I have got a task which involves a water pipe with a length of approximately 5 kilometers, passing through an area without electricity. There will be 20 chambers at certain intervals along the pipe, and pressure transmitters need to be installed in some of the chambers in a specific pattern to check for leaks. The chamber covers will be made of concrete with a thickness of approximately 3 inches.
Now, we want to monitor the condition of the chambers using sensors and have the information transmitted wirelessly, but we don't want to install antennas because the local community might destroy them as the pipe passes through their areas. We wish for the means of transmitting the signal to be installed inside the chambers themselves for security reasons, and it should also consume low power so that it can be powered by a battery that will last for a long time, like months.
Could you suggest devices that fits the description above..