Bear creek
was a 20 to 30 foot wide meandering creek located in South Pasadena in Pinellas
County, Florida. The creek is a tidal waterbody which empties into a lagoon
area which then flows into the intercostal waterway. Years of heavy growth and
sediment was causing a large sediment buildup in the lagoon causing water
quality problems. This project for DNCC involved
2,000 linear
feet of channel widening (30 foot bottom width) and dredging approximately
6,000 CY of contaminated sediment by barge from the lagoon as well as 21,000 CY
of machine excavation from the creek so as to realign, widen, and deepening the
creek to 30 foot wide. With the new creek alignment, approximately 9,750 tons
of rip rap rubble bank and shore was installed along the new bank slopes and
1,645 LF of new steel sheeting seawall was installed. A sea walled concrete
sump approximately 45 feet by 210 feet was constructed with weirs so as to trap
future sediment for annual removal.
Controlling
the water flow in the creek was the biggest issue as the work had to be
completed in the dry. DNCC installed two 24” hydraulic pumps with twin 18” HDPE
outfall pipes so as to bypass the creek’s water to a discharge point
approximately 2,000 feet down stream in the lagoon. Temporary sheeting was also
installed at the downstream end to prevent high tides from flowing into the
work areas. During major rain fall events the creek would overflow resulting in
about a week of lost time for recovery and clean up. Part way through the
project it was discovered that a design error by the EOR had occurred in the
permanent steel sheeting. This made it necessary to remove previously installed
sheeting and reinstall longer sheets and about a one year delay in the project.
This project
also included the construction of a new 3 span bridge with 24” precast concrete
piling, and a poured in place deck, and roadway reconstruction with new storm drainage, water
and sewer.