Elevated levels of E. coli bacteria forced a three-day shutdown of the popular Slide Rock State Park in Oak Creek Canyon during the Fourth of July weekend.

The recreation spot on Oak Creek just north of Sedona reopened on July 8 as levels went down to what is called a “low risk” stage. A “high risk” is declared when E. coli bacteria exceeds 235 colony forming units (cfu) in at least one sample over a period of two days.

“On Saturday July 5, we had three out of our five testing sites at the Slide Rock swim area above the 235-cfu limit and therefore declared a ‘high risk’ stage alert,” said Steve Pace, the Slide Rock Park manager.

An emergency closure order was issued by Arizona State Parks and continued for July 6 and 7, as monitoring indicated that the high levels were persisting.

“Sunday, Oak Creek again had two out of five sites showing high cfu, and Monday [July 7] one sample of 10 was over the 235-cfu limit,” said Mr. Pace. “We will continue to take two samples per day at five sampling sites to monitor the water quality in the creek and inform the public about any potential risks.

“These elevated water quality readings occur only about three per cent of the time but we take action immediately,” Mr. Pace continued.

In samples taken July 8, levels dropped to about 14 cfu for the five testing sites.

Mr. Pace attributed the elevated bacteria level is to a variety of issues including heavy use of the creek on an extremely hot day.

Creek Monitored Daily

The Slide Rock park features a natural water chute along with areas for swimming and wading in the creek.

Water quality throughout the 30-mile basin of Oak Creek has been monitored for several years, and Arizona State Parks and the U.S. Forest Service have implemented “management plans” for parts of the creek where large numbers of people swim.

Arizona State Parks built a water quality monitoring station in 1995 in the middle of Oak Creek Canyon so the State Park rangers can test the water daily at the Slide Rock swim area.

“The onsite laboratory testing facility provides test results every 18 hours, which is half the time it takes to submit the samples to off-site laboratory facilities,” said Mr. Pace. “Having the test data onsite enables park management to let all of the land management agencies and local concessionaires react faster to changing water quality conditions.”

Some of the recommendations by park rangers to keep the creek clean include using only designated restroom facilities, helping control litter, keeping pets out of the swim area, not using the creek for washing or bathing and dumping RV holding tanks in proper facilities.

E-coli, which is present in all human and animal intestines, can cause abdominal cramps and moderate to severe diarrhea. It can be washed into creeks, rivers, streams, lakes, or groundwater.

Daily water quality reports for Slide Rock swim area are provided by Arizona State Parks on a water quality hotline number at (602) 542-0202. —