With the prospect of a strong El Niño this year, experts are advising homeowners and gardeners to prepare for potentially heavier and more intense autumn rainfalls. These sudden and sometimes extreme downpours, including microbursts, can cause unexpected flooding in yards, even those previously unaffected, as water flows from nearby properties or overwhelming drainage systems.
Specialists in landscape design and stormwater management emphasize that rather than viewing rainwater solely as a problem to be diverted, it can be harnessed beneficially to improve garden resilience and reduce reliance on irrigation. “Too often we think of rainwater as a problem — a substance we must get rid of,” said Brad Lancaster, a landscape designer known for his work on rainwater harvesting.
Homeowners are encouraged to adopt strategies that slow the movement of stormwater, spread it over larger areas, and encourage absorption into the soil—practices that help prevent basement flooding and protect local waterways while replenishing groundwater supplies. Jeff Lorenz, founder of Refugia Design in the Philadelphia area, noted that the goal is to “slow water down, spread it out and soak it back into the ground.”
Reducing impermeable surfaces, such as asphalt or concrete, is a key recommendation. Replacing these areas with permeable materials like gravel or garden beds allows rainwater to infiltrate rather than run off. Frank Piccininni, owner of Spadefoot Ecosystem Solutions, pointed out that stormwater management is often narrowly associated with drainage infrastructure, but distributing water across the landscape can put it to beneficial use.
Lawns, which commonly rest on compacted soil and have shallow roots, absorb little water and may exacerbate runoff. Experts suggest shrinking lawn areas by expanding garden beds and reducing irrigation. Over-watering can saturate soil and worsen flooding, while letting lawns dry out encourages deeper root growth and greater water absorption.
Increasing plant density is also advised, as root systems enhance the soil’s ability to soak up moisture. “Plants do the bulk of the heavy lifting,” said Mr. Lorenz, with landscape architect Marissa Angell adding that minimizing exposed soil is critical for soil coverage.
Gardeners are encouraged to start stormwater management at the source of water entry, such as where runoff enters a property from roads or downspouts, by installing rain or depression gardens. These planted depressions capture and slow the initial surge of water, reducing erosion and soil displacement. Lancaster cautioned against directing runoff from roads into edible gardens due to potential contaminants.
For soggy patches, transforming these into rain gardens using native plants that tolerate both wet and dry conditions offers a practical solution. Suitable species often have deep or spreading root systems that stabilize soil and improve infiltration. Trees and shrubs provide additional benefits by intercepting rainfall and absorbing significant volumes of water; clustering trees is more effective than planting them singly, according to Piccininni. Species such as bald cypress and red maple are recommended for their adaptability to varying moisture levels.
Finally, community-wide adoption of small-scale interventions like infiltration rain gardens can cumulatively bolster neighborhood resilience to heavy rains. “If everybody had a little infiltration rain garden area that’s just 5 by 5 feet across an entire block, all of a sudden the entire community would be more resilient,” Piccininni stated.
As the autumn season approaches, these landscape adjustments offer practical approaches to managing increased rainfall linked to climate patterns, helping to mitigate flood risks while promoting sustainable water use.