void runoff_getOutfallRunon(double tStep)
//
// Input: tStep = previous runoff time step (sec)
// Output: none
// Purpose: adds flow and pollutant loads leaving drainage system outfalls
// during the previous runoff time step to designated subcatchments.
//
{
int i, k, p;
double w;
// --- examine each outfall node
for (i = 0; i < Nnodes[OUTFALL]; i++)
{
// --- ignore node if outflow not re-routed onto a subcatchment
k = Outfall[i].routeTo;
if ( k < 0 ) continue;
if ( Subcatch[k].area == 0.0 ) continue;
// --- add outfall's flow to subcatchment as runon and re-set routed
// flow volume to 0
subcatch_addRunonFlow(k, Outfall[i].vRouted/tStep);
massbal_updateRunoffTotals(RUNOFF_RUNON, Outfall[i].vRouted);
Outfall[i].vRouted = 0.0;
// --- add outfall's pollutant load on to subcatchment's wet
// deposition load and re-set routed load to 0
// (Subcatch.newQual is being used as a temporary load accumulator)
for (p = 0; p < Nobjects[POLLUT]; p++)
{
w = Outfall[i].wRouted[p] * LperFT3;
massbal_updateLoadingTotals(DEPOSITION_LOAD, p, w * Pollut[p].mcf);
Subcatch[k].newQual[p] += w / tStep;
Outfall[i].wRouted[p] = 0.0;
}
}
}
void subcatch_getRunon(int j)
//
// Input: j = subcatchment index
// Output: none
// Purpose: Routes runoff from a subcatchment to its outlet subcatchment
// or between its subareas.
//
{
int k; // outlet subcatchment index
int p; // pollutant index
double q; // runon to outlet subcatchment (ft/sec)
double q1, q2; // runoff from imperv. areas (ft/sec)
double pervArea; // subcatchment pervious area (ft2)
// --- add previous period's runoff from this subcatchment to the
// runon of the outflow subcatchment, if it exists
k = Subcatch[j].outSubcatch;
q = Subcatch[j].oldRunoff;
if ( k >= 0 && k != j )
{
subcatch_addRunonFlow(k, q);
for (p = 0; p < Nobjects[POLLUT]; p++)
{
Subcatch[k].newQual[p] += q * Subcatch[j].oldQual[p] * LperFT3;
}
}
// --- add any LID underdrain flow sent from this subcatchment to
// other subcatchments
if ( Subcatch[j].lidArea > 0.0 ) lid_addDrainRunon(j);
// --- add to sub-area inflow any outflow from other subarea in previous period
// (NOTE: no transfer of runoff pollutant load, since runoff loads are
// based on runoff flow from entire subcatchment.)
// --- Case 1: imperv --> perv
if ( Subcatch[j].fracImperv < 1.0 &&
Subcatch[j].subArea[IMPERV0].routeTo == TO_PERV )
{
// --- add area-wtd. outflow from imperv1 subarea to perv area inflow
q1 = Subcatch[j].subArea[IMPERV0].runoff *
Subcatch[j].subArea[IMPERV0].fArea;
q2 = Subcatch[j].subArea[IMPERV1].runoff *
Subcatch[j].subArea[IMPERV1].fArea;
q = q1 + q2;
Subcatch[j].subArea[PERV].inflow += q *
(1.0 - Subcatch[j].subArea[IMPERV0].fOutlet) /
Subcatch[j].subArea[PERV].fArea;
}
// --- Case 2: perv --> imperv
if ( Subcatch[j].fracImperv > 0.0 &&
Subcatch[j].subArea[PERV].routeTo == TO_IMPERV &&
Subcatch[j].subArea[IMPERV1].fArea > 0.0 )
{
q = Subcatch[j].subArea[PERV].runoff;
Subcatch[j].subArea[IMPERV1].inflow +=
q * (1.0 - Subcatch[j].subArea[PERV].fOutlet) *
Subcatch[j].subArea[PERV].fArea /
Subcatch[j].subArea[IMPERV1].fArea;
}
// --- Add any return flow from LID units to pervious subarea
if ( Subcatch[j].lidArea > 0.0 && Subcatch[j].fracImperv < 1.0 )
{
pervArea = Subcatch[j].subArea[PERV].fArea *
(Subcatch[j].area - Subcatch[j].lidArea);
q = lid_getFlowToPerv(j);
if ( pervArea > 0.0 )
{
Subcatch[j].subArea[PERV].inflow += q / pervArea;
}
}
}