Add Inflows¶
Watch this step (8:05) in the overview video.
An Inflow puts water into the domain at a place, as a flow rate in cubic metres per second. It is drawn as a line, so it works for a channel entering the study area, a pipe outfall, or an upstream catchment you are not modelling.
Inflow or rainfall?
An Inflow carries flow (m3/s) and consumes a hydrograph. Rainfall covers an area (mm/hr) and consumes a design storm. Feeding a rainfall series into an Inflow is a units error, and Hydrata keeps the two pickers separate so it is hard to make.
Draw an inflow location¶
- Open the Inputs panel from the left toolbar and find the Inflows section
- Click the pencil icon
on the Inflows layer's row to open the editor - The editor lists the locations already in this Inflow, with a + Add new row underneath. Click + Add new. On an Inflow with nothing drawn yet there is no list: the pencil starts drawing straight away
- Draw the line on the map: click to add vertices, double-click to finish
- Fill in the form that opens:
| Field | What to enter |
|---|---|
| Title | A short name for this location, for example Upstream channel |
| Data | Either Constant (one flow rate in m3/s) or Hydrograph (pick a saved hydrograph) |
- Click Save
For the tutorial, the rain falls on the whole domain, so a single Constant inflow is optional. Draw one if you want to see the control: a small steady flow on the upstream end of the Msimbazi channel is a realistic addition.
One Inflow, several locations¶
The distinction the editor makes is worth learning early, because a Scenario has exactly one Inflow slot:
- + Add new inside the editor adds another location to the same Inflow. Use this for every place water enters the same model.
- The + button in the Inflows list creates a separate Inflow. A Scenario cannot combine two Inflows, so anything you put in a second Inflow is invisible to a Scenario that selected the first.
Start times have to line up
When two locations in one Inflow use hydrographs that start at different times, Hydrata warns you before the build. Runs merge series on absolute time, so the later series contributes nothing over the gap rather than failing, which is easy to miss in the results. Fix the start times rather than dismissing the warning. A series that misses the model window entirely aborts the Run instead, which is the loud version of the same mistake.
Next steps¶
Next: define rainfall, which applies the design storm over an area instead of a line.