EFFINGHAM — Green Mountain Conservation Group and New Hampshire Rivers Council will hold a free invasive aquatic plants workshop Monday July 9, from 10 a.m. to 2 p.m. at the organization’s office located at 196 Huntress Bridge Road in Effingham. The workshop includes training on the identification of invasive aquatic plants, and the techniques and tools for monitoring them. The workshop is intended to train volunteers to integrate with the New Hampshire Rivers Council’s River Runners program. The program has monitored hundreds of sites on rivers in the state. The newly introduced invasive algae, Didymosphenia geminata, also known as Rock Snot has been a focus of the program, as well as other submerged invasive plants such as variable milfoil. Volunteers are asked to select a site to monitor and report on at least once sometime between June and October.