ERTS-1 images of two federal reservoirs in Kansas exhibit good correlation with suspended load. The major reservoirs in Kansas, as well as in other Great Plains states, are playing increasingly important roles in flood control, recreation, agriculture, and urban water supply. Satellite imagery may prove useful for acquiring timely low cost water quality data required for optimum management of these fresh water resources

James, G. W.

Magnuson, L. M.

Marzolf, G. R.

Mccauley, J. R.

Yarger, H. L.

English

NASA Technical Reports Server

Paper E 12 
WATER TURBIDITY UETECTION USING ERTS-1 IMAGERY 1 
Harold L. Yarger, James R. McCauley, Gerard W. James anti Larry M. hlagnuson, 
State Geological Survey, University cf Kansas, Lawrence, Kansas and !3 . Richard 
Mbrzol f , Division of Biology, Kansas State University, Manhattan, Kansas 
1.0 ABSTRACT 
ERTS-1 images mf two f e d e r a l  r e s e r v o i r s  i n  Kansas e x h i b i t  good 
co r r e l a t i on  with suopended load. The major r e s e r v o i r s  i n  Kansas, 
a s  w e l l  a s  i n  o the r  Great P l a i n s  s t a t e s ,  a r e  playing increas-  
i q l y  important roles i n  f lood con t ro l ,  r ec rea t ion ,  ag r i cu l -  
t ~ r e ,  and urban water supp1.y. S a t e l l i t e  imagery may prove 
usefu l  f o r  acquir ing t imely low c o s t  water q u a l i t y  d a t a  re- 
quired f o r  optimum management of these  f r e s h  water resources .  
2.6 INTRODUCTION 
The dominant l imnological  f e a t u r e  of t he  Great P l a i n s  today 
t akes  the form of r e s e r v o i r s  constructed by t h e  U.S. Anny 
Corps s f  Engineers and t h e  -.S. Bureau of Reclamation. The 
primary inf luence on t h e  r e s e r v o i r  ecosystem i s  the suspended 
material. and chemicals c a r r i e d  i n  by streams and r i v e r s .  The 
aa tho r s  a r e  studying ERTS images of Kansas r e s e r v o i r s  t o  
determine the  feasibility of monitoring these  water q u a l i t y  
i n d i c a t o r s  by s a t e l l i t e .  The r e s e r v o i r s  throughout t h e  
s t a t e ,  which should be r ep re sen ta t ive  of most Great P l a i n s  
r e se rvo i r s ,  are loca ted  i n  a v a r i e t y  of physiographic regions 
such a s  the  g l ac i a t ed  region in the nor theas t ,  t h e  v a l l e y s  and 
scarps  i n  t he  southeas t ,  t h e  d i s sec t ed  p la teau  and a l l u v i a l  
p l a i n s  a r e a s  i n  cen txa l  Kansas, and the  high planes  i n  t h e  
west. 
Tw, r e se rvo i r s ,  Per ry  and T u t t l e  Creek, have been s ing led  o u t  
f o r  c lo se  study. Approximatcly t en  water samples from each 
r e s e r v o i r  are c o l l e c t e d  during each cloud-free ERTS overpass 
and analyzed f o r  concentrat ions  of inorganic  auspendod and 
d isso lved  so l id@,  organic  suspended and d isso lved  s o l i d s ,  
chlorophyl l ,  patasrium, phosphate, and n i t r a t e  ionn. I n  addi- 
t i o n ,  secchi  d i s c  and temperature msarursmenrr are taken a t  
each sampling a t a t i on .  The two re se rvo i r@ a r e  d i r t i n c t  i n  
tetma of ad jacent  outcropping rock8 and land ure.  Per ry  d r a i n r  
'Work ~ ~ p p ~ r t e d ~  i n  pa r t .  by NASA con t r ac t  NAS5-21822 
https://ntrs.nasa.gov/search.jsp?R=19730019544 2020-03-17T08:46:52+00:00Z
a recen+.ly g l ac i a t ed  region i n  the  co rnbe l t  of ea s t e rn  Kansas. 
T u t t l e  Creek d r a i n s  the F l i n t  H i l l s  a rea  t o  the west which i s  
outcropping Cretaceous and Permian rock, The dominant land 
use is seasonal grazing and small  g ra ins .  k l a t e r  phase of 
t h i s  p r o j e c t  w i l l  be t o  test any p red ic t ive  r e l a t i o n s  der ived 
from Perry and T u t t l e  Creek on o t h e r  r e s e r v o i r s  i n  Kansas. 
Kansas reservoirs a r e  t y p i c a l l y  shallow and thua a r e  suscep t ib l e  
to mixing by s t rong winds which are a character is t ic :  c l ima t i c  
f ea tu re  of t h i s  region. Wind generated c u r r e n t s  a r e  of suf-  
f i c e n t l y  high ve loc i ty  t o  maintain a s i z a b l e  f r a c t i o n  of  t h e  
silts and c l a y s  i n  suspension and t h e  r e s u l t  is t u r b i d  
water (mean l i g h t  ex t inc t ion  c o e f f i c i e n t  % 2.5 meters'l) . 
Accordingly, r e f l e c t i n g  energy de tec ted  by ERTS is pr imar i ly  
influenced by the  suspended load ( the  predominent f r a c t i o n  of 
which is inorganic  m a t e r i a l ) .  The detsrmlnatioii  of t h e  recond- 
a r y  inf luence of organic  ma te r i a l  and chemicals on r e f l e c t s d  
energy must wai t  u n t i l  t he  e f f e c t s  of inorganic  suspended load 
are understood. The remainder of  t h i s  paper is dcvoted t o  
t h i s  aspect.  
3.0 GROUND TRUTK ANALYSIS 
The l i g h t  pene t ra t ion  depth i s  pr imar i ly  control162d by sus- 
pended load. The inverse  secchi  depth !or l / sun l igh t  pene- 
t r a t i o n  depth) is l i n e a r l y  r e l a t e d  to  suspended load up t o  
% 100 ppm (Figure 1). Least squares- s t r a i g h t  l i n e  f i t s  t o  
t hese  d a t a  y i e l d  s t a t i s t i c a l l y  equiva len t  s lopes  and i n t e r -  
cep ts .  Although inconclumive, t h e  few po in t s  beyond 100 ppm 
(not shown) i n d i c a t e  this l i n e a r i t y  may hold up to  250 ppm. The 
g r e a t e r  po in t  s c a t t e r  i n  t h e  Tuttle Creek d a t a  ie, due to highsr  
average t l r b i d i t y  r e l a t i v e  to Perry. Thia r e s u l t s  i n  a smnller 
average l i g h t  pene t ra t ion  depth and g r e a t e r  percent  error i n  
i ts  measurement by t h e  necchi d i s c  method, 
4.0 IMAGE ANALYSIS 
Approximately 30 cloud-free and ice- f ree  ERTS images of  T u t t l e  
Creek and Perry have been e l e c t r o n i c a l l y  9 l i ced  and dimplayed 
on our  IDECS syrtem. The c o l o r  coded dimplay8 were recorded 
on 35 nun f i lm  f o r  permanent s torage  and f u r t h e r  ana lys i s .  
The leva1 s l i c i n g  war dona on t h e  b a r i r  of equal  vidicon 
output  vol tage i n t e r v a l r  which i r  equiva len t  to equal  log 
d e n r i t y  i n t e r v a l s .  The maximum number o f  levels/image wam 
dettermined by tha dynamic range of t h e  p a r t i c u l a r  band over 
t3e r e r e r v o i r  sur face  and va r i ed  from 2 to 8 levelm. The 
equal  gray I e v e l r  m l e c t e d  by IDECS correopond to  nea r ly  
oqual r e f l e c t e d  energy i n t e r v a l 8  a$ definod oar the NASA 15 atop 
gray t a b l e t .  Maximum dens i ty  v a r i a t i o n  (c 0.6 to 1 . 7 )  is 
usua l ly  found on the  red band (MSSS) and corresponds t o  a 
p o w r  r e tu rn  range o i  0 t o  1, 25%.  
5 . 0  COMPARISdN OF IMAGERY WITH GROUNDTRUTH -- 
Gray l e v e l  contour maps of each image were prepared for com- 
par ison with suspended load and secchi  r iasurements  (example 
i n  Figure 2 ) .  I n  addi t ion ,  t he  d a t a  was examined i n  graphlca l  
form f o r  each r e se rvo i r  pass  (examples i n  Figures  3 and 4 ;  
The T u t t l e  Creek pass  2 da ta  e x h i b i t s  a s t rong c o r r e l a t i o n  
between gray level, suspended load,  and secchi  depth i n  t he  
green (MSS4) , red (MSS5) and i n f r a r e d  (MSS6) bands. This da t a  
i s  f a i r l y  r ep re sen ta t ive  of o ther  T u t t l e  Creek and Perry 
r a s see ,  except i n  soxne cases  the green band c o r r e l a t i o n  i s  
poor. Bands 5 and 6 normally show s t rong  c o r r e l a t i o n  with 
suspended load and eecchi dekth with band 5 being morz reli- 
able .  Band 7 is  poorly co r r e l a t ed ,  but  usua l ly  appears soh,o-- 
what b r i g h t e r  a t  t he  very tu rb id  end of t h e  r e se rvo i r .  Based 
on the  pcre water s p e c t r a l  a t t enua t ion  c o e f f i c i e n t ,  best cor re la -  
t i o n  would be expected i n  the  .reen band. This is probably, 
being obscured by haze induced by atmospheric s c a t t e r .  Fig- 
ure 5 shows band 5 c o r r e l a t i o n s  f c r  t h e  f i r s t  four  passes  
over Perry Reservoir dc t ing  from 7-27-72 t o  9-19-72.  This  
i s  represen ta t ive  of both reservoirs, i n  t h a t ,  t he  dynamic 
range over the r e s e r v o i r  surface tends t o  shr ink as winter  
approaches with lower sun angle and lower average t u r b i d i t y .  
CONCLUSIONS 
Bands 5 and 6 e x h i b i t  s t rong c o r r e l a t i o n  with suspended load 
and sun l igh t  pene t ra t ion  depth. I n  some cases  band 4 a l s o  
e x h i b i t s  s t rong  c o r r e l a t i o n ,  bu t  is not  r e l i r b l e  and i d  
probably q u i t e  s e n s i t i v e  to atmospheric coz9i t ions .  Band 7 
is poorly co r r e l a t ed ,  al though does show a b r i g h t e r  r e t u r n  
f o r  muspended load 2 100 ppm. The d i sc r imina t ion  o r  sen- 
s i t i v i t y  between gray lev191 and suspended load i s  good up @; 
100 ppm, but appears to  r ap id ly  d e t e r i o r a t e  above this l e v e l  
of t u rb id i ty .  More imagery/ground e u t h  over high Curbidi ty  
water is required f o r  f u r t h e r  i l . luminatian of t h i s  problem. 
MSS imagery obtained i n  t h e  high gain mode wmld probably 
be a g r e a t  he lp  i n  extending the  d i sc r imina t ion .  Thia is 
f e a s i b l e  because t h e  paver r e t u r n  from the  reservoir sur face  
i s  never more than 30t  of maximum r e tu rn .  
I n  sumary ,  the prospects  f o r  developing a r e l i a b l e  l o w  c o a t  
procedure f o r  p red ic t ing  suspended load from ERTS imagery 
looks very good. 
lo 1 PERRY RESLRVOl R 
ERTS-1 PASSES 1-7 
0 
u- 
20 40 60 80 100 
SUSPENDED LOAD ( P P M )  
TUTTLE CREFK RESERVOIR 
ERTS-1 PASSES 1-7 
SUSPENDED LOAD (PPMI 
FIGURE 1. Inverse secchi depth vs. suspended load for Perry 
and Tuttle Creek reservoirs.  
LAKE - TUTTLE CREEK 
PASS 2 
DATE AUGUST 14 - 
NASA IMAGE 
I D BLOCK E-1022-16391 . - - - -  - 
lMPGE BIND 5 -- 
SIJN LNGLE 54O 
---- 
FIGURE 2.  Gray level  map and turbidity measurements for Tuttle 
Creek reservoir. 
TUTTLE CREEK -- PP SS 2 -- AUGUST 14, 1972 
4 
MSS 4 
MSS 6 
TOTPL SUSPENDED SOL1 DS (PPM) 
FIGURE 3. Gray level ve. suspended s o l i d s  for Tuttle Creek 
Rerervoir. 
TUTTLE CREEK -- PASS 2 -- AUGUST 14, 1972 
6 r 
MSS 5 a 
. 
M S S  7 
SECCHI DEPTH (METERS) 
FIGURE 4 .  Gray level vs. secchi depth for Tuttle Creek 
Reservoir. 
PERRY RESERVOIR -- M S S  5 
PASS 2 
PASS 3 
PASS 4 
I I I I I 
0 50 100 150 200 250 
J 
TOTAL SUSPENDED SOL1 6 (PPM) 
FIGURE 5. Gray leve l  vr. suspended rolidr for Perry Reservoir. 


Water turbidity detection using ERTS-1 imagery

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