Page 116 - Water Loss Control

98 Cha pte r Ei g h t

8.2.5 Time Periods

• Milliseconds (used for surge analysis and leak noise correlation)
• Seconds
• Minutes
• Hours
• Days
• Months
• Years
So, as we can see there are many options for recording all of our varying parame-
ters. It is important to use parameters and units, which are both meaningful to the
country or area in which we are working, and also units, which are easily interchange-
able. So, for example, we wouldn’t want to mix cubic meters per hour of flow with
pounds per square inch of pressure. We might however use either pounds per square
inch of pressure with gallons per minute of flow or cubic meters per hour of flow with
meters head of water pressure.

8.2.6 Balancing Flows
When undertaking audits, which involve dynamic flows and not just volumes, it is
important to balance our flow inputs. To do this, we usually select a unit of flow,
for example, cubic meters per hour.
We will then identify key points within a 24-hour
Top down annual audits use profile, usually minimum night flows if we are trying
to identify leakage. The balance is a simple matter of
volumes; bottom up audits
adding and/or subtracting individual zone flows,
often use night flows.
(these might be metered areas or pressure zones) and
comparing them with supply meter or production
metered flows to ensure that we have all of the inflows and outflows for the system in
question accounted for. (Take care if storage is located inside of the areas we are trying to
balance as filling volumes will confuse the issue).
In situations where the system is not zoned in any way at all and is not intended to
be for the future, the key points within the flow balance would be

• Production meters
• Import meters or bulk supply meters
• Outlets from storage (tanks, reservoirs, and towers)
• Outlet from pumps or wells

This may seem like a relatively simple procedure but can take many hours of careful
analysis especially in large systems.
It is particularly important to properly define one unit of measure before attempt-
ing this exercise, otherwise the difference in one working unit and another could be
confused for a missing inlet or outlet and create a lot of unnecessary work load, which
in turn would create unnecessary cost.