Measure stream discharge and stage levels with this monitoring set up, centered around VanEssens TD-Diver.
USGS employs hundreds of gauges (gages) across the country. The basic principle is to install a measuring device that can read water levels, then build a rating curve to convert those water levels to stream flow (cubic feet per second). There are a number of varying devices to do that, ranging from a PVC pipe with cork bits to measure the maximum stage (but obviously not continuous water levels), to pressure transducers that measure water height based on water pressure readings, to stilling wells that provide the most accurate stage measurements of a river by eliminating turbulence and wind errors
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Some good addiitonal research/resources:
Lets explore a mid range option. This will utilize a pressure sensor from VanEssen, the TD-Diver (spec-sheet here). The all in cost including miscellaneous materials from Home Depot is under $3,000. This set up is accurate within 0.2 inches water pressure, at whatever time interval you want. See below for a breakdown of the parts:
TD-Diver
Telemetry, Diver Link
Miscellaneous parts, antenna, cable, lithium ion batteries, optical downloader (to computer)
SIM card for cellular plan
1.5" Galvanized or PVC Pipe
Flex conduit, including transition piece
Pelican box for storing electronics (protector 1170)
Post for telemetry mount
This can provide extremely accurate, onsite water level (among other variables if desired) water level measurements. This is a great option for detailed information on a watershed, and similar devices are used by USGS at several gaging locations. The downnside to this set up is cost and time. The upside is accurate measurements from a reliable source. Another more DIY centric option would be following Brett Webb's DIY pressure gage for measuring water waves (this is designed for coastal measurements). I havent taken the time to figure out how this might be adjusted to pick up streamflow, but it seems a pretty logical leap for about a tenth of the price. Furthermore, you can always start with a stick of PVC and some cork and set up a basic stage crest gage for under $100. Just make sure to get out there and checking your modeling assumptions with real world data!
