It’s been another busy week here in the City, particularly in the area of flooding and drainage. With that in mind, I thought would be a good time for me to give you a full report on drainage projects recently completed or in the works:
Forest Acres Drainage Improvements – Phase 1 and 2:This project serves a number of West Ashley neighborhoods including Washington Park and North Forest Acres.? Phase 1 was completed earlier this year to the tune of $11.4 million. With a few more property/easement acquisitions, we’ll be starting Phase 2 which will continue the installation of new pipes and open channels upstream of the former pump station. This project recently won the South Carolina ?American Public Works Association 2018 Public Works Project of the Year Award.
Church Creek Drainage Basin – Bob Horner of Weston and Sampson has completed a thorough analysis of the basin.? City Council passed new development/stormwater requirements last week to increase water retention and improve flow in the basin.? In September we will also bring to Council a contract to proceed with a project that will divert stormwater flowing into the Hickory Farms neighborhood.? Our second project will be tidal protection for the basin and we have allocated an initial $2.5 million for these projects. We have also improved the maintenance in this critical basin by increasing its frequency.
?Dupont/Wappoo Watershed Master Plan – A joint project of the City and County of Charleston involves a complete inventory of all drainage features (all conveyance pipes, culverts, ditches, etc.) ?in the basin which includes Citadel Mall, Hazelwood, and the neighborhoods adjacent to Dupont, Wappoo, and Orleans Rds. The inventory is nearly complete and we’ve identified nearly double the number of features than was anticipated (over 3,000).? Maintenance and cleaning has occurred along the way but with the completion of the inventory, a model will be employed to enable effective projects to enhance water flow out of the basin.
Westwood neighborhood – We’ve finally received the SCDOT encroachment permit that was needed to finish this project that will provide relief to St. Theresa Dr and the Westwood neighborhood. The project is advertised for bids. We anticipate the bid opening on 9/13/18.? Construction may begin in November 2018.
?Ashley Hall Manor neighborhood – City Council just approved a drainage improvement project for this neighborhood that includes upsizing drainage pipe and ditches and a new outfall. The work should alleviate the frequent flooding of the Salisbury/Falmouth area in the neighborhood. This should be completed in the next 3-4 months.
Spring/Fishburne Sts. Drainage basin, which serves the Septima P. Clark Crosstown – This a complex project including more than 8,000 linear feet of underground tunnels (120 to 150 feet below surface) that will all be connected to an outfall and pump station between the Ashley River bridges.? We will be opening bids for phase 4 of this 5 phase project on September 11th. Phase 4 is the wetwell and outfall, estimated to be around $39 million, and must be completed before phase 5, the pump station, can be started as Phase 5 will be situated directly on top of the wetwell. This project is a poster-child example of the complexity, expense, and time requirements to complete a major drainage project but it will serve more than 500 acres of the western peninsula and will keep the Septima Clark crosstown open to traffic during most rain events when complete.? I know it’s a long time coming but will be worth it. Phase 4 will take about 3 years to complete and then another 2 more for phase 5. The tunnels are about halfway complete. Funding for Phase 4 is coming from the State Infrastructure Bank and funding for Phase 5 is from the King Street Gateway TIF.
The proposed solution for the Calhoun West project is a similar tunnel/pump system that will serve the western peninsula from about Cannon St. to the Battery.? It is currently being engineered and we are securing real estate for the drop shafts needed for the tunnel system. It’s critical to know the start and end points in order to complete the engineering, which will allow more exact estimates for the funding required.? Much more to come on this one.
Low Battery Sea Wall – The iconic low battery wall along Murray Blvd was built about 100 years ago and is failing and needs replacement.? This will give us the opportunity to raise the wall and add protection against king tides, extreme storms, and sea level rise. We have completed a re-engineering to raise it further and are proceeding with permitting and will put the project out for bid late this year.? We’ve decided due to the poor condition of existing wall, to start at Tradd St. at the Coast Guard Station and work our way back to White Point Gardens. We’ve been setting aside Accommodations and Hospitality funds for this project as it qualifies as tourism-related infrastructure; we are also researching grant opportunities as an additional funding source.? Start construction in early 2019.
King and Huger St. – This corner is notorious for flooding after a gentle rain, JMT Engineers has been engaged to study the basin and ?recommend a design for the project. The study will be complete the week of 8/27. Depending on the complexity of the recommended solution, we should have design plans in about 60 days.? We plan to use Tax Increment Finance funding for a portion of this project.
Market St. Streetscape and drainage connection – There’s already a new tunnel underneath Market St which connects to our Concord St pump station (which can pump about 7.2 million gallons of water out of the City in an hour).? To date 3 drop shafts along Market St are connected to the tunnel and are already making a difference in the market area and on Market St. In the near future, the entire drainage system along Market St from Meeting St to Concord St will be greatly improved and connected to the tunnel. ??As we improve the drainage on Market St, we will re-do the sidewalks and “streetscape.” Admittedly we’ve been delayed by provisions for the undergrounding of the electric lines and other utility considerations, but we’ve finally got the easements needed in place and SCE&G is completing their design for the undergrounding.? This project should also be able to proceed to construction in 2019 and will make a huge difference to drainage in the area.
Check valve installation – Check valves are installed just up from an outfall to prevent tidal water or storm surge from entering into our stormwater systems.? With the increased frequency of higher “king tides”, these check valves go a long way to avoid “nuisance flooding” and offer some protection from storm surge. In the last two years, the City has spent approximately $755,000 to install these valves ( or replace old ones) at Beaufain St., Ackerman Dr., George Griffith Dr., Morrison Dr., East Bay St., ?Bennett and Gadsden, two on Ashley Avenue (at Cannon Park and Tradd), Rutledge, Water and Limehouse (at the Battery), Montclair, Rebellion Road, and Poulnot Lane, These valves are already making a difference.
Central Park/Wambaw Watershed on James Island – In a similar fashion to the Dupont/Wappoo project listed above, the City and County are also partnering to inventory all the drainage features of this basin, create a model, and recommend any maintenance and infrastructure improvements.? We are using the same contractor and as soon as the DuWap inventory is complete, they’ll begin on this one, fall of this year.
Signal Point Rd area improvements – County is taking the lead on this study and recommended improvements,
James Island Drainage Master Plan – In addition, the County is taking the lead on an overall plan to delineate all the watersheds on James Island, and then to evaluate and prioritize them.? In the meantime, as presented at a recent James Island Intergovernmental meeting, the City, County, Town of James Island, James Island PSD, and the SCDOT are working cooperatively on maintenance.
John’s Island Drainage Master Plan – In a similar vein, the City is taking the lead on this one and contracted with Davis and Floyd to perform a “rain on grid model” for the island. Specific projects will follow specifically for the Barberry Woods neighborhood.
That summarizes most major projects underway (more than $200,000 each).? We know there are more to come. But also wanted to advise, that there are numerous smaller projects underway or recently completed (less than $200,000), that include:
Heathwood Dr/Elton Ct., W. Robinhood and Prince St., Lord Calvert Dr., George Griffith canal, Sunnyside, Morrison Dr, and others.
I hope this information is helpful and ask that if our citizens have anything particular to report, to please call our citizens service desk at 843-724-7311 or email us at email@example.com.? My next report will be on the numerous policy issues we are addressing with respect to drainage requirements and development.
John J. Tecklenburg
Mayor, City of Charleston