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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

Stormwater Frequently Asked Questions

Why is Stormwater 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.


What Can You Do to Help?


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 This email address is being protected from spambots. You need JavaScript enabled to view it. at the Walla Walla County Public Works Department (509) 524-2710

Stormwater Background
StormwaterPhoto1 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 in permit-year 3, 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. Required to keep records of all activities required by the Phase II Permit, and to report on completed activities in March of each year.

Activities to date have primarily focused on getting the SWMP up and running. Walla Walla County received a stormwater grant of $75,000 from Ecology in 2007 and contracted with Otak, Inc for the development of three documents:

  • An inventory of the existing storm system.
  • A technical analysis of the activities needed for compliance with the Phase II Permit.
  • A financial plan for funding the SWMP

The first two documents were completed in late 2008, and the last was completed in early 2009. Walla Walla County hired a part-time Stormwater Program Manager in November of 2008 to continue the work begun by Otak, Inc.


Stormwater Code

Stormwater Photo 2

A major task for 2010 will consist of developing programs and procedures to implement and enforce Title 11, Stormwater. Title 11 contains three primary chapters: 11.04 Stormwater Utility, 11.05 Illicit Discharge Detection and Elimination, and 11.07 Stormwater Management, and each of these chapters will require significant program development to be fully integrated into County operations.



Stormwater Utility

Stormwater Photo 5

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, and a stable source of dedicated funds. Walla Walla County’s stormwater utility will be under the governance of the Board of County Commissioners, and day-to-day administration will be provided by the County Engineer. Once up and running, it is estimated that the stormwater utility will fund 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 will therefore pay a flat-rate service charge. Non-residential uses and multi-family residential uses will pay a service charge based on the actual amount of impervious area present on the parcel.
During 2010, stormwater staff will digitally measure the actual amount of impervious area on non-residential and multi-residential parcels using aerial photography and the County’s Geographic Information System (GIS), develop billing rolls, and prepare to collect the first round of stormwater service charges.


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.

In 2010, stormwater staff will continue field-locating outfalls and will update the GIS to include all information gathered as part of the process. Stormwater staff will work during the dry season to detect outfalls and look for evidence of illicit discharges on three priority streams within the UGAs of Walla Walla and College Place. Stormwater staff will develop forms for illicit discharge detection and elimination inspections and will develop a system for tracking and maintaining records.


 Stormwater Management

Stormwater Photo 3The 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 and 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.

In 2010, stormwater staff will focus on working with Community Development and Public Works staff to develop a stormwater management program specifically targeting new construction. Specific tasks to perform in 2010 include:

  • Provide stormwater training for plan review and inspection staff
  • Identify or develop a system to track projects disturbing an acre or more
  • Communicate new requirements to land owners and developers from the earliest phases of their projects so that stormwater BMPs may be incorporated into the design
  • Inspect at least 80% of construction sites disturbing an acre or more


Underground Injection Control (UIC) Well Program

StormwaterPhoto7Walla Walla County is required by state statute to locate and register all existing Underground injection Control (UIC) wells (also known as drywells) by February 3, 2011. Stormwater staff will begin this process in 2010.





Additional Phase II Permit Activities


The Phase II Permit specifically requires performance of the following in 2010:

  • Complete annual SWMP report, due March 2010
  • Identify target audiences for stormwater outreach and education activities, due February 2010
  • Develop an Operations and Maintenance Plan (O&M) Plan for the County Garage and South District Yard, and any other County facilities within the UGAs of Walla Walla and College Place, and Burbank that have the potential to adversely impact stormwater through routine operations, due February 2011.