The fourth phase of Charleston’s extended project to bring long-awaited relief for midtown flooding will be completed by fall. It is expected to reduce the amount of water on city streets significantly, according to city officials.
After years of setbacks, delays and budget overruns, the Spring/Fishburne Drainage Project, kicked off in 2009, is expected to cut storm-related flooding on Charleston’s peninsula by 20% at the completion of Phase 4, officials said.
“This is a highly complex, multi-decadal project,” said Steven Clark, who is the project’s leader for the city. “It is the most challenging and complicated development in terms of scope and scale ever undertaken by the city of Charleston.”
The city’s stormwater issue is a result of its flat, low-lying geography which leaves most collected water with nowhere to go. Furthermore, the water that does run off can pose a significant environmental threat by collecting waste before flowing into local streams, rivers and the ocean. This problem necessitated the construction of a new, complex drainage system beneath the surface of the peninsula to provide water with a place to go without harming the environment or damaging the landscape around it.
Despite challenges, Charleston’s geography beneath the surface actually became an advantage in finding a solution, city officials said.
“Charleston has a really good geological formation that’s really suitable for tunneling in at depth,” the city’s director of stormwater management Matt Fountain said last year. “It’s a super-over consolidated clay that holds up well for tunnels and it isn’t as expensive as tunneling through rock.”
In 2011, the city began Phase 1 of the project by making improvements, replacements and additions to its existing surface-level collection system. This part of the project included the addition of 175 new structures and more than 5,500 feet of new pipes added to the current system.
Phase 1 was done in 2013, but the next phase didn’t start until 2015 after resolution of funding issues. Phase 2 involved building a series of eight 180-foot drop shafts to connect surface-level drainage pipes to a mile-long deep tunnel system, which started development as Phase 3 in 2016.
The Phase 2 tunnel shafts included 8,000 feet of new tunneling and four additional entry points to provide access for large tunnel boring machinery, Clark said. By the end of 2020, phases 2 and 3 were done and the fourth phase was underway.
But at every phase, original project costs exceeded actual construction costs due to myriad setbacks, including employee shortages, historic flooding and a global pandemic. Budget overages, in fact, pushed the projected time of completion of Phase 4 to the end of this year. At present, the project is valued at $198 million, according to the city, which reportedly is $44 million over budget.
What’s happening now
In the current fourth phase of the project, which is focusing on building a water well and an outfall system, stormwater will be able to move from the deep tunnel pipe system into a holding area that will let water flow 500 feet below the surface of the Ashley River through three massive box pipes, which are sized and positioned to have minimal environmental impact on the river.
“The Spring-Fishburne project is now expected to drain millions of gallons of water from the streets of Charleston by year’s end,” Charleston Mayor John Tecklenburg said in a recent opinion piece. Reduced flooding also is expected to reduce the millions of dollars lost in Charleston each year due to flooding damages and delays.
The project’s final component, Phase 5, is scheduled for completion in 2024 and will involve the construction of a superstructure pump house, multiple pumps and supporting mechanical and electrical components. The pump house will allow the water to exit the outflow area with more than 10 times the effectiveness of gravity alone, moving over 1 million gallons of water every three minutes, according to the project’s website.
- Anyone interested in more information about the project can visit SpringFishburne.com to see live-updates, photos and videos.
Spring/Fishburne Drainage Improvement Project Phases
|PHASE||DETAILS||DATES||Estimated Phase Construction Costs||Final Cost||STATUS|
|Phase 1||Repair and replace the surface collection system and streetscape along Septima Clark Parkway.||2011-2013||$11.3 million||$14.25 million||COMPLETED|
Repair and replace the remaining surface collection system on Septima Clark Parkway and adjacent streets, place 8 vertical drop shafts to connect surface water collection to the deep tunnel system.
|2015-2017||$25.5 million||$31.5 million||COMPLETED|
|Phase 3||Construct deep tunnel system.||2016-2020||$37 millon||$43.3 million||COMPLETED|
|Phase 4||Construct wet well and outfall portion of pump station on Ashley River.||2019-Fall 2022||projected $65.3 million||n/a||ONGOING|
|Phase 5||Construct pump station: 4 pumps, supporting mechanical and electrical components, super-structure housing. Restore pump site.||estimated 2023-2024||projected $36.4 million||n/a||NOT STARTED|
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