Kite Hill Senior Design Final Presentation Fall 2015
1. Kite Hill Stormwater
Management
C. Bury, J. Davis, A. Hough, R. Middlewarth, J. Ossorio
Clemson University - Biosystems Engineering
BE 4750 Fall 2015 Senior Design Presentation
November 23, 2015
2. Table of Contents
1. Introducing the Problem
a. Kite Hill Impact on Hunnicutt Creek
2. Project Assessment
a. Defining problem, goals, constraints, considerations, and design
elements
3. Design Elements
a. Area of Interest
b. Existing Conditions
c. Design and Methodology
d. Cost Estimation
e. Design Comparisons
4. Sustainability Measures
5. Conclusion
6. Recognition of Problem
Stormwater runoff results in
● Heavy peak flows
Sediment transport / erosion
● Pollution transportation
● Destruction of downstream ecology of Hunnicutt Creek
watershed
12. Define Problem
Lack of infiltration
Pollution runoff
Damage to Hunnicutt Creek
Goals of the Project
Biological: Treat stormwater pollutants
before entering Hunnicutt Creek
Structural: Reduce peak flows and
runoff velocity of stormwater for a 10 yr
- 24 hr storm event
http://www.cnyhiking.com/NCTinPA-MinisterCreekTrail892.jpg
13. Constraints and Considerations
Constraints
Existing Infrastructure
Future Construction
http://fisheyestudios.com/gallery-categories/aerial/
Considerations
Safety
Entering for maintenance
Safety around the area
Sustainability
Minimal maintenance
Durable design options
Aesthetics
Budget
14. 3 Questions
User - Clemson University
1. Is this going to limit where people can park on campus?
2. How much maintenance is required? What does this entail?
3. Will the design be aesthetically pleasing?
Client - Clemson University Facilities, Subcontractor/Developer
1. Can the design system elements be implemented at different times?
2. What is the approximate cost of the design and installation of the project?
3. What is the expected lifetime of the structures and systems being proposed?
Designer - Stormwater Project Team
1. What regulations must we work within?
2. Is the design system resilient?
3. What funding is available for this project? What requirements would need to be met for this design to be implemented?
http://www.sciway.net/sc-photos/wp-content/uploads/tillman-hall-clemson1.jpg
15. Elements of Design
● Kite Hill Erosion Control
● Parking Lot Median
BMPs
● Enhanced Swale
● End of Pipe BMPs
Basemap: Google Maps; Highlighted Areas: J. Davis
17. Area
Section
Area of
Section
(ft2)
Slope
Percent
1 4239 12.9 %
2 2922 22.4 %
3 6033 10.6 %
4 8908 10.5 %
5 11325 3 %
6 5097 19 %
7 11848 5.6 %
8 6938 17 %
Source: Basemap: Google Maps; Area Analysis: J. Ossorio
Hill Redesign:Sub-Goals and Area of Interest
Area
Section
Area of
Section
(ft2)
Slope
Percent
9 4557 8.9 %
10 3236 18 %
11 3589 8 %
12 4642 15.1 %
13 3819 26.8 %
14 4729 9.6 %
15 5309 20.4%
16 4722 18.22 %
Goals:
1. Reduce Erosion from Kite Hill by 75% per yr
2. Safe Driving Option: Gameday parking
3. Reduce Runoff Rate by 25 % for a 25 yr- 24 hr storm
18. Existing Conditions
Universal Soil Loss Equation
(RUSLE): T= R*K*LS*VM
R- Rain factor = 250 (Pickens, SC)
K- Soil Erodibility Factor = 0.17 (Web Soil Survey)
VM- Vegetative Mulch
LS- Length Slope Factor = (Calculated separately for each area)
Estimated Soil Loss
T=(250)*(.17)*(.34)*(2.12) = 9.37 tons/ acre/ year
9.37 tons/ acre/ yr *2.601 acres = 24.39 tons =
22.13 tonnes of SOIL LOSS per
year
Erosion Estimation Runoff Volume Estimates
Soil-Cover Complex Method
CN- Weighted Curve Number = 62.8 for Sod and Mulch
P- Rainfall for 25 yr -24 hr storm = 6.77 in (Rain Data obtained
from Tony Putnam)
S- Surface Storage
Q- Runoff
Vr- Volume of Runoff
S = (1000/CN)-10 = 5.92 in
Q= (P - 0.2S)2/(P + 0.8S) = 2.95 in of runoff
Vr = 2.95 in * (2.60 acres) = 27335 ft3 =
774 m3 of Runoff during a 25 yr
- 24 hr storm
19. Existing Conditions
Photo Credit: Conor Bury, 2015
Runoff Flow Rate Estimates
Peak Runoff Rate
Qp = qp*A*Q
Q = 2.95 in
S = 5.92 in
tL= L0.8(S +1) 0.7/(1900γ0.5)
tc = tL/0.6
Weighted qp = 1.543 (cfs/ac-in)
Qp= (1.543 cfs/ac-in *2.95 in *2.60 ac = 11.6cfs
= 0.329 m3/s is the FLOW
RATE of Runoff during a 25 yr
-24 hr Storm
20. Design 1 - Hillside Terrace
Benches are covered with grass (9600 ft2) and the Risers
are covered with liriope and straw mulch (1790 ft2 = 1020
plants). The Cut and Fill Volume is 385 cu. yd
Erosion Reduction:
Soil Delivery Ratio Method for Slope 14-16%
Reduce Soil Loss per year from 24.39 tons to 1.95 tons
92 % reduction in erosion for overall AOI.
Runoff Volume:
Soil Cover Complex Method Weighted CN 65.2 to 61
Reduce Runoff Volume for a 25 yr- 24 yr storm from 7173 ft3
to 6171 ft3,
13.96 % reduce volume for the hillside area and 3.4 % for total
AOI.
Runoff Peak Flow Rate:
Peak Runoff Rate
Reduce Flow Rate from 3.48 cfs to 2.61 cfs for the hillside
area
25.18 % reduction in Peak Flow Rate.
Design Specs (Determined using Agricultural Terrace Design)
Direction 1: Length 49 ft, 14 %, 0.44 ac
Direction 2: Length 60 ft, 16.5 %, 0.2 ac
Terraces include: 2 benches (14.76 ft),
3 risers (1:1) 2.83 ft depth
Source: Basemap: Google Maps; Area Analysis: J. Ossorio
Source: Chap. 5 Physical Methods for
Erosion Control
21. Design 2 - Hillside Vegetative Cover
Hillside is covered with juniper plants and straw mulch,
but any shrub-like plants can be used for hillside cover.
Erosion Reduction:
Revised Universal Soil Loss Equation Weighted VM from 0.12 to
0.012 (Canopy of Bushes 25% and 80% grass cover)
Reduce Soil Loss per year from 7.5 tons to 1.27 tons
88.6 % reduction in erosion for the hillside area and 27%
reduction for ENTIRE AOI.
Runoff Volume:
Soil Cover Complex Method for Weighted CN from 65.2 to 48
Reduce Runoff Volume for a 25 yr- 24 yr storm from 7173 ft3 to
3339 ft3
53.4% reduce volume for the hillside area and 12.9 % for total
AOI.
Runoff Peak Flow Rate:
Peak Runoff Rate
Reduce Flow Rate from 3.48 cfs to 1.38 cfs for the hillside area
60.44% reduction in Peak Flow Rate.
Source: Basemap: Google Maps; Area Analysis: J. Ossorio
Design Specs:
Direction 1: Length 49 ft, 14 %, 0.44 ac
Direction 2: Length 60 ft, 16.5 %, 0.2 ac
Juniper Spacing: 6 ft (~1030 plants)
http://2minutegardener.blogspot.com/2011/12/p
hoto-creeping-myoporum-myoporum.html
22. Curb and sidewalk removal to add ramp
way (located 425 ft from Perimeter Road
corner)
Area: 1,588 ft2
Width of 60 ft by 25 ft
Design Driving Options
Source: Basemap: Google Maps; Area Analysis: J. Ossorio
Driveway already exists, but the proposal is to allow
access to this entrance after hours by changing
Recycling Center enclosure
New Fencing: 500 ft
Gate Removal: 53 ft
Existing Driveway at Recycling Center Semi-Driveway on Highway 76
Source: Basemap: Google Maps; Area Analysis: J. Ossorio
25. Kite Hill Erosion Reduction: Design Comparison
Hillside Redesign
Terraced Side ($25,630.00)
Pros
-Reduce erosion by 92 %
-Reduce Runoff Volume by 14%
-Reduce Runoff Velocity by 26 %
- Discourages driving on the hillside
-Instant functionality
Cons
-Has some maintenance once established (mulch and cut grass)
-Heavy Construction
Driving Options
Existing Drive at Recycling Center ($7,657.00)
Pros
- Fence is already needed for area
-Already developed Drive
Cons
-Heavy traffic around Recycling Center
Vegetative Cover ($27,542.00)
Pros
-Reduce erosion by 27% overall and 89% for the Area
-Reduce Runoff Volume by 13 % overall and 54 % for Area
-Reduce Runoff Velocity by 61%
- Discourages driving on the hillside
- Low maintenance after establishment
Cons
-3 year establishment
-Cannot Handle foot or car traffic slow recovery
Semi Drive on Highway 76 ($6,811.00)
Pros
-Allows for safer option for drivers who ride of curb on gameday
-Minimal space to preserve Green Space
-Two Entrances and Exits
Cons
-Additional Traffic on game day
32. Medians
Design Comparison
Vegetative Strip with Rain Garden
Pros
- Nearly all runoff that enters swale infiltrates
back into the ground
- Greatly reduces erosion
- Slows down velocity of stormwater
- Removes pollutants
- More permanent solution
Cons
- Eliminates most trees
- Failure issues of pavers
- Maintenance
- Expensive
Coconut Mat
Pros
- Slows down the velocity of stormwater
- Reduces erosion by 91%
- Allows for trees to stay
- Biodegradable mats
- Less expensive
Cons
- Temporary solution (possibly)
- Maintenance
- Less pollutant removal
34. Flow Diversion Techniques
Flow Diversion Options:
Concrete cut with apron & stabilization
Grated Trench Drain
Photo Credit: Conor Bury, 2015 Source: Basemap: Google Maps; Area Analysis: R. Middleswarth
35. Curb Cut with Apron
Divert flow into swale
Must set stabilizers and apron
Concrete
GCL
Erosion Mat
Source: www.lastreetblog.org
source: http://www.beinginplace.org
36. Grated Trench Drain
Source: www.trenchdrainsupply.com
Hill Area
Section
Area of
Section (A)
[m2]
Coefficient of
runoff (C )
Rainfall
Intensity (I)
[m/s]
Volumetric
Flowrate (Qreq)
[m3/s]
1 393.8 ..35 5.6E-05 0.1332
2 271.5
3 560.5
4 827.6
Driveway 432.0 .95
Total 2485.3
37. Grated Trench Drain
Qreq=(k*A*R2/3*S1/2)/n
Qreq - volumetric flowrate
k - conversion from Eng to SI
A - cross sectional area of drain
R - Hydraulic Radius
S- Slope
n - coefficient of friction
Solve for WIDTH
Cross
Sectional
Area (m2)
Hydraulic
Radius (R )
[m]
Slope
Volumetric
Flowrate (Q)
[m3/s]
Coefficient
of Friction
(n)
Base Width (b)
[m]
Peak
Capacity
Depth (h) [m]
0.062 0.198 0.020 0.133 0.013 0.352 0.176
38. Finding Peak Flowrate and Volume
Peak Runoff Rate
Qn = qp*A*Qx
Qx = runoff depth
qp - peak discharge coefficient
S = (1000/CN)-10
tL= L0.8(S +1) 0.7/(1900γ0.5)
tc = tL/0.6
L - Hydraulic Length
y - slope
Soil-Cover Complex Method
S = (1000/CN)-10
CN - Curve Number
P- Rainfall for 25 yr -24 hr storm = 6.77 in (Rain Data
obtained from Tony Putnam)
Qx = (P - 0.2Sn)2/(P + 0.8Sn)
∑Q*Area = total volume of runoff
43,847 ft3 of runoff during a 25 yr - 24
hr storm
Peak Runoff Average
Qdesign =∑(Qn*(Vn/VTOTAL))
V - Volume of basin
Q - Peak Runoff Rate of Basin
7.95 cfs flow rate of runoff during a 25
yr - 24 hr storm
39. Enhanced Swale Design
500ft stretch options:
Grassy Swale
Check Dam Swale
Must Handle a Peak Storm of:
7.95 ft3/s flow rate
43,848 ft3 volume
Source: Basemap: Google Maps; Area Analysis: R. Middleswarth
40. Peak Runoff Rate
A = b*y + z*y2
A = b*0.1 + 0.25*0.12
R = A/(b + 2*0.1*0.25)
Q = 1/n * A * S1/2 * R2/3
Q- volumetric flowrate
A- cross sectional area of drain
R - Hydraulic Radius
S- Slope
n - coefficient of friction
Trapezoidal Grass Swale
Used for channels because of side slope
stability
Easy to maintain
Large surface area for infiltration
Q = 0.225 m3/s
S = 0.06
0.225 = 1/0.033 * (b*0.1 + 0.25*0.12) *
((b*0.1 + 0.25*0.12)/(b + 2*0.1*0.25))⅔ *
0.061/2
b = 1.405 [m]
Source: www.bae.ncsu.edu
42. Enhanced Grass Swale
V=Q/A
V - velocity (m/s)
Q - Peak Flow rate (m3/s)
A - Cross-sectional area (m2)
V = 0.225/.143 = 1.57m/s [5.2 fps]
Factors affecting velocity include:
- Manning’s coefficient n
- Cross-sectional area
- Slope
- designed hydraulic radius
Source: www.scdot.org
43. Enhanced Rock Swale
Rip-rap lined swales have varying n values
Source: www.bae.ncsu.edu
0.1m flow depth = 0.32ft = 3.8in
n = 0.0395*(D50)⅙
(D50) = 3in
n = 0.047
V = 1.09 m/s
(3.2 ft/s)
Source: www.bae.ncsu.edu
44. Check Dam Design
Primary Design Benefits:
Soil Erosion
Sediment Control
Total Suspended Solids (TSS)
Flow Attenuation
Source: www.riverlink.org
Flow Through a dam
Q = h1.5/(L/D + 2.5 + L2)0.5
L = (ss)*(2d - h)
Q- flow rate exiting check dam
h - flow depth
L - length of flow
D - average stone diameter in feet
ss - check dam side slope (maximum 2:1)
d = height of dam
Secondary Benefits:
Runoff Volume Reduction
Phosphorous
Nitrogen
Heavy Metals
Floatables
BOD
45. Check Dam Design
33 ft intervals @ 6% slope
⅓ - ⅔ of the swale depth
~66% slope on upstream side of dam
Acts as terracing to reduce sedimentation and velocity
Dam Depth ft (d) Number of Dams
2.19 15.00
Flowrate through Dam (Q) [ft^3/s] 0.83
Flow depth (h) [ft] 1.46
Length of Flow (L) [ft] 0.73
Stone Diameter (D) [ft] 0.50
Check Dam Slope (ss) 0.25
Exit Velocity (ft/s) 0.54
46. Check Dam Design
Max Retainage
Volume (ft^3)
3388.6
Max Volume
From 25 yr - 24
hr Storm (ft^3)
43847.4
VMAX = N*VDAM
VDAM = ½*d*L*w + 2*(½)*d*x*L
N = number of dams
d = dam height (ft)
L = distance between dams (ft)
w = bottom width
x = x distance of side slope
Source: http://chesapeakestormwater.net/wp-
content/uploads/2014/07/swale_checkdam.jpg
51. End of Pipe “Solutions”
Upstream reductions are not enough
Most common designs are:
Detention basin
Retention basin
Submerged gravel wetland
Goals:
Reduce peak flow
Reduce pollutant runoff http://farm5.static.flickr.com/4093/4908685081_fdcd1f7966_z.jpg
52. Detention Basins
Good at removing sediment, poor at
removing dissolved pollutants
Detention basin size for our area:
200’ x 100’ x 8’
Treats 100 year, 24-hour storm
54. Sedimentation Basin Sizing
Settling velocity for sizing
Stokes Law:
SCDOT Simplified Stokes:
Vs = 2.81·d2
Vs = 2.81·(0.01mm)2 ≈ 2.81∙10-4
ft/s
≈ 8.565∙10-5 m/s
Qout= c∙i∙A = (0.8)(0.15916̅ in/hr)(4.15 acres
= 0.528433ft3s-1
From SWRCB at 90% effectiveness,
55. Gravel Wetland Sizing
“First flush” = 0.2 in · 4.15 ac ≅3000 ft3
Water Quality Volume (WQV) = 4.15 acre-inch ≅ 15,000 ft3
Hydraulic Retention Time ( ) = V / Q
= 4∙V / 4∙Q = 1~2 days
Reduces peak flow of a ten year design storm (3.7” in 6
hours) by ~90%
Wetland dimensions (each cell): L = 110 ft, W = 55 ft
59. Wetland Maintenance
Every six months:
Check for complete plant coverage and revegetate as
necessary
Ensure cells drain within 24-48 hours
Remove decaying vegetation, litter and debris
Sedimentation forebay - Remove sediment after 12” of
accumulation
Gravel treatment cells - Remove sediment after 4” of
60. Gravel Wetland vs Detention Costs
Item Cost Coverage Total
Grading $ 50,000.00 per acre 0.301 acres $ 15,050.00
Piping $ 23.00 per L-ft 36 L-ft $ 828.00
Pipe Labor $ 25.00 per hour 22 hours $ 550.00
Pumped concrete $ 100.00 per cu. yd. 18 cu. yds. $ 1,800.00
Pump Truck Rental $ 130.00 per hour 8 hours $ 1,040.00
Wetland Materials
& Installation
$ 22,300.00 per acre 0.301 acres $ 6,712.30
Total $ 25,980.30
Adjusting for 15% contingency $ ~ 30,000.00
Detention Pond cost $ 40,000.00 per acre 0.5 acres $ ~20,000.00
63. Sustainability Measures
● Economical
○ Installation
○ Maintenance
● Ecological
○ Improving Stream Health
● Social
○ Preserve natural resources
for future generations
○ Educational
● Ethical Considerations
○ Solving the problem without
damage to downstream
http://cantov.deviantart.com/art/Clemson-University-Still-Water-145243984
64. Kite Hill Erosion Control
- Terraced Hillside
- Cost: $25,000
- Vegetative Covered Hillside
- Cost: $27,000
Parking Lot Medians
- Vegetative Filter Strip w/ Rain Garden
- $350,000
- Coconut Mat
- $30,000
Project Cost Summary
McMillan Road Swale
- Grassy Swale
- Cost: $6,100
- Riprap Swale
- Cost: $11,000
- Check Dams
- Cost: $15,000
End of Pipe
- Detention Pond
- $20,000
- Submerged Gravel Wetland
- $30,000
Total Cost of All Designs = $92,000 ~ $415,000
65. 3 Questions Answered
User - Clemson University
1. Is this going to limit where people can park on campus?
2. How much maintenance is required? What does this entail?
3. Will the design be aesthetically pleasing?
Client - Clemson University Facilities, Subcontractor/Developer
1. Can the design system elements be implemented at different times?
2. What is the approximate cost of the design and installation of the project?
3. What is the expected lifetime of the structures and systems being proposed?
Designer - Stormwater Project Team
1. What regulations must we work within?
2. Is the design system resilient?
3. What funding is available for this project?
67. References
Jurries, Dennis, P.E. “Biofilters For Storm Water Discharge Pollution Removal”. Department of Environmental Quality.
State of Oregon. 2003. PDF. <.http://www.deq.state.or.us/wq/stormwater/docs/nwr/biofilters.pdf> Accessed 7 August
2015.
Mey, Gerald Vander. et. al. “Riparian Corridor Master Plan”. Campus Planning Services. Clemson University. December
2006. PDF. <http://www.clemson.edu/public/hunnicutt/documents/riparian_corridor_master_plan.pdf>
Google Maps. Accessed 13 August 2015.
Ruhlman, Melanie. President, Save Our Saluda. Personal communication. 12 August 2015.
Murphree, Brian Frank, P.E. et. al. MS 4 Outfall Inspections and Evaluation, Clemson University. Project No. 1505.
Design South Professionals, Inc. July 2015.
Dorren, Luuk, and Freddy Rey. "A Review of the Effect of Terracing on Erosion." SCAPE: Soil Conseveration and
Protection for Europe (n.d.): 97-108. Web. 15 Oct. 2015.
Watershed Hydrology and Small Catchments, BE3220. Owino, T, PhD. Clemson University. Spring 2015.
http://www.erosionpollution.com/support-files/coir_geotextiles_specification.pdf
69. References
Pitt, R. Detention Pond Design and Analysis. CE 378 Water Resources Engineering. University of Alabama. April
2004.
<http://rpitt.eng.ua.edu/Class/Water%20Resources%20Engineering/M9c2%20WinTR55%20ponds%20docs.pdf>
Northern Concrete Pipe, Inc. Price List: Reinforced Concrete Pipe. Online. Accessed 18 November 2015.
<http://www.ncp-inc.com/price1.html>
TigerDroppings. Thread: “Price per cubic yard for concrete?”. Louisiana State University-community discussion forum.
Online. Accessed 18 November 2015. <http://www.tigerdroppings.com/rant/outdoor/price-per-cubic-yard-for-
concrete/40127861/>
http://www.energy.ca.gov/sitingcases/sangabriel/documents/applicant/afc-cd/AFC_Volume-2/G%20-
%20Preliminary%20Detention%20Basin%20Calculations.pdf
Jarrett, A.R. Water Management. Kendall/Hunt Publishing. 1995.
http://nurcar.com/wholesale_catalog.pdf
http://www.homewyse.com/services/cost_to_install_sod.html
Sheng, T. Bench Terrace Design Made SImple. Department of Earth Resources. Colorado State University. 2002.
70. Acknowledgements
We would like to thank the following for all their help, guidance, patience, and
contribution to literature:
● Dr. Caye Drapcho
● Dr. Tom Owino
● Barrett Anderson
● Tom Jones
● Tony Putnam
● John Gambrel
● Dr. Cal Sawyer
● Dr. Ellen Vincent
● Dr. Paul Russell
● Melanie Rhulman
● Dr. Abdul Khan
● University of New Hampshire Stormwater Center
Editor's Notes
Conor
Here is an overview of the Clemson University watershed. Everything inside the PURPLE LINE drains into Hunnicutt Creek, and from there gets pumped into Lake Hartwell.
Our project focused on the Kite Hill area which can be seen right here (point out our area)
Conor
Here you can see two maps of our area of interest. The map on the left illustrates subsurface storm drain pipes in red.
As you can see, each flow route eventually ends up in Hunnicutt creek at the end of this pipe
Conor
The stormwater runoff results in heavy peak flows due to the high percentage of impervious surface area
This means that nearly all of the rain that falls gets quickly transported straight into Hunnicutt Creek.
This massive influx of water produces considerable erosion of the creek bed.
It is also responsible for pollution transportation from the Kite Hill parking lot, which leads to destruction within the downstream ecology
These two pictures are taken towards the top of our area of interest, looking towards Kite Hill
This shows heavy runoff and sedimentation transportation coming off of Kite Hill and running down MacMillan Rd.
This drain is supposed to be catching the runoff show in the previous slide, but as you can see, most of the water flows across
the road and into the storm drain located behind the cars seen here
Here is the end of the pipe network from the Kite Hill parking lot which shows the heavy volume of water and sediment
The water flows from this pipe, down this stream...
And into this massive crater that was created by erosion.
To give some sense of scale, this is about 20 - 25 feet deep and about 50 feet across.
Obviously this goes beyond the concern of stream health and into the realm of human safety
We defined our problem as having a lack of infiltration with heavy pollution runoff, which leads to damage downstream in Hunnicutt Creek.
Our goals of the project are both biological and structural.
Our biological goals entail biologically remediating the pollution runoff.
Our structural goals entail reducing peak flows for a 10 year, 24 hr storm event
Conor
The constraints for our project include designing around a busy existing infrastructure with high demand on space, such as traffic and parking on game day
This must be taken into account when selecting locations and materials
We must also be mindful of future planned construction projects that would compete for space
For considerations, safety is our top priority. The area needs to not only be safe for maintenance, but for local traffic, motor or pedestrian, as well
The design needs to strive for sustainability, with minimal energy and resource input for maintenance, as well as be long-lasting
It needs to be aesthetically pleasing, as well as functional
And as always, we want to be mindful of cost during design
Conor
C
The image above shows the four different areas of interest for this project.
Jeannie will talk to you about erosion control on Kite Hill.
Ashleigh will speak about the parking lot medians and the Best Management Practices, or BMPs, associated with that
Ray will propose options on different swale designs in the areas highlighted in blue,
And Jeremiah and I will speak to BMPs located at the end of pipes
So as for erosion control off Kite Hill,
We first needed to define our area of interest. This extends from the edge of the recycling facility down to MacMillan Rd.
A ridge boundary line was chosen based on the topography and likelihood of flow direction.
Because an erosion analysis was dependent upon slope, the area of interest was divided into 16 segments of like conditions.
Goals:
Reduce Erosion from Kite Hill by 75% per yr
Safe Driving Option: Gameday parking
Reduce Runoff Rate by 25 % for a 25 yr- 24 hr storm
real runoff 842 m3 = 29736 ft3
Using the Revised Universal Soil Loss Equation, we determined an estimated soil loss of about 23 tons per year.
Using the soil-cover complex method, we estimated a runoff volume of 774 cubic meters for a 25 year, 24 hour storm.
12.64 cfs
0.357 m3
The existing peak runoff rate was determined to be about a third of a cubic meter per second for a 25 year, 24 hour storm.
Spacing for Liropie is 18”
Two effective means of reducing erosion are terracing and utilizing a vegetative cover better suited to reduce flows.
These measures were developed with the intent that visitors would not drive over them.
Our design involved two benches and three risers, with a grass covering on the benches, and liriope and pine straw cover on the risers.
This design is able to reduce the overall erosion from the entire area by 92 %, as well as reduce the runoff volume over the hillside portion by 14 %, and the total area by 3.4 %
Terracing is also able to reduce the overall flow rate by 25 %
An alternative design would involve altering the vegetative cover only.
In this design, woody-shrubbing plants such as juniper are planted not only to reduce erosion by dissipating the rainfall intensity upon the soil and reducing the runoff velocity,
but also as a vegetative fence, preventing automotive traffic in certain areas that could otherwise be disturbed by the traffic.
This design is able to reduce the overall erosion over the hillside area by 89%, and a 27% reduction across the entire area
The runoff volume over the hillside portion could be reduced by 54%, with a reduction of 13% over the entire area
Vegetative cover is also able to reduce the overall flow rate by 61 %
By eliminating the hillside as an option for commuting on and off of Kite Hill, the current gate around the Recycling facility would need to be changed
Currently they close the entrance gate when at the end of the work day,
We would propose to realign the fences so that the business can be closed, but the driveway can remain open for commuting on and off the hill.
This would require about 500 ft of new fencing and the removal of about 55 ft of fencing
As another driving option, a semi-driveway can be implemented on Hwy 76, located about 400 ft from the intersection with Perimeter Road
As people drive over the curb anyway, it would be better managed to have a directed access point.
This drive would be 1600 sq. ft.
After completing the budget for the hillside designs, it was determined that the Terraced Hillside will cost approximately $25 grand to install, which includes an additional 15 % for contingency
The Vegetative Cover installation Cost is approximately $28 grand which also includes a 15% contingency
The estimated budget for the fencing installation at the Recycling Center is about $8 grand, and the installation of a semi- driveway would be around $7 grand
changing the manning’s n - between short and tall vegetation
changing the depth of the channel from 1 foot to 6 inches
. The ponding depth of the rain garden ranges between 6 and 12 inches, and the side slopes should be gently sloping (3 feet horizontal to 1 foot vertical). Side slopes that exceed this recommendation require mechanical compaction, which will ruin the infiltration capacity of the amended soil in this area and also make it much more difficult to establish plantings.
70% of the total suspended solids from 80 to 90% of the average annual runoff
phosphorus removal rate to be 25 to 50%; nitrogen removal rate was estimated at 40 to 60%
Made from a natural and biodegradable coconut fiber, these mats work to increase soil stabilization, effectively decreasing erosion and allowing vegetation to effectively take root (vegetation is optional). These mats are recommended for steep slopes such as stream bank erosion.
- the top is buried about 6 inches underneath the top of the slope - should have seeding before mat is installed - 4 to 6 years will biodegrade naturally
live stakes are dormant plant material - as they grow they will help anchor the mat - some type of tall iscantus
no till - can use horticulture crops or hay and pasture
overland flow - sheet flow (before mat)
gives enough time for the grass to establish
Hey Ash: http://www.clemson.edu/extension/hgic/plants/landscape/groundcovers/hgic1108.html
http://nurcar.com/wholesale_catalog.pdf (~$4/gal) space 16” apart on center in moderate to low flooding areas. space 12” apart in extremely high overflow area. coverage area: pi*8”*8” = ~200 sq in = ~ 1.4 sq ft. Find required area, divide by 1.4 sq ft = # of plants you need * $4/plant. Sugars.
For soil group B reduction
TSS = 60%
TP = 32%
TN = 36%
For low flows, check-dam geometry and swale width are actually more influential on flow than stone size. The average flow length through a check-dam as a function of flow depth can be determined by the following equation:
For low flows, check-dam geometry and swale width are actually more influential on flow than stone size. The average flow length through a check-dam as a function of flow depth can be determined by the following equation:
For low flows, check-dam geometry and swale width are actually more influential on flow than stone size. The average flow length through a check-dam as a function of flow depth can be determined by the following equation:
For low flows, check-dam geometry and swale width are actually more influential on flow than stone size. The average flow length through a check-dam as a function of flow depth can be determined by the following equation:
C
So we have all these design solutions upstream of the pipe, but they are not enough to thoroughly remediate pollutants
The most common end of pipe BMPs are detention basins and retention basins.
A detention basin is dry in between storms, while a retention basin has a permanent pool of water.
We focused on a detention basin design, as well as a “hybrid” between the two, called a submerged gravel wetland
C
Here we see an example of a detention basin.
Detention basins are typically used to manage peak runoff from large storm events
While they can remove some sediments in runoff, they remove little to no pollutants
The size of the detention basin needed to treat the runoff for our area of interest would be about 200’ x 100’ with a depth of 8’
This size would be large enough to treat a 100 year, 24-hour storm event
As one of our original goals was to remove pollutants from the runoff coming off Kite Hill,
this design would not be our preferred BMP
J
This figure illustrates a model developed by the University of New Hampshire.
There is a sedimentation forebay before the first cell. Flow travels from the forebay into the surface region of the next cell.
The vertical perforated pipes seen here use an elevation head and hydrostatic pressure to force flow through the subsurface system
The subsurface layer is always submerged, creating an anoxic zone where facultative anaerobic microbes can metabolically decompose pollutants
While this system typically requires a liner to prevent water infiltration into the soil below,
the hydraulic conductivity of the soil in our area of interest is low enough to not require one
In the event that flow reduces to zero, the system remains in a stable state, where further pollutant decomposition can occur
Our modifications incorporate a concrete-core-reinforced earthen dam between each cell.
This system can withstand both extended droughts and peak flows from a large storm event.
Using parameters we found from From the California EPA State Water Resources Control Board
We started looking into calculating the settling velocity using a classic form of Stokes law,
but found too much variability. We later came across a simplified version of Stokes law
in an SCDOT Stormwater manual that that fell under the same parameters we were working under.
We calculated the settling velocity, the discharge for a 2 yr, 24 hour storm,
and the effective surface area, length, and width for 90% sediment removal.
SCDOT Stormwater Manual
Reports Cecil as d15 = 0.0066 ~ 0.0043 mm
If d15 < 0.01 mm, use simplified Stokes,
where,
d = particle diameter in mm
Vs = settling velocity in ft/s
Designing the channel as parabolic ensures uniform velocity along any cross-sectional slice normal to the channel length regardless of position within the cross-section (Assoc. Prof R.J. Keller, CIV3264, Dokuz Eylül University, Turkey)
J
From our literature review, we found that nearly all surface pollutants are washed off in the first fifth of an inch of rain.
This first flush became a necessary parameter to accommodate in our design.
We also needed to allow enough residence time for the microbes to decompose the pollutants.
We therefore sized the submerged zone within our gravel wetland to accommodate both this first flush
plus our water quality volume of 1 in over the entire 4.15 acres,
as well as the necessary hydraulic retention time needed to obtain the same results as the Univ. of New Hampshire study.
This design size also reduces the peak flow of of a 10 year, 24 hr storm by ~90%
Here we see a representative diagram of how we are proposing to lay out this design.
A maintenance crew could access the basin from a proposed service road which would run alongside the forebay.
(if asked: A crew with shovels, or potentially a bobcat could dredge out the wetland cells.)
J
This hydrograph illustrates roughly a 90% reduction in peak flow from the University of New Hampshire study.
To get a similar influent peak flow in Clemson, SC would require a 5-yr, 24hr storm (NOAA data).
This design would reduce a 5 year peak flow from about 300 GPM to about 30 GPM.
J
This figure illustrates the percent reduction of pollutants in this study. TSS, TPH-D, DIN, and heavy metals such as ZN are all reduced by more than 90%.
The performance in P removal was much less than the other pollutants in this study. However there was still more than 50% removal.
(DIN has a similar performance in the warmer months, but considering this study was conducted in New Hampshire, our warmer climate in SC will allow for greater microbiological activity, likely improving the performance in colder months.)
TSS - Total Suspended Solids
TPH-D - Total Petroleum Hydrocarbons as Diesel
DIN - Dissolved Inorganic Nitrogen (sum of nitrate and ammonia)
Zn - Zinc
TP - Total Phosphorous
J
Here we see a checklist for maintenance to be performed about every 6 months
which would include dredging and checking for plant health
(if asked: from our literature review, we found a common round estimate of $1500/yr in maintenance)
J
We performed a rough itemized cost estimate for the gravel wetland. Our rate values came from interviews and web references.
A more accurate estimation would come from the R.S. Means Building Construction costs, but purchasing access to this alone would have exceeded our design budget.
Our price for a detention pond was referenced from a published estimation by a professor at the Univ. of Alabama.
Adjusting for contingency, our cost estimation for installation of the gravel wetland was under $30,000. The cost estimation for the detention pond was about $20,000.
Conor
Sustainability measures for this project include economic sustainability - we want it be economically feasible both in the installation
and maintenance phases
Ecological sustainability is obvious - we want to improve the health of Hunnicutt Creek
There is also a measure of social sustainability as we want to do our best to preserve the natural resources that we have for future generations
Ethical consid
In summary, we saw a significant improvement from existing conditions with each individual measure.
With the added benefit of breaking our analysis into modules, each element can be implemented individually, collectively, or sequentially as per the User’s preference.
The cost range from our lowest collective cost options to the highest collective cost options ranges from $92,000 to $415,000.
So when we started this project, we asked three questions each likely asked by the end user, the client, and the designer
1. No
2. Depending on the designs chosen, maintenance will vary, but in general, the designs are mostly low maintenance.
3. While aesthetics are of course subjective, the designs presented all take aesthetics into account
1. The overall drainage design was made to allow the different system elements to be implemented at different times
2. Depending on the designs chosen, the total cost for the projects range from $70,000 to $400,000
3. Given proper maintenance, the structures should last be able to last indefinitely, or at least until the next major project in the area
1. Must work within the EPA stormwater regulations, Clemson University design standards, “Waters of the US” under the Clean Water Act
2. Given proper maintenance, the structures are resilient and are able to withstand large storms
3. Clemson University has set aside about $150,000 for this area
