WRM web version, node type: Start Node
A WRM scenario can include any number of start nodes.
A start node is characterised by a time series of flow data, and a flow multiplier
for easy scaling of the input data.
Start Node Types, subclasses:
The following start node types are supported; they have the same basic structure,
but represent different sources of water
(treated separately in the groundwater mass budget, for example)
and with different data requirements for any cost-benefit analysis (not yet implemented).
- Generic: can represent any type of water input, natural flow (a spring),
pumped (groundwater wells), or piped or by channel (interbasin transfer),
depending on which data are supplied;
- Well: representing pumped flow from groundwater;
with a cost structure depending on groundwater head, should be
coupled to an aquifer;
- Spring also from groundwater (should be coupled to an aquifer) but without
pumping, thus a different economic evaluation;
- Subcatchment:representing inflow from a sub-catchment, can be estimated with the
RRM rainfall-runoff model;
structurally equivalent to inter basin transfer.
- Transfer: representing inter-basin transfers.
- Desalination: for coastal location, seawater de-salination is also an option.
- Water harvesting: describes water harvesting schemes; they are characterised by
Flow from a water harvesting node is calculate from the rainfall (in mm)
on the coollection area, corrected by the efficiency.
- an effective collection area,
- an efficiency % of precipitation collection,
- a precipitation time series and multiplier
||one of: generic, well, spring, catchment, transfer, desalination
||META data block, consisting of author, ctreation and modification dates,
free text description
||optional link to a river basin OBJECT
||optional link to an Aquifer (for sub-types well and spring)
||time series of flow linked from the model TS data base;
||scales the time series data, provides the possibility to convert data sets
of different units to a common unit (m³/s for flow).
|Economic (cost) data:
- annualized investment costs;
- fixed operating costs (annual);
- variable, OM costs, proportional to the flow.
Dynamic output time series:
A StartNode generates no output other than mirroring its input (flow).
Reports and Statistics:
Statistics of a single flow time series; average, min, max, (SD., % of TOTAL inflow)
- To account for the cost of pumping (start,GWater), a unit cost
per m3 pumped should be added to the node data structure as a
first simplified representation. More exact estimates depending on the groundwater table (head)
require the use of a simple groundwater accounting and local geological and well data also.
- Start node types spring and pumped well should be coupled to
- For pumped wells, a local analytical model of draw-down would
make it possible to monitor wells falling dry; would require aquifer parameters
of conductivity anmd storativity, and additional well data (depth).