SPILL/BLTM: Main Scenario Editor
The main scenario display and editor consistes of
- A button menu
- A header with scenario meta data
- Four panels with the different input fields.
The button menu
Under the close and help buttons,
the second row of the button menu contains from left to right:
||runs the current scenario and shows the results
||invokes the scenario consistency, completeness and plausibility checker
||copies the current scenario as the basis for editing a new one
||deletes the current cenario (note: only the owner can delete a scenario)
||saves (commits) the current scenario and any changes to the data base
The scenario header shows some basic descriptive and meta data, namely:
- The name of the scenario;
- A short description in the text field under the name;
- The owner or author of the scenario;
- The last modification date;
- The name of the WRM model scenario this scenario is based on;
- The name of the start node for the spill;
- The location of the scenario (derived from the WRM scenario location).
There are four panels or sub-windows for the main input data:
- Upper left: Basic scenario parameters;
- Upper right: Hydrology (flow);
- Lower left: Spill or pollution load;
- Lower right: River geometry (cross-sections).
Basic scenario Parameters
- Segment length: defines the model area of interest downstream of the source, in km.
- Number of gridpoints: longitudinal discretization or resolution,
anything between 20 and 200 will look and perform resonably well.
- Duration of the simulation, in hours (currently restricted to 48 hours to guarantee
matching time series of flow data);
- Timestep for the presentation of results, in minutes.
- Water qualitry standard (for the assessment of results);
- Longitudinal dispersion coefficient:
Mixing occurs along the length of the river due to the horizontal and vertical
gradients of velocity. In addition, irregularities of natural channels
The phenomenon is called longitudinal dispersion.
The mass balance equation for constant cross-section area, river flow,
dispersion, and no other inputs of S expect at the outfall is:
where x and t are distance and time,
U is the stream velocity, S the substance concentration,
K a decay constant, and Ex is the longitudinal dispersion coefficient.
- Pollutant substance (selected from the Aquatic Pollutants data base).
Hydrology (river flow)
The hydrology of the scenario is defined as a flow in m³/s.
The user can select a flow pattern in terms of:
- a time series of flow values (48 hourly data points).
- a multiplier (applied to each value).
The river geomatry is defined in terms of:
For these cross sections, a specialised geometry editor is provided.
- The overall length of the segment;
- A set of trapezoidal cross sections.
The spill itself is defined in terms of the totasl mass spilled, and its distribution over time.
Again, a dedicated editor for the spill pattern is available triggered
from the EDIT button in the correponding display panel (lower left corner) of the scenario screen.