Surface Water Quality

​Monitor​ing Techniques​

​​Staff performs six different types of monitoring in local streams and lakes. Information about what is monitored, how it's done, and where it occurs is organized as follows. Please scroll down for more infor​mation about these topics.​

  • Fixed Interval Monitoring​
  • In-Stream Stormwater Monitoring
  • Lake Monitoring
  • Biological Monitoring
  • Stream surveys
  • Continuous Monitoring and Alert Notification Network

Rain and water levels in streams and lakes across Mecklenburg County are also monitored with 71 rain gauges, 3 lake gauges, and 50 stream gauges.  Please see gauges and hydrologic data in and around Charlotte and Mecklenburg County for more information.

Fixed Interval Monitoring 

For Fixed Interval Monitoring (FIM), staff either collects a surface water sample ("grab sample") for analysis in the lab or they test the water right at the stream or lake with a hand-held meter. See this map of FIM locations where the following parameters are measured monthly. ​

  • Temperature
  • Dissolved Oxygen
  • Enterococcus Bacteria
  • Ammonia Nitrogen
  • USGS Suspended Sediment Test (SSC)
  • Zinc (dissolved)
  • Arsenic
  • Nickel
  • Silver
  • Chromium
  • Beryllium
  • Conductivity
  • Fe cal Coliform Bacteria
  • pH
  • E-coli Bacteria
  • Nitrite and Nitrate
  • Total Kjeldahl Nitrogen
  • Total Phosphorous
  • Suspended Solids (TSS)
  • Suspended Solids
  • Turbidity
  • Hardness
  • Copper (dissolved)
  • Lead (dissolved)
  • Cadmium

In-Stream Stormwater Monitoring 

For In-Stream Stormwater Monitoring, automated samplers collect several samples during a storm event. As the flow of a stream increases, the number of samples being collected increases too. This provides information about pollutant levels during the ENTIRE storm. Samples are combined into a composite sample and tested for the following parameters. See this map of In-Stream Stormwater Monitoring locations.  The following parameters are measured at each location:

  • Temperature
  • Dissolved Oxygen
  • Enterococcus Bacteria
  • Ammonia Nitrogen
  • Turbidity
  • Chromium
  • Zinc
  • Lead
  • USGS Suspended Sediment Test (SSC)

  • Conductivity
  • Fecal Coliform Bacteria
  • pH
  • E-coli Bacteria
  • Nitrite and Nitrate
  • Total Kjeldahl Nitrogen
  • Total Phosphorous
  • Suspended Solids (TSS)
  • Copper

Lake Monitoring 

​For Lake Monitoring, staff collects surface water samples and information about lake conditions six times a year across three lakes: Lake Norman, Mountain Island Lake, and Lake Wylie. See this map of Lake Monitoring locations. The following parameters are measured at each location: ​

  • Secchi Disk depth
  • Conductivity
  • Alkalinity
  • Total Kjeldahl Nitrogen
  • Nitrate + Nitrite

  • Temperature
  • ​​Dissolved Oxygen
  • pH
  • Fecal Coliform Bacteria
  • Ammonia Nitrogen​

Biological Monitoring 

For Biological Monitoring, staff assesses fish and macroinvertebrate, or "bug", communities twice a year. Different types of fish and macroinvertebrates are more sensitive or tolerant to pollution than others. Staff can assess the health of a waterbody by the types of fish and macroinvertebrates they find. Fish and macroinvertebrates can be one of the best holistic indicators for assessing water quality. See this map of Biological Monitoring locations.

Stream Walks 

For Stream Walks, approximately 20% of all streams in watersheds over 50 acres throughout Charlotte and Mecklenburg County are walked by staff in an effort to find illicit discharges and document watershed conditions. This equals an average of approximately 270 miles per year.  This allows staff to walk all these streams every five years. During these walks, the following activities are performed:
  • Documentation of the location, condition, and flow of all outfalls (aka pipes) that are over 12 inches in diameter.
  • Testing of water flowing from an outfall during dry weather. (Stormwater outfalls should typically not have flow during dry weather) 
  • Testing surface water quality at stream junctions and documentation of watershed conditions.

For more information please see Stream Walks as part of the Illicit Discharge Detection and Elimination Program. 

​Continuous Monitoring and Alert Notification Network 

The Continuous Monitoring and Alert Notification Network (CMANN) is a network of automated samplers across the County where data is collected once per hour, 24 hours per day. This network provides an automated system that can be especially helpful for identifying problems that need a quick response. The faster staff can respond to a pollution incident, the less potential damage to a stream or lake. A map of current locations is available on our CMANN website.​​