10. W.Q.I.
• The Water Quality Index was developed by the
National Sanitation Foundation as a standard
system to compare different bodies of water.
• To determine the WQI, a series of nine tests
were performed. These tests were: dissolved
oxygen, fecal coliform, pH, Biological Oxygen
Demand (BOD), temperature, total phosphate,
nitrates, turbidity, and total solids. We also did
a water discharge test which we use to
measure the flow of the creek in cubic feet per
second. 10
11. • After the tests are completed, the WQI for each
section of the creek can be computed.
• To formulate the WQI, we first computed Q-
values.
• We multiply this number by a weighting factor,
which provides a measure of the relative
importance of each test to overall water quality.
• The water quality index ranges from zero to 100.
- 0 - 25 is very bad
- 25 - 50 is bad
- 50 - 70 is medium
- 70 - 90 is good
- 90 - 100 is excellent
• The bio-indicator tests weren’t part of W.Q.I., but
did give us a water quality rating.
11
13. Sample W.Q.I. Form
W e ig hting
Te s t R e s ults Q -value Fac tor T o ta l
DO % s at. 0 .1 7
Fe c al C olifor m c ol/1 0 0 mL 0 .1 6
pH units 0 .1 1
BOD mg /L 0 .1 1
Te mpe r atur e c hang e in C 0 .1
Total P hos phate mg /L 0 .1
N itr ate s mg /L 0 .1
Tur bidity J TU 0 .0 8
Total S olids mg /L 0 .0 7
Overall Water Quality Index ___ 13
14. 2008 Precipitation
12
10
8
Inches
6
4
2
0
May June July August
Rainfall
14
15. pH
8.4
8.1
Site 1
7.8 Site 2
pH Level
7.5 Site 3
Site 4
7.2
Site 5
6.9 Site 6
6.6
6.3
June 3 June 17 July 23 August 5
& 18 &24
15
Date
16. Change in Water Temperature
2.5
2
1.5
Degrees Celcius
Site 1
Site 2
1
Site 3
Site 4
0.5
Site 5
0 Site 6
June 3 June 17 & July 23 & August 5
-0.5 18 24
-1
Date
The higher the change, the worse the water quality. 16
17. Total Solids
1800
1600
1400
Site 1
1200 Site 2
1000
mg/L
Site 3
800 Site 4
600 Site 5
400 Site 6
200
0
June 3 June 17 & July 23 & August 5
18 24
Date
The higher the concentration, the worse the water quality. 17
19. Fecal Coliform
1400
1200
colonies/100 mL
1000 Site 1
Site 2
800 Site 3
600 Site 4
Site 5
400 Site 6
200
0
June 3 June 17 & July 23 & August 5
18 24
Date
19
20. Flow
90
80
Cubic feet per second
70
Site 1
60 Site 2
50 Site 3
40 Site 4
30 Site 5
20 Site 6
10
0
June 3 June 17 & July 23 & August 5
18 24
Date
20
21. Turbidity
500
450
400
350 Site 1
Site 2
300
Site 3
JTU's
250
Site 4
200
Site 5
150
Site 6
100
50
0
June 3 June 17 & July 23 & August 5
18 24
Date
21
22. Dissolved Oxygen
100
90
80
70 Site 1
% Saturation
Site 2
60
Site 3
50
Site 4
40
Site 5
30
Site 6
20
10
0
June 3 June 17 & July 23 & August 5
18 24
Date
22
23. 5 Day Biological Oxygen Demand
5
4.5
4
Site 1
3.5
Site 2
3
Site 3
ppm
2.5
Site 4
2
Site 5
1.5
Site 6
1
0.5
0
June 3 June 17 & July 23 & August 5
18 24
Date
The higher the change, the worse the water quality. 23
24. Nitrates
70
60
50 Site 1
Site 2
40 Site 3
ppm
30 Site 4
Site 5
20 Site 6
10
0
June 3 June 17 & July 23 & August 5
18 24
Date
24
25. Phosphates
2.5
2
Site 1
Site 2
1.5
Site 3
ppm
Site 4
1
Site 5
Site 6
0.5
0
June 3 June 17& July 23 & August 5
18 24
Date
25
26. WQI Averages by Site
Good
70
65
60 Medium
WQI
55
50
Bad
45
Site 1 Site 2 Site 3 Site 4 Site 6 Site 5
2003 Averages 2004 Averages 2005 Averages
2006 Averages 2007 Averages 2008 Averages
26
27. WQI Averages by Date
Good
70
65
60 Medium
WQI
55
50
Bad
45
May June July August
Month
2003 Averages 2004 Averages 2005 Averages
2006 Averages 2007 Averages 2008 Averages
27
28. 2003 - 2008 Chemical Test Average Comparisons
30
25
20
15 2003 Averages
2004 Averages
10 2005 Averages
2006 Averages
5
2007 Averages
0 2008 Averages
pH
.
s
ge
es
p.
.D
e
m
at
at
ar
.O
Te
itr
ph
ch
B
N
os
is
in
D
Ph
e
ng
ha
Chemical Test
C
28
29. 2003 - 2008 Chemical Test Average Comparisons
1200
*2006 Fecal Coliform
1000 Average 8,058 col/100 mL
800 2003 Averages
2004 Averages
600 2005 Averages
2006 Averages
400 2007 Averages
2008 Averages
200
0
D.O. % Sat. Turbidity Fecal Coliform Total Solids
29
Chemical Test
30. Chemical Test Conclusions
• Fecal coliform readings still very
sporadic
• Dissolved Oxygen still very low
• Nitrates very high this year
• Overall water quality lower this year
probably due to increased nitrates
• Discharge up this year but turbidity is
down
30
33. Beaver-Shell Creek
WQI Comparison
70
60
50
40 Beaver Creek
WQI Average WQI
Shell Creek
30 Average WQI
20
10
0
Early Late June July August Summer
June Average 33
37. 2008 Flood Study
Date Avg. Total Solid Solid
Width Flow Solids
and Depth Discharge Discharge
(ft) (cfs)
Time (ft) (mg/L) (lbs/min) (tons/hr)
5/30/07 110 8.42 2243 9300 78145 2344
6/8/08 130 8.98 4328 8950 145138 4354
X cu ft 60 sec 28.32 L X mg 1g 1 lb 1 ton 60 min
1 sec 1 min 1 cu ft 1L 100 mg 453.6 g 2000 lb 1 hr
37
41. Website
• http://newman.esu8.org/project.html
OR
• http://newman.esu8.org/
• Click “Our Students”
• Click “Student Projects”
• Click “Watershed Project”
• You can see our data and further
information concerning this project,
including pictures. 41
43. Thank You To:
• Lower Platte North Natural
Resource District
• PrairieLand RC&D
• Natural Resource Conservation
Service
• Nebraska Department of
Environmental Quality
• Shell Creek Watershed 43
Improvement Group
