Under the federal Clean Water Act, the U.S. Environmental Protection Agency (EPA) establishes Ambient Water Quality Criteria (AWQC) for bacteria to protect human health. Currently, the EPA uses Escherichia coli (E. coli) as an indicator of fecal contamination of receiving waters. These federal criteria state that for fresh waters designated for use as recreational waters, the mean over a year period should not exceed 40cfu/100 mg for E. coli.

The Wolf River's total cfu/100mg for fiscal year 2023 was 64 cfu/100mg measured in Germantown (Lansdowne Park). Anything over 40 cfu/100mg is considered impaired. There are many factors that add to this number in the City that include agricultural uses to the east as well as domestic animal waste in the City. Germantown is one community within the Wolf River watershed that includes Collierville and Fayette County communities to the east. The City is working with other communities to reduce the rate of cfu/mg in the Wolf River watershed as a whole and the significant decrease over five years shows the effort is working.

*The FY2024 results will be updated once testing is completed.

Turbidity is the measure of clarity of a waterways in Germantown. In streams, erosion and other surface runoff can increase, which can result in harm to habitat areas for fish and other aquatic life. Sediment particles, for example, can provide attachment places for other pollutants, notably metals and bacteria. For this reason, turbidity readings can be used as an indicator of potential pollution in a water body. Turbidity is normally measured by an instrument called a Nephelometer. This instrument determines the scattering of light and is measured in standard Nephelometric Turbidity Units (NTU).

Seasonal variations in turbidity will be observed as indicated in the quarterly fluctuations on the graphs. Normal levels of turbidity can range from less than 1 NTU in clear, pristine streams/rivers to over 200 NTU in murky streams/rivers. The soil composition in this area includes suspended sediments such as silt, clay, and inorganic materials, leading to higher turbidity levels. In West Tennessee, a turbidity level of 200 NTU or lower is considered acceptable. The City is actively implementing processes to reduce sediment levels and effectively manage runoff water in accordance with TDEC best management practices. Additionally, the City is continuously enhancing its stormwater management system each fiscal year to decrease sediment in local watersheds. Within the City, the total dissolved solids (TDS) in streams/rivers can vary from 50-250 mg/L, depending on the time of year as indicated in the quarterly data. Fluctuations in TDS levels can have detrimental effects on watershed health. Excessive or insufficient concentrations of TDS can restrict growth and potentially result in the death of aquatic organisms.

Germantown draws it water from the Memphis Sand Aquifer that is a shared resource of Arkansas, Mississippi and Tennessee. The level of the water table can naturally change over time due to changes in weather cycles and precipitation patterns. In addition, the pumping of wells can have a great deal of influence on water levels below ground, especially in the vicinity of the wells. If water is withdrawn from the ground at a faster rate than it is replenished, then the water table can become lower, resulting in a "cone of depression" around the well. It is expected that the aquifer will draw down during summer and early fall due to higher usage and drier conditions. Historically, the aquifer recovers nicely during the lower demand, higher rainfall months of winter and spring.