Water Quality

Storm wa·ter n: Surface water resulting from rain or snow.

MS4: Municipal Separate Storm Sewer System, a sewer system in which stormwater flows to a local waterway through a series of conveyances that are separate from the sanitary, or wastewater, sewer system. Stormwater conveyed to a local waterway by the MS4 is not treated in Water Quality Treatment Center. MSD's MS4 program is permitted by the Kentucky Division of Water.

Why care about Stormwater Quality?

Stormwater contains pollutants that come from areas developed by people, and those pollutants effect our community’s water quality. The amount or volume of stormwater that runs off of urban and suburban areas is often greater than the amount of stormwater that runs off forests and farms. Buildings, rooftops, roads and driveways are made of solid, impervious surfaces, so stormwater runs off these areas. In forests and on farms, trees, plants, crops and natural soils allow stormwater to soak into the ground, so less stormwater runs off these areas. As the amount of stormwater runoff increases, so does the amount of pollution it picks up.

What Is MSD Doing To Improve Stormwater Quality?

MSD has developed a Stormwater Quality Management Plan (SWQMP)—a roadmap for stormwater management activities to comply with the Stormwater Quality Program permit. The SWQMP is reviewed every year and updated annually if needed. The Stormwater Quality Program permit and plan are based on eight program areas designed to improve stormwater quality. 

  1. Public Education, Outreach, Participation and Learning Experiences
  2. Illicit Discharge Detection and Elimination  
  3. Industrial Program 
  4. Construction Site Stormwater Runoff Control 
  5. Long-Term (Post-Construction) Stormwater Runoff Control 
  6. Good Housekeeping/Pollution Prevention Program 
  7. Monitoring 
  8. Performance Assessment and Reporting

Stormwater Quality Monitoring Program

MSD collects over 3 million individual water quality records each year. This monitoring program provides a detailed picture of the health of streams in Jefferson County. Monitoring results are summarized on an annual basis in the Stormwater MS4 Annual Report, and complete data are provided electronically annually to the Kentucky Division of Water (KDOW). Every two years, MSD publishes a Synthesis Report, called the State of the Streams, that summarizes water quality trends.

How is Water Quality Measured?

In 1988, MSD and the United States Geological Survey (USGS) began monitoring water quality and stream flow throughout the Jefferson County area. The Long-Term Monitoring Network has changed over the years and currently includes 27 monitoring sites. The monitoring sites were selected to represent streams in each of eleven watersheds.  

Types of Stream Monitoring

Fish: Fish have been used for many years to indicate whether waters are clean or polluted, doing better or getting worse. Knowing whether fish live in the water is not enough – we need to know what kinds of fish are there, how many and their health.  

Aquatic insects: Insects that live on the bottoms of streams are called aquatic insects or benthic macroinvertebrates. Aquatic insects also have been used for many years to evaluate stream health. We need to know what kinds of aquatic insects there are and how many of each type are present.  

Stream Habitat: Stream habitat is the underwater environment that is used as a living space by fish, aquatic insects, other plants and animals.  Streams that have a variety of habitats and places. Gravel and shade are characteristics of good habitats. Eroding banks, large amounts of silt and sediment, and straightened stream channels are characteristics of poor habitats.

Algae: MSD monitors the amount and types of algae present in streams. Algae range from very small plants that can only be seen with a microscope to large green growths seen in some streams. Stream flow, shade and the amount of fertilizers in the water influence the amount and types of algae that are present.  

Stream Flow: MSD and the US Geological Survey work together to monitor stream flow and water quality using permanent gauges and water quality meters. Measurements of stream flow and water quality are collected every 15 minutes.

Water Quality: MSD monitors a water quality four times per year at the 27 Long-Term Monitoring Network sites. Samples are analyzed for a variety of parameters including levels of fertilizers, sediment and metals.

Recreational Monitoring: Between May 1 and October 31 every year, MSD collects five bacteria samples per month at each Long Term Monitoring Network site.  

Wet Weather Monitoring: MSD performs water quality monitoring during storm events at least three times at each Long Term Monitoring Network Site every five years.