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Public Works

Phone: 913-715-8300

1800 W Old Highway 56, Olathe, KS 66061

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Stormwater Projects

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Useful Reports

Below is a list of reports completed on behalf of, in conjunction with, or using data provided by the Johnson County Stormwater Management Program.

Understanding NOAA Atlas 14, Vol. 8 June 2013 - Presentation on new NOAA Precipitation Frequency Estimates for the Kansas City Metropolitan Area

Calibration of Hydrologic Design Inputs for a Small Urban Watershed in Johnson County, Kansas October 2011 - The design of stormwater drainage, detention and BMP systems requires realistic values of hydrologic inputs such as Rational C factors, runoff curve numbers and volumetric runoff coefficients. In this report researches utliized gage data from a small urban watershed to calibrate hydrologic lag times, Rational C values, and runoff curve numbers.

Guidelines for Continuous Simulation of Streamflow in Johnson County, Kansas, with HEC-HMS June 2010 - Continuous simulation of streamflow is useful for predicting the streamflow impacts of land-use changes and stormwater management practices. This report provides guidance for continuous simulation of streamflow in Johnson County with the HEC-HMS Hydrologic Modeling System of the U.S. Army Corps of Engineers.

Flood Routing on Small Streams: A Review of Muskingum-Cunge, Cascading Reservoirs, and Full Dynamic Solutions This report presents flood wave routing methods that have been adapted for small, naturally meandering streams. Two approximate flood wave routing methods are evaluated against two “fully dynamic” solutions on four natural streams in northeastern Kansas.

Rock Creek Watershed Planning Final Feasibility Report This report includes the stream assessment methodology and results, recommended stream restoration projects, a presentation of BMP concepts, an implementation strategy for best management practices throughout the watershed and probable costs associated with these projects.

Local Applications of Fluvial Geomorphology Attempts at stream stabilization, either using ‘hard’ structural methods or ‘green’ geomophologically-based methods can be successful if a careful approach is chosen. This study proposed a method for developing regional curves based solely on hydraulic modeling. Regional curves relate bankfull channel geometry and discharge to drainage area and are typically used to design channel reaches in natural stream systems at locations where stream modifications are required to accommodate improved drainage structures or to address flooding, scour or erosion problems.

Water Quality

Regulations for preventing stormwater pollution

The U.S. Clean Water Act (CWA) requires water quality standards to be established and enforced by federal and state law. The CWA prohibits the discharge of pollutants from identifiable sources – such as a storm drain – into surface waters without a special permit.

The permit is called the National Pollutant Discharge Elimination (NPDES) permit for the Mulitple Seperate Storm Sewer System (MS4) and are issued by the Kansas Department of Health and Environment (KDHE) to multiple cities and Johnson County. All permit holders are required to prepare a Stormwater Management Plan describing how they will address required program elements, including best management practices, a schedule of activities and the entity responsible for implementation. The six program elements included in the NPDES MS4 permits are listed below:

  1. Public Education and Outreach
    Public education and outreach ensures greater support and compliance for the program. This measure relies on forming partnerships, using educational materials and strategies and reaching diverse audiences.

  2. Illicit Discharge Detection and Elimination
    This measure focuses on decreasing pollutant levels from illicit discharges – illegal pollution – that can significantly degrade water quality and threaten aquatic, wildlife and human health. The measure includes locating problem areas, finding the sources, removing/correcting illegal connections to the storm drainage system and documenting actions taken.

  3. Post-Construction Runoff Control
    Runoff from areas undergoing development/redevelopment has been shown to significantly affect bodies of water. This measure will help prevent damage to aquatic life and property while using the most cost-effective approach to stormwater quality management.

  4. Public Participation/Involvement
    An active and involved community is vital to the success of a stormwater management program. Public input is needed in the development and implementation of the program.

  5. Construction Site Runoff Control
    Polluted stormwater runoff from construction sites often flows to the storm sewer system and ultimately is discharged into local rivers and streams. The introduction of silt and pollutants from construction sites can harm the physical, chemical and biological components of a community's water ways.

  6. Pollution Prevention/Good Housekeeping
    Municipalities conduct many activities that can pose a threat to water quality if practices and procedures are not in place to prevent pollutants from entering the stormwater system.

For fact sheets about each of the six minimum control measures, visit the EPA Web site at http://cfpub.epa.gov/npdes/stormwater/.

Johnson County Kansas Permit and Stormwater Management Plan

The Kansas Department of Health and Environment issued a NPDES permit to Johnson County Kansas in 2014 to regulate discharges into the multiple storm sewer system owned by the County. This permit only covers stormwater discharges into the storm sewer system in the unincorporated area of the County. Most cities in Johnson County also hold NPDES permits with KDHE and are responsible for regulating stormwater discharges within city limits. The permit requires that Johnson County develop a Stormwater Management Plan that outlines how the minimum control measures listed above will be addressed. The permit and stormwater management plan for Johnson County are available at the links below. 

Johnson County Kansas MS4 NPDES discharge permit (February 1, 2014 through January 31, 2019)

Johnson County Kansas Stormwater Management Plan 

Map of area regulated by Johnson County Kansas (grey shaded area)


What Are Your City's Regulations?

Cities in Johnson County have adopted laws to prevent stormwater pollution and protect our community's water quality. Contact your city hall to learn more about your city's specific regulations regarding stormwater pollution prevention.


What You Can Do

Can You Help?

Yes! You can be a stormwater steward. That means in simple, every day activities, like bagging your pet’s waste or taking your car to a commercial wash, you can help keep harmful pollutants out of our waterways.

How to Prevent Stormwater Pollution:

  • Use fewer lawn chemicals and don't water right away. Try using compost instead of chemical fertilizer. Don't water after applying lawn chemicals and don't apply them before a heavy rainfall is predicted.
  • Clean up after your pets. Carry disposable bags while walking your dog so you can pick up and dispose of pet waste in the trash. In your own yard, pick up pet waste, bag it and put it in the trash. Leaving it in the grass sends unsafe bacteria into the storm drains when it rains.
  • Recycle used oil. Find an oil recycling center near your home or work to properly dispose of used oil. Johnson County has more than 30 used-oil recycling sites, such as gas stations, automotive supply stores and lubrication service centers. For a list of sites, go to www.recyclespot.org
  • Sweep driveways and sidewalks rather than washing them off with the hose. Remove grass clippings, dirt and other debris and dispose of it properly.
  • Use a commercial car wash to minimize the effects on the environment . If you wash your car at home, do it on the grass. Use biodegradable, phosphate-free, water-based cleaners only. Use a spray nozzle to save water.
  • Properly dispose of trash and yard waste. Contact your city hall for your community's instructions for proper trash and yard waste disposal.
  • Use household products as directed. Properly store and dispose of all hazardous household products at a hazardous waste facility permitted facility.
  • Shop smart. Purchase and use nontoxic, biodegradable, recycled and recyclable products whenever possible.


Yard Waste Management

Yard Waste Management Frequently Asked Questions

Is it OK to dispose of leaves on stream banks? There are leaves there already and I've heard it helps to stablize the stream bank. No-- It is true that there are trees and other vegetation next to streams and leaves from those trees fall into and around the stream, but as with many things in life, too much can be a bad thing. The natural system is equipped to break down and process the leaf litter that is there naturally, but dumping leaves in or near a stream overwhelms the system. Too much decomposing organic waste adds excess nutrients into our streams and lakes that can lead to unsightly algae blooms which also can be harmful to pets and humans. As algae dies, it uses oxygen in the water, which causes depletion in oxygen in the water for aquatic life and can cause fish kills. 

Is it OK to put leaves in the storm drain? No-- it is illegal to dump anything, other than clean water, into the storm drain. Not only is it bad for water quality because stormwater is not treated, it can cause clogs in storm water catch basins which could result in localized street floodiing. And this causes increased maintenance costs for your city, which could result in higher taxes for you. 

Will mulch mowing leaves cause thatch in my lawn? I'm worried because have several mature trees in my yard. No-- research from Michigan State University Hancock Turfgrass Research Center has shown that you can mulch up to 6 inches of leaves into your lawn. To do this effectively, it is best to stay ahead of the leaves and not try to mulch 6 inches at once, but mulch frequently throughout the fall season. Also, make sure and have your mower blade sharpened before the fall season to ensure effective mulching. Research has shown that core aeration and fertilizing your lawn with a fertilizer that has a high nitrogen (N) and low phosphorus (P) content will help break down the leaves into a useable resource for your healthy lawn. (When purchasing fertilizer, check the Nitrogen (N), Phosphorus (P), and Potassium (K) contents. Lawns in Johnson County generally do not need additional phosphorus.) 

Additionally, thatch is not caused by mulching leaves or grass clippings into your lawn. Thatch is caused by many factors which include, frequent and shallow watering, excessive use of nitrogen fertilizer and pesticides, compacted and poorly aerated soils, and infrequent, high mowing. 

Is it OK to blow or rake my leaves into the street-- doesn't the city pick them up? Most cities in Johnson County do not offer a leaf removal service. The street sweepers you may see on your street are there to pick up the leaves that fall on the street and ONLY those leaves that fall on the street. They are not equipped to remove a large amount of leaves, such as those raked intentionally from a yard, The cities of Westwood, Westwood Hills, and Roeland Park do offer a city-wide leaf pick up service, but only on specific days. Contact your city for details. The cities of Fairway and Mission Hills have negotiated on behalf of their residents with a third-party contractor to provide a fee-based leaf-collection service. Most other cities in Johnson County have weekly curbside yard waste collection, but require leaves to be in paper bags or in a container clearly marked as yard waste. 

Visit http://bit.ly/loveryourlawn to learn more. 



Report Stormwater Pollution

You can help your city by identifying and reporting potential sources of stormwater pollution. To report stormwater pollution in your area, call the Stormwater Hotline at 913-715-6900 or fill out this online form.

If reporting pollution after business hours, please call the Johnson County Environmental Department 24-Hour Response Service at 913-715-6900. If you witness discharges of hazardous materials-- dial 911 to contact the fire department.

Reporter Information
Incident Location
example: "Blue River at 69 Highway" or "151st and Nall"
Description of problem in or near a stream
Description of problem on land away from a stream
Narrative Description of Pollution Found
Suspected Violator
Enter the characters shown in the image.