Stormwater
Stormwater
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)
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
- 2023 Stormwater Management Plan Supplement and 2022 Annual Report
- 2022 Stormwater Management Plan Supplement and 2021 Annual Report
- 2021 Stormwater Management Plan Supplement and 2020 Annual Report
- 2020 Stormwater Management Plan Supplement and 2019 Annual Report
- 2019 Stormwater Management Plan Supplement and 2018 Annual Report