This is a picture of a typical data collection station. This particular station measures only the height of the water in the nearby river, providing data from which streamflow can be calculated. Measurements are logged and stored every 15 minutes, then transmitted to the GOES-9 satellite every 4 hours.
Power is provided by solar cells that charge an internal battery.
Stations can monitor a wide variety of conditions, including things like water and air temperatures, turbidity, dissolved gas content, soil moisture, wind conditions, solar radiation, seismic activity, structural stability, snow depth, or precipitation.