Elevated water temperatures in local streams are often caused by a lack of adequate shading along waterways, as well as increased runoff from impervious surfaces like roads and parking lots. Urban development and erosion of soil and sediment contribute to warmer water, which can be harmful to cold-water fish like salmon and trout. Warmer water can reduce survival rates for juvenile fish, disrupt migration, and hinder natural spawning processes.
Stormwater runoff from impervious surfaces absorbs heat and carries it into our waterways, raising water temperatures. Soil erosion can also add to this issue by carrying warm sediment into streams. While streamside trees provide shade that helps prevent the water from overheating, many communities have lost these natural buffers due to development.