The Missouri Department of Natural Resources has adequately characterized water chemistry on large and medium rivers using its fixed station network, run in cooperation with the U.S. Geological Survey. Smaller streams, however, which are both more numerous and often more susceptible to water quality problems due to a smaller volume of flow, are not sampled on a regular basis. The absence of this kind of data reduces the ability to assess impairment, due to extensive (regional scale) stressors, of smaller streams and also to define, on a regional basis, “background” water quality which is important in setting goals for remediation projects.

The Water Quality Monitoring Section staff, as well as regional office staff conduct chemical monitoring on these smaller streams. Field measurements obtained during each visit include flow, water temperature, conductivity, pH and dissolved oxygen. Samples are collected and returned to the department's Environmental Services Program laboratory.

Samples are collected for these analyses:
alkalinity hardness acidity sodium
ammonia nitrate nitrite chloride
lead sulfate phosphorus total nitrogen
cadmium zinc magnesium calcium
iron nickel manganese potassium
bicarbonate alkalinity total Kjeldahl nitrogen

Some of these monitoring sites are in watersheds that are considered to be typical of regional land use, and whose stream water quality is believed to be influenced only by these extensive land uses and not by a specific discrete pollutant source. Data from these streams will be used to define “background” water quality of smaller streams in the state within the specific physiographic region the stream is located. Knowledge of this “background” level of water quality is important for implementation of the antidegradation requirements in Missouri’s Water Quality Standards (10CSR20-7.031), for development of nutrient criteria for streams and for setting target goals for regional scale water quality management projects.

The remaining streams are impacted by existing, or threatened by future, point or nonpoint water pollution sources. Water quality data from these sites will have three general types of uses:

  1. Comparison to established state water quality standards to determine if the stream is in compliance with these standards, and where applicable, this data could be used to develop Total Maximum Daily Loads,
  2. Comparison to regional “background” water quality to determine if water quality in the stream deviates from regional norms, and
  3. Determine if there are any discernable temporal trends in water quality.