Using Submersible Dewatering Pumps to Reconstruct Galveston, Texas
By Mike Bjorkman Jul 14, 2014
The sea level along the Gulf Coast is rising faster than most places on the globe. Galveston, Texas, has experienced a 3-ft 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 water/sand slurry is tough on pumps — particularly aluminum dewatering pumps. When Boyer Construction was doing work in Galveston, Texas, the contractor 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 ft above sea level.
After the 1900 Hurricane, a 17-ft seawall that ran three 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 ft 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 more than 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.
Impact of 2008 Hurricane
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 ft 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 that 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, more than 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 that will minimize the life of most dewatering pumps.
Looking for help in keeping its dewatering pumps from wearing out, Boyer Construction called BJM Pumps distributor Pumps of Houston for its 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.
These pumps offered the flow range and high lifts required for a broad spectrum of applications. From 2 hp (flows to 180 gpm and heads to 55 ft) to 10 hp (flows to 475 gpm and heads to 117 ft), 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 its Galveston jobsites, and were pleased with their performance and service life. Over the subsequent two years, Boyer Construction purchased more than 25 LWA units.
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.
Mike Bjorkman is vice president and director of marketing for BJM Corp., a supplier of electrical submersible pumps to industrial and municipal markets throughout the United States, Canada and South America.
Submersible PumpsUsing 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.