Among natural organic matter (NOM) defined as the complex matrix of organic materials abundant in natural waters, a gradual accumulation of recalcitrant organic matter (ROM) has been observed in impounded water bodies such as a lake or dam reservoir in spite of extensive efforts made to curtail organic pollutant loadings generated in their catchment areas. This paper aims to identify the effect of diffuse pollution resulting from allochthonous organic matters on the temporal and spatial characteristics of organic matters in a stratified dam reservoir, Daecheong Dam, using both intensive observation and CE-QUAL-W2 model simulation. With the limitation of observation data in terms of organic matters of inflow waters from boundary tributaries and impounded water in the reservoir, organic matter was represented by organic carbon including labile particular organic carbon (LPOC), refractory organic carbon (RPOC), labile dissolved organic carbon (LDOC), and refractory organic carbon (RDOC). Both autochthonous and allochthonous origins of organic carbon were considered in the modeling of eutrophication of the reservoir water using CE-QUAL-W2. The result of simulation during the period from 2001 to 2005 was observed to be a gradual accumulation of particular organic carbon (POC). It is clear that the model calculation results enable the explanation of the internal and external movement of constituents in the reservoir. In particular turbidity and NOM were well related in the upper region of the reservoir according to flow distance, gradually changing to dissolved form of organic matter, DOC affected organic matter concentration of reservoir water quality compared to turbidity.
Keywords: accumulation, CE-QUAL-W2, organic carbon, reservoir, turbidity