Water service providers continue to explore opportunities for water storage and conveyance systems to enhance the future and reliability of their systems while also providing environmental benefits and security in meeting growing demand for safe, reliable water. According to the 2018 Strategic Directions: Water Report survey, demand for water storage and conveyance projects is driven primarily by resiliency and redundancy (79 percent) goals, population growth (67 percent) and the need to replace aging infrastructure that is at or beyond its design life (63 percent) (Figure 1).
The path forward will not be easy. The industry sees the lack of project funding and long, drawn out project development cycles — including environmental clearance, regulatory review and permitting — as among the key challenges (Figure 2). As a result, most utilities inevitably opt to patch their systems with short-term remedies; sometimes an inability to take systems out of service for complete rehabilitation or replacement leaves them no other choice.
Figure 1: What are the drivers contributing to your needs for additional water supply storage and transmission infrastructure?
Figure 2: What are the major challenges you see in the development and delivery of water storage and transmission infrastructure?
No matter the challenges, there is a dire need to harness and store water in the western United States, where climate change and prolonged periods of drought impact the ability of municipal agencies to meet water supply demand in dry years. In other parts of the country, changing patterns in climate have contributed to unprecedented flood events with corresponding impacts to water quality and billions of dollars in damage to property. Throughout the Midwest and South Central region of the country, cities and municipal agencies are looking at large capital spends involving tunnels and other forms of underground storage and conveyance to address flood concerns and combined sewer overflows (CSOs).
In addition, much of today’s aged infrastructure is being taxed at capacity and has reached the end of its useable service life. Survey results show that all respondents agree that the top priorities are renewal and replacement.
Investing in Technology and Innovation
When it comes to the design, construction, and operation and maintenance of dams and tunnels, vast opportunity lies in utilizing the power of data and predictive data analysis to identify solutions related to long-term system reliability and redundancy, as well as the efficiency and energy neutrality of systems operations. In addition, the import of construction technology from other parts of the world continues as part of the innovation in the construction of these types of facilities.
Looking to dams as an example, there are two projects nearing construction that will make use of an asphaltic concrete core because of limitations on locally sourced materials that would more typically be used to provide the effective “plug” for these dams.
There are huge improvements in tunnel construction methods, specifically using single pass and pre-cast concrete segments with sophisticated tunnel boring machines (TBMs). Compared to 10 to 15 years ago, today’s TBMs are sophisticated machines, the result of years of technological advances. Not only can they address difficult and differing ground conditions that were once considered impossible to tunnel through, but these advances in TBM technology are allowing project managers to manage and marginalize many of the ground risks.
Tunneling also can allow for a more practical solution in built urban environments because it removes surface disruption to nearby buildings, utilities and structures. Plus, surface area in urban settings is limited, leaving little opportunity to perform the work necessary to address a flood issue or CSO (e.g., install large basins that could store the CSO that occur during rain events). In rural or mountainous regions, tunneling can serve as a solution to spare the landscape. Tunneling can mitigate the significant impacts that would otherwise occur with surface construction and the challenges that make surface construction difficult or challenging.
With increased use and economies of scale, the cost of high-strength and fiber-reinforced pre-cast concrete segments has come down, affording owners a higher quality and more reliable tunnel lining system in all types of ground conditions.
Today, mega water tunnels are being considered for marquee conveyance projects such as the California Department of Water Resources’ California WaterFix project, which will rely on two large, four-story tall tunnels and associated intake structures to carry fresh water from the Sacramento River. Harris County in Houston, Texas, is also investigating a large tunnel program to address stormwater and flood issues. These projects — and many others like them — will likely directly benefit from advancement in TBMs and tunnel segments.
Dam Safety Relies on Asset Management
Aging dam infrastructure has caused dam safety to become a major concern for owners and the public, with recent significant flood events resulting in the failure or near failure of these facilities. There are considerable challenges in evaluating the condition of dams and their appurtenances because of limitations on direct observation and testing. In addition, key questions exist with respect to current and representative design criteria for dams and reservoirs related to flood. The cost to address repair and rehabilitation of dams — or their appurtenances such as gates and spillways — is staggering, and can be on the order of five to 10 times the amount of the original construction costs. This does not take into account the even more significant socioeconomic aspects and threat to life, property and the environment.
To address this critical issue, Black & Veatch is advancing an asset-management approach to dam safety that is integrated with the standard practice. Data analytics and asset management strategies are successfully used for complete assessment and safety of dams, and owners/ operators are helped to identify gaps in their management of these critical and often vital assets.
Survey results show that the industry is on board with this approach because the majority of agencies and utilities are considering implementing asset management tools and approaches (72 percent), followed by data and analytics (56 percent), and the corresponding smart and integrated infrastructure solutions (49 percent) (Figure 3).
Figure 3: What are some of the innovative approaches you have considered in evaluation and development and rehabilitation of your storage and transmission infrastructure?
Encountering and Managing Risk
Dams, tunnels and other heavy civil construction involve significant risks because of the extensive use of the ground in construction and the linear nature of construction operations. Data analytics and rigorous business case evaluations have enhanced understanding of these risks — as well as the associated uncertainty in cost and schedule for these types of projects — allowing for better decisions to be made on the configuration of projects that meet a particular need. In addition, implementing a formal risk process over the full life cycle of planning, design and construction is demonstrating benefit by allowing companies to anticipate and mitigate project challenges ahead of their potential occurrence.
Heavy civil dams and tunnels for storage and conveyance can benefit from the full arsenal of risk management strategies – from planning to design, construction and commissioning. As shown in the survey results, most owners (73 percent) continue to rely on traditional design-bid-build and low cost selection processes (Figure 4).
Figure 4: What forms of project delivery does your organization utilize?
There is great opportunity to embrace the benefits of pre-qualification, early contractor involvement or alliance contracting approaches. The same goes for contract risk management documents such as geotechnical baseline reports and escrow documents, and management tools such as risk register.
While it is true that conventional design-bid-build is still used extensively, it is encouraging to see increasing use of program or project development strategies using owner’s engineer, construction managers and even alternative delivery options such as progressive design-build and construction manager at risk (CMAR) to achieve early contractor involvement in these projects.
Moving from “Future-Ready” to Now
Obstacles remain as many agency and utility leaders continue to struggle to educate a skeptical public about the value of water – whether harnessed or actively in use.
The world is changing, and clients who invest in smarter, leaner ways to deliver projects — and who are open to ideas of program management, owner’s engineering, risk assessment and asset management — will be in the right place at the right time.
As the water industry continues to advance, “future-ready systems” won’t be a buzzword much longer because those that have the foresight to invest in risk and gap analysis — and take a hard, unbiased look at their assets — begin to see greater success when planning projects to make their systems more resilient and reliable.