Why does the Arboretum Waterway look so yucky?

The Arboretum Waterway is shaped like a flowing creek, but all natural inflow into the channel was eliminated before the turn of the 20th century to prevent flooding in Davis.  In the late 1960s, the Arboretum Waterway was constructed along the old stream channel as a storm water retention pond.

During dry weather, the Arboretum Waterway typically receives no inflows.  In the Central Valley climate, the lack of fresh water combined with warm weather and sunlight creates ideal conditions for algae growth.  The water looks bad, but it supports an abundant number of fish, turtles, and birds.

To improve water quality aesthetics, the campus recently began routing all of the highly treated water from the campus wastewater treatment plant through the western half of the Arboretum Waterway.  Results have been mixed, but the general consensus is that this has improved water quality in that section of the Waterway. Arboretum Waterway Improvements Environmental Review