A research programme for water cycle restoration

Bridging field practice and scientific inquiry

A lot can come out of collaborations between academics, eco-practitioners, and regenerative agriculturists. If you are in academia or engaged in research, here are some water-related issues that could benefit from a more rigorous hydrological and ecological modeling approach.

These problems draw on observations and techniques from practitioners, regenerative farmers, and indigenous water-harvesting traditions. Field experience shows how interventions influence water flow, soil moisture, and vegetation, but we need to test whether these insights hold true and quantify their effects. Using high-resolution models, remote sensing, and other scientific tools can provide clearer guidance on what works, where, and at what scale. More scientific rigor can make it easier to change laws and governance strategies on these issues.

1. Slowing Water to Recharge the Land

Brock Dolman’s catchy slogan, “Slow it, sink it, spread it,” captures the essence of interventions that slow runoff, allow water to sink into the soil, and spread it across the landscape to maximize retention. A critical question is: how much should water be slowed, sunk, and spread to achieve measurable benefits, and what thresholds of intervention trigger ecological and hydrological regime shifts in a bioregion?

Slow water draws on centuries of indigenous and traditional water-harvesting practices, as well as modern permaculture innovations. Techniques include zai pits in the Sahel, half-moons in arid landscapes, swales and keyline designs on hillsides, and terraces, leaky weirs, and infiltration basins on farms. Communities report improved soil moisture, groundwater recharge, streamflow, and vegetation health, yet these effects have rarely been rigorously quantified.

Laura Norman of the United States Geological Survey (USGS) and colleagues [Norman 2020, 2022, 2025] have been pioneers in slow water research, they have shown that strategically placed rocks and leaky weirs can increase late-season streamflow by 20 to 30 percent, directly boosting watershed hydrology. These results demonstrate how modifying physical flow can store water and sustain baseflow, providing a foundation for more resilient ecosystems.

Beyond streams, slow water interventions help landscapes retain wet-season rainfall into the dry season. By storing water in soils, small dams, and aquifers, landscapes maintain higher moisture levels when the rains stop. This retained water supports dry-season evapotranspiration, helps trees and plants access water, sustains local humidity, and can contribute to increased localized convective rainfall through the small water cycle.

The research question is this: Can different slow water techniques, individually and in combination, increase groundwater levels, enhance local precipitation recycling, and sustain plant water availability during dry periods? How much slowing, sinking, and spreading triggers significant regime shifts in watershed hydrology and ecosystem productivity? Addressing this requires hydrological and micrometeorological modeling coupled with field validation to capture how stored water modifies energy partitioning, moisture flux, and atmospheric feedbacks.

A movement around slow water has been promoted by Brock Dolman, Erica Gies, author of Water Always Wins, permaculture, agroecology, and regenerative agriculture. Rigorous research can help quantify exactly how much water should be slowed, sunk, and spread to achieve these benefits at scale.

2. How Do Groundwater Levels Impact Wildfire Risk?

Wildfires are commonly associated with heat waves or short-term rainfall deficits, but long-term groundwater depletion may also play a critical role. NASA remote sensing studies have observed correlations between low soil moisture and increased wildfire incidence [Sazib 2021], indicating that regions with depleted subsurface water can remain flammable even when rainfall is moderate.

The research question is this: To what extent does widespread groundwater extraction drive higher wildfire risk, and how does hydrological drought influence forest fuel dryness? If it is possible, how much do we have to restore our groundwater , via techniques like slow water, rainwater harvesting, and managed aquifer recharge, to lessen wildfire risk signficantly? Integrating water table depth, root-zone soil moisture, and fuel moisture content could help develop predictive models that go beyond conventional atmospheric drought indicators. Understanding this mechanism could pinpoint areas where aquifer and soil restoration would most effectively reduce flammability.

3. Regenerative Agriculture and Aquifer Health

Agriculture contributes heavily to both groundwater depletion and pollution. Regenerative agriculture improves soil structure, builds soil organic matter, boosts infiltration, and reduces nitrate leaching, providing a potential pathway to restore aquifers while improving water quality.

John Cherry, a pioneer in hydrogeology, framed a key question during our recent interview: What scale and duration of regenerative agriculture adoption could measurably raise groundwater tables while lowering nitrate concentrations to safer ranges? Answering this requires a coupled hydrology-solute transport model that captures how improved soil structure, microbial activity, and denitrification enhance both water quantity and quality. Success would demonstrate that agriculture can restore aquifers rather than degrade them.

4. Land Restoration’s Impact on Precipitation Recycling and the Small Water Cycle

Field research by Ronny Meier [Meier 2021], Millán Millán [Millán 2014], and others shows that even relatively small-scale restoration - 10 kilometers by 10 kilometers - can measurably increase rain. Millán Millán’s experiments in Spain revealed how soil moisture, groundwater, and fog contribute to localized rainfall.

These observations challenge conventional climate models, which suggest that larger areas must be restored to influence rainfall. Models may fail to capture intense, localized convective loops created by patches of enhanced evapotranspiration. Slow water interventions can inject moisture into the convective boundary layer locally, triggering rainfall without raising relative humidity uniformly across the region. Millán Millán’s climate models and Oliver Branch’s [Branch 2019] micrometeorological models support this.

The research question is this: How can high-resolution field data and micrometeorological observations be integrated into climate models to capture scale-dependent effects, and how much land restoration is required to restore rainfall?

5. Breaking the Drought-Fire-Flood Watershed Death Cycle

Expert practitioners like Zach Weiss and Sepp Holzer propose that landscapes can become caught in a self-reinforcing cycle of degradation, called the Watershed Death Spiral. Drought dry soils and make vegetation more flammable. Fires remove cover, potentially creating hydrophobic soils that amplify flood risk when rains return. Floods wash away soils that are needed to absorb the rain, a process which replenishes aquifers and increases precipitation recycling. This drought-fire-flood sequence leads to erosion, sediment loss, and accelerated watershed degradation. The drying of our continents via a variety of processes like river channelization, wetland depletion, groundwater depletion, deforestation, and the paving over of the land is contributing to the drought-fire-flood cycle.

The research question is this: How can a dynamic ecohydrological model capture these feedback loops, and what level of water cycle restoration might shift a watershed from a destructive regime to a regenerative, resilient state? Integrating fire, flood, soil, and vegetation parameters into a system-level model can help identify interventions that decouple drought, fire, and flood, ultimately building long-term resilience.

6. Groundwater as a Driver of Biome Flips

Groundwater can determine which ecosystems dominate a landscape. When water tables drop, deep-rooted species may die, allowing grasses, shrubs, or desert-adapted plants to take over. In some regions, this triggers rapid, often irreversible biome flips.

The research question is this: When groundwater declines, can it trigger sudden shifts from forest to savanna, or wetland to desert? How do these hydrological drivers influence ecosystem resilience? How much water restoration of the cycle do we need to do to protect our ecosystems? Addressing this question requires integrating dynamic groundwater models, vegetation physiology, and fire-climate feedbacks, especially where water stress interacts with human land use. Observations in riparian and groundwater-dependent ecosystems show strong local effects, but systematic understanding of groundwater-driven biome flips remains limited. Filling this gap could improve predictions of ecosystem collapse, guide restoration priorities, and safeguard biodiversity.

These questions are just the start of a research agenda. Working together, scientists and eco-practitioners can uncover even more questions and insights. By combining field observations with remote sensing and high-resolution modeling, we can put numbers on the benefits of nature-based solutions, guide restoration efforts where they’ll have the most impact, and help communities adapt to and mitigate environmental and climate challenges around the world.

Branch, Oliver, and Volker Wulfmeyer. “Deliberate enhancement of rainfall using desert plantations.” Proceedings of the National Academy of Sciences 116, no. 38 (2019): 18841-18847

Meier, Ronny, Jonas Schwaab, Sonia I. Seneviratne, Michael Sprenger, Elizabeth Lewis, and Edouard L. Davin. “Empirical estimate of forestation-induced precipitation changes in Europe.” Nature Geoscience 14, no. 7 (2021): 473-478 https://www.nature.com/articles/s41561-021-00773-6

Millán, Millán M. “Extreme hydrometeorological events and climate change predictions in Europe.” Journal of Hydrology 518 (2014): 206-224

Norman, Laura M., Kristine Uhlman, Hanna A. Coy, Natalie R. Wilson, Andrew M. Bennett, Floyd Gray, and Kurt T. Ehrenberg. ““Leaky Weirs” capture alluvial deposition and enhance seasonal mountain-front recharge in dryland streams.” Applied Water Science 15, no. 2 (2025): 29

Norman, Laura M. “Ecosystem services of riparian restoration: a review of rock detention structures in the Madrean Archipelago Ecoregion.” Air, Soil and Water Research 13 (2020): 1178622120946337.

Norman, Laura M., Rattan Lal, Ellen Wohl, Emily Fairfax, Allen C. Gellis, and Michael M. Pollock. “Natural infrastructure in dryland streams (NIDS) can establish regenerative wetland sinks that reverse desertification and strengthen climate resilience.” Science of the Total Environment 849 (2022): 157738.

Sazib, Nazmus, John D. Bolten, and Iliana E. Mladenova. “Leveraging NASA soil moisture active passive for assessing fire susceptibility and potential impacts over Australia and California.” IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 15 (2021): 779-787.