Stormwater Drain Cover


Stormwater runoff is the water that flows off of roofs, driveways, parking lots, streets and other hard surfaces during rainstorms. Rather than being absorbed into the ground, it pours into ditches, culverts, catch basins and storm sewers. A storm drain maintenance program is required to ensure that ditches, culverts, catch basins and storm sewers are kept clean of sand, silt and other debris that may plug the system.

Learning More

In an area with natural ground cover, only 10% of rainwater becomes runoff. The rest is absorbed or evaporates. In urban areas, up to 55% of rainfall can become storm water runoff. Learn more about stormwater at the Washington Stormwater Center.

Public Education & Publication Participation

The City of Kennewick works with its sister cities through the Franklin Conservation District to provide education to our area schools. If you are interested in setting up a session in your classroom, please work through your school's representative to contact the Education Coordinator at the Franklin Conservation District.

The City  partners with sister cities to provide educational outreach at the following events:
  • TRAC Spring Home and Garden Show
  • Benton Franklin County Fair
  • Engineers / Contractors / Builders / Landscapers 
  • Homebuilders Association Annual Stakeholders Meeting (January)
The City of Kennewick has completed an Effectiveness Study on the Drain Ranger Education & Outreach program as required under S8.A of the City's NPDES Stormwater Permit - click here to view the report. We would like to thank our partners at the Franklin Conservation District, the other participating eastern Washington Permitees and the staff at the Washington State Department of Ecology involved in the project. If you are interested in the Drain Ranger course materials or would like to sign up to be trained on how to present the material, this is available at the link above.

Stormwater Design, Construction and Post Construction Management

Contractors need to keep all dirt, construction materials, and water on their site and out of the City's storm system. Review the information on the Erosion and Sediment Control Flyer to see how to keep the street and storm system clean and avoid an inspection hold on your work, or even a fine.

The City of Kennewick has adopted the use of the Stormwater Management Manual for Eastern Washington in its most current version. For stormwater design, construction and post construction management within the City of Kennewick, please follow this manual as well as the City's codes and standards which take precedence.

2020 Stormwater Comprehensive Plan

2020 Addendum to the Southridge Area Stormwater Master Plan

2019 Southridge Area Stormwater Master Plan

2007 Stormwater Comprehensive Plan

1990 Stormwater Comprehensive Plan

Predicted Soil Infiltration Map

In 2023, the City completed a partnership with other eastern Washington Stormwater Permitees to complete a study on the use of non-vegetated swales for filtration. The intent of this study was to identify sediment removal options for stormwater treatment without the use of irrigated landscaping. Click below to see the results of the study.

Non-Vegetated Filtration Swale Effectiveness Study

Low Impact Development

In compliance with the new municipal stormwater permits issued by the Washington State Department of Ecology (Ecology), the City of Kennewick recommends the use Low Impact Development (LID) for new developments and redevelopment unless site conditions are prohibitive. Ecology received initial funding from the Legislature to provide Free LID training. These training, the Eastern Washington Low Impact Development Guidance Manual, and other resources are available online through the Water Quality Section of the Washington State Department of Ecology website.

NPDES Stormwater Management

The City of Kennewick manages stormwater in accordance with the current Eastern Washington Phase II NPDES Permit through the Washington State Department of Ecology and the City of Kennewick Comprehensive Stormwater Plan.  

Stormwater Annual Reports