Huntsville Converts Ordinary Drainage Canal Into Parkway

Wed July 07, 2004 - Southeast Edition
Giles Lambertson

You don’t have to be a rocket scientist to figure out that Huntsville, AL, has hit upon an attractive plan to turn an ordinary drainage canal into a parkway.

A Decatur, AL, civil engineering consultant company, Civil Solutions, is turning the plan into reality.

Under project manager Shane Cook, tons of dirt already have been moved and many cubic yards of concrete poured. Yet there is not much to show for it, not above ground anyway.

The canal project is one piece of a larger puzzle being assembled in downtown Huntsville. The biggest piece already is in place: the Von Braun Center.

The South Hall of the 29-year-old center contains 100,000 sq. ft. (9,000 sq m) of exhibition space and is the city’s centerpiece of convention and entertainment activity.

The canal project will enhance the center’s appeal. It also is being constructed in coordination with a new 300-room Embassy Suites Hotel. In fact, the restructured stream will flow between the new hotel, which is to be completed in January 2006, and the South Hall of the Von Braun Center.

The center, the canal and the hotel all owe their existence to a spring that lies just eastward and is the final piece of the puzzle.

When John Hunt built a cabin almost 200 years ago next to a big spring, he became the namesake of what became Huntsville. That spring still bubbles forth in Big Spring International Park, filling 3-acre (1.2 ha) Big Spring Lagoon and sending excess water over the lip of the spillway that is situated in its southwest corner.

Until earlier this year, the spilled water flowed through the open, slope-sided canal that ran past South Hall. Then city leaders agreed to redevelop the area. As a result, today the spillway water flows underground –– but only temporarily.

The Elkmont, AL, contracting firm of Miller & Miller Backhoe buried the stream. The contractor poured 1,120 ft. (339 m) of culvert measuring 4 ft. by 8 ft. (120 by 240 cm) to form the culvert structure. It runs parallel to the canal and consumed slightly more than 1,000 cu, yds. (760 cu m) of concrete. Sherman Concrete Pipe Co. of Huntsville was the supplier.

The open canal water from the spillway then was diverted into the culvert to be carried past the Von Braun Center to Pinhook Creek on the other side.

Rerouting the spillway water will let Christopher Plumbing and Electrical Co. of Huntsville build a handsome new canal practically on the bed of the old one.

The buried culvert itself is not a temporary structure. It will not become scrap concrete after the new canal is in place and water diverted back to it. Rather, the underground structure will have storm drains routed to it to protect the quality of the canal water.

In times of heavy rains, the culvert also will give the area extra capacity to handle flood waters.

Before the finished canal phase of the project is undertaken, however, a bridge will be built. Christopher won the $2.2 million contract to build the canal and erect an arched bridge that will carry Monroe Street traffic over the spillway stream.

The bridge replaces a simple culvert that previously cut beneath the roadway. The arched four-lane bridge will lift the surface of the roadway and therefore will require new elevated approaches in the roadbed.

The bridge is a pre-cast modular structure fabricated by CON/SPAN Systems out of Dayton, OH. A Birmingham dealer, BridgeTek, is supplying the structure that measures 48 ft. (15 m) long and will be delivered and set in place on abutments in a matter of hours. Because CON/SPAN bridges are delivered in segments 8 ft. (240 cm) wide, large cranes are not required to set them.

“It gives us a nice arched bridge in a timely fashion,” Cook said of the process.

The span is a key architectural feature of the redevelopment. A ledge on its outside edge will let masons cover the facade of the bridge and of the retaining wall approaches to it with a pattern of stacked stone with a limestone cap. That mirrors other stone work in the area and exposed areas of the new canal also will share the pattern.

Christopher Plumbing crews will reconstruct the dam in the area of the spillway, and the spillway relocated southward to line up with the route of the new canal. To work on the spillway and in the area immediately below it will require temporary damming of the last 50 ft. (15.2 m) of the lagoon before it reaches the dam.

Tony Christopher of Christopher Plumbing said he is using for the first time in the 45-year history of the company an AquaDam product to hold back the water.

The California manufacturer of AquaDam products provides flexible polyethylene and woven polypropylene fabric structures. When filled with water, the structures become rigid and function as temporary barriers against running or pooled bodies of water.

The AquaDam units range in capacity from 1,200 gallons (4,560 L) per 100 ft. to 125,000 gallons (475,000 L). Empty, the structures weigh 75 lbs. (34 kg) per 100 ft. on up to 8,000 tons (7,200 t).

Cook called an AquaDam “a big inner tube pumped full of water.” In this case, the “inner tube” will extend approximately 300 ft. (91 m) across the narrowed end of the lagoon and, when filled, will create a barrer 5 ft. (150 cm) high.

The bridge and segment of canal beneath it are scheduled for completion next March.

The overall footprint of the redevelopment project that includes acreage for the $40 million hotel incorporates a second and much larger culvert. It was constructed earlier by Christopher Plumbing and measures 60 ft. (18 m) in width, 12 ft. (3.6 m) in height and about 950 ft. (286 m) in length.

“It’s the biggest culvert we’ve ever done,” Cook said speaking from the standpoint of Civil Solutions. “In fact, it’s one of the biggest culverts in the state.”

The poured-in-place $3 million structure consumed about 25,000 cu. yds. (19,000 cu m) of concrete. Alabama Concrete Co. supplied it.

Tony Christopher said he encountered no obstacles in fabricating the culvert other than wet winter and spring weather. The project was started in December and completed in May.

John Deere equipment dominated the work site during the earth-moving phases, with 330 trackhoes digging, 750 dozers pushing and 544 loaders depositing the earth in Terex off-road trucks.

This second culvert replaced another open canal that had carried the water of Fagon Creek through the area. Unfortunately, the new hotel was to go up in the same area.

Now the buried creek water will flow beneath the parking lot of the Embassy Suites hotel on its way to being emptied into Pinhook Creek.

The only unexpected event that the project manager has run into before now was a mix-up about utilities. Fiber optic communication lines originally were to have been relocated. However, city officials changed their minds about the layout of the area’s power grid network.

Consequently, sensitive lines of communication ended up being strung overhead from poles while contractors moved earth and poured concrete beneath them.

“I still can’t believe that it happened,” Cook said of the utilities confusion.

The only complication the project manager foresees in the next year is coordinating separate projects so that they mesh smoothly on the ground.

“We are going to have to do a lot of coordination,” he said.

The busy site will have one crew erecting a new hotel and a “skywalk” that will connect the hotel to the Von Braun Center. Another crew will be building a parking lot for the existing 288-room Hilton Hotel that sits nearby. And contractors will simultaneously be working on four or five municipal projects, including completing the canal that will be 15 ft. (4.6 m) wide and will slip between the hotel and convention center and under the connecting skywalk.

The canal project and auxiliary work is being paid for through a combination of Economic Development Association grant money from the U.S. Department of Commerce as well as funding from the city, the Alabama Department of Transportation and the U.S. Corps of Engineers.

The city of 180,000 became home 50 years ago to an international population thanks to the space and rocket industry that sprang up there. City leaders hope the second hotel and redeveloped waterway will help attract more conventions to the downtown center.