JoCo Home Owners/Builders

Stormwater runoff can be a big problem for home owners. Unless it is properly managed, runoff from a heavy rainstorm can flood your home and cause a lot of costly damage. It can also pollute our drinking water supplies, adding to the cost of our municipal water bills.

Where does stormwater runoff go to?

Stormwater that enters storm drains on the streets and in the parking lots of Johnson County is collected into a storm sewer system, which eventually discharges into the Kansas River system (or the Missouri River or Marais des Cygnes River depending on where you live in the county).

How is stormwater regulated?

Water that flows out of pipes into the river and its tributaries is considered a point source  and is regulated under the National Pollution Discharge Elimination System (NPDES). Permits are issued by the Kansas Department of Health and Environment (KDHE) under authority delegated to it by the Environmental Protection Agency (EPA) to regulate water quality of stormwater discharges. Cities in Johnson County are required by the Stormwater Management Plan to obtain NPDES permits and regulate the amount of runoff (water quantity) and the amount of pollutants in runoff (water quality) that is discharged from their storm sewers into the Kansas River and its tributaries. These permits specify things like how much sediment, nutrients from fertilizers, bacteria, pesticides, and other pollutants can be in the water when it is finally discharged to the river.

What can you do to reduce stormwater runoff?

All of this means that residents in Johnson County may find themselves working with their municipal stormwater offices to reduce runoff from homes and gardens, housing developments managed by home owners associations, commercial developments and agricultural lands. Luckily there is a lot of help available to JoCo residents to assist them throughout the process, and we provide resources in the following sections to help you understand where to go and what to do to get the help you need.

What causes stormwater runoff?

Housing and retail developments are full of surfaces that do not absorb water-- hard, impervious surfaces like roofs, driveways, sidewalks, and roads. These impermeable surfaces can cause problems with stormwater management. A natural prairie has plants with deep roots and thick topsoil that absorbs much (if not all) of the rain during a Kansas thunderstorm; contrast this to a housing development, where much of the surface area absorbs little (or no) stormwater. The increased runoff from impermeable surfaces can cause headaches for homeowners, who have to deal with flooded basements, cracked foundations and costly repairs.

During a 1" rainstorm, a house with a 2000 square foot roof will have over 1000 gallons of water running off of it! That's a lot of water, especially if it comes shooting out of a neighbor's downspout aimed at your property.

What are the consequences of increasing stormwater runoff?

By increasing the amount of impermeable surfaces in the Kansas River watershed, developments can increase the chance of floods. Without proper planning, there is the potential for creating a dangerous situation for flood prone communities. This is one of the biggest reasons to carefully manage stormwater runoff.

But there are other important reasons as well. Like drinking water. Stormwater runoff entering storm drains makes its way to streams, reservoirs and eventually the Kansas River itself. Many communities obtain their drinking water directly from these sources. This means that  pollutants carried by runoff into surface waters will have to be removed by municipal water treatment plants, potentially increasing your water bill.

What causes sedimentation in our reservoirs?

Poor construction practices can greatly increase the amount of sediment in runoff. This is important, since sedimentation is a major problem in the Army Corps of Engineers flood control reservoirs on the Kansas River system. These reservoirs were built to hold back stormwater and reduce the amount of flooding in downstream communities. But now we are finding that soil particles washed into streams during storms are causing sedimentation in Clinton, Perry and Tuttle Creek Reservoirs. The big federal reservoirs on the Kansas River are rapidly filling in with sediment, which reduces their storage capacity. When this happens they are not able to hold back flood waters.

They are also unable to store sufficient amounts of drinking water for our growing communities.

These two problems are an important concern, and the Kansas Water Office funds many projects to reduce sedimentation in Kansas streams and rivers, and hence in the reservoirs. These projects attempt to cut off the problem at the source-- stormwater runoff. This is one of the reasons why the Johnson County Stormwater Management Programhas adopted a series of Best Management Practices for Home Builders.

What is pollution from runoff?

Stormwater washes fertilizer, herbicides, and pesticides off of lawns. Fertilizers increase nutrients in reservoirs, leading to algal blooms and "skunky" tasting water and expensive water treatment problems for municipalities.

Incorrect or excessive use of pesticides and herbicides by home owners leads to pollution in the Kansas River and has caused the Kansas Department of Health and Environment to issue health warnings. A good example of this was the fish consumption advisory that was in place for many years between Lawrence and Eudora because of contamination by Chlordane, a pesticide used in homes to prevent termites. The Chlordane advisory has recently been lifted, although a PCB advisory is still in place. (Click here for more information about current fish advisories in the Kansas River.)

What can you do to help?

In the next two sections we discuss some of the things you can do to reduce stormwater runoff and improve the quality of water running off of your homes and yards. We also discuss requirements for managing stormwater in housing developments under Johnson County's Stormwater Management Plan. Working together we can protect our homes from flooding and make sure that we always have good, clean and abundant drinking water supplies.

Is my home in the Kansas River Watershed?

Below is an interactive Google Map which shows that a large part of Johnson County (outlined in red) falls in the Lower Kansas River Watershed (outlined by the purple line). In fact, the northern border of the county is created by the Kansas River, which separates Johnson County from Wyandotte and Leavenworth Counties (and prevents JoCo from being a perfect square). If you live in the Johnson County portion of the Kansas River watershed your activities have a huge impact on the Kaw-- JoCo is the fastest growing and most densely populated part of the watershed and managing stormwater runoff is a major challenge for the County. Please help us reduce damage from polluted stormwater by following the suggestions in this section.

View Kansas River Watershed in a larger map