In the case of Bois d’Arc Lake in Fannin County – the first major reservoir built in Texas in over 30 years – it took years of planning and permitting, $1.2 billion of construction work, five major contractors, dozens of subcontractors, and a workforce of about 1,000 at the peak of construction.
In addition to the new 16,641-acre reservoir northeast of Bonham, Texas, contractors for the Bois d’Arc Lake project built an entire system to treat and transport water into the existing pipeline for the North Texas Municipal Water District (NTMWD). That included a 110-foot-tall, concrete intake tower and raw water pump station at the lake, pipe to transport the water to the new treatment plant built in Leonard, Texas, and a treated water pipeline that ties into NTMWD’s existing regional system.
To make room for the lake, the project also required nearly $80 million of utility relocations, 11 miles of state and county roadway construction and improvements, and over 17,000 acres of environmental mitigation.
With frequent droughts and surging growth in north Texas, the primary purpose of the project is to provide a reliable new water source. Once the lake fills and meets safety requirements, it will also open for boating, fishing, and other recreational activities.
The cost of the $1.6 billion Bois d’Arc Lake program was shared by the 80 communities that receive water from NTMWD. The Texas Water Development Board provided $1.477 billion in low-interest financing through the State Water Implementation Fund of Texas, saving more than $240 million in interest costs.
The project broke ground in May 2018 and the reservoir started impounding water in April 2021. When the new treatment plant finishes commissioning and begins operations this year, it will treat and deliver up to 70 million gallons of drinking water per day to NTMWD’s service area.
In order to complete all the project pieces on a tight schedule, NTMWD chose Construction Manager at Risk (CMAR) delivery.
“Cramming all that work into four years with the resources that are there, we really had to have that collaborative delivery method in place,” said Adam Payne, Program Construction Manager for the project’s Program Manager, Freese and Nichols of Fort Worth, Texas.
Instead of dividing the work by location, NTMWD decided to award five construction contracts based on work type.
The first CMAR – Archer Western of Irving, Texas, part of The Walsh Group – handled heavy civil earthwork. That included clearing the reservoir footprint; constructing the 2-mile-long, 90-foot-tall earthen dam; and building the 210-million-gallon, 70-acre terminal storage reservoir adjacent to the new treatment plant.
As the CMAR for heavy mechanical work, Garney Construction of McKinney, Texas, oversaw the raw water pump station at the dam, as well as the water treatment plant and high-service pump station in Leonard.
Garney also constructed the project’s two pipelines under a separate CMAR contract. Thirty-five miles of 90-inch-diameter pipeline will transfer water from the lake to the storage reservoir and 25 miles of 84-inch-diameter pipeline will move treated water from the Leonard plant into NTMWD’s existing distribution system.
The last CMAR, Austin Bridge & Road of Coppell, Texas, handled the road and bridge improvements designed to provide ease of navigation around the lake. That included more than 6 miles of new road, with a 1.3-mile-long bridge built across the lake. Their contract also included three public access boat ramps and an Operations Center at the lake with classrooms and meeting spaces.
To meet permit requirements, the last piece of the project mitigated over 17,000 acres of nearby land to pre-agricultural conditions.
For that work, “We started with CMAR delivery,” said Steve Long, Program Manager for NTMWD through most of the project and now a Senior Engineer at Freese and Nichols. “Once we realized the mitigation industry has a better delivery method, we halted that process and went with a full-service provider.”
In the last four years, Resource Environmental Solutions (RES) of Houston planted 6.3 million trees and 3,200 acres of native grasslands, enhanced 8,500 acres of wetlands, and restored 70 miles of streams.
“In the 17,000 acres for the reservoir, there were a lot of existing utilities that would be inundated,” explained Cesar Baptista, NTMWD’s Deputy Director of Engineering and Capital Improvement Program.
That included transmission lines for the Fannin County Electric Cooperative. “We basically cut their service in half,” Baptista said. “The lake severed three main circuits that had to be relocated without affecting service.”
In addition, a main pipeline for the Bois d’Arc Municipal Utility District traveled under the lake site, so NTMWD negotiated with them to create two systems by drilling a well and building new storage on the north side of the lake. Oncor needed to relocate 138,000-volt and 345,000-volt electric transmission lines, and the roadwork displaced many other utilities.
“It was a huge team effort,” Payne said. “At the program management level, we had folks dedicated to keeping tabs on the schedule and managing those utility contracts because there were so many.”
The project team also worked with Rayburn Electric Cooperative to build two new substations and 12 miles of transmission lines to serve the new treatment plant and its pump station. An additional 6 miles of transmission lines power the dam and raw water pump station.
“Early in the CM process, we got with local landowners to secure thousands of tons of sand for the sand beds on the back side of the dam,” said Jeff Polak, Archer Western’s Program Manager.
Several sand pits around the nearby Red River were reopened, saving millions of dollars in trucking and material costs, Polak said.
In addition, Archer Western worked with Freese and Nichols to confirm geotechnical information within the project footprint, locating nearly 7 million cubic yards of heavy clay for the dam.
“Every yard of that clay was located within 2 miles of the dam,” Polak said. “Our calculation was a savings of over $30 million in trucking costs because there was a sufficient quantity in close proximity.”
Processing the clay for placement required special equipment. “It’s a sheepsfoot-type compactor – a large drum with steel teeth,” Polak explained.
Archer Western’s dam subcontractor – Phillips & Jordan, Inc., headquartered in Knoxville, Tennessee – searched around the country to procure six of the required compactors. Large farm tractors then hauled the compaction wheels around the site to process the clay in place.
“There were 50 steps, so nearly 100 miles of 12-inch-tall, 10-foot-deep soil cement steps,” Polak said.
To install the steps, Phillips & Jordan customized their own equipment. “It was almost like a paving system but with a conveyor, excavator, and special form to slowly slide along the base of the dam and place the steps one at a time,” Polak said.
Crews batched and mixed the soil cement onsite, then placed it on the conveyor. Starting at the base of the dam, they worked up about three-quarters of the face. At that point, they moved the system to the top of the dam to finish constructing the soil cement steps.
“It was a lot slower process from the top of the dam because of minimal access,” Polak said. “The dam has a 4:1 slope, so down at the base, before there was any water impounded, there was a large, dry surface with plenty of room. When they got to the top of the embankment, it was only 20 feet wide, so it was limited access for two-way traffic. There was barely enough room with the large off-road trucks that hauled the soil cement to the placer.”
At one point, as many as 50 trucks were moving embankment around the site. With other aspects of construction also active at the time, Archer Western implemented a complex traffic control plan and logistical schedule.
Work on the soil cement steps took over a year, starting at the end of 2020 and lasting through 2021. However, “Once we got above a certain elevation, we were able to close the gates and start capturing water for the lake as we finished working,” Polak said.
The project team originally anticipated it would take three wet seasons for the lake to fill. However, with low rainfall amounts last year, NTMWD now hopes that by fall 2023 the lake will reach its storage capacity of 367,609 acre-feet of water.
- Owner – North Texas Municipal Water District; Cesar Baptista, Deputy Director of Engineering and Capital Improvement Program; Aliza Caraballo, Program Manager
- Program Manager – Freese and Nichols, Fort Worth, Texas; Adam Payne, Program Construction Manager; Steve Long, Senior Engineer
- Construction Managers at Risk – Archer Western, Irving, Texas; Garney Construction, McKinney, Texas; and Austin Bridge & Road, Coppell, Texas
- Environmental Mitigation Contractor – Resource Environmental Solutions, Houston
- Dam, reservoir, and terminal storage – Archer Western started work in May 2018 and reached substantial completion in summer 2022.
- Environmental mitigation – RES started work in August 2018. In spring 2022, they finished mitigation and began the monitoring and maintenance that will continue up to 20 years until permit requirements are met.
- Raw water pump station, water treatment plant, treated water high-service pump station, and dam maintenance facility – Garney started work in November 2018. They began testing the water treatment plant in fall 2021.
- FM 897, Fannin County roads, recreational boat ramps, and lake office – Austin Bridge & Road started roadwork in May 2018 and finished in August 2020. They began work on the boat ramps and recreational facilities in September 2019 and reached substantial completion in fall 2021.
- Raw water pipeline and Leonard to McKinney treated water pipeline – Garney began work on the raw water pipeline in March 2019 and reached substantial completion in fall 2021. They started the treated water pipeline in April 2020 and anticipated reaching substantial completion in March 2023.
The work will include:
- Expansion of the lake’s raw water pump station
- A second 70-million-gallons-per-day phase of the water treatment plant
- Expansion of the high-service pump station
- Addition of a second cell with 210-million-gallon capacity at the treatment plant’s terminal storage reservoir
Editor’s Note: This story is part one of our feature on the Bois d’Arc Lake project. Look for part two in the May issue of Texas Contractor.
Photos courtesy of North Texas Municipal Water District