Low Battery Restoration Project

Phase I - Tradd Street to Ashley Boulevard

Tropical Storm Irma, Sep. 11, 2017

Cover photo by  Jared Bramblett 


Historic Background

Changing Landmass

This map by J. H. Colton & Co. shows the extents of the City of Charleston in 1877, thirty years before the Low Battery seawall was constructed on filled land.

By the end of 1911, 47 acres had been reclaimed and was divided into 191 residential building lots.

Slide the bar to view the changing land mass from 1877 (left) to 1919 (right).

Original Seawall Design

The Low Battery was constructed as part of a large land reclamation project undertaken in two phases:

  • The first section (1909 - 1911) extended from Tradd Street to King Street.
  • The second phase (1917 - 1919) extended from King Street to "the Turn" at the intersection with East Battery Street.

Map of the Battery seawall

The concrete wall of the Low Battery was constructed on a timber deck supported by timber pilings. The seaward face of the Low Battery is skirted with concrete panels attached to timber sheeting and batter piles. Together this formed a retaining wall system to retain the landside fill.

Cross-section design of the existing seawall (left), seawall excavated during reconstruction of the Turn (center), and construction of the existing Low Battery seawall (right).


Identifying the Problem

Existing Condition

The seawall has withstood many storms, but the damage is clearly evident in the large cracks, crumbling concrete, exposed rebar, and eroded base along the entire length of the Low Battery seawall.

Photos by: Johnson, Mirmiran & Thompson (JMT)


Construction

Phase I - Tradd Street to Ashley Boulevard

Map showing the Low Battery Restoration by phase of construction

Construction on the Low Battery Restoration Project began with Phase I, extending from Tradd Street to just beyond Ashley Boulevard. Phase I construction started in December 2019 and is now complete and open for public enjoyment. Construction of Phase II extends from the completed Phase I to just before Limehouse Street, and work is expected to take about one year.

View the slideshow below by clicking on the arrows to the right and left.

Construction Highlights

<-- Click the ARROWS to view -->

Demolition

Gulf Stream Construction Co. began construction in December 2019 on the river side. The first order of business was erecting fencing and demolition of the roadway.

Micro Pile Installation

Instead of pounding massive steel piles into the earth, a network of micro piles were delicately drilled and grouted 81 feet, well into the Cooper Marl.

Structural Concrete

It takes a lot of rebar and concrete to raise the seawall 2'. In the distance, the newly constructed wall looks almost ready for pedestrians, but there are more layers of fill, rebar, and concrete to add.

New Water and Sewer

To maintain the integrity of the roadway, new and improved utilities were installed. Lead service lines were eliminated from the newly installed meters back to the water main.

New Storm Drain

Installation of bigger storm drains, an additional outfall, and four water quality structures has already improved area drainage.

Granite Curb

Granite curb plays a crucial part in the signature look of the Historic District. It was salvaged where possible and replaced at the seawall, the median, and the residential sidewalk along the entire length.

Parklet & Raised Table

Adding "parklets" and redesigning the intersection adds pizzazz to this tourist attraction, but it also incorporates new pedestrian safety and accessibility features.

Sidewalk

By installing new sidewalk along the residential side of the street, the entire length of Murray Blvd is now more accessible, beautiful, and safe. Check out the horsetrack driveway.

Road Paving

Who doesn't like driving on new asphalt? Most of the construction took place on the river side of the street, but new asphalt along the entire street meant construction was almost complete.

Landscaping & Hardscaping

The finishing touches include palmetto trees, bluestone, granite cobbles, and YES - there's still plenty of parking!


Results

Quantifying the Increased Protection from the Tide

Raising the height of the seawall 1.8', an elevation that will match the height of the High Battery seawall, will have a significant benefit to the immediate area during storm events. Only two storms in recorded history have created a storm surge that would overtop the new seawall. Hurricane Hugo generated a whopping 20' storm surge in 1989, which is 8' above the new seawall height! (A storm in 1940 would have just overtopped the new wall by less than one foot.) In the unfortunate event the river overtops the new seawall or the area is hit with a large amount of rain at high tide, the increased size of the newly installed storm drains means the Battery will drain quickly when the tide subsides. King Tides alone will not be a problem along the Battery because all outfalls will have valves to keep the tidal water in the Ashley River where it belongs.

The existing seawall compared to the new seawall.

The completed project - Murray Boulevard at Ashley Avenue. Photo by Jerry Martin

The completed project - Murray Boulevard at Tradd Street. Photo by Jerry Martin

Content provided by the City of Charleston Department of Stormwater Management and Johnson, Mirmiran & Thompson.

Cover photo

Jared Bramblett

Drone photos

Jerry Martin

Construction photos

Laura Boisclair

Existing seawall photos

Johnson, Mirmiran & Thompson

Slide the bar to view the changing land mass from 1877 (left) to 1919 (right).

Map of the Battery seawall

Map showing the Low Battery Restoration by phase of construction

The existing seawall compared to the new seawall.

The completed project - Murray Boulevard at Ashley Avenue. Photo by Jerry Martin

The completed project - Murray Boulevard at Tradd Street. Photo by Jerry Martin

Content provided by the City of Charleston Department of Stormwater Management and Johnson, Mirmiran & Thompson.