How to monitor the specific position of 10 km long rice irrigation pipe?

A water pressure detection device (serial number) is installed at intervals, and the water pressure signal is sent to the monitoring center by radio, and the monitoring center can judge according to the received water pressure signal. (hint: the equipment is simple, but it is more troublesome to go through some formalities in the local radio department. In China, there is a short radio frequency that anyone can use, but the power is limited. Even if the monitoring center is located in the middle, it may not be able to transmit signals, and the signals are even worse in rainy days. It's time for the radio management department to take a walk