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Special Presentation: Freshwater Discharges to the Lake Worth Lagoon

October 29, 2013 (Tues.)

10:30 am

Palm Beach County
Board of County Commissioners Workshop

  
PBC Governmental Center
6th Floor Commission Chambers
301 N. Olive Avenue
West Palm Beach
  

For more information contact PBC ERM at
(561) 233-2400.

Palm Beach County Department of Environmental Resources Management Links
Lake Worth Lagoon Initiative Partners

Palm Beach County

 

South Florida Water Management District

 

Florida Department of Environmental Protection

 

The Palm Beach County League of Cities

 

Florida Inland Navigation District

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Outreach Efforts
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WPBcanalS155
Structure 155 discharges water from the WPB Canal
(C-51) to the Lagoon.
Muck
Muck sediments cover large areas of the Lagoon's bottom. 
SeagrassSurveyDiver
Poor water clarity makes it challenging to survey seagrasses in the Lagoon.
Muck Covered Oysters
Oysters covered in muck sediments in the Lagoon.
John's Island Oyster Reef
A newly created oyster reef near John's Island.
Bryant Park Wetlands
Material staging area for the Bryant Park Wetlands project.
October 2013
Lake Worth Lagoon E-News
Sustained, High Volume Drainage is Hurting the Lagoon
  
Months of higher-than-normal rainfall have led to extremely high discharges of freshwater, and the associated nutrient and sediment loads into the Lagoon, setting back efforts to improve water quality and enhance aquatic habitat. 

   

Primary Canals that Discharge Freshwater to
Lake Worth Lagoon

  • Three primary canals (C-17, C-51, C-16) carry large volumes of freshwater from the watershed and discharge into Lake Worth Lagoon.
  • The Lagoon has received sustained, high volume discharges due to months of above-average rainfall.
  • The C-51 (West Palm Beach Canal) accounts for the majority of the total freshwater discharge to Lake Worth Lagoon.
  • Discharges from Lake Okeechobee account for some of the freshwater to the Lagoon so far this year.
Biological Impacts
Increased Nutrient Loads 
 

Nitrogen/Phosphorus loads are highly related to canal flows and stormwater runoff that carries pollutants off the land. These nutrient loads increase algae production and reduce water clarity.

More "Muck" in the Lagoon

 

The fine-grained sediments and organic matter in stormwater settle out as "muck" sediments which cover large areas of the Lagoon's sandy bottom, seagrass and bottom-dwelling organisms. Wind and wave action re-suspend the sediments, clouding the water and reducing the light available for seagrass. 

Water Clarity is Poor 

 

Suspended sediment and tannins (from decaying plants) reduce the depth to which sunlight can penetrate. Sunlight is critical to growth and reproduction of underwater seagrasses.

Seagrass Die-Off 

 

Years of environmental monitoring show a direct relationship between freshwater discharges and seagrass extent and density. This year marks the lowest recorded seagrass coverage since monitoring began in 2000. Seagrasses provide shelter for juvenile fish, food for manatees and sea turtles, and improve water clarity by stabilizing bottom sediments.

Oyster Mortality

 

Oysters near discharge areas have been impacted due to low salinity and deposits of muck sediments.

Lake Worth Lagoon Should Rebound

The Lagoon received similar high volume freshwater discharges in 2004 (Hurricane Jeanne) and 2005 (Hurricane Wilma). Environmental monitoring efforts documented devastating biological impacts. It took two years for the Lagoon ecosystem to rebound.  

 

Today, environmental managers expect it will take at least 2 to 3 years for the Lagoon to recover and rebound from the recent high volume freshwater discharges, which began in 2012 during Tropical Storm Isaac.

Monitoring and Restoration Continues

Seagrass Monitoring Efforts Continue

 

Mapping of seagrass in the Lagoon is approximately 35% completed. When compared to seagrass coverage in 2007, preliminary results indicate a recession and in some areas a loss of seagrass beds in the central and southern segments of the Lagoon. The field work is expected to be completed by the end of October.

John's Island Oyster Reef Project - Phase 2 Underway

 

The 5-acre project planned east of John's Island is underway. Half of the $800,000 project costs are being shared by the Florida Inland Navigation District. To date 5 of 32 pods have been constructedView Project Fact Sheet [PDF]

Bryant Park Wetlands

 

Sand, coming from the Fullerton Island Restoration Project in Jupiter, is now arriving at the project site. Barges began transporting material the first week of September. Construction is expected to last 4 to 5 months. View the Project Fact Sheet [PDF]

Bryant Park Living Shoreline 

 

The County was recently awarded $40,000 by National Endowment for the Arts to design, engineer, and create a sculptural living shoreline. The sculptural elements will be designed to support the growth of mangroves, spartina, and oyster reefs and will be incorporated into a portion of the 2,600 linear feet of Bryant Park shoreline.  

Our Best Hope to Sustain a Healthy
Lagoon Ecosystem
  • Increase water storage within the watershed to reduce freshwater discharges.
  • Improve stormwater treatment.
  • Continue to encourage Best Management Practices for agricultural businesses within the watershed.
  • Redirect freshwater discharges to areas of need in southern counties (Broward & Dade).
  • Maintain and expand sediment management projects such as the C-51 Canal Sediment Management Project, which created a trap to capture sediments prior to their discharge into the Lagoon. Additional muck removal from Lake Okeechobee will help restore its ability to filter water before it reaches any discharge structure.
  • Modify the C-51 Canal's S-155 control structure to trap more muck sediments.
  • Continue collaborate efforts through the Lake Worth Lagoon Initiative.
Palm Beach County Department of Environmental Resources Management | (561) 233-2400 | adodd@pbcgov.org | http://www.pbcgov.com/erm
2300 N. Jog Road
4th Floor
West Palm Beach, FL 33411

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