Underwater Box Culverts Preserve Fish Habitat

Conservation of fish populations links environmental projects in Washington and Illinois

By Leslie Lichtenberg

On the surface, there are few similarities between an Illinois ship canal and a Washington creek, but the species swimming in both water sources are connected by similar conservation efforts, which both resulted in the application of precast concrete.

The management of fish

Since the early 1990s, the Washington State Department of Transportation (WSDOT) has managed a fish barrier removal program designed to inventory and rectify highway culverts that block fish passage. Fish barrier removal in Washington state in particular is driven by the need to provide salmon and other fish with freshwater access so they can spawn. Barriers to the natural habitat impede this spawning process and inhibit salmon recovery. High water velocity, inadequate water depth and large culvert outfall drops are just a few of the more common factors in old culverts that create fish barriers. The aging culvert at Jim Creek in Joyce, Wash., was originally installed to allow for water flow, but without consideration of fish passage.

“The objective is to enhance the salmon population by relieving old fish barriers,” said Ted Reynolds of Utility Vault Co., Auburn, Wash., the precast concrete manufacturer for the Jim Creek project. “The original culvert, in this case a steel-plated arched pipe, was probably considered standard 30 years ago.”

Under a cooperative program with the Washington State Department of Fish and Wildlife (WDFW), the fish barrier removal initiative has identified more than 600 existing barriers for correction. WSDOT culvert barriers are corrected or modified under several scenarios – in conjunction with highway projects, as stand-alone projects, during routine maintenance or through a special retrofit program. Through the efforts of the fish passage program, more than 220 miles once blocked by barrier culverts have been reclaimed, according to WSDOT reports.

“Once these problem culverts are corrected, the benefits to fish habitat are real and immediate – in many cases, fish have been observed upstream of improved culverts within weeks of restoring access,” according to the WSDOT Environmental Services Web site.

The priority fish culvert replacement project at Jim Creek, which temporarily closed State Route 112 west of Port Angeles, began construction in September 2003 with the excavation of a 1,000-foot-wide construction area, including a 25-foot-deep roadway.

“One of the biggest challenges with this project was that the excavation was so deep, approximately 35 feet from the road surface,” said Sean Coleman of the Port Angeles-based Bruch & Bruch Construction Inc., contractors for the project. “We had to build a 30-foot retaining wall about five feet from the edge of the culvert and then run the wall 65 feet along the culvert in order to bring in a crane pad,” he said.

The three-sided precast concrete replacement culvert, measuring 10 feet high, 28 feet wide and 144 feet long, was transported and placed using a 500-ton crane. Forty-three sections were used to build the culvert.

From start of excavation through the reopening of SR 112 the culvert installation took about 35 days, but it was not without its share of trials.

“We had a very limited window of time, since WSDOT would not allow us to close the road until after Labor Day,” Coleman said. “This was compounded by the fact that due to spawning cycles, we knew we had to be out of the stream by the end of September. Having precast concrete pieces sped up the placement process considerably.”

Although less than a quarter mile of road was affected, the six-week closure of SR 112 in the Jim Creek vicinity was a potential downside of the project.

“We were able to close the road with this particular project, but a convenient detour is not always possible, so time was of the essence,” Reynolds said.

Another potential obstacle included pumping of the creek, which required the use of six different pumps from various locations. During the initial stages of the project, the creek was pumped 24 hours a day for approximately 18 days. Still, these issues, coupled with heavy rainfall in September 2004, did not deter WSDOT from replacing the culvert and completing the project in mid-October during the creek’s low-flow period. Those involved in the $870,000 undertaking agree that manpower and the use of precast concrete enabled the project to be completed on time and within budget. “Our crews were out there working 12- to 14-hour days, six days a week,” Coleman said.

In terms of time and cost savings, there was not a competitive alternative to precast concrete.

“The alternative would have been to build a standard bridge, which would have required abutments, girders and things of that nature – all of which would have to be cast in place,” Reynolds said. “Given the constraints and challenges of this project, precast contributed tremendously with respect to ease of installation and reduction in time and labor.”

More than 1,700 miles from Washington state, Illinois is home to the famous Chicago Sanitary and Ship Canal (San-Ship), one of the busiest waterways in the nation. Built in 1910 as an expansion to the Illinois-Michigan canal, the San-Ship was a vital link in helping to build the Midwest. Connecting the south branch of the Chicago River to the Des Plaines River, the present-day San-Ship runs about 165 feet wide and 25 feet deep. This man-made channel, originally constructed to reverse the flow of the Chicago River – long ago a site for sewage dumping – has evolved today into a two-way conduit through which a growing range of exotic species migrates between the rivers and the Great Lakes. These species, which are not indigenous to the area, compete with or prey upon native species of plants, fish and wildlife. Many carry diseases or parasites that could potentially disturb the aquatic environment and economy of nearby areas.

Zebra mussels, responsible for recent die-offs among Great Lakes waterfowl, and Asian Carp, many weighing upwards of 100 pounds, along with the Grass Carp, African Water Flea and Round Goby, are just some of the invasive species that are using the San-Ship to migrate to other bodies of water, according to a 2001 article in Wisconsin Natural Resources magazine. With this in mind, the U.S. Army Corps of Engineers, under the auspices of the National Invasive Species Act (1996), launched a demonstration project to limit the spread of aquatic invasive species via the San-Ship Canal. Working with the Illinois Department of Natural Resources, the Corps identified an electrical fish barrier as the optimal tool for effectively reversing the invasion of “nuisance species” without interfering with regular canal traffic.

“This array is by far the largest and most unique electrical barrier in the world,” said Jeff Smith of Smith-Root Inc.

Smith-Root, based in Vancouver, Wash., developed the technology for the barrier, which measures 160 feet across and 400 feet long. As general contractor and patent holder of the system, Smith-Root designed and oversaw the barrier installation, which involved laying electrodes perpendicular to the flow of water across the bottom of the canal. Forty precast concrete panels, each weighing between 6,000 and 10,000 pounds, were set in the water and notched at the top for the placement of large 4 x 4 ingots.

“The voltage is distributed evenly throughout the entire water column, but because the barrier is graduated, fish coming into it will feel the fringe effect of the electrical field and ultimately be washed out by the current,” Smith said.

The duality of the electrical barrier, acting as both a barricade for the invasive species and a repellent for the fish, is a key factor in its success.

“In nearly all applications, it is 100 percent effective,” Smith said, adding that in the case of the San-Ship, the electrical field is completely unaffected by canal traffic. At approximately 1 to 2 volts per cubic inch of water, the field is non-lethal and, because of its 35-foot-depth along the bottom of the canal, the electrical disturbance does not upset the natural flow of water.

The 2-foot square precast concrete supports, in varying lengths between 16 feet 5 inches and 9 feet 8 inches long, were chosen over cast-in-place because of time and cost savings. Aurora Concrete Products of Aurora, Ill., was chosen as the precast manufacturer for the job.

“The Corps was looking at pouring the concrete on site, but that would have required bringing in cranes to pour, strip and set these large support beams,” said Stephen Fossler, president of Aurora Concrete Products. “In terms of quality control, precast was the way to go.”

“We use a lot of precast in our projects because it saves time and expense,” added Smith. “Using precast allows us to set the concrete supports directly in the body of water rather than having to ‘de-water.’”

Building on the success of a demonstration project in 2001, the second phase of the electrical fish barrier at the San-Ship Canal is on target for a March 2005 completion date.

In the meantime, government agencies, working with both public and private stakeholders, will continue to seek environmental solutions to the problems threatening the nation’s fish, wildlife and other natural resources.

“For environmental purposes, commercial fishing and maintaining balance in the entire ecosystem, you can’t underestimate the importance of projects like this,” Fossler said.

The application of precast concrete in environmental projects nationwide is growing, and precast manufacturers such as Utility Vault and Aurora Concrete Products are redefining their services to stretch beyond that of our nation’s infrastructure, and to help sustain America’s ecosystems for years to come.