Test Basin
The overall dimensions of the test basin design can accommodate a PLUG capable of sealing a 40-foot breach. The test basin is 150 feet long at the base. The slope on all four sides is a 1-3 ratio. The height of the levee walls is 12 feet. The 12-foot-high slopes ensure that in any condition, the water coming into the test basin could not overtop the levee. Other features of the breach include a safety handrail on top of the levee directly behind the breach and a wide access area behind the breach that has road surfacing material from which a crane could be placed if needed during testing.
On the southeast corner of the test basin, an overflow spillway was incorporated to allow water a passage into the catch basin while the PLUG was emplaced in the breach. This is designed to be able to pass at least 2,100 CFS of water without overtopping. The entire spillway area was covered with flowable fill material to prevent erosion.
Source Basin
The purpose of the source basin is to supply water to the test basin during a PLUG test so that the volume of water coming into the test basin matches the volume leaving the test basin through the breach. By maintaining the water level in the test basin as a test is in progress, the desired flow rate is sustained. The source basin has a capacity of 2.2 million gallons. It is 94 x 94 feet at the base, with 1-3-ratio sloped embankments and a depth of 17 feet. To achieve a flow rate of 2,000 CFS into the test basin, hydraulic head and flow control gates 20 feet in length open at 1-inch per second.
Catch Basin
The catch basin can hold the combined total of water in the source basin and test basin, approximately 4 million gallons. The depth of the catch basin is 12 feet in relation to the earthen levee slopes. The catch basin contains a stilling basin to dissipate the energy of the water coming from the test basin. Flowable fill material placed around the stilling basin and at the base of the test basin spillway prevents damage from erosion. Two features were used to prevent the catch basin from overflowing: A 24-inch riser pipe placed at 9 feet above the basin floor and an emergency spillway excavated into the embankment gate.
The water return system replenishes the source basin with water that has been collected in the catch basin in 20 hours. The pump used for the water return has a minimum capacity of 1,833 gallons of water per minute. It has a discharge size of 12 inches. Piping that carries the water from the pump back to the source basin is 14 inches in diameter, leaving a margin in case a larger pump is desired for future tests.
Piping
The type of piping is Max Flow Spiral Rib Pipe from Southeast Culvert, Inc. in Auburn, GA. The piping is 54 inches in diameter, and it conveys water from the source basin into the test basin and from the test basin into the catch basin. The pipe is aluminized steel that has a minimum life of 75 years when installed in the recommended environment. There are six runs of pipe that extend from the inlet structure to the outlet structure. In all, the facility uses 1,017 feet of pipe.
Control Gates
The flow control gates for the source basin and test basin structures were designed and fabricated by Golden Harvest, Inc of Burlington, WA. The main components of the gate include a guide rail, gate head, stem, stem guide, stem coupler, wall bracket, and various seals. The guide rails contain ultra high molecular weight polyethylene seating faces and the gates contain neoprene face seals for low leakage. The gate actuators are hydraulic cylinders. The cylinders have a 5-inch bore and a 2-inch diameter rod with a 60.25-inch stroke. Two hydraulic power units (HPU) provide hydraulic pressure to the cylinders—one to power the source basin gate actuators and one to power the test basin gate actuators. The HPUs contain an electric-powered, 2.75-cubic inch displacement pump that can deliver a flow of 19.1 gallons per minute at 1,750 revolutions per minute, assuming 92 percent efficiency.
Power
The ERDC Department of Public Works (DPW) installed power at the facility. The HPUs for the gate actuators demand 3 Phase 480 volt power to operate. DPW installed two utility poles to bring the power overhead from an existing pole to the site. There was a pole placed on top of the levee embankment at the southwest corner of the source basin. The other pole was placed to the west of this new pole leading to the existing pole. From the pole at the source basin, the power lines were run underground in conduit to the HPUs at the source basin and test basin. DPW terminated the power lines to the HPUs. A disconnect switch for the power service is located at the pole on top of the source basin levee.
Construction
Construction of the Facility began on June 14, 2010 and was completed on October 25, 2010, after CHL engineers performed two successful acceptance tests.