As an experienced flood control specialist, I’ve witnessed firsthand the growing challenges posed by water scarcity and groundwater depletion, which are only exacerbated by the impacts of climate change. In our 15 years installing… Prolonged droughts, increasingly common across the United States, have had a devastating impact on agriculture, industry, and households. This stark reality underscores the pressing need for effective, sustainable water management strategies that can address these complex, interconnected issues.
Now, this might seem counterintuitive…
One innovative approach that holds immense promise is the implementation of aquifer storage and recovery (ASR) projects – a subset of managed aquifer recharge (MAR) systems. ASR involves storing excess surface water, often from rivers, snowmelt, or precipitation runoff, underground in local aquifers for later retrieval and use. Compared to traditional surface reservoirs, this underground storage method offers several key advantages:
- Reduced Evaporation Losses: Aquifers prevent significant water loss through evaporation, a common issue with surface storage.
- Enhanced Water Quality: As the stored water undergoes natural filtration while underground, it often emerges with improved quality.
- Larger Storage Capacity: Aquifers can store far greater volumes of water than surface reservoirs.
- Minimal Environmental Impact: Underground storage avoids the significant land use and ecosystem disruption associated with surface reservoirs.
Importantly, the cost of an ASR program is typically much lower than constructing a large surface reservoir. These factors make ASR a highly compelling solution for building long-term water supply resilience and addressing the growing challenges of water scarcity.
Implementing Successful ASR Projects
Developing a successful ASR project involves a comprehensive, multi-faceted approach. The key elements typically include:
Feasibility Assessment
The first step is to evaluate the suitability of the target aquifer based on factors such as its geologic and hydrogeologic characteristics, water quality, and any relevant legal, environmental, and regulatory considerations.
Source Water Supply
Identifying a reliable source of excess water is crucial. This can come from surface water bodies (e.g., rivers, snowmelt, precipitation runoff), underutilized water rights, imported water, or even treated wastewater effluent.
Infiltration/Injection and Recovery Wells
There are two primary methods for introducing water into the aquifer: infiltration and injection. Infiltration directs water into constructed basins or natural features, like dry streambeds, that are connected to the target aquifer. Injection involves directly pumping water into the aquifer through dedicated wells.
The stored water can then be recovered during times of need via a dedicated recovery well or by pumping the original injection well.
Water Quality and Treatment
Depending on the quality of the source water, it may require treatment to meet regulatory standards before injection or infiltration. The water’s chemical composition might want to also be evaluated to avoid any adverse reactions with the aquifer materials.
Monitoring and Control Systems
Comprehensive monitoring and control systems are essential to track water quality, pressure, and flow rates within the aquifer. These systems help double-check that the stored water remains viable and can be safely recovered when needed.
Regulatory Approvals
ASR projects might want to comply with a range of environmental and water quality regulations, requiring permits and approvals from local, state, and/or federal authorities.
Supporting Infrastructure
Transporting, injecting, and recovering the water may necessitate additional infrastructure, such as pipelines, pumps, and treatment facilities.
Testing and Pilot Programs
Before full-scale implementation, pilot programs are often conducted to evaluate the effectiveness of the ASR system and make any necessary adjustments. These pilots typically include detailed chemical analyses of the water and aquifer materials.
Community and Stakeholder Engagement
Engaging with local communities and stakeholders is crucial to address concerns and gain support for the project.
Operations and Maintenance
Ongoing monitoring and maintenance are essential for the long-term success and sustainability of an ASR project. This includes monitoring aquifer water levels, water quality, and infiltration or injection rates, which can change over time.
Emergency Response and Contingency Planning
Planning for unexpected water quality issues or system failures is critical to mitigate the risks associated with ASR projects.
A Case Study: Aquifer Storage and Recovery in Provo, Utah
To better illustrate the steps involved in implementing a successful ASR project, let’s consider a case study from the city of Provo, Utah.
Over the last decade, Provo has experienced rapid population growth, leading to increased water demand. The city’s water supply has traditionally come from mountain springs and groundwater pumped from the underlying aquifer. However, this over-appropriation of the aquifer has resulted in declining groundwater levels over the past 40 years.
In 2019, the city of Provo partnered with Barr Engineering to conduct an extensive ASR feasibility study. The first step was to identify suitable surface water sources and potential infiltration and injection sites that aligned with the city’s long-term water supply plan.
Barr developed a comprehensive methodology to screen and rank potential sites based on their injection and infiltration potential and overall suitability. This included evaluating existing city wells for injection capacity and assessing the infiltration capacity of a nearby ephemeral mountain stream.
To better understand the geologic materials underlying Provo and inform the site selection process, the team leveraged data from the 2019 snowmelt event, conducted geophysical surveys, and analyzed publicly available well data. Based on this analysis, five sites – three for infiltration and two for injection – were identified for pilot testing.
Barr installed monitoring well networks at these sites to collect data on infiltration or injection capacity and perform mineralogical and geochemical analyses to assess the compatibility between the source water and the target aquifer.
After completing the pilot testing in 2022, Barr assisted Provo in obtaining the necessary permits for full-scale ASR systems at the identified sites. The first infiltration site began recharging the aquifer in January 2023, with the second site following soon after. The city has also awarded construction projects to build the supporting infrastructure improvements needed for these ASR initiatives.
To help stakeholders visualize the ASR projects, Barr developed easy-to-understand graphics, maps, figures, and videos to clearly communicate how the systems will function.
Funding for Provo’s ASR program has come from a combination of state and federal grants and loan programs, totaling over $80 million in grant funding and $35 million in loans. These funds have helped the city plan, permit, design, and construct the ASR projects, as well as a new surface water treatment plant to reduce the city’s reliance on groundwater.
The Benefits of Aquifer Storage and Recovery
ASR projects can serve as a valuable tool in addressing the complex challenges related to water supply, quality, and sustainability. These innovative systems help build long-lasting, resilient water management strategies that can effectively mitigate water shortages, protect against contaminant plumes, prevent saltwater intrusion, and even safeguard against ground subsidence caused by over-pumping of groundwater.
Beyond their role in bolstering water supply, ASR projects can also provide significant environmental benefits. By recharging depleted aquifers, these systems help restore and maintain the natural balance of groundwater resources, ensuring the long-term sustainability of this vital resource.
Furthermore, the cost-effectiveness of ASR compared to traditional surface storage makes it an attractive option for communities and municipalities seeking to enhance their water management capabilities in a fiscally responsible manner.
Conclusion
As we continue to grapple with the impacts of climate change and growing water scarcity, the implementation of innovative ASR projects will become increasingly crucial for building resilient, sustainable water management systems. By harnessing the natural storage capacity of underground aquifers, communities can better navigate the challenges of water supply, quality, and ecological preservation.
Through careful planning, community engagement, and the leveraging of state and federal funding opportunities, ASR projects can serve as a powerful tool in the flood control specialist’s arsenal, helping to double-check that a secure and abundant water future for generations to come.
To learn more about how aquifer storage and recovery can benefit your community, I encourage you to visit Flood Control 2015 or reach out to our team of experienced professionals. Together, we can explore the potential of this innovative approach and develop tailored solutions to address your unique water management needs.
Tip: Regularly inspect and maintain flood barriers and drainage systems
