Lakewood Estates Drainage Design

As part of a continuing civil contract, DRMP was tasked with a drainage study and design to develop alternatives to reduce chronic residential street and yard flooding in the Lakewood Estates neighborhood.  Hydraulic grade issues were found during construction of the Lakewood Estates Drainage Improvements project therefore responsiveness was critical in order to maintain the construction schedule.

DRMP was specifically tasked to create an ICPR Version 4 model to determine the feasibility of a stormwater pumping station to alleviate flooding along Pinewood Drive and Knollwood Avenue.  DRMP was also tasked with evaluating options to provide drainage solutions to address flooding in the low areas on the eastern side of the basin along Pinewood Drive. DRMP evaluated the system for the mean annual 24-hour (2.33-year), 5-year 24-hour, 10-year 24-hour, 25-year 24-hour and 100-year 24-hour events.  The constraints for the evaluation were to eliminate the direct runoff into Tookes Lake while minimizing adverse impacts to Lake Ebert and reducing flooding along the roadways.

DRMP performed a preliminary analysis of the existing drainage system for an order of magnitude comparison of the peak stages (existing vs proposed) for the Pinewood area and Lake Ebert. The alternative analysis included pumping alternatives and two gravity alternatives. Each gravity alternative upsized the existing proposed storm drain along each of the respective roads.  In addition, to maintain grant funding for the project from the Southwest Florida Water Management District (SWFWMD), it was determined that the CDS unit previously located at the outfall to Tookes Lake would need to be inserted along the outfall along Pinewood Drive. This was required to provide for water quality treatment of this basin in a similar manner as the permitted system, and thereby meeting the intent of the original design.  Construction cost estimates for all alternatives were generated using the bid unit prices from the Contractor.   The results of the study determined that a stormwater pump station was not a preferred alternative due to the higher construction cost and long term maintenance. As an alternative to pumping, a gravity solution was recommended along Packwood Drive that would provide comparable flood protection to the pumping systems. In addition, the analysis showed no adverse impacts for all storm events up to and including the 100-year event. Treatment was provided by the proposed placement of a CDS unit along Parkwood Drive to comply with the SWFWMD grant funding. 

This project relieved the chronic flooding in the Lakewood Estates area. Stormwater runoff is transported more efficiently to retention areas. And water quality is improved through the CDS system which will filter out pollutants, trash and unwanted sediments.