Looking for a hands-on local creek water quality project for high school

[Avery18]

I'm a high school science teacher trying to design a new, engaging unit on environmental science for my 10th graders. I want them to do a hands-on experiment that measures something real in our local community, like water quality in a nearby creek or soil pH in different parts of the school grounds. The challenge is finding a protocol that's robust enough to yield meaningful data with basic lab equipment, but also safe and manageable within a standard 50-minute class period over a couple of weeks. Does anyone have a tried-and-true high school science experiments for local environmental monitoring that worked well for student groups?