The ability to predict the amount and character of natural organic matter (NOM) in a drinking water supply can allow operators to anticipate coagulant or disinfectant demand. In systems consisting of two reservoirs of differing water quality in series, the ability to predict water quality can impact decisions of transfer from an upstream reservoir to a downstream reservoir. CE QUAL W2 version 2 is a two dimensional laterally averaged hydrodynamic and water quality modeling program that is capable of modeling reservoir storage, and vertical and longitudinal gradients of temperature and 21 water quality constituents. With minor modifications, this program can be used to model NOM surrogates including total organic carbon (TOC), dissolved organic carbon (DOC) and the absorbance of ultraviolet light at a wavelength of 254 nm (UV 254). UV 254 can be an effective predictor of disinfection byproduct formation potential (DBPFP). Together, UV 254 and DOC can be used to calculate specific UV absorbance (SUVA) which is an effective predictor of NOM removal by coagulation. Wachusett Reservoir is part of an unfiltered supply for a large metropolitan area. This reservoir receives significant transfer from another reservoir with lower NOM levels. CE QUAL W2 effectively predicted TOC, DOC, UV 254, and SUVA at the withdrawal from Wachusett Reservoir by including temperature dependent and light induced decay of organic matter and organic matter formation by algal growth with an intensive hydrodynamic model. It may be possible to implement simpler model and include the same mechanisms to predict concentrations of NOM surrogates, which could aid in making operational decisions. Includes 15 references, table, figures.