Watershed Based Plan - Identify and Prioritize Resource Issues

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5. Identify and Prioritize Resource Issues

Oak Creek has been designated a “Unique Water” designation due to the diversity and high demand on its uses. Unfortunately, this valuable Arizona resource has experienced occasional deteriorization in water quality, which violates the high standards set for by its unique water classification in Oak Creek Canyon.

Many people have studied the incidents of high bacterial counts. The Impact of Sediment Fecal Coliform Reservoirs on Seasonal Water Quality in Oak Creek, Arizona (Water Resources, vol 35, 1999)(Crabill, et al) reports on the data collected weekly between 1994 and 1996 with the Oak Creek National Monitoring Program. This work reports on both fecal coliform counts in the water column as well as in the sediment. Two distinct major reservoirs of fecal pollution within Oak Creek Canyon were identified in the study. The first area is at the uppermost sampling point (above Pine Flats and the Slide Rock area). Moreover, the report demonstrates that water quality can become impaired without the presence of recreational users. Deterioration of water quality was observed to occur during or shortly after storm events when recreational users were not present.

Dr. Gordan Southam conducted further water quality research during 1998 and 1999 to examine the genetic composition of Escherichia Coli bacteria (The Oak Creek Canyon Escherichia coli Genotyping Project, November 2000). The project revealed high temporal and spatial variability in the sources of E. coli from the water and sediment, which demonstrates that the fecal pollution comes from multiple sources. The fecal
pollution in Oak Creek is not a re-growth phenomenon. Moreover, most of the fecal pollution comes from the natural animal populations in the canyon with sporadic and seasonal impacts from human, dog, cattle, horse and llama sources. Single fecal release events, based on the E. coli diversity index comparable to an individual animal suggest that a single animal can cause a direct impact to the sediment and water pollution.

Nonpoint sources of pollution contribute significantly to the fecal coliform levels in Oak Creek. Strategies should be developed to address nonpoint sources of animal fecal material transport. During recent interviews with campground hosts at Banjo Bill, Cave Springs, and Pine Flats campgrounds, the camp hosts revealed that a number of skunks, raccoons, and foxes live in or around the campgrounds. Certain animal populations will increase in close proximity to human activities.

Animals kept by humans (horses, cows, llamas, dogs, etc) need to be located within the watershed and strategies developed to reduce the nonpoint transmission of fecal coliform.

Stormwater runoff, especially during the summer months, increases the fecal coliform pollution in the water column and the sediment. The Slide Rock State Park E. coli sampling data clearly demonstrates the increases in fecal coliform during rainfall events.

Point source discharges containing E. coli have not been identified in Oak Creek Canyon. Further investigation is needed to document actual sources of wastewater discharges from existing properties. The Slide Rock State Park daily water quality testing over the last several years has revealed random occurrences of high E. coli counts during periods of no rainfall. The occurrences are not repeated on a weekly basis or during high volume usage at Slide Rock State Park. The high E. coli incidents, during non-rainfall periods, demonstrate a possible point source contributor. Further water quality testing over a period of more than once daily is needed to further evaluate the spatial relationships of E. coli dispersal above Slide Rock State Park.

Used diapers along Oak Creek are a documented problem. Efforts should be undertaken to identify the quantity and location of the diaper issue in combination with enhanced trash removal activities along Oak Creek.