What I do could be easily adapted to any environment. I am currently using the ASDXAVX001PGAA5.ASDXAVX001PGAA5. Honeywell 0-1psi sensor but will be evaluating the HSCDLNN160MGAA5 sensor as I need to measure deeper water than 27". My system uses a Drop tube that sits one inch from the bottom of a tank, it then pumps air into the tube pushing all the water out of the tube. the sensor then measures the pressure built up when the water returns in to the tube. If you can find sensors that can be submersible, they could just sit on the bottom or at the end of rope tied to a buoy and measure the weight of the water. For wells, a drop tube could work just as easy. some of the Honeywell sensors are designed for water, so you would just need to encapsulate the electronics.
I don't think that the Atmospheric pressure is going to have much of a affect on the water pressure, so not sure why you would need to compensate. but if you did, a second atmospheric sensor could give you the differance for a referance and honeywell also makes these in Diff if you prefer. They also come in I2C, and SPI interface.
Not sure if this is relevent, but I messure water depth with simple pressure sensors, and can get really accurate to within a 1/4". Basically, 27.6807" of water = 1psi. For well water, this might be fairly simple, but for a pond or river you will need to keep the sensor from getting covered, clogged or sweped away.
Hey Terry - but how can I entice you both to stop lounging around in the Mediterranean and come to NY? I'm still trying to figure out how to get the MODBUS RS-488 outputs from my Power Logic Monitors accessible via a browser on the net. I have been working with some guys at SUNY Orange but so far just learned about all the underlying complexities and flavors of MODBUS. I do have ethernet in the power house 1500 feet away in a hole w no radio reception. Used a couple of XE104 power-line modems for $99 where the fiber optic solution would be more than 10X that. That's the kind of solution I like. I wrote up the whole thing somewhere on my blog under 'long distance ethernet'.
I wanted to ask your opinion of Low Energy Nuclear Reaction (LENR). Ever since NASA has endorsed it I've been very excited about it but I still would like to see and feel it before making any commitments. So much going on in the LENR - Cold fusion world including Rossi's Ecat and Hyperion. Just Google LENR and NASA or SPAWAR or DIA or CERN. All big names are trying to capture a piece of the current action while at the same time distancing themselves from their previous denials of cold fusion, thus the name change.
This Summer we have to design and build an Arduino-based version of this! People are also looking for an easy to use accurate well water depth and pond depth system.. Solar/wireless is where to go for this kind of stuff.