Temperature: Temperature is an important regulator for aquatic communities; plankton, bug, and fish species have a preferred temperature. Temperature also correlates to the amount of oxygen present in the water – cooler water holds more dissolved oxygen. Finally, temperature controls the rate at which chemical reactions occur, such as the conversion of nitrate-nitrogen to ammonia-nitrogen. All temperatures in our watershed were in the normal range. Several factors affect water temperature including riparian buffers or shading, watershed inputs, and surrounding land uses.
Dissolved Oxygen: Moving water tends to contain a lot of dissolved oxygen, whereas stagnant water contains less oxygen. Bacteria in water can consume oxygen as organic matter decays. Excess organic material in lakes and rivers can cause oxygen-deficiency, causing a water body to “die.” There were areas of oxygen depletion in our watershed, which can be attributed to lower water levels, as well as an overabundance of decaying material.
Transparency: Water transparency in streams reflects the downstream depth at which you can see through the water. Tubes measured 60 centimeters, so any values greater than 60 centimeters exceed our ability to detect a change in water transparency. Low numbers (10 cm) indicate poor transparency while those in the 70 centimeter (2 foot) range indicate good transparency. When stormwater runs across the land, it collects sediment – when this sediment reaches the river, transparency declines.
E. coli is an organism whose presence indicates pathogen concentrations in surface waters. E. coli is present in the intestines of all warm-blooded mammals and can survive and reproduce outside of the body. Untreated sewage, combined sewer overflows, polluted discharges, and animal waste all contribute E. coli to surface waters. In Indiana, concentrations measuring greater than 235 colonies/100 mL do not meet water quality standards. These sites are shown in yellow and red.
Orthophosphate: Phosphorus is typically the nutrient which limits the productivity in aquatic communities. Phosphorus can be measured in many forms including orthophosphate or soluble reactive phosphorus. This form of phosphorus is the soluble, organic, readily available form of phosphorus. Higher phosphorus concentrations typically lead to higher levels of productivity. Increased productivity can result in increased concentrations of algae or plants, which can result in decreased dissolved oxygen concentrations, taste and odor problems, and create poor habitat for aquatic communities. The field results indicate elevated orthophosphate throughout the watershed. This is likely due to recent rain events carrying sediment and nutrients, like phosphorus, into adjacent streams.
Nitrate+Nitrite: Nitrate-nitrogen and nitrite-nitrogen, like orthophosphate, represent the available nitrogen in an aquatic system. Nitrogen is also available in the atmosphere and can move from the air into the water by nitrogen-fixers. Nitrogen can readily convert between different forms, especially nitrate and nitrite. Conversion to and from ammonia also occurs when dissolved oxygen is available in the system. Nitrate and nitrite concentrations are displayed below with red representing higher concentrations. Nitrate-nitrogen concentrations measuring higher than 2 ppm can inhibit aquatic communities. Concentrations higher than 10 ppm violate the state water quality standards. Levels of nitrite+nitrate are higher throughout the watershed.
pH: pH is a measure of the amount of hydrogen ion available in the water. Water pH determines the solubility and biological availability of chemicals, including nutrients such as nitrogen and phosphorus, and metals, like copper or lead. Typical pH levels in streams measure between 6.5 and 8.5. pH levels are indicative of the geological materials in the drainage area. Additionally, the amount of photosynthesis occurring in the stream can affect pH levels. In our watershed we had ideal pH levels at all of our monitoring sites.