I'm looking to conduct water level monitoring in streams and rivers for water resource engineering purposes. My plan is to use Arduinos and Raspberry Pis in conjunction with a pressure transducer, as Pis and Arduinos work with the telemetry system and water quality sensors that I have chosen for the project.
However, the standards in British Columbia, Canada (where I work) require that the sensor must have a 2 mm accuracy to collect "Grade A" data. Grade B data requires 5 mm accuracy, and as it turns out a pressure transducer with these accuracies are hard to find unless you spend >$500 per pressure transducer.
Does anyone know if a low cost ($300 max, but preferably $50 to $150) pressure transducer designed for measuring water with 2 mm or 5 mm accuracy exist? I'm also open to other technologies as well.
Page 4 in the attached in BC's standards doccument is attached if anyone is interested in checking it out.