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.
Agricultural Runoff Model parameters: Flow routing: 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 | Dimensionless | 0.5 | 0 | 1 |