of quantitative remote control over pollution of water 
areas to be achieved by measuring of water transparency. 
The TOIIKAM scientists have developed an original 
technique for evaluation of water relative transparency 
by aerial photography - it provides real-time measure 
ments at low costs. An aircraft drops down some buoys 
with weights suspended from them at a specified depth*, 
then aerial spot photography is carried out along the 
design routes, image density of the negatives showing 
the suspended objects and water surface is analysed and 
the water transparency is determined from the data thus 
obtained. 
Fig. I shows the pattern of tabing the measurements, 
Fig.2 the procedure for determination of water relative 
transparency. 'The following symbols are used in the dia 
gram of Fig. I: (^,02 - two positions of air-survey ca 
mera (ASC) for route survey; P t ,P 2 - two successive 
aerial photographs; f - ASC focal distance; A 1 - buoy 
position on water surface; A - underwater object (co 
lour spot) as target; h - depth of colour spot submer- 
length of beam travel through water; angle of 
incidence and refraction of optically-focused beam. 
In the first photograph the target-object is found 
in the main point Q t of the picture. 
is travel length of light beam from a bright source 
through the water, 
gence; a ti a 2 
pho to graphs; 
- points indicating colour spots at the 
r c - radius vector of point a 2 ; t ~ 
h 
(1 
angle of refraction p, 1 
the law of refraction ^ 
is defined on the basis of