Water Resources Model: a tutorial introduction This tutorial should help a novice user to build a WRM application using the on-line tools of the web version. For more details on the components that make up a WaterWare system,   see the on-line User and Reference Manual

Preparatory steps
Initial steps involve

1. Defining the spatial and temporal scope:
   • get a large enough map of the river basin to be modelled,
   • define the watershed boundaries; please note: WRM operates on arbitrary NETWORKS of hydraulically connected elements that may span more than one hydrographic basin (interbasin reansfers) !
   • select a reference year (not necessarily starting with January, but the water year for the basin; make sure this is a year with reasonably complete data such as precipitation and flow observations, and good data or estimates for the water demans of the main consumers.
2. Preparing data on the main components:
   based on spatial and temporal choices,
   • draw a list of the main components (try to adopt the structure defined by the River Basin Object data base that should eventually hold the underlying basin description),
   • their connectivity (how does water get from one to the other ?
   • draw a diagrammatic representation of the network with the major nodes and their connectivity);
   • compile and preapre the basic data describing each of the components over the year chosen;
   • preapre and import the various time series neeed for the individual nodes;
   • define the uderlying aquifer(s) and decide which nodes need to interact with the groundwater.

With the editing tools, the individual structural components (nodes and associated time series, reaches, and aquifers) can now be prepared.

Step by step
A good approach is to to

• First just select and roughly define the major NODES, one by one, (always followed by the definition of the connecting reach) - keep in mind: a well formed network must have a least one START node and at least one END node, - and make sure to use the right node type for diversions and confluences with only two outflow and inflow branches, respectively - give the nodes meaningful names that suggest their function and position, and a basic description, that will make clear what they represent and which assumptions have been made;
• Define connecting reaches for each new (set of) node(s), and view the resulting graph: does it make sense, is it complete ?
• Refine the individual node definitions by specifying all necessary data and the various time series.
• Use the consistency checker to keep track of missing data, or consistency and plausibility problems.

• Build your scenario step by step, test repeatdly; if you test each step, it is relatively easy to identify problems: if the previous version tested ok, it is the latest change .....
• Once the network is more complex, you may wish to keep and re-use a backup copy, by saving the modifications to alternating names like scenario-name and scenario-name.last so you can always revert to the previous, working version if things go wrong.

There are, other than the network that distributes the water, only a few principal node CLASSES that are important:

1. INPUT nodes, where water enters the "system"; please note that for combined surface-groundwater systems, several nodes just move water between the two domains, i.e., Start nodes (generic, pring, well) and Recharge nodes.
2. DEMAND nodes, that consume water, or at least take water from either surface of groundwater sources; here it is important to discriminate between extractions and consumptive use, only the latter affecting the water budget, while the former have to be satisfied to make the latter possible !
3. RESERVOIRS that store and re-distribute water somewhat independent from the natural flow regime; in that, they are similar to the aquifers, but with very different scales and dynamics.
4. Underlying the network of nodes and reaches are one or more (optional) aquifers for a more complete water budget and the explicit description of conjunctive use, including estimates of aquifer yield and sustainable use patterns.

Please note that in addition to flow (demands, release targets, etc.) the model also uses time series of temperature and precipitation.

The time series are stored and managed in a data base, and can be selected through the node editor. To import a time series , a new tool to support import to the data base on-line is available.

The basic structure and format of model time series is described in the corresponding Reference Manual pages.

The time series data basically consists, for every day of the simulation year, of tuples of the form: TIMESTAMP VALUE and can easily becompiled in a spreadsheet and exported as a csv type file.

Networks and Connectivty
A well-formed network connects all nodes with the required number of reaches. A minimal but trivial network consistes of a START node and one END node. It does nothing but route its inflow to its outflow.

In a realistic network, flows from more than one input node are allocated to seveal DEMAND nodes, with the water allocated to demand node according to a range of possible strategies defined for the diversion nodes, that control these allocations.

The reach or network editor helps to configure well formed networks.

The consistency checker checks a scenario and reports a range of error conditions detected.