When it RAINS...

Today's weather can be bust or boom, and bioswales and rain gardens help control the overflow during boom times.

- SUSAN M. BRACKNEY

No matter where you live and garden, odds are you’ve noticed at least some changes in your local weather patterns over the last several years. Throughout much of the United States, for instance, we’ve seen new extremes — more intense rains punctuated by prolonged periods of drought.

A 2019 research brief released by the policy- neutral nonprofit group Climate Central notes that for every degree Fahrenheit rise in temperature, our atmosphere can hang onto about 4% more water vapor. That means as temperatures go up, the stage is set for even heavier deluges when it does rain. Climate Central researchers analyzed the rainiest days of the year for 244 U.S. cities and determined that, “Since 1950, the wettest day of the year has gotten wetter in 79% of the cities analyzed.

“In addition to getting stronger, extreme downpours are happening more frequently than in the past. In 80% of the cities analyzed, the top 1% of rain events have been recorded disproportionately recently.” Just how recently? More than 1⁄3 of the cities Climate Central studied set their rainfall records since 1990.

TOO MUCH, TOO FAST

When our gardens get buckets of rain fall dumped on them in a more compressed amount of time, we’re at greater risk for flooding — and greater risk of losing precious topsoil in the process. Rather than slowly penetrating and subsequently filtering through layers of soil to recharge the local groundwater, extreme rainfall becomes fast-moving runoff.