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

http://www.clemson.edu/public/hunnicutt/about.html

Recognition of Problem Stormwater runoff from Kite Hill and Kite Hill parking lot resulting in:● Erosion

● Pollution transportation

● Destruction of downstream ecology of Hunnicutt Creek watershed

Photo Credit: Conor Bury, 2015

Photo Credit: Conor Bury, 2015

Photo Credit: Conor Bury, 2015

Photo Credit: Conor Bury, 2015

Define ProblemLack of infiltration

Pollution runoff

Damage to Hunnicutt Creek

Goals of the ProjectThe goal of this project is to biologically treat stormwater runoff, and increase infiltration back into the ground to improve the water quality of the downstream watershed of Hunnicutt Creek. ● Reduce peak flow rates● Slow velocity ● Improving quality

○ Reducing soil erosion ○ Treating pollution

■ Microbiological and Phytological processes■ Physical mechanical filtration and ionic exchange capacity

within the soil layers itself

Constraints and Considerations Constraints

Existing InfrastructureFuture ConstructionTheoretical data/ Experimental Data Multiple advisorsBudget

http://fisheyestudios.com/gallery-categories/aerial/

ConsiderationsSafety

Entering for maintenanceSafety around the areaProhibiting pollution to groundwater

SustainabilitySelf-sustaining

Biological FiltrationPossible Implementation

MS4 RegulationsRiparian Corridor Master Plan

Aesthetics

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?

4. What reduction of runoff can be expected?Client - Clemson University Facilities, Subcontractor/Developer, Stormwater Project Team

5. Can the design system elements be implemented at different times?

6. What is the approximate cost of the design and installation of the project?

7. What is the expected lifetime of the structures and systems being proposed?

Designer - Stormwater Project Team8. What regulations must we work within?

9. Is the design system resilient?

10. What funding is available for this project? What requirements would need to be met for this design to be implemented?

http://nypost.com/2014/09/24/frat-activities-banned-at-clemson-university/

Source: Basemap: Google Maps; Highlighted Areas: J. Davis

Elements of Design ● Kite Hill Erosion Control

● Parking Lot Median BMPs

● Enhanced Swale

● End of Pipe BMPs

Basemap: Google Maps; Highlighted Areas: J. Davis

Sub-Goals of Hill Redesign1.Reduce Erosion from Kite Hill by 75%

per yr2.Reduce Runoff Volume by 50 % for a

25 yr- 24 hr storm3.Safe Driving Option: Gameday parking

Area Section

Area of Section (m2)

Slope Percent

1 394 14 %

2 272 20 %

3 560 12 %

4 828 11.5 %

5 1052 9.5 %

6 479 19 %

7 1101 8.2 %

8 642 17 %

9 423 5 %

10 290 18 %

Source: Basemap: Google Maps; Area Analysis: J. Ossorio

Area of Interest Defined

Universal Soil Loss Equation T= R*K*LS*C*PR- Rain factor = 250 (Pickens, SC)K- Soil Erodibility Factor = 0.17 (Web Soil Survey)C- Cropping Factor = 0.01 (For complete Meadow)P- Conservation Practice = 1 (Assume not preventive practice)LS- Length Slope Factor = (Calculated separately for each area)

Area Section

Length Slope Factor

1 2.5

2 2.7

3 2.2

4 2.5

5 1.3

Estimated Soil Loss

T=(250)*(.17)*(.01)*(1)*(22.6) = 9.5625 tons/ acre/ year

9.5625 tons/ acre/ yr *1.54 acres = 14.726 tons =

13.36 metric tonnes of SOIL LOSS per year

Area Section

Length Slope Factor

6 3

7 1.1

8 3.5

9 0.7

10 3.1

Photo Credit: Conor Bury, 2015

Runoff Volume Estimates Soil-Cover Complex Method CN- Curve Number= 61 (Urban Area Grass Cover Open Area, HSG B, <75% grass cover)P- Rainfall for 25 yr -24 hr storm = 6.77 in (Rain Data obtained from Tony Putnam)S- Surface StorageQ- Runoff Vr- Volume of Runoff

S = (1000/CN)-10 = 6.39 inQ= (P - 0.2S)2/(P + 0.8S) = 2.538 in of runoffVr = 2.538 in * (1.54 acres) = 21,850 ft3 =

618.7 m3 of Runoff during a 25 yr - 24 hr storm

Photo Credit: Conor Bury, 2015

Runoff Flow Rate Estimates Peak Runoff Rate Qp = qp*A*QQ = 2.538 inS = 6.39 intL= L0.8(S +1) 0.7/(1900γ0.5)tc = tL/0.6

Area Section

Flow Length

(ft)

Slope (%)

tC

(min)qp

(cfs/acre-in)

qp *A

(cfs/in)

1 256 14 4.8 1.8 0.18

2 155 20 2.7 2 0.2

3 282 12 5.6 1.6 0.224

4 325 11.5 6.4 1.5 0.30

5 360 9.5 7.7 1.4 0.364

Area Section

Flow Length

(ft)

Slope (%)

tC

(min)qp

(cfs/acre-in)

qp *A

(cfs/in)

6 252 19 4.1 1.85 0.222

7 450 8.2 9.8 1.3 0.351

8 330 17 5.6 1.6 0.256

9 411 5 11.8 0.8 0.08

10 375 18 5.8 1.6 0.16

Weighted qp = 1.517 (cfs/ac-in)Qp= (1.517 cfs/ac-in *2.538 in *1.54 ac = 5.93 cfs

= 0.168 m3/s is the FLOW RATE of Runoff during a 25 yr -24 hr Storm

Design Option 1: Terracing with ExistingDriveway at Recycling Center

SDR- Soil Delivery Ratio = 14 %LS for 60 ft - 13% = 3 LS for 15 ft - 13% = 1

3 = 9.5625 ton/ac/yr1 = (⅓) * 9.5625 ton = 3.1875 tons per terrace

Source: Basemap: Google Maps; Area Analysis: J. Ossorio

3 - 15 ft Terraces have the potential to reduce Soil Loss per year from 9.5625 ton/ ac to 0.518 ton/ac, a 95 %

reduction in erosion.

Terrace Designs that encourage more infiltration and velocity reductions

Design Option 1: Terracing with ExistingDriveway at Recycling Center

Source: Basemap: Google Maps; Area Analysis: J. Ossorio www. intechopen.com

Driveway already exists, but the proposal is to allow access to this entrance after hours by changing Recycling Center enclosure

Design Option 2: Create an entrance driveway to Kite Hill

Driveway allows for safe maneuvering on and off of Kite Hill

The Paved Area should mimic current runoff behaviors

PermeableSurface Storage (S) 6.39 in/ac and Q

= 2. 538 in 25 yr- 24 hr to avoid runoff increase

Asphalt Has Surface Storage (S) of 0.204 in

[CN = 98] and Q = 6.538 inNeed to decrease curve number of

other areas to compensateOverall Runoff increased from

2.54 in to 2.94 inSource: Basemap: Google Maps; Area Analysis: J. Ossorio

Design Option 2: Create an entrance driveway to Kite Hill

Erosion Control (Goal: Reduce by 75%)Universal Soil LossT=R*K*LS*C*P

P: The addition of a Conversation practice like contouring can reduce on a slope of 9-12 %

P factor will decrease from 1 to 0.60 for that area

LS: The factor will decrease because the slope % will need to be cut down to 12% or less a safe drive

C: Heavier vegetation (erosion control covers) can be added on sides to allow for less erosion

Runoff Velocity and Volume (Reduce Volume by 50%)Soil-Cover Complex Method

CN: By implementing different land cover with lower Curve Numbers can reduce the volume and velocity

Peak Runoff RateS: To implement the driveway the % slope

will be decreased, which will help slow velocities

Kite Hill Erosion Reduction Design ComparisonOption 1 Pros -Reduce erosion significantly-Preserve green space of Kite Hill-Potential to slow velocity and reduce runoff -Discourages driving up side of Kite Hill Cons -Expensive Soil Conservation Practice -Construction and Maintenance of terraces-Failure to maintain terraces can result in degradation of bench (possible landslide)-Adds heavy traffic volume at the Recycling Center

Option 2 Pros -Allows for two entrances for heavy traffic-Reduce Erosion with implementations -Allows for safer travel up side of Kite Hill Cons -Driveways require slope % of 12 % or less for safety-Require extensive cut and fill into the Hill -If driveway is permeable, extra maintenance to prevent clogging of the pores-Reinforce permeable pavement -May increase runoff velocity

Flow Diversion TechniquesFlow Diversion Options:

Concrete cut with apron & stabilizationGrated Trench Drain Flow Diverting Speed Bumps

Must handle QR=0.168 m3/s

Photo Credit: Conor Bury, 2015 Source: Basemap: Google Maps; Area Analysis: R. Middleswarth

Curb Cut with ApronDivert flow into swale Must set stabilizers and apron

ConcreteGCLErosion Mat

May disturb swale function

Source: www.lastreetblog.orgPhoto Credit: Conor Bury, 2015

Grated Trench DrainQ=(k*A*R2/3*S1/2)/n

Q- volumetric flowrate A- cross sectional area of drain

R - Hydraulic Radius S- Slope

n - coefficient of friction

Source: www.trenchdrainsupply.com

Source: www.lastreetblog.org

Enhanced Swale Design500ft stretch options:

Grassy SwaleRiprap SwaleCheck Dam Swale

Source: Basemap: Google Maps; Area Analysis: R. Middleswarth

Trapezoidal Swale

Used for unlined channels because of side slope stability

Easy to cut grass and maintainLarge surface area for infiltration

Enhanced Grassy and Rocky SwaleQ=(k*A*R2/3*S1/2)/nQ- volumetric flowrate A- cross sectional area of drainR - Hydraulic Radius S- Slope n - coefficient of friction

For soil group B reduction- TSS = 60%- TP = 32%- TN = 36%

Source: www.bae.ncsu.edu

Source: www.bae.ncsu.edu

Enhanced Grass SwaleV=Q/A

V - velocity (m/s)Q - Peak Flow rate (m3/s)A - Cross-sectional area (m2)

Factors affecting velocity include:- Manning’s coefficient n- Cross-sectional area- Slope- designed hydraulic radius

Source: www.bae.ncsu.edu

Enhanced Rock SwaleRip-rap lined swales have varying n values

Source: www.bae.ncsu.edu

Check Dam DesignPrimary Design Benefits:

Soil ErosionSediment ControlTotal Suspended Solids (TSS)Flow Attenuation

Secondary Benefits:Runoff Volume ReductionPhosphorousNitrogenHeavy MetalsFloatablesBOD

Source: www.riverlink.org

Check Dam Design33 ft intervals @ 6% slope⅓ - ⅔ of the swale depth~66% slope on upstream side of damActs as terracing to reduce sedimentation

and velocityFlow Through a damQ = 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

McMillan Road Enhanced Swale Design ComparisonCheck Dams Pros

- Inexpensive - Reduces erosion and sediment transport- Allows infiltration- May discourage illegal parking

Cons- Requires periodic repair and sediment

removal- Allows infiltration- Doesn’t treat oils

Grassy / Riprap Swale (dry)Pros

- Simple Installation- Easy Maintenance- Aesthetically Pleasing

Cons - May form rills- Higher velocity- Less treatment and infiltration than other

methods

Alternatives

Sources: www.austintexas.gov

Source: www.thisoldhous.com

Source: www.lakesuperiorstreams.com

Sub-Goals of Median Redesign1.Reduce the Velocity of Runoff2.Allow Infiltration into Medians3.Prevent Sediment Loss

Area of Interest Defined Parking Lot Medians

1234

56

7

Area (m2)

Slope (%)H.

Slope (%)V.

1 385.11 10.8 1.0

2 613.41 4.2 0.9

3 923.9 6.7 0.8

4 929.79 6.1 1.0

5 735.48 6.4 1.2

6 695.93 5.9 1.4

7 601.01 5.0 1.6

Source: Google Maps

Design 1 - Vegetated Filter Strip Manning’s EquationV = (k/n)*Rh

(⅔)*So(½)

k: coefficient to convert unitsk = 1.486 (US Customary Units)

n: Gauckler-Manning’s coefficient short vegetation - 2 to 6 inches: 0.04 tall vegetation - 12 to 24 inches: 0.08

Rh: hydraulic radius - Rh = areaCS/wetted perimeter

So: slope of channel length bedParabolic Channel Design

Slope V (short veg 12”) f/s

V (short veg 6”) f/s

V (tall veg 12”) f/s

V (tall veg 6”) f/s

1 0.01 0.330 0.083 0.165 0.041

2 0.009 0.297 0.074 0.149 0.037

3 0.008 0.264 0.066 0.132 0.033

4 0.01 0.330 0.826 0.165 0.041

5 0.012 0.396 0.099 0.198 0.49

6 0.014 0.462 0116 0.231 0.058

7 0.016 0.528 0.132 0.264 0.066

Design 1: Vegetated Filter Strip

Excavation - cut and fill using pavers Curb cuts versus curb stops

http://www.lowes.com/Outdoors/Pavers-Retaining-Walls/_/N-1z0wgaf/pl

http://www.publicdomainpictures.net/view-image.php?image=3409&picture=parking-lot

http://www.estuarypartnership.org/sites/default/files/fieldguide/examples/swale.htm

http://www.hrwc.net/stormwaterbmps.htm

Vegetated Filter Strip

Soil - gravel layer Plants

http://www.clemson.edu/psapublishing/pages/HORT/IL87.PDF

http://www.watershedmanagement.vt.gov/stormwater/htm/sw_gi_bmp_bioretention.htm

http://www.emuseum.org/alcoa-foundation-outdoor-classroom

Design 2 - Erosion MatCoconut Fiber MatVegetation Live stakes

T= R*K*LS*C*PR- Rain factor = 250 (Pickens, SC)K- Soil Erodibility Factor = 0.17 (Web Soil Survey)C- Cropping Factor = 0.01 (For complete Meadow)P- Conservation Practice = 1 (Assume not preventive

practice)LS- Length Slope Factor

- For the steepest slope - Control Mat 40 (Granite Environmental) - 80% efficiency of sediment removal

http://www.in.gov/legislative/iac/20120404-IR-312120154NRA.xml.html

Erosion Mat

Permeable Pavement

Miscanthus Grass

http://www.in.gov/legislative/iac/20120404-IR-312120154NRA.xml.html

http://www.vwrrc.vt.edu/swc/NonPBMPSpecsMarch11/VASWMBMPSpec7PERMEABLEPAVEMENT.html

http://www.hgtvgardens.com/flowers-and-plants/maiden-grass-miscanthus-sinensis-morning-light

Medians Design ComparisonOption 1 Pros -Reduce sediment, pollutants and velocity of stormwater-Allow more time for infiltration of stormwater -Adds more green area to Kite Hill (aesthetically pleasing) Cons -Steep slope adds more complex issue-Maintenance -Failure of pavers

Option 2 Pros -Allows for more infiltration -Reduce erosion with vegetated matCons -Failure of permeable pavement

-Sediment clogging -Anaerobic issues

-4 to 6 year life span-Pollutant removal -Maintenance

End of Pipe “Solutions”● Upstream reductions are not enough

● Most common designs are:○Detention Basin

○ Retention basin■ Submerged gravel wetland

Detention Pond● Reduce peak flows

● Little filtration

● Little to no pollutant conversion

Source: https://stormwater.files.wordpress.com/2009/05/img_4745.jpg?w=640

Retention Pond

Source: http://water.epa.gov/scitech/wastetech/upload/2002_06_28_mtb_wetdtnpn.pdf

Settling VelocitiesStokes Law for settling velocities:

where, VS: settling velocity VP: volume of particleρP: density of particle CD: drag coefficient ρ: density of fluid AP: surface area of particle g: gravitational constant

Settling Velocities cont.To get the VP and AP,

Approximated particle geometry as sphere

Found mean particle diameter (d50) for Cecil Sandy Loam(low: 0.2 cm, high: 7.4 cm; Source: Web Soils Survey)Low end value used to determine minimum settling velocity

Calculated mean particle volume (4/3· ·r𝜋 3) and surface area (4· ·r𝜋 2) VPmin = 0.004189 cm3 APmin = 0.125664 cm2

Settling Velocities cont.To get the ρP, ρ, and CD,

An average soil particle density value: 2.66 g/cm3

Assuming pure water at 4oC and 1 atm: 1 g/cm3

CD can be determined experimentally or using representative values

Unfortunately this value can change dramatically depending onthe number of particles fallingthe true particle geometryaggregate particles vs single particlesturbulence generated by mass particles falling

Settling Velocities cont.Given the high level of variability,

SCDOT Stormwater ManualReports Cecil as d15 = 0.0066 ~ 0.0043 mmIf d15 < 0.01 mm, use simplified Stokes,

Vs = 2.81·d2

where,d = particle diameter in mmVs = settling velocity in ft/s

Settling Velocities cont.SCDOT Stormwater Manual

Reports Cecil ranging in particle sizes as 0.001 ~ 1.4 mm,

Vs = 2.81·(0.001)2 ≈ 2.81·10-6 ft/s ≈ 8.56·10-7 m/s

Vs = 2.81·(1.4)2 ≈ 5.51 ft/s ≈ 1.68 m/s

Sizing a basin is not enough.Vegetation, microbial, and aggregate filtration necessary.

Filtration

Source: http://www.deq.state.or.us/wq/stormwater/docs/nwr/biofilters.pdf

Source: J. Davis

Submerged Gravel Wetland

http://www.neiwpcc.org/neiwpcc_docs/GravelWetlandNutrientCyclingFinalReport3-31-10.pdf

Rational Equation for Peak Discharge:

Q = ciAWhere,Q = peak discharge [cfs]c = runoff coefficienti = rainfall intensity [in/d]A = area [acres]

Five year design storm:

Q = (0.8)(4.73in/d)(4.15ac)Q = 293GPM

Sustainability Measures ● Economical

○ Feasibility ○ Maintenance○ Location

● Ecological○ Improving Stream Health

● Social○ Educational

■ Foundation in Clemson’s Will

■ Biosystems Engineering● Ethical Considerations

○ Solving the problem without damage to downstream

http://cantov.deviantart.com/art/Clemson-University-Still-Water-145243984

Time Line

ReferencesJurries, 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.

Widomski, Marcin K. "Terracing as a Measure of Soil Erosion Control and Its Effect on Improvement of Infiltration in Eroded Environment." Ed. Danilo Godone. Soil Erosion Issues in Agriculture (2011): 315-34. InTech. Web. 15 Oct. 2015. <http://www.intechopen.com/books/soil-erosion-issues-inagriculture/ terracing-as-a-measure-of-soil-erosion-control-and-its-effect-on-improvement-of-infiltration-in-erod>.

Watershed Hydrology and Small Catchments, BE3220. Owino, T, PhD. Clemson University. Spring 2015.

http://www.erosionpollution.com/support-files/coir_geotextiles_specification.pdf

http://water.epa.gov/scitech/wastetech/upload/2002_06_28_mtb_wetdtnpn.pdf

http://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/pubs_specs_info/unhsc_gravel_wetland_specs_6_09.pdf

http://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/presentations/NJASLA%20subsurface%20gravel%20wetland.pdf

http://sfrc.ifas.ufl.edu/urbanforestry/Resources/PDF%20downloads/Rushton_2001.pdf