The signs are related to bacteria levels. Every summer in the creeks, as the temperature increases and water flow decreases, we see an increase in bacteria at many of our monitoring sites. Some amount of bacteria is always present in creek water, but less water in the creek concentrates any bacteria present, and higher temperatures increase the amount of time bacteria can live in the water, and even multiply.
Our monitoring program measures water temperature, dissolved oxygen, pH, conductivity, turbidity, nutrients (nitrates and phosphates), and levels of the bacteria E. coli. E. coli is found in the feces of warm blooded animals, including humans, and is used as an indicator bacteria, meaning that it is both easy to test for and also tends to be present when other, more harmful bacteria and microorganisms are present. (Some strains of E. coli are harmful, but most are non-pathogenic and live harmlessly, in fact helpfully, in our bodies.) Sources of E. coli include animal and human waste, and tend to be more concentrated in urban areas, where we have more sewage leaks, dog parks, etc. When levels of the indicator bacteria E. coli are high it means that people, and especially small children, the elderly, and people with open wounds, should avoid contact with the water.
We test Little Deer Creek before it enters Pioneer Park, within Pioneer Park at the dog park/open field, and downstream of the park, and find that the site within the park typically has the highest E. coli concentration of all three sites. Based on this pattern, we can infer that the source of E. coli is specifically targeted to that area. Potential sources include waste from the dogs using the dog park, a septic or sewer leak specific to the park, or potentially fecal contamination from kids playing in the creek, although this would likely be a small source.
Thank you for this information. However my husband and I were really upset to see this sign much later, up stream from where we had been playing in the water with our toddler (near the horseshoe area). Please post more signs to help protect the littles and others.
Hi Colleen, I’m sorry the sign wasn’t where you were in the creek. The city is the one who can post the signs, but I will check in with my contact there to see if they can put more up in the relevant areas.
There is still only one sign posted by the city as they do not wish for this knowledge to be known or shared. That’s how Nevada City works. Sweeping something like this under the carpet is so much easier. Meanwhile children, dogs and adults continue to play in this bacteria ridden water unknowingly…until they see the “one” sign posted in the picnic area. Love how this city loves to protect their citizens much in the way they did during the pandemic. It’s all about the no-talk rule.
Hi Gail, the city has now posted many more detailed signs around the park entrances and creek area.