to be composed of 57-meter-square pixels. Other investigators have warned of 
problems in using Landsat data in this format for water quality studies (Olsen, 
et al., 1981). They showed that resampling can alter band 6 and band 7 data 
for water bodies by as much as seven counts. However, it was not possible to 
obtain a copy of this image in a nonresampled format. 
Table 1 lists the band passes sensed by the Landsat multispectral scanner. 
Table 1. - Band passes sensed by the Landsat 
multispectral scanner 
  
  
Channel Wavelength band (um) Color/spectrum 
4 9. 5-—-0. 60 Green 
5 0.6 - 0.70 Red 
6 0.7 - 0.80 Near infrared 
7 0.8 - 1.10 Near infrared 
  
About 25 percent of the surface area of the reservoir was obscured by clouds 
and their shadows (see figure 1).* Also on September 9, 1981, the EPA acquired 
imagery of the reservoir with an airborne Daedalus Model 1260 eleven channel 
multispectral scanner. Six flight lines were flown between 9:40 and 10:50 a.m. 
MDT, at an altitude of 6560 meters above mean sea level, yielding a nominal 
pixel size of 11.5 meters square. Clouds and their shadows impaired the utility 
of the data obtained for the lower reaches of the reservoir. Table 2 lists 
the ten band passes used in this study. Figure 2 shows an example of this 
imagery. The data were received in the remote sensing laboratory in the form of 
computer compatible tapes produced at the EPA Environmental Monitoring Systems 
Laboratory in Las Vegas, Nevada. 
Table 2. - Airborne multispectral scanner 
channels used in this study 
  
  
Channel Wavelength band (um) Color/spectrum 
1 0.38 - 0.42 Near ultraviolet 
2 0.45 - 0.50 Blue 
3 0.50 - 0.55 Green 
4 0.55 - 0.60 Green 
5 0.60 - 0.65 Red 
6 0.65 - 0.70 Red 
7 0.70 - 0.79 Near infrared 
8 0.80 - 0.89 Near infrared 
9 0.92 - 1.10 Near infrared 
10 8.00 - 14.00 Thermal infrared 
  
ANALYSIS OF LANDSAT DATA 
The water quality specialists who had sampled the reservoir supplied the remote 
sensing lab with 1:62 500 scale maps annotated to show sample site locations. 
  
* Figures are at end of paper. 
604 
With 
cons 
Twer 
mear 
recc 
Robi 
valu 
Me as 
Chlc 
then 
conc 
Dr af 
as c 
for 
Usef 
and 
Depe 
]n | 
In | 
Tot: 
R4, 
CR5 
the 
Hav: 
by i 
be « 
num: 
us ii 
to « 
ori: 
figi 
of « 
chle 
lm 
tra! 
pho 
rad 
phy 
Airl 
aS | 
dis 
coul 
dig 
ide