Moving water hundreds of miles to where the population needs it requires skills and techniques to keep disruptions to a minimum, along with a large infusion of communications.
Water conveyance represents a historic achievement that dates back 2,400 years to the Roman aqueducts. Those aqueducts solved the problem of the time, but the issue of water conveyance has continued throughout history. Though civilization has built great cities on coastlines, rivers and lakes, the need to move water to where people live continues unabated.
In the 21st century, with the world’s population approaching 7 billion people, a demand to bring water from point “A” to point “P” (people) exists like never before. Most of the worlds cities are experiencing significant growth, and the specter of drought exists in pockets of the globe.
“These water conveyance projects touch a lot of people,” said David Egger, Black & Veatch Senior Vice President and Director of Heavy Civil. “It is a very big challenge to put together, including a lot of time spent incubating the proper plan. There’s the permitting process, the approval process and the acquisition of land, just for starters.”
Throughout its history, Black & Veatch has been involved in numerous water pipeline projects, and today the company brings its experience and expertise to bear in varied locations, including Hong Kong and Texas, and even an agrarian state such as North Dakota.
In Hong Kong, the land is densely populated, with the buried infrastructure from different utilities thickly congesting some areas. This situation makes conveying water from Lantau Island to Cheung Chau Island a challenge, but Black & Veatch has determined the proper technological solution – Horizontal Directional Drilling (HDD).
The HDD method involves drilling vertically into the seabed then horizontally to the destination. Vertical drilling at Cheung Chau Island, home to 23,000 people and also a popular tourist destination, will connect to the horizontal drilling. HDD typically only requires sufficient space for the launching and receiving sites.
This 500 millimeter (approximately 20 inches) submarine pipeline will traverse 1.4 kilometers (under 1 mile) with minimal impacts to the water quality and ecology of the channel between the islands. The project will not disturb the seabed, with minimal effect on the fisheries and marine traffic, and it will improve the reliability of the freshwater to the island.
“Liaison with the public to minimize disturbance and repeated excavations is the key factor to successfully carrying out the construction,” said Stephanus Shou, Black & Veatch Client Account Manager. “HDD is well received by the Green Groups, Rural Committee and Islands District Council, along with fisherman and the marine culture association in the public consultation.”
Egger added that Black & Veatch is seeing an increase in trenchless technology, such as HDD, and tunneling in water conveyance projects.
“Trenchless technology minimizes the impact on the environment and people,” he said. “We have a number of projects involving trenchless technology because clients have increased confidence with trenchless and tunneling methods. In the marketplace, there are more HDD subcontractors, resulting in decreased costs, which have led to clients becoming more comfortable with these new methods.”
Tackling Conveyance in Texas
The Dallas-Fort Worth metropolitan area experienced one of the largest population growths of any U.S. metropolitan area during the last decade. The area grew 25 percent to bring its total population to 6.4 million people, the fourth largest U.S. metropolitan area.
Put that significant growth in a drought-susceptible area and the result is a highly populated area that likely would be thirsting for more drinking water in the future if action isn’t taken to increase the water supply.
Black & Veatch is helping to solve that potential situation by beginning work on a 28-mile section of a 150-mile pipeline that will bring water from Lake Palestine in southeastern Texas to Lake Benbrook west of Fort Worth. The project is being executed for the Tarrant Regional Water District.
“This project is being delivered in a regional fashion, with the Dallas Water Utility cooperating and teaming with the Tarrant Regional Water District,” Egger said. “This is the best way to approach projects of this magnitude, given the costs involved and the environmental issues. In the past, a utility would tap a source and then another would also send a different pipeline to the same source, and that piecemeal approach is no longer sustainable in today’s market.”
The below-ground Integrated Pipeline (IPL) will range from eight to nine feet in diameter as it winds itself in a northwesterly direction to the Dallas-Fort Worth area.
“When you cross a highly populated area with all of the infrastructure, you get a lot of concerned people,” said Dale Cherry, Black & Veatch principal in charge of the IPL. “We help support the client, who is the face of the project, with information that can answer all of the property owners’ questions. Face-to-face communication is the best form, so we want to make sure our client has the best information possible.”
He noted that potential clients may need assistance with questions concerning noise, safety, traffic congestion, land acquisition and more.
“If a client needs help in working with the public, we will gladly share our history and experiences with them so they can see how to handle these situations in order to minimize any surprises,” Cherry noted.
Restoring Land as it was Found
Even North Dakota, one of the least-populated states in the United States, needs water conveyance. But what the state lacks in people, it more than makes up for in fertile farm land, and it’s that farm land that needs water.
Black & Veatch recently completed the preliminary design of a 122-mile, 66-inch diameter pipeline that stretches from the Missouri River basin and Lake Sakakawea eastward to the Red River. The project, known as the Red River Valley Water Supply Project (RRVWSP), has been discussed since the 1940s.
One of the projects issues is how the soil will be handled as excavation work occurs for the pipeline.
“Anytime you move water via a pipeline, it is disruptive,” Egger said. “Even if the pipeline just goes through the edge of a field, we have to be sensitive to the people and the productivity of the land that is affected.”
To that end, Black & Veatch has worked with the strip mining industry in North Dakota, which is affected by the same issue in its pursuit of coal. Black & Veatch has learned through this effort how to properly return the soil as it was, where the topsoil remains the topsoil and the growing zone soil remains the growing zone soil.
“The intent is that crops disrupted by the pipeline work would produce the same yield after the project as before,” Egger said.
Moving water requires energy, and moving water greater distances takes more energy. Egger noted that clients are increasingly seeking ways to optimize energy costs regarding water conveyance.
“To help lessen energy costs, Black & Veatch is using more intelligent control systems and integrating hydropower generation into our conveyance systems,” Egger said. He said this can result in the most efficient means to move water for utilities.
“Wherever there is gravity flow or storage in dams, we need to examine the potential for hydropower generation,” Egger noted. “Small hydro and low-pressure hydro systems are an old idea that is new again, thanks to new and improved equipment and government policies around renewables.”