Water Quality Data Monitoring 101

The Adopt-A-Stream program is part of a larger Smith Creek Watershed Restoration Project. The town will be studying Smith Creek Watershed over the next four years (2013-2016) to determine the level of impairment and generate a restoration plan to improve water quality, habitat, and aquatic life. Our hope is to collect water quality data and conduct improvement projects to remove Smith Creek Watershed from the 303d impaired water list.

Funds for this project were provided by Southeast Environmental Education Alliance as part of an EPA mini Environmental Education grant in the amount of $4,425 and the North Carolina Division of Water Resources (formerly North Carolina Division of Water Quality) EPA 319 (h) grant in the amount of $100,000.

Volunteers participating in the Adopt-A-Stream Program collect water quality data at 20 monitoring stations evenly distributed in the 13 subwatershed areas of Smith Creek Watershed. Parameters collected include; water temperature, turbidity, dissolved oxygen, nitrogen, phosphorus and pH. If the water quality data values are outside of acceptable ranges, town staff will collect additional samples and conduct a field investigation at the sample site to determine the cause and source of the problem.

Browse the interactive map below to review water quality data collected by volunteers. Click on the star icon for details about each sampling station.  If there are no stars visible on the interactive map shown below, press the "+"  to zoom-in and the stars will appear.


Water Temperature, degrees Fahrenheit

Water temperature can greatly influence aquatic life in a stream. High temperatures can harm the fish, cause a fish kill and create a perfect habitat for algae blooms and bacteria growth. These increased temperatures are due to several factors including: lack of stream shade and direct runoff from hot parking lots or roadways.


Turbidity, NTU

Turbidity is the muddiness or "cloudiness" of the stream due to high concentration of suspended sediment particles. This sediment comes from eroded soil that is dislodged by upstream erosion from both natural and manmade sources. Clay or clay loam soils are usually the culprit, as they are suspended in the water 72 hours or more due to their small particle diameter size and weight as compared to sand which drops out of the water column very quickly and is deposited as sand bars.

Turbidity levels near 0 NTU (Nephelometric Turbidity Units) appear clear. While levels into in the 1,000's appear muddy like chocolate milk. A healthy stream is typically below 50 NTU. Turbidity can be caused by construction erosion/sedimentation violations, unstable stream banks, and large storm water runoff. After deposition, the clay particles can clog the gills of fish, smother fish eggs, and even kill aquatic life.


Dissolved Oxygen (DO), ppm

Dissolved Oxygen is the amount of oxygen available for fish and aquatics to breathe. A high DO is good a low DO is bad. Typical levels are around 20+ ppm (parts per million). Low DO can be caused by increased algae growth, high water temperatures, increased nitrogen and phosphorus, and little stream flow and mixing.


Nitrogen and Phosphorus (N and P), ppm

Nitrogen and Phosphorus are the building blocks of life however; values over 20 ppm can be dangerous or even toxic to fish and other aquatic life. Typical levels of N and P in a stream are around 2-6 ppm. Excess nitrogen and phosphorus comes from over application of fertilizer (usually made up of 10-10-10; 10% N, 10% P, and 10% K). Free soil tests (link) are available to determine what fertilizer to use for your lawn and garden. Additional sources of N and P can be from pet waste, sediment, yard clippings and untreated stormwater runoff.

Stormwater best management practices or BMPs are installed at stormwater pipe outfalls to treat the excess volume, nutrients such as Nitrogen and Phosphorus, and sediment coming from neighborhoods and commercial sites. Different types of BMPs include: dry ponds, wet ponds, bioretention areas (large soil filters with plants or sod), constructed wetlands, scour holes and level spreaders.


pH, 0-14

pH is measured on a scale of 0 to 14, with 7 being neutral. Acidic levels are those less than 7, and basic (alkaline) levels are those that are greater than 7. The pH of a stream is normally between 6 and 8. Both an increase and decrease in pH can harm fish and other aquatic life. A high or low pH can be a result of change in the concentration of hydrogen ions. The pH of water determines the solubility (amount of hydrogen ions can be dissolved in the water) and biological availability (amount of hydrogen ions can be utilized by aquatic life) of chemical constituents such as nutrients (e.g., phosphorus, nitrogen, and carbon) and heavy metals (e.g., lead, cadmium, copper).

Water Quality Data Monitoring 101
Stormwater Engineer