Stormwater Information

Help us keep Walla Walla County facilities clean and our creeks healthy.
To report illicit discharges (anything entering a storm drain that isn’t stormwater) call (509) 524-2710

Why Stormwater is Important
Today, we know that urban stormwater runoff is the largest remaining contributor of water quality pollution to the urban waterways of the United States. The problem is magnified when development occurs without addressing stormwater pollution, which puts additional stress on the environment. When land is converted from its natural state to one of parking lots, buildings, lawns, streets, and sidewalks, rainwater that once soaked into the ground now flows over the hard, or impervious, surfaces and becomes urban stormwater runoff. The water picks up pollutants such as dirt, fertilizers, pesticides, oil, and bacteria on its way to the nearest storm drain or creek. Unlike sewage, which is collected and treated at a wastewater treatment plant, anything that flows into a storm drain empties directly into the nearest stream or creek, normally without any treatment.

It’s a Community Effort
We all need to do our part to keep the stormwater clean, because the stormwater that reaches the streams and rivers or infiltrates through the ground and into the aquifer may contain pollutants. The Columbia, Snake, Touchet and Walla Walla Rivers plus Mill Creek and their tributaries are important waterways to the residents of the county, both for the aesthetic value and the financial value they bring to the area. Local residents rely on ground water and surface water for drinking water. If stormwater or spills are allowed to filter through the ground polluted and untreated, the pollutants may accumulate and make the aquifer unusable as a drinking water source. This in turn means higher costs to the residents if the aquifer must be cleaned and treated to become usable again.

A major part of the Stormwater Management Plan process is the inclusion of public comments and participation. The Plan is not meant to be a burden on the residents of the Cities and the County, it is meant to be a tool that aids in protecting the quality of our surface waters. We want to encourage the public to become actively involved in the planning process.

If you have any questions, please contact Seth Walker at the Walla Walla County Public Works Department (509) 524-2710

Stormwater Background
Stormwater discharges in Walla Walla County are regulated by the Eastern Washington Phase II Municipal Stormwater Permit (Phase II Permit), issued by the Washington State Department of Ecology (Ecology). The Phase II Permit became effective on February 16, 2007, and applies to the portion of Walla Walla County that lies within the Urban Growth Areas (UGAs) of the cities of Walla Walla and College Place, and the urbanized areas in and around unincorporated Burbank.The Phase II Permit requires Walla Walla County to develop, implement, and enforce a stormwater management program (SWMP) aimed at improving the quality of stormwater runoff over a 5-year permit period. We are currently operating under the third permit issued by Ecology, and at the end of this 5-year permit cycle Ecology will re-issue the permits, most likely with expanded requirements.

Generally, Walla Walla County is required to address the following six components in its SWMP:
  1. Public Education and Outreach Public Participation and Involvement.
  2. Illicit Discharge Detection and Elimination.
  3. Construction Site Stormwater Runoff Control.
  4. Post-Construction Stormwater Management for New Development and Redevelopment.
  5. Pollution Prevention and Good Housekeeping for Municipal Operations.
  6. Record keeping of all activities required by the Phase II Permit, and reporting of completed activities in March of each year.
Activities to date have primarily focused on complying with the six components listed above. However, the current Permit issued to the County has expanded requirements which include compliance with Total Maximum Daily Load (TMDL) requirements as well as Monitoring and Assessment, including Effectiveness Studies (self-assessment). These most recent requirements are addressed and included in the SWMP and the County’s Annual Report. The current SWMP and Annual Report are posted on the County Stormwater website under the Stormwater Documents heading.  

Stormwater Code
Stormwater, Title 11, was written and adopted by the County Commissioners in 2009. Title 11 contains three primary chapters: 11.04 Stormwater Utility, 11.05 Illicit Discharge Detection and Elimination, and 11.07 Stormwater Management.

Stormwater Utility
A stormwater utility is an organization that manages, governs, and funds activities exclusively related to stormwater. Major benefits of forming a stormwater utility include having a centralized, organized, methodical approach to planning for future improvements, repairs, and emergencies, with a stable source of dedicated funds. Walla Walla County’s stormwater utility is under the governance of the Board of County Commissioners, and day-to-day administrations are provided by the County Engineer. The stormwater utility funds approximately 35% of the County’s stormwater management activities.

The stormwater code establishes a fee structure based on land use. Single-family residential parcels show the least amount of variability of impervious area (which is used as a proxy for determining stormwater runoff) and therefore pay a flat-rate service charge. Non-residential uses and multi-family residential uses pay a service charge based on the actual amount of impervious area present on the parcel. During 2010, stormwater staff digitally measured the actual amount of impervious area on non-residential and multi-residential parcels using aerial photography and the County’s Geographic Information System (GIS). Walla Walla County collected the first round of Stormwater service charges in March of 2011. 

Illicit Discharge Detection and Elimination
The Phase II Permit requires Walla Walla County to map its storm drain system, periodically inspect storm drain outfalls for evidence of illicit discharges, and to respond to reports of illicit discharges.

Stormwater staff has a protocol for illicit discharge detection and elimination inspections and a system for tracking and maintaining records. 

Stormwater Management
The County has also adopted code for the management and treatment of stormwater runoff from new development and redevelopment. The stormwater code adopts Ecology’s Stormwater Management Manual for Eastern Washington as a guidance document and requires on-site retention and dispersal of stormwater, preferably through infiltration. The code requires that new projects that disturb more than an acre provide construction-phase Best Management Practices (BMPs) to prevent dirty stormwater from running offsite, clogging catch basins and pipes, and fouling streams. The code also requires that large projects that disturb more than an acre include post-construction BMPs to treat stormwater.

Stormwater staff continues to focus on working with Community Development and Public Works staff to maintain a stormwater management program specifically targeting new construction.

Construction site operators and Design professionals interested in learning more about the County’s NPDES Phase II Permit, the appendices to the permit, the Construction Stormwater General Permit, and the BMP’s in the Stormwater Management Manual for Eastern Washington (SMMEW) can obtain useful information regarding Stormwater requirements and components.

Certified Erosion and Sediment Control (CESCL) training classes are available across Washington State.

Walla Walla County hosts a CESCL re-certification class, open to Municipal employees, Construction operators, Design professionals, and all other current card holders, every three years.

Underground Injection Control (UIC) Well Program
Walla Walla County is required by state statute to register all newly constructed Underground injection Control (UIC) facilities with the Department of Ecology. Stormwater staff maintains these facilities as they are constructed and become operational.

Additional Information and Phase II Permit Maintenance Activities
Walla Walla County currently owns approximately 500 stormwater facilities including catch basins, infiltration facilities, and outfalls. These facilities, located in the Walla Walla, College Place, Waitsburg, Touchet and Burbank areas are divided into two zones. Stormwater staff inspects one zone each year. This ensures that all stormwater facilities will be inspected every two years.

During inspection, stormwater staff measures and records the amount of sediment in each facility. Facilities which have accumulated sediment equal to or greater than 6 inches are placed on a storm system cleaning (vactor priority) list. These facilities are generally cleaned in October of the same calendar year.

For More Information and What You Can Do to Help
However, the current Permit issued to the County has expanded requirements which include compliance with Total Maximum Daily Load (TMDL) requirements as well as Monitoring and Assessment, including Effectiveness Studies (self-assessment). These most recent requirements are addressed and included in the SWMP and the County’s Annual Report. The current SWMP and Annual Report are posted on the County Stormwater website under the Stormwater Documents heading.