Infrared Testing

Infrared thermography can be used as a method of testing for leaks which do not surface. The method is quite expensive and in many cases is undertaken by flying over the areas to be tested. The method will work only if the temperature of the water escaping from the leak is different from that of the ground into which the leak is leaking. This method has been used successfully for testing transmission mains in rural areas, but would probably not be the method of choice for dense urban areas, where there would be too many confusing traces from other sources, such as sewer lines, for example. The author has also heard of some operators using this method to detect reservoir leakage.

Testing for Reservoir Leakage

Large amounts of leakage can be lost through either leakage from the structure of the reservoir or from reservoir overflow. Leakage from the structure itself is probably more common in older underground brick or block-built reservoirs which have not been lined, but leakage can occur in other forms of storage too.

A level drop test can be performed to check whether reservoir leakage is present.

The easiest way to check for leakage is to isolate the reservoir from the system by closing the inlet and outlet valves. This is usually done at night. Once the reservoir is isolated, a depth test over time can be performed either by simply measuring carefully the drop...