Rainfall was the biggest challenge facing the project team of the soon-to-be completed $147-million Bolsa Chica Lowland Restoration Project in Huntington Beach, CA.
According to Jack M. Fancher, coastal program chief and Bolsa Chica program manager of the U.S. Fish and Wildlife Service of Carlsbad, CA, the 1,300 gross acre (526 ha) Bolsa Chica Restoration site is an historic wetland with its elevations mostly below sea level.
"There is no drainage and very shallow groundwater. After any rainfall," he explained, "the work area got very wet and unworkable very quickly. The contractor knew all that and bid the job and schedule to do the earthmoving with dry land equipment in year one of the two-year schedule, with an hydraulic dredge finishing the project excavation in the second year."
"In Southern California, a semi-arid region," he added, "rainfall is normally confined to several winter months and only about 15 inches in a year."
The winter of 2004-2005, Fancher continued, in southern California, was the second or third highest rainfall total in record history — nearly 37 in.
"Heavy construction equipment work came to a standstill with every day of delay, threatening to blow the schedule and postpone the dredging phase," he said, noting that the prime contractor, Kiewit Pacific Co., failed in its attempts to pump off the surface water because the heavy construction equipment still could not work on the marsh soils with the shallow groundwater.
Eventually, Kiewit Pacific solved the problem of working earthmoving equipment in liquefying soils by drilling hundreds of groundwater extraction wells around the work areas, he explained.
According to Fancher, the specialized well drilling equipment made it possible to do the work required in the soft soils by lowering the groundwater beneath the surface where the heavy construction equipment was moving.
"By that time," he said, "the earthmoving schedule was weeks behind. Kiewit Pacific brought in many more Challenger-drawn scrapers and, like a very fast carousel, ran them one after another in a circuit to move a lot of dirt much faster to get back on schedule. After the agonizing months of slow, muddy inaction, it was very exciting to see all of that heavy construction equipment moving in a well coordinated 'dance' to get back on schedule."
Fancher explained that eight public agencies, forming a "Steering Committee," were the project's proponents. They made strategic decisions and held the project's purse strings.
They included the U.S. Environmental Protection Agency, the U.S. Army Corps of Engineers, the National Marines Fisheries Service, the U.S. Fish and Wildlife Service, the California State Lands Commission, the California Resources Agency, the State Coastal Conservancy, and the California Department of Fish and Game.
The U.S. Fish and Wildlife Service served as the lead agency for construction, the environmental impact study, the contaminants cleanup technical committee, and the lead agency on the project's final design.
The project, Fancher explained, is located in Orange County, CA, adjacent to Huntington Beach.
The purpose of the project was to restore portions of the wetlands ecosystem of the Bolsa Chica Lowlands. The project area covers approximately 247 acres (100 ha) and it restores tidal influence from the Pacific Ocean to approximately half of this area to reinvigorate the wetlands ecosystem.
To achieve the biological benefits of tidal restoration, direct connection to the Pacific Ocean was re-established through the creation of a new tidal inlet that cuts through Bolsa Chica State Beach and crosses the Pacific Coast Highway near the Huntington mesa.
Included in the project, Fancher said, was the construction of the 367-acre (148 ha) tidal basin. To build it, approximately 2.7 million cu. yds. (2.06 million cu m) of material was removed from 175 acres (70.8 ha) within the basin to support depths varying between 4 and 7 ft. (1.2 and 2.1 m) below mean sea level (MSL).
Excavated silts, clay and contaminated material were moved on-site to build project construction features.
Approximately 1.3 million cu. yds. (993,921 cu m) of hydraulically dredged sand was used to pre-fill an ebb bar, he added. Levees for the full tidal basin required 456,000 cu. yds. (348,637 cu m) of sand, 366,000 cu. yds. (279,827 cu m) of sand was required for three nesting areas, 190,000 cu. yds. (145,265 cu m) of sand was needed for beach nourishment fills, and 98,300 cu. yds. (75,156 cu m) of sand was required for an inter-tidal shelf for cordgrass. In addition, about 17,000 cu. yds. (12,997 cu m) of moderately contaminated material was hauled off site, he noted.
Fancher said the project also includes a muted tidal basin, a pocket muted tidal basin, nesting habitat islands, an ocean inlet, an entrance jetty, shoreline and bridge revetments, an ebb shoal, a Pacific coast highway bridge and retaining walls, an oil service bridge, and a groundwater barrier.
He explained that the 180-acre (72.3 ha) muted tidal basin was created using three custom-designed water control structure connections between the full tidal basin and the muted tidal basin.
These water control structures consist of flap gates, sluice gates and self-regulating tide gates to regulate the tidal influence. Additional site modifications included improvements for tidal channels and overflow structures.
Continuing, he said that the pocket muted tidal basin is an isolated pocket of land on the north side of the East Garden Grove Wintersburg Flood Control Channel that formed the northern boundary of the project.
Hydraulic connections, consisting of two parallel box culverts, were installed under the mesa slope into the outer Bolsa Bay adjacent to the tide gates of the adjacent flood control channel.
In addition, he noted, three nesting areas were created on 20 acres (8 ha) within the site for federally listed endangered species. Nesting areas were constructed using 366,000 cu. yds. of material excavated from the full tidal basin at elevations from 4 to 10 ft. (1.2 to 3 m).
Fancher said an ocean inlet also was constructed to the full tidal basin that was 350 ft. (106.7 m) in width between the levee crests and encompass an area of approximately 3.7 acres (1.5 ha) when it was completed. As the inlet was excavated, he continued, approximately 190,000 cu. yds. (145,265 cu m) of sand was placed on the adjacent state beach for beach nourishment purposes.
Fancher said that to stabilize the inlet, two stone jetties were constructed to prevent the entrance channel from closing. Each jetty is about 350 ft. (106.6 m) long, running from the Pacific Coast Highway to the jetty tips. Each jetty is nearly 100 ft. (30.5 m) at its base. The amount of rock in the inlet, jetty and under the bridge totals approximately 72,000 tons (65,317 t). Armor stones, ranging from 6 to 8 tons (5.4 to 7.3 t) each, were used on the ocean-exposed jetty tops.
In addition, rock bank protection was placed inside the inlet east of the bridge for erosion protection in the flood shoal of the full tidal basin. The total amount of rock in these is approximately 138,000 tons (125,191 t).
To stabilize the down-coast region near Huntington Cliffs from the loss of the existing beach, assure sand movement along the beach and maintain beach stability, an ebb shoal was constructed just outside the inlet mouth surf zone.
The equilibrium volume of the ebb shoal consists of 620,000 cu. yds. (474,024 cu m) of sandy material, Fancher continued. About 850,000 cu. yds. (649,871 cu m) of sandy material from the full tidal basin was placed in the ebb shoal location over approximately 45 acres (18 ha) of soft bottom substrate using a hydraulic dredge.
Furthermore, Fancher said, a new bridge was constructed along the existing Pacific Coast Highway alignment parallel to Bolsa Chica State Beach. The bridge has four traffic lanes and a physically separate safety vehicle/bicycle path for the local beach traffic along the Bolsa Chica State Beach.
Continuing, he said that roadway drainage improvements were constructed in the inlet/Pacific Coast Highway Bridge vicinity. Retaining walls were used to minimize land requirements along the west side of the bridge.
Fancher said the bridge structure is a 10-span, cast-in-place deck slab structure that is 420 ft. (128 m) long and supported on driven pre-stressed concrete piles that range from 18- to 24-in. (45.7 to 61 cm) in diameter. Each has a 70-ton (63.5 t) capacity, he added, noting that construction of the Pacific Coast Highway Bridge, included maintenance of four lanes of traffic during construction by using a detour along the inland edge of the existing right of way.
Fancher also said that in order to maintain existing oil field operations on a parcel isolated by the new ocean inlet, a two-lane oil service bridge was built over the new inlet parallel to the Pacific Coast Highway Bridge.
This bridge structure also consisted of a 10-span, cast-in-place deck slab structure that is 420 ft. (128 m) long and supported on driven concrete piles with the same standards as those used for the Pacific Coast Highway Bridge.
The two-lane structure also includes a 9.8-ft. (3 m) wide utility platform that accommodates production lines for oil field operations, including oil, gas and water lines in casings.
Approximately 10,000 ft. (3,048 m) of groundwater barrier was constructed to prevent groundwater and salinity intrusion under the adjacent neighborhoods. The salinity intrusion barrier was driven 30 ft. (9.1 m) deep. An extraction well system was installed to control shallow groundwater levels. The extraction wells are connected to a vacuum pump that discharges into the muted tidal basin, he added.
Fancher said the project also included a community outreach program that consisted of placing signs along the project's margins. These signs featured Web site and voice-mail phone numbers for recorded answers to frequently asked questions. The project's Web site contained basic and background information, documents, maps and figures, site and construction activity photos, and a recent events chronology.
"We also held 'town hall' briefings and monthly update meetings with support groups," he added.
In addition, Fancher said, weekly coordination meetings were held throughout the construction.
As part of the project, the general contractor, Kiewit Pacific, was issued a federal contract that included liquidated damages on the completion of the state highway bridge and on completion of the overall project, Fancher said.
"The project timelines were met and no penalties were imposed on the prime contractor," he added.
"There were severe weather problems in the winter of 2004-2005," he explained. "Record-breaking rainfall occurred when earthmoving equipment was scheduled for operation. The prime contractor recovered from this near disaster by pumping water out of the work area, implementing the aforementioned groundwater extraction well system, and by bringing in more earthmoving equipment," he added.
Development team members included Kiewit Pacific Co. of Vancouver, WA, general contractor; Moffatt and Nichol Engineers of Long Beach, CA, construction manager and design contractor; and the U.S. Fish and Wildlife Service of Carlsbad, CA, owner.
In addition, a variety of inspectors for the Pacific Coast Highway Bridge from the California Department of Transportation also served on the project team, he noted.
"The Bolsa Chica wetlands project is at the cutting edge of a new and evolving science," said Shirley Dettloff, a member of the conservation group, Amigos de Bolsa Chica, and a former member of the California Coastal Commission.
"Not many wetlands have been restored in the world, especially in an oil field," Dettloff added.
Dettloff, who's been fighting for the wetlands for 30 years, said, "Even we locals sometimes forget that this was the second largest functioning oil field in the state of California for years, since the 1930s."
This project required a large volume of heavy construction equipment. Owned equipment included a Case 9280 pulling 41-in. (104 cm) disc, a Caterpillar 765 pulling 36-in. (91 cm) disc, a Caterpillar 765 pulling 24-in. (61 cm) disc, a Caterpillar 765 BG roller, a Caterpillar D-6 bulldozer with a double 5x5 roller, and a D-7 LGP bulldozer.
It also included a Caterpillar 365 excavator, a Volvo A-40 articulated truck, two Caterpillar D4000 articulated trucks, a Caterpillar 365 excavator, three Caterpillar 765 articulated trucks, and Caterpillar 966, 980 and 988 loaders.
It also consisted of a Caterpillar 14G grader, a Caterpillar 330B excavator, a Caterpillar 436 backhoe, an Ingersoll Rand SD-100 roller, a Caterpillar 825 roller, a Caterpillar 950 loader, a Caterpillar D-4 bulldozer, a Pettibone Super 8 and a Super 15 forklift, a Grove 25T RT crane, a Bidwell 4800 concrete paving machine, and two 75KW, two 80KW and 10 25KW generators.
Fancher said subcontractors provided an Ingersoll Rand DD130 roller, a Massey Ferguson Skip Tractor, a track-mounted Drill LLM 80 and Spiradrill, a Manitowoc 2900 crane with a pile driver and drill, a Manitowoc 4100 crane with a pile driver attachment, a Caterpillar 988 with forks, a super forklift, an Electric Portable 16-in. (40.6 cm) hydraulic cutter and suction dredge, and three work/skiff boats.
Quinn Rental of City of Industry, CA, provided four Caterpillar 835 LGP scrapers and two 855 Double Can LGP scrapers; Mathews Machinery of Santa Fe Springs, CA, provided a Volvo L120 loader; JLS Pumping of Oakview, CA, provided a concrete pump; and Associated Power of Wilmington, CA, provided two 22KW generators.
Construction, Fancher said, began Sept. 3, 2004 and will be completed Sept. 30. CEG
This story also appears on Crane Equipment Guide.
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