—Estimating and mapping salinity patterns of 
estuaries under optimum thermal-salinity relation- 
ships. 
—Delineating drainage patterns of tributaries 
having heavy overhanging foilage. 
—Identifying well mixed and poorly mixed estu- 
aries. 
—Identifying bed and bank sediments. 
—Locating offshore bars and breaker regions. 
—Monitoring construction of such harbor engi- 
neering structures as jetties, docks, groins, etc., 
and their effect on circulation patterns and sedi- 
ment dispersal. 
—Locating sources of pollution having thermal 
characteristics. 
—Detecting both submarine and terrestrial springs. 
—Studying water turbulence. 
—Recording wind streaks, hence wind direction. 
—Locating shoal areas. 
—Locating sea ice and identifying its type, age, and 
fracture patterns. 
Studies using infrared were conducted in 1966 
on the Merrimack River Estuary, Massachusetts, 
by the U.S. Geological Survey. Airborne infrared 
imagery was obtained in August and September of 
the estuary from Haverhill to Plum Island at low, 
flood, high, and ebb tides. 
From the imagery, thermal effects of papermill 
waste, its diffusion in the river at various phases of 
the tidal cycle, and individual sewage outfalls were 
detected easily. Estuarine flushing was found to 
vary widely in different parts of the lower estuary. 
The surface expression of the freshwater-seawater 
interface could be seen clearly. 
Infrared imagery in the Merrimack study pro- 
vided a synoptic, integrated, comprehensive, and 
rapid method to detect pollution sources involving 
thermal differences. It was useful in determining 
circulation patterns in the estuary. The imagery 
provided a synoptic view of the estuary surface’s 
thermal condition at high, low, flood, and ebb 
tides. It precisely delineated the salt water front at 
flood and high tides and defined the main channel 
at low and ebb tides. 
The imagery also disclosed that the salt water 
front during flood tide diverts the polluted river 
discharge to the southern shore and over the 
shallow shellfish areas, thereby causing contamina- 
tion. Data collected on temperature, salinity, tidal 
fluctuations, etc., provided a standard for semi- 
quantitiative interpretation of the imagery. Dis- 
advantages of the infrared system are that it is not 
an all-weather reconnaissance system, it reveals 
nothing about the type of pollutant, and it 
determines relative, rather than absolute, temper- 
atures. 
Other successful experiments using airborne 
infrared systems for thermal pollution studies are 
being conducted in the Columbia River at Rich- 
land, Washington. Infrared imagery and radio- 
metric measurements are being collected from 
aircraft, and the data are being processed by 
several computer techniques developed to produce 
qualitative and quantitative displays. One is used 
for qualitative evaluation of thermal data from a 
three dimensional color display (Figure 37). 
Figure 37. Oblique three-dimensional display 
of infrared image collected over Columbia 
River near nuclear reactor site of the Atomic 
Energy Commission's Hanford Project. 
(Battelle Northwest photo) 
Turbulence patterns and mixing zones near 
atomic reactor coolant discharge points in the 
Columbia River are being determined. Isothermal 
maps of the river surface are being plotted. The 
rapid scanning infrared imaging systems obtain 
measurements that reveal detailed turbulence and 
VI-101 
