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Public Works

Phone: 913-715-8300

1800 W Old Highway 56, Olathe, KS 66061

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About SMP

Johnson County Stormwater Management Program

The Johnson County Stormwater Management Program (SMP) is a department of the County government that partners with the 20 cities in Johnson County as well as other cities, counties and agencies in the Kansas City metropolitan region on stormwater management related issues.

Stormwater management issues addressed by the SMP include:

  • Provide 75 percent of funding for study, design and construction of stormwater improvements in Johnson County communities.
  • Update and maintain Countywide floodplain mapping
  • Manage grant funded projects intended to mitigate flooding conditions and improve the water quality of stormwater runoff.
  • Provide technical support to the cities on stormwater management related issues.
  • Provide public education and outreach associated with stormwater management.
  • Coordinate and collaborate with communities, counties and local, regional, state and federal agencies in the Kansas City Metropolitan region on stormwater management related issues.

SMP aims to provide the level of service and standard of care Johnson County property and business owners expect and deserve.

The SMP works directly with cities to fund design and construction projects. If you believe you have a flooding problem in your neighborhood, contact your city.


Who Does What In Stormwater Management?

The Johnson County Stormwater Management Program partners with Johnson County cities to fund the planning, design and construction of projects to alleviate flooding and improve water quality issues from the broad countywide level of the watershed. If you feel you have a flooding condition or a water quality issue in your neighborhood or know of one in your community, please contact your city.

The real “front line” of stormwater management occurs at the city level, where staff and the public interact to make the choices that best serve their community.

Cities manage localized flooding, erosion and water quality issues. City staff and elected officials determine projects needed in their communities.

The SMP provides cities with 75 percent of finding for eligible projects, using a countywide sales tax.


Advisory Council

Stormwater Management Advisory Council

The Board of County Commissioners adopted Board Resolution No. 76-90—creating the Johnson County Stormwater Management Advisory Council (SMAC). SMAC is an advisory group composed of one appointed representative for each of Johnson County 's 20 cities as well as non-voting members from the four surrounding counties, Kansas City , MO , and the Mid-America Regional Council. SMAC primarily operates as an advisory body to the Board of County Commissioners and performs the following functions:;00 

  • Review recommendations of the Stormwater Management Program
  • Make recommendations to the Board of County Commissioners

In addition, SMAC provides the mechanism to complete the following efforts:

  • Ensure the stormwater funds collected through the 0.1 percent sales tax levy are consistently applied using the same rational basis without concern for jurisdictional and political boundaries.
  • Use the stormwater funds collected through the 0.1 percent sales tax levy to correct the more severe flooding problems throughout the County with cost-effective solutions.
  • Provide a think-tank to consider new and innovative ways to properly manage stormwater

SMAC operates under and is governed by Board of County Commissioner approved By-laws.


All meetings are held at the Johnson County Public Works Facility

1800 W Old 56 Hwy, Olathe, KS 66061

Date Time Location Meeting Packet
9/16/2016 7:30-9:00 AM Johnson County Public Works Meeting Packet
4/29/2016 7:30-9:00 AM Johnson County Public Works Meeting Packet
9/18/2015 7:30 - 9:00 AM Johnson County Public Works Meeting Packet


Funding and Budget


Dedicated sales tax

Since the Kansas Legislature approved a 1/10th of one percent sales tax for the purpose of funding stormwater management efforts, Johnson County 's Stormwater Management Program (SMP) has provided 75 percent of funding for eligible projects in cities.

  • To date, nearly $200 million of stormwater study, design and construction projects have been, or are currently being completed through the SMP and the cities.
  • For the 200-plus projects, approximately $150 million has been paid for by the 1/10th of one percent sales tax.
  • On average, SMP spends more than 90 percent of the total budget annually to study, design and construct stormwater projects and to fund county and regional stormwater quantity and quality related projects. Improvements include widening open channels and replacing culverts and bridges, protecting the natural stream corridor and enhancing water quality.

Annual Budget

Program expenditures as approved by the Johnson County Board of County Commissioners


History and Goals


DRAFT 2016 Strategic Plan

Johnson County’s Urban Services Division engaged Black & Veatch Corporation (Black & Veatch) to lead the development of a comprehensive update of the SMP Strategic Business Plan. A Steering Committee was established and provided the Black & Veatch team with essential information, input and guidance throughout the updating process. A cross section of stakeholders comprised the Steering Committee, including staff and elected officials from smaller and larger cities as well as officials from the County Commissioner, County Manager’s office and Johnson County Public Works & Infrastructure department. The DRAFT report is available at the links below. 

Executive Summary

Full Report


SMAC Comments & Response Summary

DRAFT Strategy Fact Sheets

Alternative Funding Sources

Funding Approach and Criteria

System Management

Flood Damage Reduction

Water Quality Focus

Watershed-Based Organization


History of SMP

In 1988, the Kansas Legislature authorized counties to adopt a 1/10th-cent sales tax for the purpose of funding stormwater projects. Johnson County was the only county to implement the tax. These funds, dedicated to stormwater management, allow Johnson County 's Stormwater Management Program (SMP) to create a yearly stormwater management plan and provide 75 percent of funding for eligible projects in Johnson County and the cities.

The Board of County Commissioners created the SMP and the Stormwater Management Advisory Council (SMAC) in the early 1990s. SMAC helps coordinate stormwater efforts and advises the County Commissioners on stormwater management related issues.

SMAC is comprised of voting and non-voting members. Voting members are comprised of a representative from each of the cities in Johnson County and Johnson County . Non-voting members are representatives from other communities in the Kansas City metropolitan area, local, regional, state and federal agencies, and interested people.

Current Goals Of The Program

The Johnson County Stormwater Management Program (SMP) is focused on:

  • Keeping the public informed and educated about stormwater and flooding
  • Studying and mapping floodplains
  • Encouraging emergency preparedness for flood events
  • Securing funding for stormwater projects
  • Helping city and county officials coordinate efforts to address stormwater quality and runoff issues throughout the region.


Policies and Procedures

The Stormwater Management Program operates and functions as defined in the Board of County Commissioner approved Program Policies and Administrative Procedures. These policies and procedures are reviewed on a regular basis and revised as necessary to meet the changing needs of the cities and the changing requirements for stormwater management.


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.