Overland Flow

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(No Transcript)
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Our Proposition

• During the past few years, there have been
  noticeable changes in our stream, as well as a
  noticeable difference between our site data and
  the data from the other sites. We wanted to
  determine whether our data was normally intense,
  or if something fishy is going on and we need to
  take more in-depth studies.

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Our Problem Flashiness of Our Stream

• The term flashiness is the frequency and speed of
  short term changes in the flow of the stream,
  especially during runoff events. Flashiness is
  very important when considering how the stream is
  flowing. Certain changes in the land usage and
  management, such as the human development over
  the past many years, may lead to an increase or
  decrease in the flashiness of our stream, which
  often results in the weakening of aquatic life.
  See figure A.

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Increased run-off
Human development
Precipitation
(leads to)
(influences)
Impervious surfaces
Geological features
(cause)
(influence)
(Causes)
High degree of flashiness
(Causes)
(causes)
(causes)
Erosion
Flooding
Intense Turbidity
(causes)
(can cause)
(leads to)
Sedimentation in streambed
Habitat degradation
(causes)
Figure A
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Intense Turbidity

• As shown in Figure A, a high degree of flashiness
  can cause intense turbidity. This caught our eye
  because our stream has been experiencing high
  variations in turbidity throughout its history.
  We made our proposition because the data from
  past monitoring expresses that there are
  noticeable changes in the turbidity amounts.

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Turbidity Data

• In order to see if the turbidity from our site
  was normally intense or not, we analyzed and
  compared to sets of years (years 2003-2004 and
  years 2005- 2006). Our null (initial) hypothesis
  is that the turbidity data is normal. Our
  alternative hypothesis is that the turbidity data
  is not normal and something fishy is going on
  where we would need to do more research.

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Turbidity Data (means)
Set A
Set B
2003-2004
2005-2006
60 60 60 60 60.3 60.3 47.3 39.3 60 60 60 60
60 60 59.2 59.1 9.17 7.75 49.3 60 61.7 39.7
These are the two data sets that we compared, Set
A and Set B, from the past four years.
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Our analysis
Set A (2003-2004)
Set B (2005-2006)

• __
• X 46.592
• 20.117
• N 10

• __
• X 57.267
• 6.457
• N 12

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Claim The turbidity in the stream is
normal.Opposite claim The turbidity in the
stream is not normal.Ho (Null) Stream is
normal.Ha (Alternate) Stream is not normal,
need further research.Test null
directly.Conclusion Reject null.or. Fail to
reject null.
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Errors could make in calculations--Type I
error - reject the null hypothesis and it is
really true --Type II error - fail to reject the
null hypothesis and it is false
2SampZTest (A,B) Z -1.61 P 0.1073
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Our Calculations (Test 1)

• We want to be 95 confident with our
  calculations, so ? 5 or .05 (Use 0.05 because
  it is middle ground between Type 1 Type 2
  error.)
• Ho µA µB(normal) p gt ? so, p gt 0.05
• Ha µA µB(not normal) p lt ? so, p lt 0.05

0.1073 gt 0.05 Fail to reject Ho P gt
0.05 Ho µA µB
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Two-tailed test (test 2 cont.)--Test
statistic z-score.--Critical Region--Critical
Value
Z -1.61 -1.610(orange) gt -1.645(green) Z
score is not in critical region, so
failure to reject Ho.
z
-1.645
1.645
0
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Conclusion

• Based on our calculations and the two tests,
  there is not sufficient evidence to warrant
  rejection of the claim that our stream has an
  unusual turbulence of turbidity. This means that
  nothing unusual is going on with our site, and
  that our proposal for more research into why it
  is unusual is not needed because our site is
  normally intense.