SARASOTA COUNTY LIDO KEY HURRICANE STORM DAMAGE REDUCTION

SARASOTA COUNTY – LIDO KEY HURRICANE & STORM DAMAGE REDUCTION PROJECT Information Presentation BOCC Joint Meeting City of Sarasota County US Army Corps of Engineers 22 October 2013 Sarasota, Florida Presented by: Milan A. Mora, P. E. Jason Engle, P. E. James La. Grone Kathleen Mc. Connell BUILDING STRONG®® US ARMY OF ENGINEERS | Jacksonville District US ARMY CORPS OFCORPS ENGINEERS | JACKSONVILLE DISTRICT

2 OVERVIEW – PROJECT SCOPE § Authorized WRDA 1999 • Authority was contingent on a feasibility assessment of the project. 1971 • 2002 Feasibility Study with Environmental Assessment (amended April 2004) determined that project was technically sound, environmentally acceptable and economically justified. 1986 2006 BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

3 OVERVIEW – PROJECT FEATURES Project Scope § § § Project Length (ft) = 8, 280 (R-35 to R 43) § § Three groins along the southern portion Design berm elevation (ft) = +5 NGVD Approximately 460, 000 cy of design and 615, 000 cy of advance material (1, 075, 000 cy for Initial Const) Borrow Areas: Big Sarasota Pass (BSP) & New Pass 5 -year nourishment interval over 50 -year life 615, 000 cy required for each re-nourishment D 2 C B BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

4 PROJECT PLAN § 1) Placement: • Place approximately 1. 1 M CY of sand on Lido Key § 2) Source: • Obtain Sediment for Nourishment of Lido Key • Egmont Key (Tampa Bay) • Offshore of Longboat Key • Ebb Shoal at Big Sarasota Pass (BSP) • New Pass – Future § 3) Retain: • Construct Three (3) groins at the south end of Lido Key BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

5 PLACEMENT – LIDO KEY 2013 MHW Line 80’ Design Berm @ 5’ MHW Line Design Berm Advanced Berm MHW Line Advanced Berm 150’ FDEP Monument R-39 (Lime Tree Resort/Condos) BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

6 SOURCE – BSP BORROW AREAS D 2 C B BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

7 RETAIN – SOUTHERN GROINS t ach Be hmen s uri o N ta Re BUILDING STRONG® in US ARMY CORPS OF ENGINEERS | Jacksonville District

PROJECT PLAN – BORROW AREA QUESTIONS? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

BORROW AREAS? § What are the proposed borrow area footprints? § How will this affect Big Sarasota Pass morphology? § How will this affect Siesta Key? § What are the effects on the navigation channel? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

BORROW AREA FOOTPRINTS D 2 C B BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

Relic Chan nel BSP MORPHOLOGY In the long term: annel Ch rginal Ma Flood Dis tal Lob e Ma in o Flo Eb r a d. M ha nn l e nn b. C ha al C gin el Updrift Shoal Do Att wndr ach ift me nt These areas will be deeper Existing Conditions BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

HOW WILL THIS AFFECT SIESTA KEY? % Increase in wave energy here and here % Decrease in wave energy here and here BUILDING STRONG® Results from the CMS morphologic model yields No indication of increased erosion over the Existing Condition at Siesta Key US ARMY CORPS OF ENGINEERS | Jacksonville District

EFFECT ON CURRENT NAVIGATION? Navigable water greater than 6 m depth without project BUILDING STRONG® Navigable water greater than 6 m depth with project No significant difference in navigable water depths without and with project US ARMY CORPS OF ENGINEERS | Jacksonville District

PROJECT PLAN – SOUTHERN GROINS GENERAL QUESTIONS? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

SOUTH LIDO KEY GROINS § What are the plans for the groins? • How long are they? • How much space is between them? • How big are they? • Can I walk along the beach? • Can I swim in the surf zone? • Can I navigate past them? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

HOW LONG? HOW MUCH SPACE IN BETWEEN ? 460’ 800’ 600’ 350’ 2004 BUILDING STRONG® 500’ Present Day US ARMY CORPS OF ENGINEERS | Jacksonville District

HOW BIG ARE THEY? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

CAN I WALK ALONG THE BEACH? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

CAN I SWIM IN THE SURF ZONE? CAN I NAVIGATE PAST THEM? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

PROJECT PLAN – SOUTHERN GROINS HYPOTHETICAL QUESTIONS? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

What if the groins do not work? § What is the effect on Lido Beach? § What is the effect on Siesta Key? § How will the groins affect the ebb shoal in BSP? § Why nourish the beach if we are installing structures? BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

WHAT IS THE EFFECT ON LIDO KEY? WHAT IS THE EFFECT ON SIESTA KEY? Sediment Bypassing to BSP Ebb Shoal Downdrift Effects Groins are constructed to anchor the nourishment template – not to intercept Sediment at the expense of downdrift beaches or ebb shoal morphology! BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

How will the groins affect the ebb shoal in BSP? Sediment Bypassing to BSP Ebb Shoal Downdrift Effects Adequate sediment bypassing at the seaward end of the groin structures will deter the growth of a crescentic shoreline. Adequate bypassing to the Ebb Shoal ensures that BSP will maintain its morphology – seen by lack of erosion in the shoal itself BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

Why nourish the beach if we are installing structures? Groins are constructed to anchor the nourishment template – not to intercept sediment at the expense of downdrift beaches or ebb shoal morphology! Groin construction without an associated nourishment project can lead to downdrift erosion and a lack of sediment supply to downdrift systems The groins are designed to work with the nourishment design template – should the beach erode shoreward of the design template, Emergency measures are implemented BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

Groins – Anchor the Nourishment h ac ent e B hm ris u No 1986 in ta Re 1983 1981 BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District

LIDO KEY SPP Questions/Discussions Milan A. Mora, P. E. Project Manager Jacksonville District Water Resources Branch 701 San Marco Boulevard Jacksonville, FL 32207 904 -232 -1454 millan. a. mora@usace. army. mil BUILDING STRONG® US ARMY CORPS OF ENGINEERS | Jacksonville District