The inflow to a reach (Rch) from upstream (other than the first reach) is defined as the amount flowing downstream from the node (Node) immediately above the reach.
UpstreamInflowRch = DownstreamOutflowNode
The flow out of a reach into the downstream node equals the flow into the reach from upstream plus surface water and groundwater inflow to the reach minus evaporation, flooding to catchments, and groundwater outflow (inflows from surface water and groundwater are entered directly -- see Supply and Resources\River\Reaches). This downstream outflow from the reach will become the upstream inflow to the node immediately below the reach (or the outflow from the river as a whole if there are no more nodes downstream of the reach).
DownstreamOutflowRch = UpstreamInflowRch + SurfaceWaterInflowRch + GroundwaterFlowToReachGW,Rch - ReachFlowToGroundwaterGW,Rch - EvaporationRch - RiverFloodingRch
Unless using the groundwater "wedge" model, outflows to groundwater are a fraction (entered as data -- see Supply and Resources\River\Reaches) of upstream inflows to the reach.
ReachFlowToGroundwaterRch = ReachFlowToGroundwaterFractionRch x UpstreamInflowRch
Evaporation is calculated as a fraction (entered as data -- see Supply and Resources\River\Reaches) of upstream inflow to the reach.
EvaporationRch = EvaporationFractionRch x UpstreamInflowRch
Flooding is calculated as a fraction of streamflow that exceeds the River Flooding Threshold (entered as sdata -- see Supply and Resources\River\Reaches).
RiverFloodingRch = RiverFloodingFractionRch x (UpstreamInflowRch - RiverFloodingThresholdRch ) { if UpstreamInflow > RiverFloodingThreshold }
= 0 { if UpstreamInflow <= RiverFloodingThreshold }