Water Quality Monitoring

Sub-Watersheds

The Storm Water Department has identified 15 sub-watersheds with in the city limits: 

Basin Map
  • Brushy Fork Creek
  • Fiddlers Creek
  • Little Creek
  • Lower Mill Creek
  • Lower Salem Creek
  • Lower Silas Creek
  • Lower South Fork of Muddy Creek
  • Middle Mill Creek
  • Middle Salem Creek
  • Muddy Creek
  • Peters Creek
  • Salem Lake
  • Upper Mill Creek
  • Upper Salem Creek
  • Upper Silas Creek

Water Quality Sampling Program Overview 

Dry Weather

Conducted quarterly, 24-hour composite samples are taken every 15 minutes by automated samplers, which are deployed at 15 sites. All pollutant parameters are composite (except fecal coliform - grab) and sent to an outside, state-certified laboratory for analyses. A current meter is utilized to determine flow discharge of the stream. Pollutant concentrations and flow discharges are used to calculate the pollutant loading of the waterway. Prior to any dry-weather sampling event, there must be 72 hours without rainfall.

Wet Weather

Man Checking a Water MonitorConducted annually, automated, sequential samplers are placed at each of the 15 sites during a representative storm event. Each sampler is programmed to capture "the first flush" in the first 30 minutes of rainfall (triggered to start by the stream level of a rain gauge), then muticompositing each hour of the storm event, up to six hours.

During the storm event, the sampler records the stream level and time is plotted into a storm hydrograph, which computes total, first flush and hourly flow discharge. Simple math is used to calculate the percentage of hourly versus the total discharge. For the hour in question, Stormwater personnel can calculate and mix a flow-weighted composite sample for the storm event. All pollutant parameters are composite (except fecal coliform and oil and grease - grabs) and sent to an outside, state-certified laboratory for analyses. Pollutant concentrations and flow discharges are used to calculate the pollutant loading of the waterway.

Prior to any wet-weather sampling event, there must be 72 hours of dry weather.

Water Quality Index

Conducted monthly, grab samples are obtained for certain pollutant parameters at 46 sites. Good water quality is crucial for aquatic life abundance, as well as human health. The water quality parameters listed below are taken with instantaneous, multi-parameter meters which indicate the possible presence of sediment transport, industrial wastewater, or nonpoint source discharges in our waterways.

Water quality is monitored for:

  • Ammonia
  • Biochemical Oxygen Demand
  • Conductivity
  • Dissolved Oxygen
  • Fecal Coliform
  • Nitrates
  • pH
  • Temperature
  • Total Dissolved Solids
  • Total Phosphates
  • Turbidity
Sampling over a Bridge

Sampling Parameters 

Sampling parameters include:

  • Biochemical Oxygen Demand
  • Cadmium
  • Chlorides
  • Chromium
  • Fecal Coliform
  • Lead
  • Nickel
  • Nitrates
  • Nitrites
  • Total and Dissolved Copper
  • Total and Dissolved Phosphorus
  • Total and Dissolved Zinc
  • Total Kjeldahl Nitrogen
  • Total Suspended Solids
  • Turbidity

Elimination of Illicit Discharges

Staff tracks and eliminates old sewer connections, floor drains and other prohibited connections. This program identifies permitted and acceptable discharges and investigates complaints about unusual discharges.

Pollution Prevention Monitoring

Staff provides guidance to commercial and industrial sites in reducing the amount of pollution which runs off their property to storm drains that flows directly to streams without treatment. Staff utilizes pollution prevention audits, site specific monitoring, and distribution of information for waste reduction.