Fast-Track Pump Station Project Provides Reliable Water Source During Droughts

Construction Complexities

Early procurement of construction packages combined with challenging site conditions created complexities during construction. Because design was not finalized prior to bidding, design changes that occurred after bidding had to be properly communicated to the contractor. Examples include changes as small as moving a 1-inch ball valve and as large as correcting the coordinates of a structure.

Early on, site conditions for both the pump station and pipeline made construction difficult, and groundwater, rainwater and river water needed to be addressed. Pipeline construction relied on berms and ditches for routing surface water and dewatering wells for preventing groundwater intrusion into the trench, while pump station construction focused on providing a water-tight cofferdam and dewatering wells to isolate excavation from the river and groundwater to keep the excavation dry.

Installing the sheet pile cofferdam was a significant challenge due to higher-than-normal river levels at the beginning of construction that lasted several months. Higher flows increased river velocities, slowed cofferdam progress, and brought debris and damage to an uncompleted section when a tree hit the sheet pile, requiring reinstallation.

The sheet pile cofferdam was designed for a 50-year flood elevation to accommodate construction through high river conditions and successfully reduce the risk of overtopping the shoring system that could have led to costly project delays. Due to the large size of sheets, the contractor developed an alternative to shipping materials by barge. In order to achieve the required height for flood protection, the contractor first installed a traditional sheet pile approximately 55 feet long and then welded additional length.

Tracking the river level was crucial to safely completing construction and tracking progress throughout cofferdam construction, excavation for the structure, and concrete placements for the wet well. The contractor identified construction to be completed during drops in the river
level, such as waler and tie-rod installation, and adjusted construction sequencing accordingly. Tracking the river level was also crucial for pipeline construction; the contractor started in the middle of the route heading east but quickly moved work to the section near the pump station and river when the river level dropped, allowing for “dry” construction through a slough and set of oxbows connected to the Sabine River.

Garney Companies, Inc., the CMAR selected for the project, implemented an extensive safety program that led to project completion with zero accidents. Staff members on-site included 22 subcontractors, 10 equipment representatives, along with SRA, engineering and CMAR staff. In total, construction included approximately 420,000 man-hours completed in the field by various contractors and 5,000 inspection hours provided by the engineer and SRA.

Safety discussions began during pre-construction and took place regularly during planning and scheduling meetings. In addition, safety was a crucial element of daily task planning and essentially became a part of every aspect in the construction process.

During CMAR evaluations, safety records and history were used by SRA and the engineer as part of the CMAR selection. An important aspect was the prospective CMAR’s staff. For the Sabine River Pump Station project, Garney assigned an On-site Safety Manager who was supported by the Corporate Regional Safety Manager. This attention to safety was utilized during selection of every bid package for subcontractors and suppliers.

The main aspects of the project’s safety program included the following:

• ​​​​Job-site orientation (general site-specific safety items) for all project staff
• Subcontractor safety outreach program
• COVID-19 safety practices
• Monthly jobsite safety meetings
• Biweekly safety audits performed by the job-site safety team
• Weekly toolbox safety meetings
• Individual meetings for sharing Garney safety materials with subcontractors held by On-site CMAR Safety Manager
• Daily safety briefings with staff conducted by the On-site Safety Manager
• Daily Safety Task Awareness Cards utilized by construction teams
• Additional, periodic safety inspections implemented by SRA’s Safety Manager and the CMAR’s Regional Safety Manager
• Safety awards program for special project milestones
• A jobsite safety plan that included Personal Protection Equipment (PPE) and drug enforcement policies
• Quarterly Safety Shutdowns on Garney self-performed portions of the project included safety training and other construction techniques

SRA and the project team worked closely with the Texas Parks & Wildlife Department (TPWD) to develop a plan for minimizing environmental impacts in the 128-acre project area. This included accommodations for land and aquatic life with the following measures in accordance with environmental regulatory requirements:

Nest Surveys

To ensure that birds were not impacted along the pipeline right-of-way, the team completed nest surveys of the project site and pipeline easement prior to clearing the project area, paying close attention to spot migratory birds and bald eagles. These efforts were in compliance with the Bald and Golden Eagle Protection Act and Migratory Bird Treaty Act.

As a result, construction clearings took place outside the migratory bird nesting season. When clearing was completed during the nesting season, crews established appropriate buffers around any observed active nests.

Aquatic Resource Recovery Plan (ARRP)

SRA developed an ARRP that addressed recovery and relocation of native fish and mussels behind the cofferdam in the Sabine River and Gulf Coast Canal as well as within the pipeline oxbow crossings. The plan aimed to control and limit the impacts of dewatering, maintenance or construction.

As part of the plan, SRA and the design consultant performed a mussel survey and relocated mussels approximately 1,100 feet upstream from the pump station site along the west bank of the river. These efforts were in compliance with the Aquatic Resources State Law.

The team also surveyed and provided further protection measures for state-listed species, including the Rafinesque’s big-eared bat, alligator snapping turtles and common snapping turtles, northern scarlet snakes, and timber rattlesnakes.

Cultural Resources Investigation

Completed for the entire 128-acre project area, the resulting report confirmed no significant findings by the THC and USACE.

Construction Measures

The team installed sediment control fencing and implemented erosion control measures through the use of no-till drilling, hydromulching and/or hydroseeding.

The multiphase engineering and construction effort included: