Water Depth and Temperature Sensor - Unidata 6542B
This analog output sensor provides accurate long-term measurements of water depth and temperature in bores, drains and rivers.
The 6542B can measure water depths of up to 20 m and comes in five standard ranges: 1, 2, 5, 10 or 20 metres of water.
It has an accuracy of better than +/-1% of full scale and water level and temperature outputs are available as two separate analogue voltage outputs for connection to a data logger.
Its rugged stainless steel casing, Delrin nose-cone, support cable and 25mm diameter make it ideal for bore monitoring.
The support cable contains a vent tube for barometric compensation and a Kevlar support member for longitudinal stability.
The 6542B measures hydrostatic pressure, from the weight of the water above it. The data recorder you connect it to outputs this as water level.
If you want to monitor more than just water level and temperature, the 6542B is a good choice, since you'd need a data logger anyway and could connect any extra sensors into it. However, if you only want to monitor water level and temperature, consider using the 8007WDP as it has an internal data logger.