Direct Rainfall (Rain on Grid) Modelling Guidance: Difference between revisions

:::* Exclude buildings from the rainfall polygon and represent the rainfall that would be falling on the building using <font color="blue"><tt>Read GIS SA RF</tt></font> inflow boundaries. To do this, digitise a 2d_sa_rf polygon for each building (with a buffer of one of more 2D cells) where the building footprint has been excluded from the direct rainfall region. The 2d_sa_rf input will convert the input rainfall hyetograph to flow, deposited initially on the lowest 2D cell, then for subsequent timesteps distributed over all wet cells, within the 2d_sa_rf regions (ie. on the ground surrounding the building). Refer to TUFLOW <u>[[TUFLOW_Example_Models#Boundary_Condition_Options | Example model EG03_005.tcf]]</u> for a demonstration of this inflow boundary condition option.

:::* Exclude buildings from the rainfall polygon and represent the rainfall that would fall on the building using <font color="blue"><tt>Read GIS SA RF PITS</tt></font> inflow boundaries. This approach is similar to the previous method, although instead of directing the inflow to the ground surrounding the building, it is directed into the sub-surface drainage (underground pipe) system. To implement this approach every 2d_sa_rf polygon must encompass at least one 1D pit. If multiple 1D pits are within a single 2d_rf_sa region, the flow from the polygon is split equally between the 1D pits. The pits can be snapped to a 1D node, connected via the pit-search distance or via an x-connector, to allow captured by the pit to enter a 1D representation of the sub-surface drainage system.

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