~ ~ ~ PURPOSE ~ ~ ~ this subroutine computes loadings from urban areas using the USGS regression equations or a build-up/wash-off algorithm
~ ~ ~ INCOMING VARIABLES ~ ~ ~ name |units |definition ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ dirtmx(:) |kg/curb km |maximum amount of solids allowed to |build up on impervious surfaces hru_km(:) |km^2 |area of HRU in square kilometers ihru |none |HRU number nsweep(:) |none |sequence number of street sweeping operation |within the year qp_cms |m^3/s |peak runoff rate sedyld(:) |metric tons |daily soil loss caused by water erosio surfq(:) |mm H2O |surface runoff for the day in HRU tconc(:) |hr |time of concentration thalf(:) |days |time for the amount of solids on |impervious areas to build up to 1/2 |the maximum level tnconc(:) |mg N/kg sed |concentration of total nitrogen in |suspended solid load from impervious |areas tno3conc(:) |mg NO3-N/kg sed|concentration of NO3-N in suspended |solid load from impervious areas tpconc(:) |mg P/kg sed |concentration of total phosphorus in |suspended solid load from impervious |areas twash(:) |days |time that solids have built-up on streets urbcoef(:) |1/mm |wash-off coefficient for removal of |constituents from an impervious surface ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ ~ ~ OUTGOING VARIABLES ~ ~ ~ name |units |definition ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ twash(:) | ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ ~ ~ LOCAL DEFINITIONS ~ ~ ~ name |units |definition ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ ~ ~ SUBROUTINES/FUNCTIONS CALLED ~ ~ ~ Intrinsic: Exp, Max, Log SWAT: Regres, sweep
~ ~ ~ ~ ~ ~ END SPECIFICATIONS ~ ~ ~ ~ ~ ~
USGS regression equations The sediment loading from urban imprevious area is assumed to be all sitly particles build-up/wash-off algorithm
rainy day: no build-up, street cleaning allowed
calculate amount of dirt on streets prior to wash-off calculate wash-off of solids expression in () qp_cms in mm/hr set time to correspond to lower amount of dirt amounts are kg/ha sus_sol * .001 = t/ha The sediment loading from urban imprevious area is assumed to be all sitly particles dry day