The Agricultural Runoff rainfall-runoff model allows the user to implement the functionality of the Irrigator Demand Model as a rainfall-runoff model at the Functional Unit level. It is used to represent cropping areas in sub-catchments which are rain-fed and not part of a command area which receives water from a dam (regulated irrigation). Return flows are added to the sub-catchment outflow, not directly to the river. Also available is the option to add flow routing to return flows, to represent the function of routing parameters in standard rainfall-runoff models.
Functional unit area should be equal to the maximum irrigated area plus any undeveloped area.
There are four model parameters which are available for calibration and are set up in the main Rainfall Runoff (RR) Model table interface.
Agricultural Runoff Model parameters: Use algorithms for Ts, Tq and SFI parameters in Ihacres
Parameter | Description | Units | Default | Min | Max |
Ts | Time constant governing the rate of recession of slow flow (Ts > Tq) | Time step | 10 | 1 | 100 |
Tq | Time constant governing the rate of recession of quick flow | Time step | 1 | 1 | 10 |
Vs | Proportion of slow flow to total flow | % | 0.5 | 0 | 1 |
| Soil Moisture Capacity | % | 0 |
Flow routing:
The model parameters Ts, Tq and Vs use the same algorithms as the Ts, Tq and SFI parameters, respectively, in the Ihacres Rainfall Runoff Model.
Beyond the parameters which are set up in the RR table, the Agricultural Rainfall-Runoff model is configured with the same options as those of the Irrigator Demand Model options. The Feature Editor column in the Rainfall Runoff Model table is used to access and configure these.
Not available or relevant at Functional Unit level:
- ordering
- account sharing
- opportunistic water
- forecasting