The DCVA ("StreamWatch") is a yearly study of water quality in the Darby Creek watershed. While it is possible to measure water quality and water pollution, the animals in the creeks have much to tell us about water quality – they spend their entire lives in the creek. In the "Streamwatch" macroinvertebrates (animals without backbones that are macro- large enough to see with the naked eye) are collected. These organisms have all been labeled as pollution tolerant, pollution sensitive, or facultative- meaning they can live in healthy or in impaired (polluted) environments. The collections are done in the spring at a variety of locations throughout the watershed. The same spots are checked every year so that we can watch the quality of the water in the creeks over time. In the autumn we identify the organisms and calculate a "biotic index" a mathematical measure of stream health based on the proportions of pollution tolerant, pollution sensitive, and facultative types of organisms at the study sites.
We welcome volunteers who wish to learn the stream side and the laboratory techniques! In addition, we are meeting with local residents, schools, scout troops, etc. to encourage the groups to adopt sections of the stream for monitoring. DCVA is also working with interested groups to provide the required training, equipment and technical support to monitor the sites.
This is a great opportunity for you to get in the creek, take samples, work with the samplers, and see what is living in Darby Creek. We take samples from five locations on Darby Creek: Bartram Park in Darby, Darby Creek Road in Havertown (downstream from the Haverford Reserve), Skunk Hollow in Radnor, the Brandywine Preserve at Waterloo Mills in Easttown, and the Swedish Cabin in Upper Darby. What a great way to meet others and learn more about Darby Creek!!
The insects and bugs we collect provide a snapshot of the health of Darby Creek. This is the ninth year of intense sample collections and identifications. From this long-term sampling, a trend of the stream health at each site has been determined. Each year we compare our findings from the water quality determinations from the previous years. It’s a way of getting the big picture from a lot of very small bugs! But getting into the stream and collecting the bugs is only part of the stream watch program.
The next step will be to identify the bugs pulled from the stream. We then can identify the level of water quality for that section of the creek. The Insect Identification Workshop will be scheduled for this coming fall. Please check the DCVA web-site for more information as we get closer to this time.
Article : 2018 Stream Watch