Lake Roberta Dredging and Stormwater Improvements

Hampton Terrace Residents,
HTNA was just made aware today that the City of Tampa was going to start the dredging of Lake Roberta today, May 2 2019.
After a few phone calls to ask what was going, the City had promised to keep HTNA informed of the project plans, the City sent out the information below. Please reach out to HTNA at Hamptonterraceneighborhoodassoc@yahoo.com with any questions and we will do our best to answer them.
Your in Community,
HTNA Board

CITY OF TAMPA TRANSPORTATION AND STORMWATER SERVICES DEPARTMENT

306 East Jackson Street, 6N • Tampa, Florida 33602

Jane Castor, Mayor

Lake Roberta Stormwater Improvements
Program Summary Update
Program Summary:
• To enhance water quality and to improve the general environmental health of Lake Roberta, the City plans to remove the accumulated lake sediments. Currently, the deepest part of the lake is about 6’ deep. The dredging project is targeting a new depth of 10’. It is anticipated that approximately 10,000 cubic yards of wet sediment consisting of silt, sand, muck and decomposed vegetation will be dredged from the lake in this project. The increased storage capacity, called the permanent pool volume, will restore the health of the lake and its ability to provide water quality treatment for the stormwater runoff entering the lake from the surrounding area. This project has been budgeted in fiscal year 2019 for a total project cost of $450,000. The dredging operation will begin in May, 2019 and should take approximately 6-8 weeks to complete.

Dredging Process:
• The dredging operation will primarily consist of deploying a barge mounted hydraulic dredge with a large cutter suction head (similar to a tiller blade) lowered to the desired pond bottom elevation that will fluidize the bottom sediment allowing it to be pumped through a pipe to the staging and dewatering area located at the west end of the lake. The dredged material will be pumped into large “geotubes” that will retain the sediment and allow the excess water to seep through the sides of the bags and return to the lake. Once the geotubes have adequately dewatered the sediment, the dredged material will be loaded into trucks and hauled to the City’s transfer station at the Port of Tampa where it will be stockpiled and processed for final disposal. To enhance dewatering of the dredged materials, polymers will be added that bind the soil particles together. This treatment also works to reduce turbidity in the lake during dredging operations. This process is environmentally friendly and meets Florida Best Management Practices for lake dredging.

FAQ’s:
• Where will the sediment be taken? Dredged material will be hauled to the City’s transfer station at the Port of Tampa for further processing and disposal.
• What activities can I expect to see occurring in and around Lake Roberta? A temporary staging area will be developed at the west end of the lake for sediment dewatering and stockpiling. A large temporary aggregate driveway will be placed for trucks to enter for loading. This driveway will help to reduce soils being tracked from the site onto the local streets. This area will also likely be used to deploy the dredge equipment into the lake.

• What will become of the littoral shelf (shallow planting area) at the west end of the lake? The littoral shelf will be used for the temporary staging area for the dredging operation. SWFWMD and EPC have granted permission to remove the littoral shelf at the completion of the dredging operation. Removal of the littoral shelf will maximize the storage and water quality treatment capacity of the lake. EPC is requiring that aquatic vegetation be planted around the pond to mitigate for the loss of the littoral shelf.

• Will the carp that are controlling the unwanted vegetation remain in the pond after it is dredged? The wet-dredging operation is considered environmentally friendly and should not result in any long-term detrimental effect on the ecosystem of the pond. Although there may be some incidental impacts to fish and wildlife within the lake during the dredging operation, the carp, as well as, other fish and wildlife is expected to survive and better thrive after the dredging has been completed. The City will fund all future nuisance vegetation removal.

This Program Update and future updates will be posted on our website at the following link:
https://www.tampagov.net/tss-stormwater/lake-roberta-stormwater-improvem...
Contact Information for questions or additional information.
• For construction activities, please contact Richie Grayes at Richie.Grayes@tampagov.net or 813-310-1356.
• For environmental inquiries, please contact Heather Maggio at tss2018projects@tampagov.net or 813-274-8371.
• For all other inquiries or concerns, please call our 24/7 TSS Customer Service line at 813-274-3101.

Other Planned City Projects in your Area
Flooding Relief Project Entering the Design and Permitting Phase:
Stormwater Engineering is in the process of implementing a $30 million dollar design/build flooding relief project within the 780 acre Southeast Seminole Heights drainage basin. The project is co-funded by the City of Tampa and the Southwest Florida Water Management District (SWFWMD). The design and permitting of this project is slated to occur in 2019 with construction to begin in 2020. A design/build team of professionals has been selected and an agreement is currently being negotiated. Public information meetings will be held during the design phase of this project.
This regional project will provide flooding relief to a large part of the Southeast Seminole Heights area including relief for the flooding that occurs on Roberta Circle. The project will increase outfall capacity in areas downstream of Lake Roberta. Although no work will be done in or around the lake, planned downstream improvements will help to relieve flooding in the Lake Roberta area.
Clifton Street sediment and trash removal upgrades:
The existing sediment trap under Clifton Street at the west end of the lake is not adequately capturing the sediment and trash. Stormwater engineering is evaluating options to replace it with a more efficient unit. The City is budgeting this replacement in FY 2020.
Roadway Resurfacing and Traffic Calming Improvements:
The City’s Transportation Division currently plans to resurface roadways in the Lake Roberta area. That project is being delayed until after the lake dredging operation has been completed. For more information, please visit the website for this project at the following address: https://www.tampagov.net/tss-transportation/info/projects/hampton_terrac...
• For Road Improvements, please contact Jorge Uy at Jorge.Uy @tampagov.net