- 2136 - 
A systematic study of the effects of water pollution.in West Germany(Schneider, 
1972), using a combination'of remote sensing methods, was conducted for the 
Saar River, which flows through an industrial agglomeration near the city of 
Saarbrucken. Two flights were made with an infra-red line scanner at a height 
of 1,000 metres above the river surface at 5.50 a.m. and 6.00 p.m. Also, test 
flights were conducted with an infra-red radiometer/thermometer in a helicopter 
flown at 100 metres. The resultant measurement curves gave the absolute 
surface temperature of the river at the time of the flight. Out of 17 outfalis 
for cooling waters, 15 were exactly determined on the thermal imagery. It was 
necessary to compare the imagery taken on both flights, as six thermal sources 
did not show up on imagery taken before sunrise, but were identified on the 
evening imagery. In contrast, only two thermal sources did not show up on the 
evening imagery, wbich were identified on the early morning data. These 
differences are probably due io processes in the plants. 
There have been similar reported studies of thermal water pollution using infra- 
red line scanning in several other European countries, including The Netberlands, 
Sweden (Svensson, 1969 and Sellin and Svensson 1970) and France. Kamini ski (1972) 
interpreted satellite imagery from Nimbus 1, 2 and 5, ITOS-1 and NOAA-1 and 
measured temperatures in coastal waters of the English Channel and the North Sea 
which seem to correlate with neighbouring industrial and urban agglomeration. 
5.7 Monitoring Water Pollution Sources 
Multidate aerial photography will provide a continuing record of conditions and 
associated pollution problems in the aquatic environment. In addition, it often 
reveals changes in the quality and population of living organisms that inhabit 
the area. The frequency of coverage depends upon the nature of the site being 
monitored and the dynamic components being observed. Aerial photographic surveys 
of industrial localities along waterways will cover areas and facilities where 
pollution sources may originate, such as industrial plants, storage areas, waste 
treatment facilities and transportation structures. The presence of such complexes 
would alert the interpreter to suspect discharges or spills of hazardous pollutior 
substances. Some outfalls occur only at certain periods of the day and unless 
the photography is taken at the time of active discharge, it may not be possible 
to detect water discolouration. However, the presence of discharge structures, 
pipes, holding tanks, canals and signs of residue along the shoreline are usually 
reliable indicators of a potential pollution source. 
Aerial photography taken for vater pollution surveys should meet certain criteria. 
The film filter combination(s) should be suitable for making the necessary 
distinctions between the discharged substance and the receiving waters. Usuaily 
colour photography best meets this requirement. The scale of photography should 
be adequate for detecting and identifying features associated with poliuvant 
outfalls and spilis, such as liquid storage tanks, pipelines, sewage treatment 
plants, raw material and waste hoiding features, industrial facilities, shipping 
docks and structures and mining cperations. The scale range most suitable for 
such interpretations usually i: about 1/5,000 to 1/10,000. Regional surveys for 
reconnaissance mapping are commonly obtained at small scales of 1/40 ,000 to 
1/60,000, followed by larger scale coverage of selected areas, where concentrations 
of facilities usually associated with pollution sources are observed. 
One of the most valuable uses of remote sensing data in evaluating water pollution 
effects is its application to change detection for studies related te agriculture, 
forestry and land development. The status of the vegetation is analysed to 
determine its identity, nealth and vigour as a base line for pollution studies. 
Application of fertilizers, pesticides, herbicides and minerals to land areas has 
been detected in rum-off water. Unexplained changes in vegetation communities 
are in many cases the first indicators of environmental damage by water pollution. 
Colour infra-red photography is most useful in such vegetation studies. Where 
changes are detected, it is often helpful to obtain photography taken in the past 
to compare with current imagery in order to evaluate the magnitude and extent of 
the changes.