There are various methods for doing water surveys, and the most common are as follows:
1. By Direct Observation:
If on the ground there is any soft spot or green spot in lawns or formation of springs at odd places, it is sign of leakage in underground pipe lines. At such places the ground can be excavated and the pipe joints should be inspected and repaired.
2. By Sounding Rod:
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This rod detects the leaky pipe, by emitting sound of leak. The rod is kept touching the pipe and the ear is placed on the top of rod. If there is any leakage its sound will be heard. Sounding rod is penetrated in the ground upto pipe line and the inspection is done. To magnify the hissing noise of leaks acquaphone or sonoscope can be used.
3. By Hydraulic Gradient Line:
This method is used in locating the correct position of the leak. First the hydraulic lines are drawn and these lines interect at the place of leak.
4. By Waste Water Meters:
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Generally Deacons waste water meter is used for this purpose. Fig. 19.11 illustrates the essentials of Deacons waste water meter. It consists of a disc held in balance by a counterweight and when water passes, it is forced down.
The movements of the disc are directly transferred by a system of levers to a pencil point, which moves on a graph paper mounted on drum. The drum continuously rotates in clockwise direction by a clock-wise arrangement. Thus the rate of flow of water is automatically recorded on the graph paper.
5. All unauthorized connections can be detected by thoroughly inspecting the pipelines and house connections. Unauthorized connections can also be detected by intelligence department, by investigating through persons.
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6. Leakage and carelessness in private buildings can be detected by inspecting the fittings and pipe joints. The inspection should also be done at nights to check the carelessness.