WPS Agenda 10/08/2012 WIGGIN'S PASS
SUBCOMMITTEE
MEETING
AGENDA
OCTOBER 8, 2012
Wiggins Pass Sub-Committee Meeting-10/8/2012
1. What is being considered at the BCC meeting tomorrow?
a. Item 11C-Special Treatment Overlay Permit approval.
b. Previous approvals EAC and the Planning Commission
c. LDC—St Overlay Commitments.
2. Outstanding issues and Concerns
a. FDEP Permit
I. FDEP has deemed the Permit application complete—Ready to issue permit.
ii. ST Overlay permit required for County to write The Letter of Consistency.
iii. Letter of consistency is required prior to the FDEP permit issuance
iv. Language on sand distribution with the State Park
b. USACE
i. Biological Opinion for Piping Plovers—FWS—Critical Path
ii. Biological Opinion for Sea turtles - NMFS has recommended a dredge cycle
during Daylight Hours only— resolution required
iii. Army Permit drafted after FDEP permit and all BO are resolved
c. Peer Review
i. Notified that a peer review of design is required by County Management
ii. Olsen Associates from lax to conduct.
411 iii. 8 weeks required with target completion date of 12/15/12
iv. Modifications to design may be required but not anticipated.
d. Technical items of concern
i. Hydraulic prism and pressure of straightened channel
ii. Dredge cut of Channel
iii. Time Value analysis of money
iv. Independent dredging
3. Probable schedule
a. All work must be completed by the beginning of turtle nesting season on 5/1/13.
b. NMFS-12 hour dredge requirement is a project killer.
c. NMFS BO for turtles resolution by 1.1/15/12
d. FWS BO for Piping Plovers by 12/15/12
e. Peer review by 12/15/12
f. Letter of consistency by Collier County by 11/1/12
g. FDEP permit by 12/1/12
h. USACE permit by 1/15/13
i. Bid package and bidding complete by 2/1/12
j. Presentation to BCC by 2/12/13 for award
k. Mobilization and begin Dredging by 3/1/13
I. Substantial completion by 5/1/13 (All work complete)
• m. Cleanup and demobilization by 5/15/13.
1
• Wiggins Pass Tidal Prism in the Four Channels
The hydraulics of Wiggin Pass cannot be determined with a causal observation. The shape of the
flood shoal and channel appears to show a dominate southern channel from Vanderbilt Lagoon,
but this flow is only about half that from the east. The east channel from the Cocohatchee River
is actually the dominate channel and the shape of the flood shoal is cause by another coastal
process.
Based on calculations through one full tide cycle, the contribution from the north, east and
south channels were determined during modeling. The flow from the north, east and south
channels contribute approximately 29.6%, 45.6%and 23.8%, respectively, based on absolute
tidal prism (volume of water). The figure below illustrates the flow in each respective channel. It
shows the tidal prism (cubic meters) versus hours of a tidal cycle.A cubic meter(M3) is equal to 35
cubic feet.
175,000
*West
150,000 - s •
I
__..__. —North
125,000 -4 , ÷
i East
I 100,000 —
South
411, i 1 I
v 75,000 " •—
o
o ,
50,000
I •25,000
10,a, 0 _..
Il
i
E
___.._
13 -25,000 i ;a rt" r t
a
I ia
-50,000 > I
! k 4.P
tit -75,000 _I
-. , t
100,000 - ..._.._.� _ t- _ ._,. __........__..
I
7
-125,000 '
I -150,000 _.___.._, r____ .. .E
-175,000 _ _. ¢- r __.._.-
j 0 3 6 9 12 15 18 21 24 7.7
Time(Hours)
Instantaneous Discharge (Mn)
I
I
0 The figure shown below is the inlet flood shoal and channel. The red arrows illustrate the
primary sand pathway into the inlet, which leads to growth of the flood shoal over many decades.
It is this growth of the flood shoal that has pushed the main flood channel north against Barefoot
Beach. In addition,the mouth of the south channel is dredged periodically to remove the eastern
deposition of these sands. During periods of the higher tide range and large river flows,the east
flow tries to cut a channel thru the flood shoal, but does not have enough persistence to succeed.
or, .
• ,
4r ��
s
r s°
Principal Sand Pathway to Flood Shoal
In general, the combined north and south channel flows are nearly equal and counter act each
other,while the eastern flow dominates with almost 50%of the combine flow.
The discharge from the Cocohatchee River during the wet (tropical)weather season can
contribute significant flow to the tidal prism.
The new design will have a smaller dredged cross section, but will maintain a deeper navigation
depth after 4 years. The average ebb channel width decreases from 250 feet to 200 feet between
the 2000 permit dimension and the proposed new channel, and the dredge depth will be a foot
shallower. Ultimately this will produce a straighter channel with almost a 6.8 foot NAVD depth
remaining after 4 years. A historic comparison of the channel dimension is illustrated in the table
and figures below.
I
1
Station Location Bottom
Width(ft) Depth(ft) Overdredge
NAVD Depth(ft)
• Corps 1980 Ebb Channel 150+100 -13.3 1.0
Throat * +50-150 -10.3 1.0
Flood Side
Channel 50 -9.3 1.0
2000-7 Permit Ebb Channel 250 -13.3 1.0
Throat 150 -8.8 1.0
Flood Side
Channel 125 -6 0.0
2011 Dredge Ebb Shoal 200(170') -13.0 1.0
Throat 150 I -8.7 1.0
Proposed 2010
240- 160 -12.0
Permit Ebb Channel * 1.0
Throat 160 -12.0 1.0
Flood Channel 130 -7.7 1
1 1.0
' 1
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-300 .200 -100 0 100 200 300 400
4—m4—South Distance From SOU th Mae of 2U10 Channel North—*
...
Figure. The 2010 dredged dimension versus
110 the prelimary and final plan cross section at Station 1+00.
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FIGURE 34
WIGGINS PASS
it
DESIGN CHANNEL CROSS—SECTION
.• 166
COASTAL PLANNING & ENGINEERING, INC.
1
• WIGGINS PASS
RECOMMENDED PLAN
_.,
DEPTHS
_
FT. NAVD
0 ■ i
— -1.68' \ 3' DRAFT
MEAN LOW WATER
1 I s
_ I .\7/ / /
Orr
—
5
"PP; 3.8' NAVIGATIONAL
—
-
4 CLEARANCE
i
7 7
-
1 / 52'/ ADVANCED
— /
.
-10 / MAINTENANCE
4 /
-12.0' r zy_ . T
-15 —
DEPTHS LEGEND:
FT. NAVD
— — — — — DREDGE LIMITS
CHANNEL LIMITS
// /1///, BETWEEN IDNGF1INLLGs
0