The majority of the 91,000 dams in the United States were built decades before modern engineering standards were established, which causes today’s experts to question their integrity. Evolving regulations and design standards, in addition to suburban sprawls encroaching into dam inundation areas, continuously render existing dams non-compliant. Dams historically have been very safe, so owners and regulators may have become complacent over the decades. Particularly catastrophic failures have catalyzed remediation measures; for example, the federal government began to highly regulate levees and funded billions of dollars’ worth of evaluations and repairs in New Orleans after Hurricane Katrina.

Raise Dams to Increase Storage Capacity

Aging infrastructure may require dam operators to lower reservoir levels, negatively impacting water supply reliability for the communities that depend on it. With extreme weather events causing a sense of whiplash between severe drought and severe rain, dam owners must be prepared to collect the precipitation when it falls; reservoir storage needs also will increase as our populations grow. Water supply dams store runoff, rain, and snow melt — providing a surplus supply from wetter seasons to withstand drought. These dams also provide flexibility to adapt to changing conditions, maximize long-term storage, extend the life of existing water resources, and offer emergency backup supply.

Perform Regular Maintenance to Mitigate Risk

While the threats may seem invisible at times, dams are under persistent attack. Erosion impacts the earth below and around the structures, requiring reinforcements or new foundations. Concrete itself weakens with elemental exposure, experiencing chemical reactions that affect its stability, and seismic hazards drive the need for retrofits and replacements. Fortunately, regular maintenance and retrofits can prolong a dam’s safe operation to over 100 years and bring your facility into today’s standards. Keep your operations running smoothly with maintenance performed at regular intervals including:

• Compliance with local, state and federal regulations

• Thorough daily, weekly and monthly inspections (as appropriate) to proactively identify issues and plan both minor and major repairs

• Regulatory inspections and associated remediation measures, as necessary

• Periodical underwater mapping (or bathymetric reservoir surveys) to assess below-water elements, monitor sediment accumulation, and estimate when infrastructure may be impaired by sediment

• Condition evaluation of sophisticated mechanical and electrical systems (for example, annual gate cycling as required in California)

• Vegetation management on embankments and adjacent to downstream toe

Leverage Modern Technology

Physical upgrades are facilitated by the following digital tools:

• 3D Visualization. Utilize 3D modeling tools for rapid comparative assessments of facility surface features, gate structures and potential gate binding issues, concrete monolith movements, roller-compacted concrete and spillway surface evaluations, and embankment movements such as sliding and sloughing.

• Risk Evaluation Software. Risk-based decisions are supported by innovative software tools such as RiskMAP, and ShakeCast that are intended to help dam owners identify, mitigate and respond to structural and downstream issues.

• Void Detection. Stay current with new technologies that enhance your abilities to detect voids under or adjacent to concrete features (such as spillways) and at walls meeting embankments. Advanced remote-operated vehicles can be equipped with the latest technologies including sonar, LiDAR, kinematic Global Navigational Satellite Systems (GNSS) and high-resolution digital cameras to provide above- and below-water data.

• Computational Fluid Dynamics (CFD) Modeling. Use CFD modeling to simulate real-world conditions and optimize dam operations by evaluating the suitability of gates to adjust mass flow rates, turbine configurations and water pressure.

• Data Analytics. Leverage the power of data analytics to monitor and plan operations and maintenance (O&M) activities — including performing cost/benefit analyses to determine if a particular repair or upgrade is worth the cost before making the case to your stakeholders.

Utilize Advanced Materials to Enhance Structural Integrity

Materials such as fiber-reinforced composites offer superior strength and durability, improving the structural integrity of dam components. High-performance concrete formulations, incorporating advanced additives and admixtures, contribute to increased strength and durability; low-carbon cements and alternative supplementary materials (such as natural pozzolan and pond ash) lower carbon footprints. Smart materials embedded with sensors can monitor structural health in real-time, providing crucial data for predictive maintenance. By incorporating these technological advancements in materials, dams can achieve higher levels of safety, efficiency, and adaptability to evolving environmental conditions.

Dams are critical for hydropower development; when water passes through a dam, hydroelectric power can be generated using turbines. Many utilities are looking into diversifying their portfolios to include this type of clean and renewable energy — both pumped storage hydropower and “run-of-river” hydropower. As part of the dam modernization process, it’s important to evaluate your existing infrastructure (or future plans) for hydropower capabilities. Hydropower offers the following key benefits:

• Serves as a renewable and pollution-free energy source as an alternative to conventional power generation, with pumped storage as a dispatchable backup

• Offers O&M flexibility based on quick ramp-up and shut-down times

• Provides flood control, irrigation support and clean drinking water

Meet Growing Energy Demands with Pumped Storage Hydropower

Unfortunately, obtaining permits to construct a new facility on a running river can take decades and is nearly impossible in the United States today; luckily, retrofitting existing reservoirs with different types of hydropower infrastructure is still very possible. Dam owners should consider implementing pumped storage systems which are much easier to permit because they don’t require you to dam up a river or stream. Pumped storage systems feature a configuration of two water reservoirs at different elevations that generate electricity as water moves down the higher reservoir to the lower reservoir and passes through a turbine. By releasing water to generate power at times of need, pumped storage is a burgeoning industry that meets a major need for intermittent renewable energy. These systems can be designed as open-loop or closed-loop:

• In open-loop pumped storage hydropower systems, the upper and lower reservoirs have an ongoing hydrologic connection to a naturally flowing water feature (such as a river or stream) through a tunnel, using a turbine and motor to move water and generate electricity.

• Closed-loop pumped storage hydropower systems are not connected to an outside body of water, and therefore do not need to be located on a river or stream because they are self-contained. In closed-loop systems, the upper and lower reservoirs are still connected through a tunnel and use a turbine and motor to move water and generate electricity.

Take an Environmentally Friendly Approach

Sustainable dam modernization practices may include powering systems with renewable energy to minimize the environmental footprint, integrating fish-friendly technologies to preserve aquatic ecosystems, and using native vegetation on slopes to prevent erosion and contribute to biodiversity. Water utilities also should consider increasing the visibility of hydropower, using carbon-neutral construction materials, prioritizing sustainable water management practices, and engaging local communities. The goal is to balance the need for infrastructure improvements with the preservation of natural habitats.

Offer Recreational Opportunities

According to the National Hydropower Association (NHA), hydropower is more than just a leading generator of renewable electricity. Throughout the United States, hydropower facilities (and their associated dams and reservoirs) are providing recreational opportunities for surrounding communities. Forms of recreation include hiking and boating access trails, fishing piers, picnic areas, educational signage and beaches. Recreational opportunities may be leveraged as the deciding factor for stakeholders to approve funding for your dam project.

Dams are classified by hazard potential by the American Society of Civil Engineers (ASCE). A high hazard potential rating doesn’t necessarily mean that the dam is at an increased risk for failure; it means that if a failure were to occur, the consequences would likely be direct loss of human life and severe property damage. In the past two decades, the quantity of high hazard potential dams has more than doubled as larger developments replace once-rural dams and reservoirs. Eighty-one percent of these dams have established an emergency action plan, but ASDSO estimates there are still more than 2,300 deficient dams with high hazard potentials. Dam failures are a risk to public safety and other major infrastructure including roads, bridges and water systems —potentially costing billions of dollars in damages. In contrast to the many safety risks associated with aging dams, modernized dams protect the public in many ways:

• Facilities can be designed for flood control in high-risk areas to protect downstream homes, businesses, and schools.

• Reservoirs provide a reliable, resilient and robust water supply in times of drought.

• Water discharge temperature and volume can be regulated for downstream fisheries and other environmental reasons.

Implement ‘Safety by Design’ Best Practices

Reduce project lifecycle risk to construction personnel, facility employees and community members by incorporating safety considerations throughout the design process of a new dam facility. Leverage 3D modeling to enable engineers to “walk” through the design before it’s built, evaluate subsurface data, detect clashes, and mitigate constructability. Utilize sophisticated risk-based evaluation techniques to prioritize repairs and enhancements. For existing dams, it may be too late for major design considerations, but safety can still be optimized with more intentional approaches to O&M. The use of drones has proven to be an effective way to remotely perform inspections in areas that are unsafe or inaccessible for humans, such as interior penstocks.

Educate the Surrounding Community

When it comes to dam safety, it’s essential to be proactive rather than reactive. Dam owners, local governments, and emergency management professionals should consider educating your surrounding communities on the potential damage from a dam failure. This awareness will push policymakers towards decisions to enable appropriate land use, emergency response planning, funding for maintenance and rehabilitation — effectively reducing risks to the community, the economy, and to your dam’s long-term resiliency.

Prepare for Natural Disasters

Dam operators must have an emergency plan ready to go for natural disasters including long-term and short-term preparation measures and post-event responses. All personnel and stakeholders should be well-versed in how to communicate and execute on this plan to protect your assets and the surrounding community. Depending on the region, the biggest natural threats to dams that you must prepare for include:

• Hurricanes precipitation that could lead to flooding (even from the downstream side with risks of the dam reversing)

• Freezing temperatures and ice formation

• Earthquakes

• Wildfires blocking access to critical infrastructure and affecting reservoir water quality

• Droughts that reduce reservoir intake below design standards

Black & Veatch’s eBook on natural disaster resiliency explains how critical infrastructure operators should plan, prepare, respond and recover in the face of extreme weather events, earthquakes and wildfires.

Dam modernization strategies for existing facilities and the design and construction of new facilities are essential for preserving water, providing energy and protecting lives. Critical steps towards dam modernization include increasing storage capabilities, integrating hydropower systems and proactively mitigating high-risk safety concerns. Changing regulations and downstream development can be incredibly problematic for dam operators, and equally far out of your control. In order to future-proof your new dam or modernize existing infrastructure, it’s key to anticipate evolving capacity needs, regulatory requirements, increasingly extreme weather events and other changes downstream.

Collaborate with an Expert Advisory Partner

Consider collaborating with an expert advisory partner to identify feasible actions that are innovative, economically realistic and locally appropriate for your region’s geography and population density. Many dam owners cite lack of funding as the main reason for deferred maintenance; expert partners also can advise on how to leverage funding for high-hazard potential dams and advocate for increased financial support. When selecting your advisory partner, it’s ideal to go with a “one-stop shop” engineering, procurement and construction (EPC) firm. Many international EPC firms offer comprehensive in-house expertise in safety and risk management, program and construction management, alternative project delivery methods, hydropower O&M, pumped storage, maritime and coastal engineering, water tunnels and conveyance, spillways and levees. The right partner can advise on exactly which technologies and modifications will be the most impactful based on your unique site, existing infrastructure, budget, and goals.