WREC

Great Bend Region Fall 2015 Sample Results

Volunteers sampled 169 stream sites on Friday,  September 11 between 2 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 water temperatures 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 red and cooler temperatures are shown in blue. Several factors affect temperature including riparian buffers or shading, watershed inputs, and surrounding land uses. Compared to Fall  2014, water samples throughout the watershed were on average several degrees warmer, possibly due to the hotter and drier late summer months in 2015.


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 red, while lower pH levels are displayed in yellow and ideal pH levels are shown in green. Compared to Fall 2014, pH levels have remained fairly stable throughout most of the watershed, with some improvement in the eastern and western sections as well as higher than ideal pH levels in two northern sections.

 

 

Transparency - Samplers measured water transparency using transparency tubes. Water transparency in streams reflects the distance downstream that you can see through the water. Tubes measured 114 centimeters, so any values greater than 114 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. Compared to Fall 2014, transparency in the subwatersheds has improved in the north, but decreased in the south.

 

 

 


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. These results are from laboratory measurements made on water collected by volunteers from the subwatersheds, and is more accurate than the test strips that were used in the field. Lab measurements of orthophosphate are slightly higher in several subwatersheds compared to Fall 2014 results, but overall are good for the watershed.


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 slightly lower in the northern half of the watershed compared to Fall 2014 results.

 


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 red. Compared to Fall 2014, E. coli concentrations have increased across the watershed.

 

 


Ammonia - Ammonia is present in streams as a dissolved form of nitrogen that is readily available for use by algae. At a high temperature and pH, higher concentrations of ammonia are present and can become toxic to stream biota. Similar to nitrogen and phosphorus, excessive amounts of ammonia can cause algae blooms and eventually deplete the water’s dissolved oxygen content causing hypoxia. Sources of ammonia in streams can be attributed to a variety of inputs, including: fertilizers, mammal waste, and industrial manufacturing runoff. Ammonia is not a nutrient that can easily be tested for in the field, so ammonia testing is done at the water quality lab. Compared to Fall 2014, ammonia levels are higher across the watershed, and are possibly connected with the increased water temperatures and pH observed this season.