Canadian Underground Infrastructure Logo

Dewatering pumps help reconstruct Galveston

Storm surge attacks a seawall protecting coastal city.
Storm surge attacks a seawall protecting coastal city.

Company info

123 Spencer Plain Rd
Old Saybrook, CT
US, 06475

Website:
bjmpumps.com

Read more

When dealing with a construction site that is underwater or where the water table is just above sea level, contractors have to insure that the excavation stays dry and safe for workers. This can be extra challenging where you have conditions affected by water depth and conditions such as silt and sand. Additionally, these conditions may vary based on seasonal weather or tides. It is extremely important to have contractors who have investigated historical data and who monitor fluctuations in water levels and speeds of flow, thereby decreasing risks to workers and the success of the project.

One of the primary decisions of the contractor, based on the hydraulic conditions, is what pumping equipment to utilize. This decision will be based on numerous jobsite conditions such as; flow required to mitigate water seepage, depth of a coffer dam, and solids content. The contractor’s selection of pump type usually comes down to self-priming centrifugal or submersible pumps.



Engine driven self-priming pumps are one of the choices available to contractors.

Self-Priming Centrifugal Pumps

One drawback of using end suction centrifugal pumps is that they do not fare well when the liquid is below the pump centerline. Liquid must be delivered to the pump so the process can begin. Air on the suction side (piping and pump casing) of the pump needs to be totally evacuated. If air exists in the centrifugal pump, it will become “air bound” and incapable of pumping. The self-priming centrifugal, a specialized end suction pump design, creates a vacuum at the impeller eye to continuously remove air from the suction line. The pump is not capable of compressing the air during the priming phase and it must be allowed to escape through the discharge. As air is removed, atmospheric pressure forces water up the suction piping to the pump, allowing the pump to operate. The self-priming process occurs automatically once the pump is started with the initial quantity of liquid. This priming process can be complicated when the pumped liquid contains sand or solids. The practical suction lift limit for self-priming pumps is around 8m (26 feet) of liquid under ideal conditions.

The disadvantages of self-priming centrifugal pumps are numerous. Any small vacuum leak, such as sealing areas around connectors in the suction line, or pump seals can prevent the unit from priming. The pump will continuously pull air from the leak instead of the air in the suction line, thus, never allowing the priming cycle to be completed.

This is a common cause of priming failure. The leak can be very small or invisible to the naked eye but can prevent priming.

The diameter and length of the suction hose or pipe can also affect prime time due to the volume of air to be evacuated during pump priming. This extended priming time can add heat to the liquid which can further extend prime time.

Self-priming pumps need to be located as close as possible to the water source. It is best to be located directly above the coffer dam with as few restrictions (such as elbows) as possible to reduce friction. Again this can present problems dependent on the excavation location.

Once the pump is primed and pumping it will require adequate net positive suction head (NPSH) to remain pumping without suction limitations. Without sufficient NPSH, a self-priming centrifugal pump can cavitate and lose prime. Lifts through long suction lines, especially containing obstructions, can be plagued by cavitation problems resulting in unacceptable noise levels and possible equipment damage.

If a self-primer is required to lift water 15 feet or more from the source to the pump’s suction, the pump capacity could be decreased significantly. Submersible pumps, being located below the water level, typically do not have this same suction limitation.

Most self-priming centrifugal pumps on remote applications utilize engine drives which in itself can present operational issues such as fuel levels for long run times, engine oil condition, and other prime mover maintenance issues.

Hard metal submersible pumps with integral agitator provide long service life in dewatering excavations where entrained sand is a problem.

Submersible Pumps

Using submersible pumps can offer many operational and application advantages.

Pumps are submerged directly into the water for immediate use and unit cooling thereby eliminating priming issues or extended prime times. No worker intervention is required. Pumping action occurs from direct submersion in the liquid feeding the pump without the need for a suction line.

Submerged pumps are quiet. Cavitation issues are extremely rare, and may occur when the sump is too small for the size of the submersible pump that is in it. Submersible water pumps are lighter in weight and highly portable.

The versatility and low maintenance of submersible pumps make them an ideal option for dewatering service. No regular maintenance is necessary. Submersible pumps usually need to be fully submerged. The water around a submersible pump actually helps to cool the motor.

A Case Story Using Submersible Dewatering Pumps to Reconstruct Galveston

The sea level along the Gulf Coast is rising faster than most places on the globe. Galveston Texas has experienced a three foot rise since the disastrous flood of 1900 that killed thousands of people. One of the toughest jobs in rebuilding the infrastructure of a city that is just a few feet above sea level is keeping the water out of your construction site – particularly water that is laden with sand. Pumping a water/sand slurry is tough on pumps – particularly aluminum dewatering pumps. When Boyer Construction was doing work in Galveston, Texas, they had to deal with this condition.

Galveston Island, located in Southeast Texas, runs west to east, and is slightly tilted to the northeast end, where the City of Galveston is located. The north side of the island opens up to a protected harbor, while the southern side faces the Gulf of Mexico. Before the 1900 Hurricane - which still holds the unenviable record of the most deadly natural disaster in American history with 6,000 deaths - the highest point in Galveston was 9 feet above sea level.

After the 1900 Hurricane, a 17 foot seawall that ran 3 miles long (since extended) was built to protect the city and its people from other storms. Constructing the seawall was easy compared to the next step, which was raising the entire city up to the edge of the seawall, then sloping the island down 8 feet above sea level on the north side of the island, so water getting over the sea wall would drain into the bay. This engineering feat, worked on for over 10 years, was accomplished by pumping a sand and seawater slurry underneath buildings to raise the island. The seawater ran off leaving the sand, and thus building up the island. Since then, hurricanes have hit Galveston, but never having the impact of the great 1900 storm.

In September 2008, Hurricane Ike devastated Galveston Island along with the Bolivar Peninsula, and Gilchrist, Texas with sustained winds of 110 mph, and a 22 foot storm surge. Property damage was estimated at $29.5 Billion and 135 people died in the United States due to the storm. The downtown area of Galveston had 6 feet of standing water in it after the storm passed through. As is always the case after a hurricane hits a populated area, the rebuilding effort takes years of hard work, and millions of dollars to repair the damage done. One of the companies, who worked on the rebuilding of Galveston, was Boyer Construction.

Boyer Construction is a 20 year-old construction and engineering company specializing in Civil, Electrical, Mechanical and Inland Marine construction projects. Based in Northwest Houston in an 18 acre facility, over 250 engineers, master electricians and plumbers, equipment specialists, and skilled fabricators, have worked on various rehabilitation and infrastructure replacement projects throughout Southeast Texas.

Many of those projects, including those in Galveston required dewatering pumps to be used on coffer dams and large excavation jobs. These demanding services require continual operation, pumping water that is often laden with silt and sand.

Couple continual cycling with salt and brackish water and you have elements which will minimize the life of most dewatering pumps.

Looking for help in keeping their dewatering pumps from wearing out, Boyer Construction called BJM Pumps distributor in Houston, Pumps of Houston for their advice and help. Cory Marcotte, one of Pumps of Houston’s sales engineers suggested that they try one of BJM Pumps’ LWA Series of hard metal dewatering pumps. The LWA Series

submersible lightweight agitator pumps provided a heavy-duty solution at an economical cost. They offered the flow range and high lifts required for a broad spectrum of applications. From 2 horsepower (flows to 180 GPM and heads to 55 feet) to 10 horsepower (flows to 475 GPM and heads to 117 feet), they are designed and constructed for difficult services. The LWA is a proven performer on tough dewatering services such as sand, silt, coal fines and spent drilling mud. The impeller and wear plate are made of abrasion resistant chrome iron, while the agitator and volute are constructed in hardened ductile iron – perfect for the salt/sand slurry and solids-laden water Boyer Construction would encounter. The integral agitator is designed to mix settled solids with pump water to maintain a steady solids concentration and discharge volume.

Boyer Construction field tested a couple of LWA pumps on their Galveston jobsites, and were delighted with their performance and service life. Over the subsequent two years, Boyer Construction purchased over 25 LWA units.

Conclusion

Every jobsite has its own particular set of pumping conditions. Selecting the optimum pump for the service takes the collaboration of a competent contractor and a hydraulic specialist. The right choice of equipment can make a substantial impact on the timely completion of the project and your bottom line results.

Coastal developments along the Gulf are at risk from storm events.
Dewatering pumps are required in high water table areas to keep construction sites dry.

More from Storm Water

New commercial development in Moncton meets strict runoff regulations

The new McLaughlin Place retail centre found the solution to meeting the local mandate of eliminating any increase in storm water runoff while maximizing the number of parking spaces. Instead of using a detention pond or sump, the designers decided to use a system of chambers under the parking lot that would collect and hold storm water runoff from the lot and rooftops. The one hectare commercial development with five buildings will open this year and is located near the Université de Moncton. Plans call for apartment buildings to be added in the future.

Six critical emergency response steps

For many living in urban environments, mornings involve an alarm clock, a shower, a cup of coffee, and a commute of some sort – often including underground public transportation. However, while many are catching a subway on the way to work, not many understand how complex and vital their city’s underground infrastructure is to their morning routine. That is, at least, until something goes wrong.

Quebec City storm water quelled with underground chamber system

Engineers from SNC-Lavalin found the way to meet stringent storm water drainage regulations for a portion of the new Centre Vidéotron site by designing two underground retention systems. Managing storm water runoff is a prime concern for Quebec City because the area is prone to flooding. The multipurpose, 18,000-seat arena, spread out over some 7.2 hectares (18 acres), opened in September 2015.

Precast concrete box sections specified for storm water detention structure

Precast concrete box sections were specified for an underground storm water detention tank to enable the construction of the Humber Mews Townhomes project on Evans Avenue in Toronto. The system was selected because it could reduce the total peak runoff being discharged from the site during all storm events. Using precast units would reduce construction costs and time. Other pre-manufactured solutions were considered, nevertheless, a precast system was selected as the preferred option. The structure met the service life requirements through the proven durability of precast concrete.

Trimble launches new version of its smart water management software to streamline utility field operations

Trimble has announced the latest version of its smart water mapping and work management software—Trimble Unity 3.0. Trimble Unity is a cloud-based, (GIS) centric software-as-a-service (SaaS) solution for smart water management. Version 3.0 includes new features and workflows and also offers an App Builder and new integration capabilities to simplify connecting mobile workers with maps and data from back office enterprise systems.

CDS stormwater treatment

The CDS hydrodynamic separator uses swirl concentration and continuous deflective separation to screen, separate and trap trash, debris, sediment, and hydrocarbons from stormwater runoff. CDS captures and retains 100% of floatables and neutrally buoyant debris 2.4mm or larger, effectively removes sediment, and is the only non-blocking screening technology available in a stormwater treatment device.

ADS announces addition of new Stormtech chamber

Advanced Drainage Systems, Inc. (ADS) has announced that it has added a low-profile, high strength chamber to its StormTech product line. The StormTech SC-160LP Chamber is 12-inches tall with an installed volume of 15 cubic feet of water for underground infiltration and detention systems. The new unit requires 14 inches of total cover to carry AASHTO HS-20 live loads, which reduces site development costs in shallow applications by minimizing the amount of needed fill and maximizing open infiltrative areas.

Imbrium Systems releases new on-line Stormwater design tool

Imbrium Systems has announced the release of the new on-line PCSWMM for Stormceptor - an advanced stormwater treatment sizing and design tool. PCSWMM for Stormceptor is the fastest, easiest way to determine the most appropriate size hydrodynamic separator/ oil grit separator for your site.

Subscribe to our free newsletter

Get our newsletter

Learn more

DESIGN TOOL FOR STORMTECH CHAMBERS

Advanced Drainage Systems, Inc. announced a new on-line program for designing and estimating the cost of a stormwater system constructed with its StormTech Chambers. Available for free on www.ads-pipe.com, the ADS StormTech Design Tool enables engineers, owners and contractors to design customizable underground stormwater management systems. Designs are produced in both PDF and CAD formats, with data provided that allows users to estimate a total installed cost.

STORMTANK ARCH FOR LARGE FOOTPRINTS

Brentwood is extending its stormwater product line with the introduction of the StormTank Arch to provide a solution for large-footprint, subsurface stormwater management projects.

Riverside community uses fusible PVC pipe for stormwater outfall

Established in 2010 through the adoption of the Keswick Neighbourhood Structure Plan (NSP), Keswick on the River is a new community in southwest Edmonton, Alberta. Bounded by the North Saskatchewan River to the west and the Windermere Golf and Country Club to the north, the 200-acre neighbourhood is named for a quaint town in northwest England and features more than 1,500 homes that offer old world English architecture designed to look and feel like a country village. Future residents of Keswick on the River will enjoy riverside living, playgrounds, a nature trail system and easy access to Edmonton.

Storm drain system succeeds in salt marsh for mega-mall complex

In early 2014, the Tsawwassen First Nation started construction of two mega-malls. To accommodate stormwater runoff from this 73-hectare project, a large-diameter pipeline was designed and installed under the public roads surrounding the sites. The selection of the pipe needed to take into consideration corrosion resistance, due to the salt water environment, and had to offer structural strength because of the poor deltaic soil conditions in this seismically active region of British Columbia.

WEF Launches MS4 Stormwater and Green Infrastructure Awards Program

The Water Environment Federation (WEF), has announced a new national municipal stormwater and green infrastructure awards program. Developed through a cooperative agreement with the U.S. Environmental Protection Agency (EPA), the program aims to recognize high-performing regulated Municipal Separate Storm Sewer Systems (MS4s) and inspire them to exceed requirements through innovative and cost-effective approaches.

CULTEC Introduces New, Ultra-High Capacity Recharger 902HD Stormwater Chamber

CULTEC, Inc. has introduced its newest and largest chamber to the stormwater market – the Recharger 902HD. This ultra-high capacity model offers the benefit of minimizing project costs by maximizing storage volume in a given footprint. The Recharger 902HD is an ideal solution for high-volume stormwater management systems due to its lightweight maneuverability, shipping and stockpiling benefits and design flexibility.

CULTEC Launches new StormGenie Drawing Software For Streamlined Stormwater System Design

CULTEC, Inc. has released StormGenie v.2.5, the newest version of its automated drawing program. StormGenie is a convenient AutoCAD plug-in tool used by engineers, contractors and landscape architects to quickly create preliminary stormwater system proposals and final designs and generate project-specific drawings for the company’s Contactor and Recharger stormwater chambers. The updated version of the software can now draw from both CULTEC’s Stormwater Design Calculator and HydroCAD’s Chamber Wizard.

Azek Permeable Pavers

Following a two-year test of various types of pavement, The Living City Campus at Kortright, a centre of excellence for urban sustainability in Vaughan, Ontario, has shown positive results for AZEK Permeable Pavers. The Toronto & Region Conservation Authority (TRCA) incorporated the pavers as a test surface in a 1,200 sq. ft. portion of the centre’s parking area.

Subscribe to our free magazine

Get Our Magazine

Paper or Digital delivered monthly to you

Subscribe or Renew Learn more

Brentwood Introduces Stormtank

Brentwood is extending its stormwater product line with the introduction of the StormTank Pack to provide a light-duty solution for subsurface stormwater management. The Pack is a cost-effective alternative for non-load-bearing applications and is commonly utilized under landscaped areas such as parks, plazas, and backyards. It is designed for optimum infiltration and integration in bio-retention and rainwater harvesting applications.

MRAT Helping Municipalities Plan For Extreme Weather

Imagine if a municipality could plan for an extreme weather event by designing its infrastructure to minimize the damage to areas most vulnerable to flooding. The result could mean millions in savings to cities and homeowners, and to insurance companies that could be spared a costly spike in claim payouts.

Stormwater drainage system succeeds due to high performance pipe

To help control costs and meet the requirements for the deep burial of a road expansion’s new stormwater drainage line, a highly-engineered corrugated pipe from Advanced Drainage Systems, Inc. (ADS) was used. The ADS N-12 HP pipe is designed and manufactured to handle heavy dead and AASHTO designated live loads without any additional bedding or special fill. More than 1,840 feet of the pipe was used in diameters ranging from 12 to 60 inches. In one area, the 60- inch diameter corrugated pipe is covered by 21 feet of fill. The project was originally specified to use rubber-gasketed reinforced concrete pipe (RCP).

Stormwater treatment device

Brentwood Industries, Inc. is extending its stormwater product line with the launch of StormTank Shield. This device is designed to improve sumped inlet treatment and reduces pollutant discharge through gross sediment removal and oil/water separation.

Downspout removes zinc and other heavy metals from roof runoff

StormwateRx LLC, a provider of industrial stormwater treatment and filtration systems, announced the availability of Aquip Downspout, a new configuration of the Aquip stormwater filtration system specifically for attachment to roof downspouts. Aquip Downspout removes particulate and dissolved zinc and other heavy metals that are often present from facilities with zinc-coated or galvanized metal roofing or HVAC equipment. Stormwater running off of facilities with galvanized metals is a major cause of zinc pollution and aquatic toxicity in local waterways. Installing Aquip Downspout on a building with galvanized roofing can permanently reduce zinc concentrations by 98%, helping industrial facilities meet stormwater benchmarks for zinc and other metals.

Reliable check valve

Over twenty years of field operation, research, development and engineering enhancements have combined to make the Tideflex TF-1 Check Valve today’s most reliable check valve. The bill is formed into a curve that returns to a closed position every time, achieving the tightest possible seal for backflow operations, particularly at low flow rates. The eccentric, flat-bottom design allows installation where the invert of the pipe is close to the floor.  The stronger engineered spine provides long-term performance while handling water weight. When you specify the patented TF-1 Check Valve, you are guaranteed a proven record of maintenance-free backflow prevention.

Stormwater design calculator

A new and improved stormwater design calculator is now available from CULTEC, Inc. The calculator is an MS Excel-based spreadsheet for designing stormwater systems using the company’s chambers. It can be used as a standalone tool to generate report outputs based on a project’s parameters.
The calculator provides chamber specifications, a material list, and bed detail as well as calculates a cross section detail together with the breakdown of storage provided by the system. Additionally, it includes full data sheets with metric and English units to qualify project calculations. An enhanced interface includes easy navigation and product images. 

Laminate windows store energy and convert it to electricity

An innovative new patented technology transforms office building windows into “solar farms” and allows these structures to reuse collected energy and become self-sufficient in the event of a power outage. This technology also allows building owners to return electricity to the main electrical grid and generate income.

Largest electric vehicle trial in Canada

Hydro-Québec has announced that 10 Mitsubishi i-MiEVs were delivered this morning to Boucherville businesses selected for the third and final phase of the largest electric vehicle (EV) trial in Canada. The project, which was launched in 2010, will continue until the end of 2013.

Subscribe to our free newsletter

Get our newsletter

Learn more

Renewables, natural gas to dominate near-term power industry growth

Renewable energy capacity will more than triple, while doubling its overall percentage of the U.S. energy mix, by 2036. In addition, natural gas could overtake coal as the primary fuel for U.S. power generation. These conclusions and many more are among key findings from Black & Veatch’s year-end Energy Market Perspective (EMP).

Quebec outshines Ottawa with new cap-and-trade system to combat carbon emissions

The Quebec government has shown climate leadership with its announcement that its cap-and-trade system for greenhouse gas (GHG) emissions will come into effect on January 1, 2012, according to the citizen group Equiterre. Quebec joins California as the first two jurisdictions to implement this type of regulation under the Western Climate Initiative (WCI).

New edition of free stormwater modeling software

CULTEC offers a new edition of its free HydroCAD CULTEC modeling software. The company’s updated edition is available in conjunction with a release of the latest HydroCAD-9.1 version and can be downloaded at www.cultec.com/hydrocaddownload.html.

Gravelless drainage system

The lightweight EZflow gravelless drainage systems eliminate problems inherent with gravel drainage systems. These flexible pipe systems composed of polystyrene aggregate enclosed in a woven geotextile mesh are ideal for trench, curtain, landscape, foundation, retaining wall, and interceptor drains. The bundles come pre-assembled in 10-foot sections weighing only eight pounds and are available in 7, 10 and 15-inch diameters.

Gravelless drainage system

The lightweight EZflow gravelless drainage systems eliminate problems inherent with gravel drainage systems. These flexible pipe systems composed of polystyrene aggregate enclosed in a woven geotextile mesh are ideal for trench, curtain, landscape, foundation, retaining wall, and interceptor drains. The bundles come pre-assembled in 10-foot sections weighing only eight pounds and are available in 7, 10 and 15-inch diameters.

Inline CheckMate valve

The CheckMate Inline Check Valve is ideal for backflow prevention and odor mitigation. In outfalls, stormwater, CSO and SSO applications, the CheckMate’s custom-engineered, all-rubber unibody design eliminates costly backflow from oceans, rivers and interceptors. The valve’s unique elastomer fabric-reinforced design provides a proven record of maintenance-free performance, cost savings and results that no other inline check valve can match.

Turbine agitator line with advanced impeller designs

An extensive line of Chemineer turbine agitators with advanced impeller design options, and Kenics static mixers provide beneficial solutions for effective water treatment. Chemineer has over 50 years experience in the design and manufacture of fluid agitation equipment and is a recognized leader in advanced mixing solutions for the municipal and industrial water treatment industries.

Monitoring for sanitary sewer flow and rainfall

Gwinnett County, part of regional Atlanta, has selected FlowWorks, Inc. to manage all sanitary sewer flow and rainfall monitoring data for the Department of Water Resources on annual contract. The selection was made, in part, because of FlowWorks’ proven ability to accept data directly from Teledyne Isco and ADS flow meters.

Subscribe to our free magazine

Get Our Magazine

Paper or Digital delivered monthly to you

Subscribe or Renew Learn more