2. Lever Beach Before Reconstruction
Uniform Slope
Caused flood damage to
Hendrix Student Center
after unusually high
amounts of rainfall this
past summer
4. Objectives
analyze the changes made to the hill and determine
whether or not these changes would be adequate to
prevent flooding should we have another rainy summer
analyze how large of a rain event could be handled by the
area with the new preventative measures
contribute any ideas to further improve the design and find
other locations on campus that similar designs could be
used in order to prevent erosion and flooding
5. Lever Beach After Reconstruction
terraced part of the hill
added several rain basins
at the bottom of the hill
constructed small hills on
the slope to direct
rainwater into the basins
7. Runoff Calculation
Curve number from table 9-5 using soil group C
CN = 74
S = (1000/74)-10 = 3.52
Q = (P-0.2S)2/(P+0.8S) = 8.56 in
P = 11.94 in over 13 days of consecutive rain in
summer 2013
S = 3.52
8. Runoff Suggestions
The best way to decrease the amount of runoff would be to let the
grass grow tall which will also decreases erosion
CN = 70 with fair condition brush
S = 4.29
Q = 7.99 in
However, students want to use this land for laying out, playing Frisbee, studying,
ect. So, allowing the grass and brush to grow would leave this land unusable for
students which would not be worth the .57 inches of runoff that would be
prevented.
Our analysis shows that the runoff is pretty much as low as it can be.
9. Soil Loss Calculations (Before)
T=RLSVM
R = 250 for Clemson * (78%-30%) = 120
L = 150 ft
S = 10%
LS = 1.5
VM = 0.05
A=28000 ft2 = 0.64 acres
T = 9 tons/acre*yr = 5.6 tons/yr
1.4 tons of soil lost in one summer
10. Soil Loss Calculation (After Slope 1)
T = RLSVM
R = R = 250 for Clemson * (78%-30%) = 120
L = 100 ft
S = 7.5 %
0.8
VM = 0.05
A = 0.64 Acres
T= 4.8 tons/acre*yr
0.77 tons of soil lost in one summer
11. Soil Loss Calculation (After Slope 2)
T = RLSVM
R = R = 250 for Clemson * (78%-30%) = 120
L = 100 ft
S = 5 %
0.5
VM = 0.05
A = 0.64 Acres
T= 3 tons/acre*yr
0.48 tons of soil lost in one summer
12. Soil Loss Equation (After Terraces)
T=RLSVM
R = 250 for Clemson * (78%-
30%) = 120
L = 25 ft
S = 10%
LS = 0.7
VM = 0.05
A=28000 ft2 = 0.64 acres
T = 4.2 tons/acre*yr
0.67 tons of soil lost in one
summer (without terraces)
Add 4 terraces 25 ft apart
SDR : 0.12
Off 1st: 0.12 *0.67 = .08
Off 2nd: 0.12*(.67+.08) = .09
Off 3rd: 0.12 *(.67+.09) = .091
Off 4th: 0.12* (.67+.091) = 0.0913
0.0913 tons of soil lost in
one summer with four
terraces
13. Total Soil Loss After
0.77 tons + 0.48 tons + 0.0913 tons
1.34 tons of soil lost over one summer with changes
These means that over one summer with the
changes, about 200 pounds of soil was not eroded
that would have been eroded before the project.
For further improvement, I would have terraced the
entire hill to prevent soil erosion but it would not
have helped to control runoff
