Agenda 05/26/2009 Item #10B
Agenda Item No. 10B
May 26, 2009
Page 1 of 7
EXECUTIVE SUMMARY
Recommend Approval from the Board of County Commissioners of the Clam
Pass Maintenance Dredging Permit Application that is required to perform tidal
flushing of Clam Bay Estuary and is necessary to re-open the pass in the event of
storm closure.
OBJECTIVE: Obtain approval of the Clam Pass Maintenance Dredging permit
application for tidal flushing from the Board of County Commissioners.
CONSIDERATIONS: The existing 10-year permit that provides for tidal flushing
maintenance dredging of Clam Pass has expired and a one year extension has been
granted that will expire in July 2009.
Collier County has prepared an application for a new 10-year permit utilizing the exact
same dredging cuts and cross sections as the previous permit. The basis of the
discharge location and contours has changed to reflect existing dune elevations.
A detailed Summary of the changes from the original 10-year permit and the existing
application is attached.
A new permit is required to perform maintenance dredging for tidal flushing and
,....... dredging to open the pass if it is closed by a storm event.
The entire updated permit application can be viewed on the Coastal Zone Management
web site: http://www.colliergov.netllndex.aspx?page=1350
ADVISORY COMMITTEE RECOMMENDATIONS: The Permit Sub-Committee of the
Clam Bay Advisory Committee recommended approved this permit application 3-0 on
March 6, 2009. The entire Clam Bay Advisory Committee recommended approval of
this permit application 7 -2 on 3/19/2009. The Coastal Advisory Committee
recommended approval of this permit application 6-0 on 4/9/2009. This item will be
presented to the TDC for funding approval prior to proceeding.
FISCAL IMPACT: The Source of funds is from Category "A" Tourist Development Tax
fund 195.
GROWTH MANAGEMENT IMPACT: There is no impact to the Growth Management
Plan related to this action.
LEGAL CONSIDERATIONS: This item has been reviewed and approved by the
County Attorney's Office. This item is not quasi-judicial, and as such ex parte disclosure
is not required. This item requires majority vote only. This item is legally sufficient for
Board action. - CMG .
RECOMMENDATION: Recommend Approval from the Board of County
Commissioners of the Clam Pass Maintenance Dredging Permit Application.
............
PREPARED BY: Gary McAlpin, CZM Director
Agenda Item No.1 OB
May 26, 2009
Page 3 of 7
Clam Pass Project Scope & Changes from Previous Permit
The current permit application is drafted to maintenance dredge CUT -4 in Clam Pass,
Collier County, Florida. CUT-4 is located approximately halfway between FDEP range
monuments R-41 and R-42 and includes the mouth of Clam Pass where it meets the Gulf
of Mexico. CUT-4 Section 1 begins out in the gulf at Station 0+00 with a dredge depth
of -5.5 feet NGVD and extends east to Station 3+64 to the east. CUT -4 Section 2 has a
dredge depth of -4.5 feet NGVD and includes Section 2A which extends northeast from
Stations 4+10 to 7+10, Section 2B which turns north from Stations 7+50 to Station
10+00 and Section 2C which turns back to the northeast from Stations 10+19 to 12+50.
Section 3 has a dredge depth of -4.0 NGVD and extends to the southeast for the fmal 300
feet of the dredge template from Station 15+00 to Station 18+00. The bottom width of
the dredge template varies from 20 feet to 150 feet wide, with the mouth of Clam Pass
having an 80 foot bottom width. The template has a total of dredge length of 1550 linear
feet with a 1 foot vertical to 1 foot horizontal side slope (1:1) consistent for the entire
length of the project. The work will be conducted using a hydraulic dredge therefore the
dredge outfall pipeline must stay within the designated dredge pipeline corridor so upland
vegetation or offshore hardbottom are not adversely effected. The estimated total volume
to be removed during maintenance dredging activity will not exceed 22,000 cubic yards.
All beach compatible sand will be placed between range monuments R-42+180 and R-
44+ 100 upland of the 0 foot NGVD contour. Sand will be placed seaward of the edge of
vegetation. Any sand that is not beach compatible will be stockpiled and removed to an
offsite disposal location (County landfill or other appropriate site based on material).
The current permit differs slightly from the previous permit submitted by Humiston and
Moore in 1998. The slope of the dune changes from 1: 10 to 1: 15 and the berm width
changes from 26 feet to 15 feet. This change was necessary to better match the existing
conditions based on the survey profiles conducted in August 2008. The beach fill portion
in the previous permit had a 10 foot dune top width at elevation +8 feet NGVD and then
sloped down with a 1: 10 slope to +5 feet NOVD where the berm leveled off horizontally
for a distance of 26 feet. The fill then sloped down at a 1: 10 slope to meet existing grade
at 0 feet NOVD. The current permit has a 10 foot dune top width at +8 feet NGVD and
then slopes down at a 1: 15 slope to +5 feet NOVD where the berm levels off horizontally
for a distance of 15 feet. The fill then slopes down at a 1: 10 slope to meet existing grade
at 0 feet NGVD. Also a taper was added to the beach fill template on the south end
extending the template south approximately 100 feet in order to transition the beach fill
template back into the existing grade.
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