Lake Worth Lagoon C-51 Sediment Trap

Richard E. Barnes, Jr., PSM Ryan F. Kett, SIT

Statement of Work • Conduct a Hydrographic

Survey from Congress Ave. to S-155.

• Analyze and re-trace the surveys performed by Sea Diversified, Inc. from 2007 through 2010.

• Collect additional data immediately upstream of S-155.

• Review flow data from the SFWMD DBHYDRO data base.

• Prepare a survey drawing and report detailing our findings and making comparisons to the Sea Diversified, Inc. surveys.

• Recommendations for future surveys.

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Summit Blvd.

Forest Hill Blvd.

S-155

Sediment

Trap

Equipment & Field Procedure

Vertical Datum = NAVD 88

• Elevations established using published values

• FCE 3521 – USACOE

• Summit 10 - PBC

• Odom HydroTrac Echo Sounder to collect depth soundings.

• 0.1’ Resolution

• 200 KHz transducer

Horizontal Datum = NAD 83

• Trimble SPS351 DGPS

• Sub-Meter accuracy

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HYPACK 2013

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Cross Sections Outside of the sediment trap.

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2007 vs. 2013 Elevation

Sea Diversified, Inc.

November 2007 (as-built)

SFWMD

June 2013

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Sediment Accumulation

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Cross Sections through Sediment Trap

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2008 2009 2010 2011 2012 2013

DBHYDRO Flow Rate for S-155

Sediment Collection

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Total Accretion

Years 2007 – 2008 2008 – 2010 2010 – 2013

Total (CY) 10,478 6,401 8,643

Average / Year 10,478 3,200 2,881

Survey Conclusions

• It appears the sediment trap is working.

• There is approximately 1 foot of material accumulation per year along westerly portion of the trap after year one.

• Flow rates through S-155 do not appear to effect the performance of the trap.

• There are no significant changes in the C-51 bottom configuration upstream or downstream of the trap.

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Recommendations

• Perform hydrographic surveys twice a year at the end of the wet season and at the end of the dry season.

• Survey immediately upstream of S-155.

• Perform a hydrographic survey downstream of S-155 to the discharge into the Intracoastal Waterway.

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Questions?

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