Award-Winning Projects

Sewage Pump Station at Wahiawa Terrace

State of Hawaii, Hawaii Public Housing Authority

2025 ASCE Hawaii Section Best Small Project

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Sewage Pump Station at Wahiawa Terrace

Wahiawa Terrace is 60-unit residential complex located in Wahiawa and provides much needed housing for low-income families in the community. In 2016, extensive renovations to the housing complex were completed; however, the aging pump station was excluded from the upgrades despite ongoing maintenance issues. Due to the frequent maintenance schedule and growing concern of equipment failure at the existing sewage pump station, the Hawaii Public Housing Authority contracted TLCG to provide design services to replace the existing sewage pump station.

During the planning phase, an Architectural Inventory Survey determined that the housing complex was an “architecturally significant” site; therefore, the new pump station could only be placed in a few space-constrained areas on the property. To accommodate the various unique restrictions and requirements, TLCG designed a custom pump station featuring Flygt Adaptive N-Series submersible pumps, equipped with non-clog, adaptive impellers.

TLCG’s custom pump station design incorporated innovative technology to improve reliability of the sewage system, improve safety for maintenance staff, and reduce the risk of environmental pollution while still maintaining the property’s architectural features to meet its National Register of Historic Places designation.

Wailua Sewage Pump Station No. 1

Rehabilitation

County of Kauai, Department of Public Works,
Wastewater Management Division

2024 ACEC Hawaii Honor Award

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Wailua Sewage Pump Station No. 1 Rehabilitation

The County of Kauai, Department of Public Works – Division of Wastewater Management faced an environmental problem with its aging influent wastewater pump station at the Wailua Wastewater Treatment Plant. TLCG designed a facility retrofit to expand the wet well access to accommodate two new pumps while abandoning the dilapidated pump station. The wet well was rehabilitated with corrosion-resistant epoxy coating, and piping was brought aboveground for better maintenance access.

The facility retrofit approach reduced financial and environmental impacts associated with the timing, transportation, disposal, and labor effort that are usually required to build underground structures involving deep excavations within the groundwater table.

To minimize the cost of the wet well structural modification, the design team utilized pre-cast reinforced concrete pipe in lieu of cast-in-place concrete for the new access shaft. This reduced the concrete costs for the project and reduced the duration of construction dewatering.

Wahiawa Police Station NPDES

Improvements

City and County of Honolulu, Department of Design and Construction

2018 ACEC Hawaii Honor Award
2017 ASCE Hawaii Section Best Sustainability Project

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Wahiawa Police Station NPDES Improvements

The Wahiawa Police Station NPDES Small MS4 Permit Program Improvements project was one of the first projects in Hawaii solely developed to improve stormwater quality; it was completed prior to the issuance of local guidelines on Low Impact Design or structural Best Management Practices (BMP) standards. TLCG performed extensive research of BMP guidelines of other states’ municipalities, talked to numerous vendors of manufactured BMP devices, investigated the feasibility of each BMP to use in Hawaii-climates and selected those that were best suited for the specific site conditions at the Wahiawa Police Station.

This project achieved its objective of reducing the pollutants in the stormwater runoff to improve the water quality and overall wellness of the Wahiawa Reservoir, the State’s largest freshwater fishing area. The project also reduced offsite stormwater run-on and its potential for land and pavement erosion, added two loading spaces while increasing landscaped areas, created an easier parking configuration, and provided a renovated fuel canopy.

Mana Drag Racing Strip Improvements

State of Hawaii, Department of Land and Natural Resources

2015 ASCE Hawaii Section Best Small Project

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Mana Drag Racing Strip Improvements

The Mana Drag Racing Strip at Kauai Raceway Park is one of only two National Hot Rod Association (NHRA) member tracks in the State of Hawaii. The state-owned facility is leased to and operated by the Garden Isle Racing Association (GIRA), a non-profit organization run by volunteers. TLCG performed civil design and construction management services for the resurfacing and reconstruction of the NHRA-sanctioned drag strip to provide a safe and functional facility for motor sports on Kauai. Improvements included a new asphalt concrete pavement and a concrete launch pad.

On the weekend of July 4, 2014, the Mana Drag Racing Strip was reopened to the public. The first race of the season was a huge success. The improvements garnered compliments from seasoned race goers as the flatter, smoother, and ultimately faster track surface was a stark contrast to the previously aging track. Successful completion of the project attracted the attention of local drag racers and the NHRA – Kauai Raceway Park received an award for the Most Improved Facility in the Pacific region.

Pearl City Force Main Slip-Lining Repair

City and County of Honolulu, Department of Design and Construction

2014 ACEC Hawaii Excellence Award
2013 ASCE Hawaii Section Best Water/Wastewater/Environmental Project

Pearl City Force Main Slip-Lining Repair

This project was spurred by four consecutive pipeline breaks over a four-year period within a 250-foot section of 30-inch and 42-inch dual force mains. The project was declared an emergency because the public’s health and safety were in imminent danger due to the large service area associated with the force mains. An innovative project approach was used to expedite the design/bid/contracting process, allowing a contractor to come on board and start construction immediately. Construction documents were also completed to pre-final stages to allow for contractor involvement in developing the final construction documents to control cost, and to help realize the project on time.

TLCG elected to employ a trenchless method of construction. The minimal ground disturbance limited the impact to neighboring properties by avoiding the need to excavate the entire alignment of the force main. This approach reduced financial and environmental impacts associated with the timing, transportation, disposal, and labor effort that are usually required in open-cut excavation projects.

“The Limtiaco Consulting Group team showed outstanding technical and interpersonal skills in working through various project execution issues…” said Russell Takara, Assistant Chief, Wastewater Division, Department of Design and Construction. “Throughout the entire project period, the team conducted itself professionally and with great efficiency.”

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Makaua Stream Restoration and Debris

Removal

State of Hawaii, Department of Land and Natural Resources

2010 ACEC Hawaii Honor Award

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Makaua Stream Restoration and Debris Removal

40 days of rain in 2006 in Windward Oʻahu caused severe stream erosion, and work was needed to protect property from imminent hazards due to runoff, erosion, and possible collapse of residential structures into the stream, as well as possible impacts to Kamehameha Highway. In response to the severe rainstorm and resultant damage, Governor Linda Lingle issued an Emergency Proclamation.

The project utilized several technological tools to enhance the planning and design phases. Hydraulic analysis of the stream was computer-modeled in HEC-RAS to analyze the various stream conditions. To account for the meandering nature of the stream, a computer program created by the United States Army Corps of Engineers Coastal and Hydraulics Laboratory was also used to estimate the maximum bendway velocities at each repair site. Once preliminary designs were completed, a 3D model of the stream was made using AutoCAD Civil 3D showing the proposed bank restoration and debris removal limits.

A “fly-by” video of the model was used at one of the public informational meetings to show the attendees the layout of the stream and how the proposed improvements would tie into the existing conditions. The video was very helpful in providing the landowners a clear picture of the proposed improvements which led to the owners’ acceptance of the constructed improvements.

Sewage Pump Station at Wahiawa Terrace

2025 ASCE Hawaii Section Best Small Project

Wailua Sewage Pump Station No. 1

Rehabilitation

2024 ACEC Hawaii Honor Award

Wahiawa Police Station NPDES

Improvements

2018 ACEC Hawaii Honor Award

2017 ASCE Hawaii Section Best Sustainability Project

Mana Drag Racing Strip Improvements

2015 ASCE Hawaii Section Best Small Project

Pearl City Force Main Slip-Lining Repair

2014 ACEC Hawaii Excellence Award

2013 ASCE Hawaii Section Best Water/Wastewater/Environmental Project

Makaua Stream Restoration and Debris

Removal

2010 ACEC Hawaii Honor Award