About Louisville Jefferson County, Kentucky

Louisville’s climate is described as "moist-continental."  Winters are moderately cold with temperatures rarely below zero degrees Fahrenheit, with January being the coldest month. Average annual snowfall is about 17 inches. Summers are hot (although rarely above 100 degrees Fahrenheit) and humid, with July being the hottest month. Spring and summer months are characterized by changeable, wet weather. March has the greatest total rainfall. Yearly precipitation is approximately 43 inches. The driest month is October.

Jefferson County has eleven major stream systems: Mill Creek, Pond Creek, South Fork Beargrass Creek, Middle Fork Beargrass Creek, Muddy Fork Beargrass Creek, Goose Creek, Harrods Creek, Floyds Fork, Cedar Creek, Pennsylvania Run and Ohio River. Approximately 790 miles of streams are found within these six stream systems. The land drained by each of these streams is called a "watershed."

Jefferson County geology consists of limestone, shale, and dolomite plus alluvial and lacustrine deposits. The five major geological areas within Jefferson County are as follows:

  1. The loam soils in the northeastern part of the county tend to overlie limestone, are relatively deep, and generally well drained. They are best suited for pasture.
  2. The northern and western most parts of the county are adjacent to the Ohio River. The soils found within this area are well-drained alluvial soils with a silty sand texture. These floodplain soils represent some of the best agricultural soils in the county.
  3. The central portion of the county is in poorly drained clay-based soils. Much of this area was once considered a wetland.
  4. The geology within the southern part of the county is on steep slopes or upland areas. The soils are generally well drained, moderate in depth, composed of shaly limestone or silty loam, and are best used for maintaining forested areas.
  5. The southeastern part of the county is mostly hills, with moderate to steep slopes, and numerous sinkholes. The soils overlie limestone, and limestone fragments are commonly mixed into the soils. The soils are moderate to deep in most areas, generally well drained, and are a mixture of wind blown sediments, silt, loam and clays. They are well suited for forest and pasture.

Water – Precious Natural Resource

Water is, by far, the earth’s most precious natural resource. Three-quarters of the earth’s surface is composed of water. However, most of this water (approximately 97%) is saltwater (oceans), thus, unavailable for human consumption. Freshwater forms only about 3% of the earth’s water, with most of that in the form of ice. Water available for human use, in the form of streams, rivers and lakes, make up only 0.01% of the water on Earth. Because freshwater comprises such a small percentage of the available water on the planet and because it is absolutely necessary for sustaining life, this resource must be protected.

The Clean Water Act and Water Quality?

In 1972 the United States Congress passed the Federal Water Pollution Control Act - commonly called the Clean Water Act (CWA). The purpose of the law is to restore and maintain the "chemical, physical and biological integrity of the Nation’s waters". The goal of this law is to ensure:

  1. clean water in our streams, lakes, wetlands, estuaries, and other water bodies,
  2. that fish and associated populations can flourish and that game fish are safe for human consumption (fishable),
  3. that the Nation’s waters are safe for recreation (swimmable). This is often referred to as "fishable/swimmable".

In response to the Clean Water Act, water quality criteria/limits have been established by the United States Environmental Protection Agency (EPA). The intent of the water quality criteria is the protection of public health and welfare, as well as the protection and enhancement of water quality. States have been granted authority to design and implement their own water quality programs using the Federal program as guidance. The Kentucky Division of Water (KDOW) implements the Clean Water Act for the Commonwealth of Kentucky. The KDOW relies on the physical, chemical and biological data collected by MSD to determine the quality of the water within Jefferson County streams.

Why is Water Quality Important?

Drinking water for much of Jefferson County comes from the Ohio River upstream of Louisville. Our local streams carry pollution from Jefferson County, and discharge into the Ohio River downstream of our drinking water intake. Therefore, our activities impact the water supply for the people down river of Jefferson County. The water supply for these communities is dependent on how well we manage our streams, just as we are dependent on those communities upriver from us. Over three million people get their drinking water from the Ohio River.

We depend on our streams for recreation (fishing, wading, swimming, and canoeing) and aesthetics. Water from our streams is used to irrigate golf courses, to water farm animals, and is also utilized by fish and wildlife. Unfortunately, the poor water quality of many Jefferson County streams does not provide suitable conditions for recreational uses such as fishing and swimming, and is a degraded habitat for fish and other aquatic species.