The term “total solids” refers to matter suspended or dissolved in water or wastewater, and is related to both specific conductance and turbidity. Total solids (also referred to as total residue) is the term used for material left in a container after evaporation and drying of a water sample. Total Solids includes both total suspended solids, the portion of total solids retained by a filter and total dissolved solids, the portion that passes through a filter. TSS is measured in units of milligrams per litre (mg/L).

There are different objectives to consider natural and anthropogenic TSS variation along the river.


When the background is less than 250 mg/L, the objectives are based on Severity of Effects Value (SEV) values, derived from Newcombe and Jensen 1996. The approach relates the biological fish response to duration of exposure and suspended sediment concentration. The SEV values selected ensures that only a moderate level of physiological stress is endured by fish in this reach during 1 and 7 day exposure periods.

SEV objectives are based on Alberta Sustainable Resource Development (ASRD) and federal Department of Fisheries and Oceans‘ (DFO) mandates which strive to ensure that fish and their habitats support success in all life stages. SEV exposure periods for 1 and 7 days were used to protect fish during storm events.

It is recognized that the objectives may be temporarily exceeded during spring freshet and storm events.

The rating (condition) of the Total Suspended Solids indicator is based on the following scale: