Identification and Analysis of Hydrodynamic and Transport Characteristics of Cannonsville Reservoir

Abstract

ABSTRACT A monitoring program consisting of regular observations of temperature and conductivity in the tributaries to and water column of Cannonsville Reservoir from April through November of 1995 is described. The results are analyzed in order to identify and quantify transport processes that affect the distribution of heat and mass constituents. The low temperature of the major reservoir tributary relative to reservoir surface waters in late summer and fall is observed to cause a plunging inflow or negatively-buoyant density current in the reservoir, although evidence is provided that the plunging inflow is not the cause of the observed metalimnetic oxygen minima. A seasonal increase in the specific conductivity of the major tributary in summer creates a longitudinal gradient in conductivity in the epilimnion of the reservoir. A simple analytical model is used to estimate the longitudinal dispersion coefficient in the epilimnion over the summer based on this conductivity gradient. High-frequency observations of temperature using thermistor chains deployed late in the summer stratification period indicate the presence of internal waves in the stratified layers of the reservoir. Current measurements indicate the occurrence of episodes of current speed of a magnitude sufficient to cause sediment resuspension. The application of hydrothermal models to the reservoir to support water quality management is discussed.