was 11° Celsius (20° Fahrenheit) above the ambient water temperature in 

 the adjacent model. A temperature-time record was then made as the water 

 in the enclosed basin cooled. The rate of cooling provided a measure of 

 the surface heat exchange coefficient. 



Because the tests continued over several days during each series, the 

 base or ambient temperature of the water in the model varied. Therefore, 

 it was necessary to monitor the water temperature in the model in areas 

 which were sufficiently removed from the station site so that the tempera- 

 ture of these areas represented the ambient water temperature. During 

 both series of tests, fixed thermistor bead temperature sensors were 

 placed in the model at selected positions upstream and downstream from 

 the plant site. 



(9) Summary of Test Results . For plan 1, the intake point was 

 located about 8,000 feet offshore in about 20 feet of water on the down- 

 stream side, and the discharge was through a canal emptying into Cobham 

 Bay on the upstream side. The excess temperature distributions at the 

 times of high and low water slacks of the tidal cycle for conditions of 

 a 2,000-cubic foot per second freshwater riverflow are shown in Figure 

 3-87. Although the thermal plume (1° Celsius isotherm; not shown in the 

 figure) extended downstream to the intake point at low water slack, the 

 intake point was located at the bottom and was unaffected by the surface 

 teirperature . 



For plan 2, the intake point was located about 3,000 feet offshore 

 in about 10 feet of water in Cobham Bay on the i^jstream side, and the 

 discharge canal emptied into the main channel on the downstream side. 

 Figure 3-88 presents test results similar to those for plan 1. In this 

 case, the thermal plume at low water slack extended for a considerable 

 distance downstream and would alter temperatures in valuable seed oyster- 

 beds. The upstream extent of the plume at high water slack did not in- 

 fluence temperatures at the intake point. 



On the basis of the model results, the discharge canal was located 

 on the upstream side of the power station to avoid potential detrimental 

 effects to the seed oysterbeds. 



m. Definition of Existing Conditions--Delaware River . 



(1) Project . No specific project was related to this study. 



(2) References . U.S. Army Engineer Waterways Experiment Station 

 (1954, 1956). 



(3) Laboratory . WES. 



(4) Test Period . December 1950 to March 1954. 



(5) Problem . Tests are often conducted in a model to define 

 hydraulic and salinity regimens for conditions where prototype data are 



185 



