Flood-Managed Aquifer Recharge (Flood-MAR)
“Flood-MAR” is an integrated and voluntary resource management strategy that uses flood water resulting from, or in anticipation of, rainfall or snow melt for managed aquifer recharge (MAR) on agricultural lands and working landscapes, including but not limited to refuges, floodplains, and flood bypasses. Flood-MAR can be implemented at multiple scales, from individual landowners diverting flood water with existing infrastructure, to using extensive detention/recharge areas and modernizing flood management infrastructure/operations.
Flood-MAR projects can provide broad benefits for Californians and the ecosystems of the state, including:
- Water supply reliability
- Flood risk reduction
- Drought Preparedness
- Aquifer Replenishment
- Ecosystem Enhancement
- Subsidence Mitigation
- Water Quality Improvement
- Working Landscape
Preservation and Stewardship
- Climate Change Adaptation
- Recreation and Aesthetics
There is strong, and growing, interest across the state in understanding the benefits, limitations, concerns, costs, and funding opportunities for Flood-MAR projects. DWR plans to work with other state, federal, tribal, and local entities; academia; and landowners. Together, we will build on the knowledge and lessons from past and ongoing studies and programs, pursue expanded implementation of Flood-MAR, and make Flood-MAR an integral part of California’s water portfolio.
DWR has been working with partners to develop a systematic approach to identify floodplain restoration and expansion opportunities that provide high-quality salmonid habitat and enhance naturally occurring floodplain recharge. The Ecological Floodplain Inundation Potential (EcoFIP) toolkit facilitates the identification, analysis, and prioritization of multiple floodplain restoration opportunities at the reach or project scale. The pilot study tools help visualize and compare conceptual restoration designs for potential habitat and recharge benefits and quantify potential benefits and implementation costs. For more information, check out the StoryMaps linked below:
The California Department of Water Resources (DWR) prepared this brochure to describe opportunities that improve use of floodwater for managed aquifer recharge (Flood-MAR) to reduce flood risk, increase groundwater recharge, adapt to climate change, and provide other benefits. Recent cycles of drought and flood provide an enhanced opportunity to strengthen the nexus between the flood management and groundwater management communities. Developing a resilient flood system will require decision-making that not only manages the surface water, but also the dynamic interchange of surface water and groundwater horizontally across floodplains and vertically through the subsurface.
Flood-MAR White Paper
The California Department of Water Resources (DWR) prepared this white paper to explore opportunities to use flood water for managed aquifer recharge (Flood-MAR) because DWR recognizes the need to rehabilitate and modernize water and flood infrastructure in California. Large-scale implementation of Flood-MAR can fundamentally change how flood and groundwater management are integrated by using flood water resulting from, or in anticipation of, rainfall or snowmelt for groundwater recharge on agricultural lands and working landscapes, including but not limited to refuges, floodplains, and flood bypasses.
Flood-MAR Research and Data Development Plan
This Flood-MAR Research and Data Development Plan (R&DD Plan) presents the work of the Flood-MAR Research Advisory Committee (RAC), a multidisciplinary group of subject matter experts across 13 research themes. The RAC was tasked to identify the research, data, guidance, and tools necessary to support and expand the implementation of Flood-MAR projects. Well-formulated Flood-MAR projects can benefit Californians and the environment through improved water supply reliability, flood-risk reduction, drought preparedness, aquifer replenishment, ecosystem enhancement, subsidence mitigation, water quality improvement, working landscape preservation and stewardship, climate change adaptation, recreation, and aesthetics.
- Appendix 1: Hydrology Observation and Protection
- Appendix 2: Reservoir Operations
- Appendix 3: Infrastructure Conveyance and Hydraulics
- Appendix 4: Crop Systems Suitability
- Appendix 5: Soils Geology and Aquifer Characterization
- Appendix 6: Land Use Planning and Management
- Appendix 7: Water Quality
- Appendix 8: Recharge and Extraction Methods & Measures
- Appendix 9: Environmental - Terrestrial and Riparian/Aquatic
- Appendix 10: People and Water
- Appendix 11: Economic Analysis
- Appendix 12: Local, State, Federal Policies, and other Legal Considerations
- Appendix 13: Tools and Application Development
Merced River Flood-MAR Reconnaissance Study
DWR, in partnership with the Merced Irrigation District (MID), is studying the use of flood waters for managed aquifer recharge that can reduce flood risk, increase supply reliability, support groundwater sustainability, and enhance ecosystems in the Merced River Basin. This Merced River Flood-MAR Reconnaissance Study (study) is exploring the potential feasibility and effectiveness of Flood-MAR concepts, testing theories, and describing strategies in overcoming challenges to project planning and implementation.
The study team will assess current conditions of the Merced River watershed and the vulnerability of water management to a range of potential climate change futures. The study will also describe the public and private benefits that may be achieved through Flood-MAR strategies and quantify benefits that Flood-MAR could provide in or adjacent to the Merced River watershed.
The following is a study fact sheet and a listing of technical memorandums that will be posted as they are completed:
- Merced Study Factsheet
- TM 1 Plan of Study
- TM 2 Model Integration
- TM 3 Climate Change Vulnerability Assessment and Baseline Assumptions
- TM 4 Level 1 Analysis (existing operations and facilities)
- TM 5 Level 2 Analysis (modified reservoir operations)
- TM 6 Level 3 Analysis (modified res ops and facilities)
- Study Completion Summary
The following websites provide additional information and resources on the benefits and issues of using flood waters to recharge groundwater basins.
Supervising Engineer, Water Resources
Division of Statewide Integrated Water Management
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California is known for its variable climate. Climate change will only exacerbate this variability, so water managers are eyeing a way to capitalize on the extremes by harnessing flood waters and redirecting them into parched aquifers.
DWR requests review and comment from interested parties for the draft Flood-MAR Research and Data Development Framework. The comment period will be open until Thursday, September 20.
DWR recognizes the need to rehabilitate and modernize water and flood infrastructure in California. Floodwater for Managed Aquifer Recharge, or Flood-MAR, is an emerging water management strategy that can significantly improve water resources sustainability throughout the state.