The Fishers Health Department has issued a public health advisory after recent testing turned up unsatisfactory E. coli levels at Geist Waterfront Park.
The park was the only location flagged in the results released today. The health department said elevated readings like these frequently follow periods of heavy rainfall, when stormwater carries bacteria from urban and agricultural sources into the watershed.
Fishers sits in the Upper White River Watershed and takes in runoff from both developed neighborhoods and farm ground upstream — a combination the health department has repeatedly pointed to as the reason Geist and White River sampling sites see recurring hits.
What the advisory means for swimmers
E. coli is used as an indicator organism: its presence suggests other disease-causing organisms may be in the water. Swimming or wading in water with elevated levels can lead to gastrointestinal illness, along with skin, ear and eye infections.
In past instances of unsatisfactory results at Geist Waterfront Park, the beach has been closed to swimming until follow-up samples came back clean. Visitors planning a trip should check current beach status with Fishers Parks before heading out, and avoid swallowing water or entering with open cuts.
How the testing program works
The Fishers Health and Water Quality programs sample 40 creek and open water locations across the city. Results for nine of those areas are published monthly during the spring, summer and fall.
Beyond bacteria counts, crews track two other measures that shape water quality:
Water temperature. Bacteria multiply faster in warmer water, and aquatic organisms are more active. When higher temperatures combine with sediment from agricultural waste or leaking septic systems during a rain event, pathogenic bacteria such as E. coli can spike.
Dissolved oxygen. Oxygen in the water column is essential for aquatic life. When large algal blooms or other organic material decompose, microorganisms consume the available oxygen — sometimes leaving low-oxygen (hypoxic) or oxygen-free (anoxic) conditions, particularly near the bottom. Sensitive fish and invertebrates may move away, decline in health or die off. Moving water such as streams generally holds more dissolved oxygen than a lake or pond, and levels naturally rise and fall by season and even by time of day.