All invited to help identify the macroinvertebrates gleaned during the Oct. 3 “River Roundup” (see listing). Each child must be accompanied by an adult. 11 a.m.-1 p.m. & 1-3 p.m. (choose one session), 117 N. 1st St., Ste. 100. Free. Preregistration required at hrwc.org/volunteer/id-day/. [email protected]; 769-5123.