Introducing demand

Step-by-step Guide

When using InfoWorks WS Pro, it is important to understand how this software accounts for the demand on water networks. Demand, which can vary over time, is the water that is required by users at a given point within the network.

Water transfers can be considered a positive or negative demand on the network, depending on if the water is entering the network (negative demand) or leaving it (positive demand).

In reality, a network will also experience some degree of leakage. This leakage can be represented in InfoWorks WS Pro.

The general principles of allocating demand in a network can vary, but a typical process involves:

1. Identify the various types of customers in the network.
2. Use the 24-hour flow profile or daily usage pattern to determine how to allocate water.
3. Identify leakage using the minimum nightly flow with the assumption that the water leaving the system at this time is being lost to leakage rather than consumed by a user.
4. Subtract any known legitimate use flows from the remaining flow to find the domestic demand profile.

Demand almost always varies over the course of a day, and can be modelled using demand categories or transfer nodes. Leakage can be constant or vary over the day.

Factored demand is the most common demand type.

Direct demand is used for monitored customers, generally large consumers. The volume of water used over time is already known, so this demand type is simply applied to a node. Direct demand can be scaled if necessary.

Transfer nodes are used to model transfers of water into or out of a network.

InfoWorks WS Pro uniquely supports Customer Points.