestic uses.

The following water and nutrient balance flowsheet is based on the analysis presented in the important report “AXYS 2005”.

Land uses for agricultural production determines what soil nutrients and natural byproducts of decay processes can be flushed off the land into the lake in runoff. Urbanization affects land use and generally increases the potential for contaminant transport into Sylvan Lake.

Sylvan Lake composition has been monitored since 1983. This graph displays all values in the Alberta Environment and Parks surface water database. The chart axis extends over five orders of magnitude.

The important molecule Chlorophyll-a is a co-catalyst for conversion of CO2 to O2 by plants. It also gives the green colour to cyanobacteria and algae which, in excess, cause nuisance blooms.

Secchi disk observations are a simple way of measuring the clarity of lake water. Sylvan Lake is generally very clear with few suspended solids to scatter light and cause turbidity.

Sylvan Lake has received more than 25 metres of rain over 56 years but the lake level has varied in a narrow range .

The Total Phosphorus concentration in Sylvan Lake in 2018 was about 0.012 milligrams (12 micrograms) per litre, at the low end of the historical range for that limiting plant nutrient.

There is human impact on the lake as conductivity is increasing slowly and some conserved ions are concentrating as water evaporates and leaves the solutes behind.

Increased concentration of sodium and chloride ions are indications that winter road salt is entering the lake as Spring runoff carries dissolved salt and discharges it into the lake.

The Sylvan Lake Casino allows property owners to wager on the condition of water quality in the waterbody. There is a major incentive for surrounding municipalities to maintain the current desirable mesotrophic state.

The economic penalty to private and public property owners could be substantial if the lake became chronically eutrophic.

Satellite observation of the Lower Troposphere temperature over most of Alberta has shown variability of monthly average values but just a tiny trend in warming since 1979.

Sylvan Lake level dropped by 0.28 meters after early June by evaporation. About 11 million tonnes of water disappeared!

An evaporation rate of about 2 mm/day is typical during a Sylvan Lake summer. In 2018 it started about a month earlier than usual.

Natural tributaries and the network of municipal ditches carry surface water flow into Sylvan Lake. Measurement shave demonstrated that nutrient concentrations can exceed recommended Alberta Surface Water Quality Guidelines.

Lake sediments containing phosphorous from decayed plant material can also release soluble phosphorous back into the water column as a nutrient.

Sylvan Lake is the watershed bathtub. Surrounding land drains into the lake and the water slowly concentrates in dissolved ions.

Groundwater inventory in Central Alberta has been studied extensively and modeled by the Alberta Geological Survey.

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