2009 E3 Superior Achievement Award Winner

Marina Barrage, Singapore

Singapore
ENTRANT:CDM & PUB, Singapore's national water agency
ENGINEER IN CHARGE: Robert L. Hurdle, P.E.

Providing a bold, integrated solution to decades-old problems of urban flooding and water supply, Singapore's new Marina Barrage protects against stormwater and tidal flooding, augments a sustainable water supply serving 4.8 million people, and enhances the vibrant downtown area for both commercial and recreational benefit.	The barrage's nine crest gates, each 30 meters long and 5 meters high, can be closed (raised) and opened (lowered) to prevent flooding. In the event of power failure, the gates would float to the closed position to protect the reservoir.	To facilitate navigation in the channel throughout the construction period, the barrage was built in two stages, the first extending west from the east abutment. As the structure neared completion, a boat hoist was built to ensure uninterrupted egress/access for small work boats and pleasure craft; allow coastguard craft to patrol the reservoir; and support major events, including the recent Formula 1 Singapore Grand Prix race and the 2008 National Day parade.
The 70-tonne crest gates (as well as the 500-tonne precast bridge segments) were moved into position using floating cranes with lifting capacities of up to 3,200 tonnes. Precision engineering was required as the tolerance level for error was only -+ 2 millimeters for the centerline of the nine pivot pins of each crest gate.	Each of the seven 7.5-meter-high drainage pumps, capable of pumping approximately 3.5 billion liters per day, have 3.2-meterdiameter impellers that turn at 120 revolutions per minute.	The tidal barrage, spanning the 350-meter wide Marina Channel, impounds the 240-hectare Marina Reservoir as it is transformed into a freshwater source. During severe rainstorms, its hydraulically operated steel crest gates can be lowered to release stormwater to the sea. If tides are high, the gates remain closed and excess flows are pumped to the sea. A pedestrian bridge across the barrage links the east and west banks.

Entrant Profile

CDM and PUB have collaborated in the realization of Marina Barrage, a unique water management solution that protects Singapore's low-lying areas from the effects of seasonal flooding, establishes a new source of freshwater, and enhances the nation's downtown area. For more than 20 years, CDM, a global consulting, engineering, construction, and operations firm headquartered in Cambridge, Massachusetts, has served as main consultant to PUB, Singapore's national water agency, in joint efforts for successive water resources and drainage studies, engineering design, and construction management leading to the completion of Marina Barrage. Serving a population of 4.8 million, PUB has achieved international recognition for its innovative approach to urban water management.

Other key participants in the project include:

Architects Team 3 (architect), Singapore
SKM Singapore (structural & building services), Singapore
Design Act (designer for Sustainable Singapore Gallery), Singapore
Koh Brothers Building & Civil Engineering Contractor, Singapore
Metax Engineering (drainage pumping system & low-level sluices), Singapore
Cegelec (electrical, instrumentation & control work), Singapore
Kurimoto (designer & supplier of crest gates & stop log system), Osaka, Japan
Black & Veatch (contractor's designer/barrage structural works), Singapore
KKT Consultants (accredited checker), Singapore
AGS Consult (professional engineer for cofferdam scheme), Singapore
WL Delft Hydraulics (pumping system scale model testing), Singapore
Art-2 Gallery (art consultant), Singapore
Martin Lee Designs (landscaping architect), Singapore

Project Description

With two annual monsoon seasons, the island nation of Singapore receives approximately 245 centimeters of rainfall, but still faces challenges in securing reliable water supplies for its 4.8 million people. For Marina Barrage, CDM worked with PUB, Singapore's national water agency, to design an integrated, sustainable solution for both flood control and water supply. The barrage is a sophisticated dam that provides three main benefits: a tidal barrier and pumping station for flood control, a reservoir for augmenting water supply, and new lifestyle attractions in and around the reservoir. It is Singapore's boldest water undertaking to date-in a national history marked by innovative approaches to water management.

Integrated Approach

Focus on sustainability. The Marina Barrage, built to protect Singapore from devastating floods, simultaneously addresses the city-state's need for safe drinking water through beneficial capture and reuse while supporting its plans to stimulate the local economy and the people's interest in environmental conservation.
Barrage supports water independence. Ultimately meeting 10 percent of the nation's potable water demand, the barrage reinforces Singapore's "Four National Taps" initiative, which seeks a diversified and sustainable water supply through local catchment water, imported water, reclaimed water, and desalinated seawater.
Clean water, greener landscape. In addition to improving water quality, the barrage anchors a tropical botanical park extending from downtown and along the reservoir, which enhances Singapore's reputation as a garden city. The pump station shares space with an exhibition gallery that presents the city's environmental achievements in six interactive displays. This facility is covered by a helical grass roof featuring a 70-kilowatt solar power park, which powers some of the site's public spaces.

Quality

Multiple benefits delivered within budget. A longtime partner in Singapore's water management efforts, CDM helped deliver the S$250 million (US$167 million) project within budget. Extensive user-focused lifestyle benefits, including the visitor gallery, iconic architectural treatment, and parkland features, were completed at a 5-percent increment of the basic cost.
Public hot spot in a bustling metropolis. An iconic structure in Singapore's downtown landscape, the project visually and functionally links the east and west arms of the Marina Reservoir shoreline. Attracting 40,000 visitors during its opening weekend, the site has proven a popular destination for local residents and tourists alike. Its premier location makes the reservoir an ideal venue for international water sport competitions, cultural performances, and recreational activities.

Originality or Innovation

Versatile design ensures optimal protection. During normal operation, the structure's steel crest gates remain closed to isolate the reservoir from the ocean; outflow is directed through low-level sluice gates underlying the pumping station. In the event of heavy rains, and when the tide is low, the gates are lowered sequentially to release excess flows. When tide levels rise, the gates remain closed and the high capacity pumping station is put into operation.
Facility creates freshwater resource. By responding to a range of storm flows and tide levels to maintain near-constant levels in Marina Reservoir, the facility also allows natural flushing of salt water to transform the formerly saline basin into a fresh-water reservoir.
Construction on a monolithic scale. The tidal barrage, spanning across the 350-meter-(m)-wide Marina Channel, features nine 30-m-long hydraulically operated crest gates; seven drainage pumps, each capable of pumping approximately 3.5 billion liters per day; and an intake and 432-million-liter-per-day pumping station conveying raw water to an upland reservoir.
Original concept serves as a multi-purpose model. Marina Barrage offers an attractive model for other low-lying coastal cities confronting climate change, flooding, and demand for new water supply. Other coastal cities, like Hong Kong, New Orleans, and Dublin, are interested in the concept, and Dublin has recently undertaken preliminary studies for a tidal barrage across Dublin Bay.

Complexity

Modeling tools support project success. Complex hydrological and water-quality modeling (using the Storm Water Management Model, Water Quality Analysis Simulation Program, and MB-BASIN-a tool developed for this project) was applied to provide an understanding of the hydrodynamics of the Marina Basin and its response to impoundment. Extensive modeling helped size crest gates and pumps (among the world's largest), provided water supply projections, and defined operational protocols.
Precision engineering overcomes large-scale construction challenges. Built in a section of the Marina Channel containing thick layers of clay, the barrage structure and pumping station are supported by a foundation of approximately 850 bored piles, each between 1.0 and 1.5 m in diameter and up to 74 m deep. Floating cranes were used to install the barrage's 70-tonne gates, with supporting pivot blocks having tolerance levels of just 2 millimeters, and 500-tonne precast bridge segments.
Maintaining channel navigation during construction. Although the barrage was constructed in two stages to facilitate navigation in the channel, the route was interrupted as the project neared completion. Most marine support traffic was moved to a new pier facility constructed outside the barrage, and alternative jetty and maintenance facilities were also developed. Today, the barrage's boat hoist ensures uninterrupted egress/access for small work boats and pleasure craft; allows coastguard craft to patrol the reservoir; and supports major events, including the recent Formula 1 Singapore Grand Prix race and the 2008 National Day parade.

Social and Economic Advancement

Stability brings recreation and revitalization. The barrage steadies the upstream waterways of the Singapore and Kallang rivers, significantly enhancing urban development and shoreline recreational activities. Some US$7 billion of development is underway in the immediate neighborhood-all enhanced by the ability of the barrage to stabilize water levels.
Enhancing Singapore's downtown area. A concurrent redevelopment project includes live-work-play communities with shops, restaurants, and parks. Through this initiative and others, the barrage attracts business and advances economic growth in urban Singapore.
Promoting public interest in clean water. Taken together, the grass-covered roof ramp, the 360-degree views of city and sea, and the attraction of the reservoir for water sports or water taxi rides all serve to advance Singapore's strategic goal of bringing residents closer to water, encouraging protection and appreciation of national water resources.

Visitors to the Marina Barrage-arriving by road or water taxi-are welcomed into a central water courtyard, which includes pulsing fountains and water play features for children. The courtyard is partially enclosed by the structure housing the 2,000-square-meter interactive visitor center, and by the helical turf-covered roof.	The "Sustainable Singapore" exhibition gallery shares space with the pump station and presents the city's environmental achievements in six interactive displays.	The pump station's grass-covered "green roof" features a 70- kilowatt solar park that provides supplemental power for lighting and general purposes at the visitor center, control room, and common area. It is today the largest solar power park of its type in Singapore.
The barrage steadies the upstream waterways of the Singapore and Kallang rivers, significantly enhancing urban development and shoreline recreational activities. Some US$7 billion of development is underway in the immediate neighborhood-all enhanced by the ability of the barrage to stabilize water levels.	Attracting 40,000 visitors during its opening weekend, the site has proven a popular destination for local residents and tourists alike. Its premier location makes the reservoir an ideal venue for international water sport competitions, cultural performances, and recreational activities.	The grass-covered roof ramps, 360-degree views of city and sea, and attraction of the reservoir for water sports and water taxi rides all serve to advance Singapore's strategic goal of bringing residents closer to water, encouraging protection and appreciation of the nation's water resources.