We have fielded a lot of questions in the past few weeks about water flows and water temperatures in the South Yuba. In particular, people are asking questions like: How do flows compare to years prior? Are temperatures higher than normal?
Flows on the 4th of July were the 4th lowest at Jones Bar in the past 63 years. The graph below shows data collected on Independence Day since 1959.
According to our water quality monitoring data, which goes back to 2000, water temperatures at many of our favorite river crossings—Lang’s, Edwards, Purdon, Highway 49, and Bridgeport—are about average for this time of year. Our highest June recorded water temperature at these crossings was 26.43 degrees Celsius back on June 8th of 2013.
At these temperatures, we do see algae growing in the Yuba. Below we talk about different kinds of algae and how to identify whether or not they are harmful.
How to Distinguish Good Algae from Bad Algae
Luckily, there are 2 simple tricks to help distinguish the good algae from the bad: The Stick and Jar Tests. Note that while these tests do give a good indication of the type of algae in the water, they are not 100% perfect. We encourage anyone who comes in contact with HABs to call your doctor.
NOTE: We would like to remind the public that healthy algae is important to the ecosystems of the Yuba River watershed. We encourage visitors to protect the environment and take care to not interfere with “good” algae.
The Stick Test
STEP 1: Locate the algae built-up in the river. Is it floating on the surface? If so, grab a sturdy stick, throw some gloves on, thrust the stick into the surface mat of the algae, and slowly pull some out of the water (make sure that it does not come in contact with your skin). Next, observe the algae that you pulled out of the water.
STEP 2: If the algae pulls apart like hair or is filamentous, it is most likely a non-toxic algal bloom. On the other hand, if the stick comes out of the water like it has been thrust into a can of paint, the algae is likely to be a form of toxic, blue-green algae (Photo 2).
The Jar Test
STEP 1: For this test you will need a clear mason jar with a lid and a plastic bag. First, observe the algal mat and collect a sample of water just below the surface of the river. Make sure NOT to sample at the surface to avoid scum. Fill the jar 3/4 of the way full, screw the lid on the jar, place the jar in a plastic bag and refrigerate overnight.