Clarke County Soil & Water Conservation District

Clarke County Soil & Water Conservation District, NRCS, and IOWATER are working together to conduct water quality testing in and around West Lake. We are currently testing 6-7 sites for things such as pH, nitrogen, oxygen, phosphorus and chloride. We are working to create a history of the health of the water system that provides drinking water to Osceola and Clarke County.

 

pH is a measure of a water's acid/base content and is measured in pH units on a scale of zero to 14. A pH of seven is neutral (distilled water), while a pH greater than seven is basic/alkaline and a pH less than seven is acidic. 6.5-9 are acceptable levels for aquatic life in Iowa.

 

Nitrogen is an essential plant nutrient, but excess nitrogen can cause water quality problems. Nitrate and nitrite are two forms of nitrogen. Nitrate is very easily dissolved in water and is more common in streams. Nitrite is rare because it is quickly converted to nitrate or returned back to the atmosphere as nitrogen gas, so detectable levels are uncommon. Iowa's drinking water standard for nitrogen is 10 mg/L. Nitrite is measured on a scale of 0-50ppm. Nitrate is measured on a scale of 0-3ppm. The typical range  is determined by adding Nitrite+Nitrate and is .05-.84 mg/L with Iowa's average at .19 mg/L.

 

Dissolved Oxygen (DO) is necessary for nearly all aquatic life to survive. It is measured in milligrams per liter of water (mg/L). Iowa standards, which are set to protect life, call for a minimum of 5 mg/L of DO in warm water streams and 7 mg/L in cold water streams, measured on a scale of 1-12ppm.

 

Phosphorus is an essential nutrient for plants and animals. It is measured on a scale from 0-10ppm with typical results being between .05-.13 mg/L with Iowa averaging .08 mg/L.

 

Chloride is a chemical found in salts, which tend to dissolve easily in water. Average chloride concentrations for Iowa streams range from 16-29 mg/L.

 

So how much is a mg/L. Here are some analogies:

One mg/L is equivalent to:

   *  One inch in 16 miles

   *  One minute in two years

   *  One ounce in 32 tons

   *  One cent in $10,000