1. Hunting Island State Park Beach Restoration Project
17 May 2016

2. Project Setting 2

3. Hunting Island is ~ 4 miles long Heavily influenced by St Helena Sound
Project Setting
Hunting Island is ~ 4 miles long
Heavily influenced by St Helena Sound
Loss of 1,000-2,500 ft between 1857 and 1979
Volume loss of around 300,000 cy per year
Eight previous nourishment projects totaling over 5 million cy 3

4. Over 2,000 ft of Erosion along north end of Hunting since 1850’s
Historical Shoreline
1857
1920
1933
1964
1971
1987
2000
2011
Over 2,000 ft of Erosion along north end of Hunting since 1850’s
Harbor southern accretion accelerated in ~1970s – over 2,000 ft accretion 4

5. Previous Project 2006: 570,000 cy nourishment (Design)
2006 Hunting Island
2006: 570,000 cy nourishment (Design)
2007: Construction of 6 groins in three “clusters”
Required post-project monitoring of downcoast impacts 5

6. Sand Searches & Borrow Areas
2006 Plan
2006 As-built

7. Strategic Nourishment for Groins
Three Recreation Areas
Long-Term Erosion Rate = ~25 ft/yr
Nourished Seven (7) Times Prior To Project
Project Completed On Time Within PRT’s Budget
Feb 2006
June 2006
Feb 2007 7

8. 2005
2007
2008
2010
2011
2012

9. Project areas gained ~561,000 cy during nourishment
Island-wide Changes
Volumetric Erosion Rates
Project areas gained ~561,000 cy during nourishment
Same areas still hold 414,000 cy in 2015
Net loss of 147,000 since nourishment
Erosion rate decreased in areas updrift of groins from ~18 cy/ft per year to <5 cy/ft per year 9

10. Cabin Road Area Changes
Groin 8
South 10

11. Hunting Island
Conditions
~9 years post installation 6 7 8 11

12. Existing Conditions
2016
~9 years post installation

13. Plan Purpose Proposed Project
Nourishment of a total of 10,400 lf of beach
Maximum Nourishment Volume = 630,000cy
Two Nourishment Areas – Campground, North-South Beach
Two new ~450 ft groins (#2 and #5A)
Two potential offshore borrow areas
No work north of groin #1 or along south end
Purpose
Restoration of beach area
Reduction of erosion rates
Protection of park infrastructure
Restoration/Protection of beach habitat

14. Project Plan

15. Project Plan

16. Proposed Project
Plan
Nourishment will occur in winter months (outside of turtle nesting season)
“Piggybacking” project with Edisto Beach to reduce costs
Groin construction will occur during or immediately after nourishment
Monitoring proposed including shorebird surveys, lighting surveys, beach topography surveys, aerial photos, sediment analysis, downdrift impact
Anticipated construction length ~4 months

17. Additional Actions Proposed Project
Completion of a Biological Assessment (this week)
Completion of an updated Downdrift Impact Assessment
Additional geotechnical data collection
Pre construction surveys and monitoring