Chemical monitoring involves testing temperature (air and water), conductivity, pH, and dissolved oxygen. Similar to results of lab tests in people, measurements that are way out of normal range are reported for immediate action. Otherwise it’s generally more useful to look at trends over a period of several months to take early action before a big problem arises.
| Measurement | Normal for our area | What the results mean |
|---|---|---|
| Temperature (air and water) | N/A | Rise in water temperature could mean “thermal” pollution. |
| pH | 6-8 is considered normal. Our creek is generally between 6.5 and 7.0 | Technically a measure of hydrogen ions but think of pH as how acidic (low pH) or alkaline (high pH) something is. pH is measured on a 14-point scale where 7 is neutral. Distilled water, for example, has a pH of 7.0 |
| Conductivity | Typically, 50-1500 with ours usually between 200 to 260 | Conductivity measures the presence of ions or the number of dissolved inorganic compounds (also known as salts). There is no overall norm as conductivity is affected by geology. Limestone and clay increase conductivity while concentrations of granite lower conductivity. |
| Dissolved Oxygen | No less than 4 mg/L | Dissolved oxygen (DO2) is an indicator of a stream’s ability to support aquatic life. Things that increase DO2 include plant life, barometric pressure and turbulence. DO2 decreases with warmer temperatures, slow, still, or deep water, or an overload of decaying material. |