Surface Water

Good pool habitat Wachter 4 looking upstream

S U R F A C E   W A T E R S

Surface waters are freshwater streams, wetlands, ponds lakes and their vegetated riparian buffers. San Juan County's Clean Water Utility protects water quality and quantity by ensuring adequate flows for native fish and wildlife, and reducing nutrient and temperature pollution caused by livestock access, lack of riparian vegetation and other land use activities. Brackish waters of estuaries, lagoons, saltwater marshes and coastal wetlands are also considered surface waters that provide transition habitat to the marine environment. 

In some watersheds, surface flows are captured to provide drinking water through local Island water providers.


Improving water quality of surface waters in San Juan County is a major goal of the Environmental Stewardship Department. 

What does “improving water quality” mean?

The State of Washington has established surface water quality criteria that support designated uses of those waters for recreation, aquatic life, and human consumption. These criteria establish limits for water temperature, pH, and concentrations of nutrients, dissolved oxygen, bacteria, heavy metals and organic compounds (  The criteria are designed to keep surface waters clean and healthy. Currently some island lakes and streams exceed these limits. The Environmental Stewardship Department is working to ensure all of the islands’ surface waters meet the criteria. 

Why do we care?

            When concentrations of nutrients, bacteria, or other contaminants are too high in lakes and streams, contact (e.g., swimming, fishing) with those waters is not safe for humans, their pets, or other animals. Excess nutrients combined with warmer water temperatures can lead to blooms of toxic algae. Salmon can’t survive in streams with high water temperatures and low levels of dissolved oxygen.  Delivering high quality stream water to the ocean sustains healthy conditions in the marine nearshore environment, which is critical for survival of juvenile salmon and other species (link to aquatic species page).

What are the threats?

Human actions on land impact water quality. Runoff from impervious surfaces like roads and roofs during storms transports sediments and contaminants to surface waters.  Ground-disturbing activities too close to lakes and streams leads to erosion, which delivers sediments and contaminants to surface waters. When livestock have access to surface waters, they can degrade stream banks and channels, and contaminate the water with urine and feces. Tilling and fertilizing fields without adequate streamside buffer strips delivers sediment and excess nutrients to streams. As climate is changing, the islands are experiencing warmer temperatures and more damaging storms, with negative impacts on water quality. 

What is the Environmental Stewardship Department doing?

Using funds from the Clean Water Utility, the department regularly sweeps streets in areas with high impervious surface cover to reduce the load of contaminants that washes off during storms. Stormwater retention basins are cleaned so they function efficiently. In collaboration with the San Juan County Conservation District, the department has provided support for fencing to reduce livestock access to streams. Fenced riparian zones are being planted with native species to reduce erosion and contaminant runoff and to increase infiltration. Rain gardens have been installed to increase water infiltration, and plantings in roadside ditches help filter impurities from runoff before it reaches streams.