The document discusses a proposed stormwater management plan for a new 400-space parking lot at Clemson University. It outlines regulations regarding stormwater runoff and describes Clemson's watershed that receives runoff. The goal is to prevent parking lot runoff from entering the watershed while filtering pollutants. Calculations determine the required bioretention cell size as 75% of the water quality volume (4,500 square feet). The design includes components like plants, soil, and an overflow. Alternatives like porous pavement are also considered.

1. Clemson Parking
Stormwater
Management
Carolyn Coffey
Brendan Luther
Karris Roland
Chelsea Walker

2. Overview
● Introduction to Clemson stormwater
● Goal of the project
● Potential management solutions
● Governing equations and design
● Sustainability and Life Cycle
● Questions & Comments

3. Background and History of Stormwater
Regulations
- In 1972 the Clean Water Act prohibited any pollutant accessible to waters from a point source.
- Runoff carries sediment, pollutants, grease, or oil into storm drains and surface waters
- Water Quality Act of 1987 created a structure for different methodologies, including discharge
permits for various classifications.
On October 31, 1990 the US EPA issued the stormwater rule for the classifications of stormwater
systems subject to regulation:
● Combined sewer overflows (both sanitary sewage and industrial processes)
● Wastewater are mixed with rainwater and land runoff
● Municipal separate stormwater systems
● Separate stormwater systems
● Non-point source runoff (all runoff that is not discharged to surface waters via a discrete pipe or
conduit)

4. Clemson Watershed
● Runoff primarily flows to Hunnicutt Creek
o Pollutants from parking lots
o Soil displacement and erosion
o High peak flow rates
● Nearly 22% of campus is impervious

5. Image:
http://www.clemson.edu/public/hu
nnicutt/about.html

6. Parking services
● Growing university calls for
more on campus parking
availability
● Proposed lot with additional
400 spaces
● Between the university and
city watersheds
http://reisasphalt.com/wp-content/uploads/parking-lot.
jpg

10. Problem
● Runoff from parking lot could add to
Clemson’s flooding problems
● Need for better management practices

11. Goal
● Prevent parking lot runoff from entering
the Clemson watershed
● Filter stormwater pollutants
● Maintain pre-development hydrology
● Ensure infiltration using a bioretention
cell

12. Constraints
● Budget: $1200
● Heavy machinery might be necessary
● Permitting constraints
● Potential for large storm events
● Experience of design team

13. Considerations for Design
Soil Type
- Soil Conservation Service classifies more than 4000 different types of soils into four groups
http://www.wetlandstudies.com/newsletters/2012/september/docs/hydro_soil_groups.pdf
- The physical properties include infiltration rates and relative runoff potential
- Web Soil Survey showed the area classified as Group B.
- Group B has infiltration rates from 0.15 to 0.30 inches per hour and moderate runoff potential
- A curve number is calculated for pre and post development to indicate the runoff potential for
the area

16. Calculations
Bioretention Cell Volume
Requirement
WQv = (P*Rv*A)/12
P - Rainfall in Inches
Rv = Volumetric Runoff Coefficient
A = Area in Acres
WQv = 9598.5 ft2
Post Development
CN = 99 for parking lots
Maximum Soil Water Retention:
(1000/99) - 10 = 0.1010
Water Quality Runoff Volume:
P equals 1 inch for east coast of the United States
1”= 90% of average annual precipitation

17. Surface Area of Bioretention Cell
- Must hold 75% of Water Quality Volume
- Af = (WV*df)/[K*(hf+df)(tf)]
- WV = WQv
- df = filter bed depth
- K = coefficient of permeability
- hf = average height of water above filter bed
- tf = filter bed drain time (days)
Af = 4500 ft2
Dimensions of Cell: 15’ by 300’

18. Parking Lot Design

19. Components of Bioretention Cell
● Filter Fabric
● Gravel
● Mulch
● Plants
● Sand
● Soil Mix

20. Design of Bioretention Cell

21. Budget

22. Life Cycle Assessment: Ecological

23. Life Cycle Assessment: Ecological

24. Life Cycle Assessment: Economical
● Can decrease cost from storm water
conveyance systems
● Maryland constructed 400 ft2 bioretention
cell
o 50% reduced drainage costs

25. Efficiency
- Grading the parking lot 1% to have a
slight slope towards the bioretention cell
- Runoff will be diverted from the Clemson
watershed
- Filter and stop pollutants from getting
into the groundwater

26. Alternate Designs
- Porous Pavement
- Water quality: pollutants captured
- Volume reduction and flood
control: water flows through the
porous pavement reducing the
overall volume of runoff
- Road safety and Durability -
increases skid resistance and
pavement lifespan increases
http://www.clemson.edu/extension/hgic/water/resources_stormwater/introduction_to
_porous_pavement.html

27. Time-line

28. Looking Forward
● Cost estimates of native plants
● Run dimensions against 10 and 25 year
storms
● City of Clemson stormwater management
● Design primary overflow

29. Questions?