Nutrients in Lake Powell and Torbay Inlet

Both Lake Powell and Torbay Inlet tend to have high nutrient concentrations and poor water quality all year round. Nutrient concentrations are particularly high in winter when excessive amounts of nitrogen and phosphorus flow in from the rivers. For example, in Torbay Inlet during winter, average concentrations are double the guideline value for total nitrogen and six times greater for total phosphorus.

In Lake Powell, nitrogen concentrations are not only high in winter, but also regularly in summer. Summer nitrogen levels are high because of blooms of cyanobacterial species that can access nitrogen from the air to help them grow.

In Torbay Inlet, when the sandbar is open, exchange of water with the ocean results in some periods of lower nutrient concentrations. However, even with these slightly lower concentrations, the water quality is classed as poor.

Wading out to the sampling site at Lake Powell