Model/ items	SIMCAT	TOMCAT	QUAL2EU	QUAL2KW	WASP7	QUASAR
Types	1D, steady state, stochastic	1D, steady state	1D, steady state/dynamic	1D, steady flow	1D,2D,3D, Dynamic	1D, dynamic, stochastic
Modeling approch prosses	CSTRS	CSTRS	ADE, Equal river reaches	ADE, unequal river reaches	ADE, dynamic compartmental	CSTRS
Modeling approch prosses	DO modeling inclueds CBOD, reaeration	DO modeling inclueds CBOD, reaeration nitrification	DO modeling inclueds CBOD, SOD, reaeration respiration, nitrification, photosynthesis	DO modeling inclueds CBOD, SOD, reaeration respiration, nitrification, photosynthesis	DO modeling inclueds CBOD, SOD, reaeration respiration, nitrification, photosynthesis	DO modeling inclueds CBOD, SOD, reaeration respiration, nitrification, photosynthesis
Modeling capability	DO, CBOD, ammonia, user defined conservative parameter	DO, CBOD, ammonia, chloride user defined parameter	15 constituents including DO BOD, temp, algae, N (ON, NO₂, NO₃ NH₃), P (OP, PO₄), coliform, SOD, NCPAR	temp, PH, N (ON, NO₂, NO₃), P (OP, PO₄), DO,CBOD, TIC, alkalinity, phytoplankton, bottom-algae, SOD, detrious, pathogen	DO, temp, N (ON, NO₂, NO₃, NH₃), P (OP, PO₄), coliform, salinity, SOD, CBOD, bottom algae, silica, pesticides, OCHEM	DO, CBOD, nitrate, SOD, ammonia, unionized ammonia, temp, Ecoli, pH, conservative pollutant
Strength	Runs quickly with limited data, autocalibration	Runs quickly with limited, greater accuracy than SIMCAT	widely tested, automatic uncertanity analysis	converts algal death to CBOD, autocalibration	converts algal death to CBOD	converts algal death to CBOD
Limitations	Approach over simplistic	Approach over simplistic	Does not convert algal death to CBOD	Does not stimulate river branches	Requies extensive data, unliked sub-models	Requires extensive data