Taking the Guesswork Out of Water Leakage
Showing How Simple a Matter It Is to Detect Waste—Dispelling the Survey Bugaboo—Some Examples Cited to Show Methods Used
EXAMPLUS are always illuminative and the following experiments in the detection of water waste will be found of value to other superintendents. A checking-up of flows to discover just where the leak lies in order to repair it is of great value and should give some interesting suggestions.
The writer has been repeatedly reminded of the outstanding negligence towards the question of leakage from water works systems, and it is difficult for the wide-awake man to comprehend how any manager or superintendent can lie asleep at the switch while the water runs away.
It is true that the flat rate method of water service is conducive to this condition where the water works man can be blissfully ignorant as to whether the loss is due to leakage or the wasteful running of water on the premises of the individual consumers. If the ‘system be metered and there is a wide divergence between the total pumpage and the total delivery through the meters, the superintendent cannot then well wink at the unaccounted for water, and it behooves him to locate and curtail the losses.
In the case of either the flat rate system or the fully metered system; however, probably a part of the reason for this comatose condition with respect to leakage and losses is partly due to the general idea that the activities necessary for discovering and curtailing leaks must be so extensive that the results are not worth the effort, and the attempt of this short discussion will be to show the simplicity of the work involved in discovering leaks of any magnitude, with only a small amount of work.
We have found that a combination of the Pitometer and Geophone can produce most surprising results in finding leaks when in the hands of an experienced man, and the writer would feel that he had done a great service towards the progress of economy, if the bugaboo about Pitometer surveys could be dispelled. There is many a water works system where the serious leaks can be discovered in one or two nights’ work with the pitometer, and even the larger systems require only a correspondingly short period of time to eliminate the major troubles.
Our experience at Piedmont might be used to illustrate the principle of the most simple case which may be described, where the supply line is shown coming from the gravity source to the city reservoir, there being very few services on the supply line previous to its entrance to the reservoir; the service of the Pulp and Paper Company being the only one here shown.
For some years the paper company has been looked upon as the culprit which was stealing water from the city’s supply lines and at some times the feeling was very bitter against them. Our suggestion that “the Pitometer would produce the evidence,” brought forth the response that they were positive there were no leaks in the line because they had carefully watched that feature and, from experience, they had found that the leaks always readily came to the surface, anyway. The approximate location of valves are shown at A, B, C, D, E and F and the Pitometer setup shown at G, where it was determined that practically the full supply was passing that point. (See Plate No. 1).
After the Pitometer was in place and ready for operation, the valves were closed in succession from A to F at time of low flow in the night. No reduction in the flow passing the Pitometer at G was noted until after valve F had been closed which means that the leakage was between E and F, and by the process of a few setups, with the Pitometer run from F towards E, together with the use of a Geophone, we finally located the leak which was creating all the trouble and which was running into the river below the ordinary flow line in such a way that it had never been detected all these years.
Our experience at Patton may be used to demonstrate the more complicated case, and this would apply to any size of system by the process of breaking that system up into parts. The distribution system for Patton is shown on Plate No. 2.
Valves had been closed in certain parts of the system in such a way that valves A, B, C, D, E, F and G would serve as controlling points and with the Pitometer at X, valves A, B, C and D were closed at the time of low flow in the night and no reduction of flow passing the Pitometer was indicated until the valve D was closed, which meant that the leak was between C and D and was later definitely located by means of a Geophone and again when valve E was closed a second reduction was noted. The Pitometer was then set up at Y and the three valves at F were closed with no reduction in flow, but on closing G, a decided decrease was observed, indicating that the leak was between F and G, which was also located by the Geophone, in each case the leak flowing away underground unobserved. (See Plate No. 3).
The process as described for Patton required only a few minutes for each operation of closing a series of valves and then opening them in the reverse order as a means of using the increases in flow as a check on the original decreases in flow during the operation of closing the valves.
Several examples like this could be cited where only two or three nights have been consumed in finding the serious leaks and the superintendents of some of these plants now swear by the Geophone and refuse to be without one, such as at Etna, Edgeworth and West Newton, Pa. Our survey at Etna, Pa., of about three nights’ work, discovered two or three major leaks which reduced the electric pumping bill from about $500 to $350 per month.