with typical construction issues. Once it was designed, construction was pretty smooth. The pandemic occurred during construction of the plant, and that certainly didn’t help.” Powerful Pumping Station Water is pumped through the system via a 12,800 square feet pump station, which will push out up to 73 million gallons per day. The station includes one pump of 700 horsepower, and 5 pumps of 1,250 hp. The powerful system can deliver more than 63,000 gallons per minute. The station has a delivery capacity of 10,500 acres, pump - ing water at 140 cubic feet per second at 345 feet total dynamic head. The pumps pull water out of the canal and are delivered based on daily orders of irrigators who bought water on long term contracts. The intake structure includes a sump that is 35 feet to 86-feet wide, 80 feet long and 18 feet deep. It includes 820 cubic yards of concrete and 145,000 pounds of rebar. The pumps deliver water to 46,892 feet (8.88 miles) of pipelines that are 14 to 60-inch in diameter with 15 turnouts. “This is the first pumping plant in the project and the lands that it serves is what makes this pump station unique,’’ said Jon Erickson of the East Columbia Basin Irrigation District and project manager of the Odessa Groundwater Replacement Project. “This is an important step in getting water to the farmers that need it.” The ECBID designed the pumping station, which was built by Good- man & Mehlenbacher Enterprises, Inc. Accessing Pumps The pumps are an important part of the project, but installing and ac - cessing the pumps when they eventually need replacement was one of the important design considerations in the station’s construction. Teams will access the pumps through six roof hatches manufactured by The BILCO Company. The custom hatches, 6-feet, 6-inches x 7-feet, are fabricated with polycarbonate dome covers for natural daylight and engineered lift assistance for easy, one-hand operation. They are also modified for hand winch operation, allowing them to be easily opened and closed from inside the building. The aluminum hatches, which were supplied byAnderson Specialties, were custom-fabricated to meet unique size requirements. “They were proposed by the contractor and met the specs that we required,’’ Erickson said. “They were also important because they allowed pump andmotor access by crane.” Subsidence Issues The issues with groundwater depletion that Washington is encounter- ing is common throughout the United States. The problems, however, go deeper than the lack of water. Sustained groundwater pumping also leads to a multitude of other is- sues. Deterioration of water quality, increased pumping costs, drying up of wells, and reduction of water in streams and lakes are some of the consequences of overreliance on aquifers. So too is land subsidence, which is the gradual settling or sudden sinking of the Earth’s surface due to removal of subsurface materials.
The system includes six pumps which will be accessed for maintenance and removal through six customized roof hatches manufactured by BILCO. Photo: Cody Wurzer
Subsidence occurs when large amounts of groundwater have been withdrawn. The layers within an aquifer compact and settle, resulting in lowering the ground surface. A study this year reported that 19 percent of the world’s population will be affected by land subsidence by 2040, accounting for 21 percent of the global GDP. One of the most extreme examples of land subsidence has occurred in California’s San Joaquin Valley, a large farming com- munity. Since the 1920s, excessive pumping of groundwater at thou- sands of wells has caused land to sink as much as 28 feet (8.5 meters). Eastern Virginia has also experienced land subsidence with overuse of the Potomac Aquifer. Like the Odessa project, officials have executed a plan to enhance sustainability of the region’s long-term groundwater supply. The solution, however, is dramatically different as it uses highly treated water that would otherwise be discharged into the Elizabeth, James, or York Rivers and treats it to meet drinking water quality standards. The water is then added to the Potomac Aquifer, which is the primary source of groundwater throughout eastern Virginia. A report in 2020 from Old Dominion University and NASA’s Jet Pro- pulsion Laboratory found that Norfolk and Virginia Beach are subsid- ing at the rate of approximately 3.5 millimeters every year. The report confirmed less technical observations, but also delivered one surprise. The rate of subsidence varies by neighborhood, sometimes by as much as 15-20 percent. Critical Industry As an important economic driver in the region, water from EL47.5 and the Odessa Groundwater project will be critical to the farmers, families and businesses. Maybe farmers could have continued to draw water from the aquifer. Maybe, though, the aquifer might eventually go dry. That’s not a chance the region is willing to take.
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