In Shawnee, as in all developed areas, rainwater which falls during storm events runs off buildings, homes, parking lots and streets. This water, now defined as stormwater, travels along gutters, into catch basins and through storm drain pipes, and ultimately into the Kansas River, untreated. During this process, the stormwater picks up trash (fast-food wrappers, cigarette butts, Styrofoam cups, etc.) and toxins (used motor oil, antifreeze, fertilizers, pesticides, pet waste, etc.). These pollutants are picked up by any flowing water such as rainwater, household sprinkler systems, fire hydrants, personal hoses, etc., and transported to local waterways. To summarize, anything which is intentionally or accidentally dumped contributes to stormwater pollution. 

Mandated by Congress under the Clean Water Act in 1990, the NPDES Stormwater Management Program is a comprehensive national program for addressing non-agricultural sources of stormwater pollution that adversely affect the quality of our nation's waters. The Program uses the National Pollutant Discharge Elimination System (NPDES) to require cities to implement controls designed to prevent harmful pollutants from being washed by runoff into local water bodies. The City of Shawnee, under NPDES Phase II permit, is actively pursuing these controls today to ensure a cleaner, safer tomorrow. 

City of Shawnee Comprehensive Stormwater Management Program (CSMP)

Proper Disposal of Pool and Hot Tub Water (pdf)
Stormwater Pollution Prevention (pdf)
Johnson County Disposal of Pool and Hot Tub Water

Additional Resources
Storm Drain Stewardship
Water Resources
Illicit Discharge Prohibited
Pollution of Streams

2024 NPDES General Permit #M-KS68-SU01 (pdf)
2024 NPDES MS4 Report (pdf)
2025-2027 Stormwater Management Plan (pdf)

A floodplain is a naturally occurring area near a river or creek that floods periodically. When development adds pavement, roofs and other hard surfaces, less rainfall is filtered into the ground. Runoff to the nearby river or creek increases, and any development within that area can be subject to flooding.

Floods are one of the most common hazards in the United States. Effects can be local, limited to a neighborhood or community, or very large, affecting entire river basins and multiple states.

To find out if you are in a floodplain or floodway, for flood depth data and/or to discuss property protection measures within the floodplain, contact Public Works, at (913) 742-6009. To find out information about developing or building on a lot in or near the floodplain, contact the Community & Economic Development Department at (913) 742-6011.

Flood Insurance
Several major creeks flow through Shawnee. These larger creeks have an associated floodplain that is identified by the Federal Emergency Management Agency (FEMA). If you live along these larger creeks, you might be required by your home mortgage lender to purchase flood insurance. If you live close to a creek, you should take a careful look at your flooding risk and consider whether or not you should buy flood insurance.

Yard flooding
You may be impacted by nuisance yard flooding issues that are unrelated to stream flow. The public drainage system typically begins after neighborhood drainage reaches the street, and it is not uncommon for several yards to drain through each other before reaching the public system. In this case, it is your responsibility to protect your property from flooding. Some things to consider are:

• Ensure the ground drains away from your foundation.
• Ensure that window wells are adequately covered.
• Consider adding French drains or yard inlets to remove water more quickly between storms.

Roadway flooding
You may encounter water over the road at some locations in Shawnee during extremely large rain events. Never try to drive across flooded roadways. Just 6 inches of fast-moving flood water can knock over an adult. Twelve inches of rushing water can carry away a small car, while two feet of rushing water can carry away most vehicles. It is never safe to drive or walk into flood waters. Know your evacuation routes in the event of roadway flooding.

The City Council adopted two ordinances which will affect the development requirements for new development.

These changes will fulfill the City’s compliance activity objectives to meet the regulatory requirements of the City’s State of Kansas Water Pollution Control Permit (EPA’s National Pollutant Discharge Elimination System (NPDES) Phase II requirements) effective 2003.

In order to improve the organization of the Shawnee Municipal Code (SMC) related to Stormwater Management, the City Council also created a Stormwater Management Program Title 11 that combines four existing Chapters, adds two new Chapters and consolidate definitions and compliance regulations.

Private Detention Facility Inspection & Certification
Over the past two years, the City of Shawnee’s Stormwater Management Program has worked to establish a detention basin maintenance program by inventorying private basins and assisting property owners with maintenance and certification requirements under City Code (SMC 11.24.130 and SMC 11.24.140).

Properly maintained detention basins help manage stormwater runoff and reduce downstream flooding. A detention basin is typically a small, dry pond located on a property designed to temporarily hold stormwater during heavy rain events.

Annual detention basin certifications are now required and are due by October 1 each year. Reminder letters will be mailed to property owners later in the year.

Land Disturbance Permits (Erosion and Sediment Control)

The Land Disturbance Activity ordinance strengthens erosion and sediment control requirements across the City and increases the need for plan review, inspections, and enforcement.

Water Quality and Stormwater Treatment Facilities
Stormwater Treatment Facilities (STFs) are required to manage and treat stormwater runoff before it enters the City’s drainage system and are typically required for new development and redevelopment projects.

Annual maintenance reviews and certifications are required under SMC 11.16.160 and must be completed by a Kansas-licensed engineer or landscape architect by October 1 each year. Reminder letters and maintenance checklists will be mailed to property owners.