Author: mark.romano

Stream Use-Support Index (SUSI)
Charlotte-Mecklenburg Storm Water Services developed the Stream Use-Support Index (SUSI) to transform large quantities of water quality data into single numbers, or small sets of numbers, that can be reported in non-technical and comprehensive terms. SUSI water quality data can be easily mapped and it allows comparison of water quality in a body of water over space and time. / SUSI Data / SUSI is constructed around 5 categories of water quality data that represent the most important pollutants and indicators of environmental health in Charlotte-Mecklenburg. The categories of data included in the index are: / Water samples that generate SUSI data are collected once per month at 24 locations throughout Charlotte-Mecklenburg. Monthly, water samples are analyzed for fecal Coliform bacteria, turbidity, dissolved oxygen, pH, temperature, total phosphorus, copper, chromium, lead, and zinc. Annually, each monitoring site is surveyed for aquatic macroinvertebrates and in-stream habitat conditions. / Water temperature is affected by air temperature, stormwater runoff, groundwater inflows, turbidity, and exposure to sunlight. In considering the health of organisms, it is necessary to consider their maximum temperature and optimum temperature. / Temperature: depends on the season; but anything greater than 32 degrees C is a concern. / Conductivity measures the ability of water to conduct an electrical current. A stream’s conductivity is directly proportional to the concentrations and types of positively and negatively charged ions present. Sources of ions are both naturally occurring and anthropogenic in origin, and include soil, bedrock, human and animal waste, fertilizers, pesticides, herbicides, and road salt. / Conductivity: typically around 200 uS/cm; we are concerned if it is greater than 550 uS/cm

Dissolved Oxygen is oxygen gas molecules (O2) present in the water. Plants and animals cannot directly use the oxygen that is part of the water molecule (H2O), instead depending on dissolved oxygen for respiration. Oxygen enters streams from the surrounding air and as a product of photosynthesis from aquatic plants. Consistently high levels of dissolved oxygen are best for a healthy ecosystem.
Dissolved oxygen is measured in mg/L.
0-2 mg/L: not enough oxygen to support life. 2-4 mg/L: only a few fish and aquatic insects can survive. 4-7 mg/L: good for many aquatic animals, low for cold water fish 7-11 mg/L: very good for most stream fish
Dissolved Oxygen % Saturation: typically around 80-90%; we are concerned if it is less than 40%
Turbidity is a measure of how particles suspended in water affect water clarity. It is an important indicator of suspended sediment and erosion levels. Typically it will increase sharply during and after a rainfall, which causes sediment to be carried into the creek. Elevated turbidity will also raise water temperature, lower dissolved oxygen, prevent light from reaching aquatic plants which reduces their ability to photosynthesize, and harm fish gills and eggs.
Turbidity: typically it is less than 10 NTUs; we are concerned if it is greater than 50 NTUs, but during a rain event, it almost always exceeds 50 NTUs.
pH is a measure of a solution's acidity. In water, small numbers of water molecules (H2O) will break apart or disassociate into hydrogen ions (H+) and hydroxide ions (OH-). Other compounds entering the water may react with these, leaving an imbalance in the numbers of hydrogen and hydroxide ions. When more hydrogen ions react, more hydroxide ions are left in solution and the water is basic; when more hydroxide ions react, more hydrogen ions are left and the water is acidic. pH is a measure of the number of hydrogen ions and thus a measure of acidity.
pH is measured on a logarithmic scale between 1 and 14 with 1 being extremely acid, 7 neutral, and 14 extremely basic. Because it is a logarithmic scale there is a ten fold increase in acidity for a change of one unit of pH, e.g. 5 is 100 times more acid than 7 on the pH scale. The largest variety of freshwater aquatic organisms prefer a pH range between 6.5 to 8.0.

Hwy 51 at Sugar Creek

Gar Creek at Beatties Ford Rd.

Six Mile Creek at Marvin Rd

Four Mile Creek at Elm Lane

McKee Creek at Reedy Creek Rd

McMullen Creek at Sharon View Rd

Back Creek at Caldwell Rd

McAlpine Creek at Sardis Rd

Stream Report Form
Report Filed by ____________________________________________________

Location Name ___________________________________________________________________________
Temperature_________ Dissolved Oxygen [mg/L]__________ Dissolved Oxy % Saturation _________
pH_________ Turbidity________ Conductivity _________________
Issues with this stream/comments:___________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
Assessment of this stream (circle): very unhealthy unhealthy fair good excellent
Your assessment of the stream- [ ] very unhealthy [ ] unhealthy [ ] fair [ ] good [ ] excellent

Location Name ___________________________________________________________________________
Temperature_________ Dissolved Oxygen [mg/L]__________ Dissolved Oxy % Saturation __________
pH_________ Turbidity________ Conductivity _________________
Issues with this stream/comments:___________________________________________________________________
__________________________________________________________________________________________
___________________________________________________________________________________________
Assessment of this stream (circle): very unhealthy unhealthy fair good excellent
Your assessment of the stream- [ ] very unhealthy [ ] unhealthy [ ] fair [ ] good [ ] excellent

Location Name ___________________________________________________________________________
Temperature_________ Dissolved Oxygen [mg/L]__________ Dissolved Oxy % Saturation __________
pH_________ Turbidity________ Conductivity _________________
Issues with this stream/comments:____________________________________________________________________
___________________________________________________________________________________________
__________________________________________________________________________________________
Assessment of this stream (circle): very unhealthy unhealthy fair good excellent
Your assessment of the stream- [ ] very unhealthy [ ] unhealthy [ ] fair [ ] good [ ] excellent

Location Name ___________________________________________________________________________
Temperature_________ Dissolved Oxygen [mg/L]__________ Dissolved Oxy % Saturation __________
pH_________ Turbidity________ Conductivity _________________
Issues with this stream/comments:________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
Assessment of this stream (circle): very unhealthy unhealthy fair good excellent
Your assessment of the stream- [ ] very unhealthy [ ] unhealthy [ ] fair [ ] good [ ] excellent

Location Name ___________________________________________________________________________
Temperature_________ Dissolved Oxygen [mg/L]__________ Dissolved Oxy % Saturation __________
pH_________ Turbidity________ Conductivity _________________
Issues with this stream/comments:________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
Assessment of this stream (circle): very unhealthy unhealthy fair good excellent
Your assessment of the stream- [ ] very unhealthy [ ] unhealthy [ ] fair [ ] good [ ] excellent

Location Name ___________________________________________________________________________
Temperature_________ Dissolved Oxygen [mg/L]__________ Dissolved Oxy % Saturation _________
pH_________ Turbidity________ Conductivity _________________
Issues with this stream/comments:________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
Assessment of this stream (circle): very unhealthy unhealthy fair good excellent
Your assessment of the stream- [ ] very unhealthy [ ] unhealthy [ ] fair [ ] good [ ] excellent

Bacteriological, Metals, Nutrients, Physical and Biological