Great Bend Region Spring 2010 Sample Results

Volunteers sampled 206 stream sites on Friday, April 9th between 3 and 5 p.m.  Results of their efforts are presented below.

Temperature - Samplers measured temperature in the field directly from the stream at the time of sample collection. Temperature is an important parameter as it is the regulator for aquatic communities - all plankton, bug, and fish species have a preferred temperature. Temperature also controls the amount of dissolved oxygen present in the water - cooler temperature waters hold more dissolved oxygen. Finally, temperature controls the rate at which chemical reactions occur, such as the conversion of nitrate-nitrogen to ammonia-nitrogen. Higher temperatures are shown in darker colors. Several factors affect temperature including riparian buffers or shading, watershed inputs, and surrounding land uses. Temperatures typically measured lower during the Spring 2010 sampling than those measured during the Fall 2009 sampling event. Highest temperatures were measured in the Wabash River and other large streams.

pH - Samplers measured pH from water samples at the staging location. Water 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. Higher pH levels are shown in darker colors, while lower pH levels are displayed in lighter colors. Further observation is necessary in those tributaries where low pH levels were measured.

Orthophoshate - 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. These increases 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. Concentrations of orthophosphate measuring higher than 0.05 ppm are of concern. Subwatersheds where concentrations measure higher than 0.05 ppm will be further reviewed to identify potential nutrient sources in these locations.

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 darker colors 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. Nitrate concentrations measured much higher during the Spring 2010 sampling than those measured during the Fall 2009 sampling event.

Alkalinity - Samplers measured alkalinity from water samples at the staging location. Alkalinity and hardness also reflect the geological materials present in the drainage area. Alkalinity is a measurement of the base concentration in water. Nitrates, dissolved ammonia, orthophosphate, silicate, and hydroxides all generate higher alkalinity concentrations. As with pH, darker colors indicate higher alkalinity concentrations, while lighter colors reflect lower alkalinity concentrations. It should be noted that the preponderance of dark (>250 ppm) subwatersheds suggests that the test strips used did not have a high enough detection value.

Hardness - Samplers measured hardness from water samples at the staging location. Hardness is a measure of the mineral content including calcium and magnesium present in surface water. Hardness measurements less than 200 represent slightly hard water, while hardness measuring higher than 300 is considered hard water. Like alkalinity measurements, the predominance of dark subwatersheds suggests that the test strips did not contain a high enough detection level to correctly measure hardness in our watershed.

E. coli - E. coli is an indicator organism used to monitor pathogen concentrations with 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, input from animals, and source populations can all contribute E. coli to surface waters. In Indiana, concentrations measuring greater than 235 colonies/100 mL are deemed non-supporting of their designated use. Those watersheds which do not meet water quality standards are shown in darker colors.

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