# 1.4 Introduce the properties of junctions (demand nodes)

For junction nodes it is necessary to define the base demand and elevation. The following table summarizes the property values to be used for each of the junction nodes.

 Node ID Elevation (m) Base Demand (l/s) Junc 2 320.04 12.62 Junc 3 315.14 12.62 Junc 4 332.23 0 Junc 6 298.7 18.93 Junc 7 295.66 18.93 Junc 8 292.61 18.93 Junc 9 289.56 12.62 Junc 10 289.56 18.93 Junc 11 292.61 18.93 Junc 12 289.56 12.62

The elevation of junctions corresponds to their Z coordinates. The base demand is understood as the average water demand at a junction. Water demands are variable  during the day. As an example the activity of users is expected to be high at 19:00 ( washing, cooking, etc.) and therefore the demand is presumed to be much higher than at 23:00. In a hydraulic model these variations have to be considered. The standard way to take  them into account  is to determine a base demand (an average demand value) and a demand pattern, which is a set of multipliers (one for each hour or each time step considered in the simulations). Meaning the base demand of a node by a  multiplier in the model corresponds to a time of day 17:00 for instance. In order to estimate  the water demand at that node at 17:00. You should also know that a model could have several demand patterns, clients and/or users with similar characteristics and/or behaviors and therefore with  a comparable demand pattern. A pattern could be created for each client of the network. However  in practice it is not feasible unless a high automation level of the process is reached.

To set the properties of demand nodes the same procedures can be applied  as previously described for pipes, tanks and reservoirs. Double click on the element in  the drawing space or on the data browser window to access the property grid (see figure below). Then proceed to update the property values of demand nodes using data from  the table above. EN EN ES PT DE PL