Q: I have a steep roof that sheds an enormous amount of rushing rain. How can I handle the runoff?

A: Complaining about the rain rises to the level of competitive sport here. But when we hear they are rationing water in California, we realize things could be worse. Reminds me of this story by horticulturalist Greg Grant, speaking at the Master Gardener Seminar in February. Presenting a delightful native plant to a group, he noted the traits that recommended it.

It will grow in acid or alkaline soil. In clay or sand. Sun or shade. Wet or dry conditions. It does not need to be pruned. It is naturally roundup resistant. It is tough as nails, not invasive and blooms in white, pink or blue. To which one audience member replied, “Those are the only colors?” In digital age parlance, “sigh.”

But when you have more than 66 inches of rain a year, it is not complaining to seek a solution to the real damage erosion and a wet foundation can cause. We may not know how to drive in snow, but handling rain we do!  

(Photo | ACES) A simple rain barrel design incorporates a 42-55 gallon barrel connected to a rain gutter.

(Photo | ACES) A simple rain barrel design incorporates a 42-55 gallon barrel connected to a rain gutter.

“Handling rain” involves diverting water flow away from the home’s foundation, slowing and routing the flow to avoid surface erosion, and collecting the water for future use or slow infiltration into the landscape. Rain barrels are a smart way for homeowners to harvest rainwater for later use, while capturing the rain that would normally gush and pool around the foundation. Harvested rain provides a free, natural resource for combating drought. It’s a win-win for Mobile, the rainiest city in America.

Use this link to an Alabama Extension video on rain barrels:  http://www.aces.edu/urban/RainwaterCollection/Workshops.php.
For a simple design, begin with a 42-55 gallon barrel. An FDA food-grade barrel that contained foodstuff is perfect. Do not use recycled containers that have held caustic or poisonous materials. Large plastic trashcans can also be used.

• Drill a 15/16-inch hole about 6 to 8 inches from the bottom.
• Screw a three-quarter-inch spigot snugly into hole.

• If using a PVC spigot, apply PVC cement to threads when it is about three-quarters of an inch tightened. Finish tightening. If using a brass spigot, apply Teflon tape to the threads and tighten.

• If connecting a gutter downspout, use a sabre saw to cut a hole in the lid to fit the spout. Use a 3-inch vinyl downspout elbow to connect the downspout to the barrel.

After inserting the downspout, caulk around the hole. No gutter downspout? Take off the lid of the drum or trash can and cover the opening with a fine fiberglass screen to reduce mosquito breeding. Place the container where it will catch the water flowing off your roof. Use Bacillus thuringiensis (Bt) products to kill mosquito larvae, and for algae, treat water with submersible bacterial packets sold in pond supply stores.

Rain barrels are preferred but aren’t the only option. The goal is to get all that water away from the foundation of the house, routing it to a distant site for slow infiltration into the surrounding landscape. One method is to run the downspout (or barrel overflow line) away from the foundation of the house to empty into a below-grade collection system — a French drain — that acts to temporarily collect, then slowly release, the rainwater into the soil below grade, thus eliminating surface pooling and erosion.

Another option is to cut a surface channel lined with landscape cloth and rock — sometimes called a dry river bed — to carry water away from the house foundation to deposit it in a distant area, preferably where plants can make use of it, such as a dry area, a rain garden or a bog garden. For any of these options, it is crucial to have a slope away from the foundation of the house.

Finally, if your runoff and erosion problems do not respond to your efforts, call the Alabama Extension Office for assistance, 251-574-8445, or consult a local professional for an engineered solution.

QThere is an area in my yard where water collects after rain. Would this be a good place for a rain garden or small pond? The holes dug there for perc tests for a septic tank all filled with water.

AThe phrase “rain garden” creates a beautiful image of April showers on a meadow of yellows and blues and greens. Many of us assume rain gardens are for soggy sites, but actually, rain gardens must drain well. Rain garden plants survive periodic (rather than constant) inundation, followed by drying.

Another misconception is that rain gardens must be “dug out” like a bowl. In fact, a rain garden can be level or planted in just a slight depression of several inches. The plants that work for rain gardens include many of our native selections: Zephyr/ Rain Lily; Blue/Yellow Flag Iris/virginica I. pseudocoris; Swamp Sunflower/Helianthus angustifolius*; Blazing Star/Liatris spicata; Sorghastrum nutans/Indian Grass; and Cardinal Flower/Lobelia cardinalis; Indian Blanket and Black-eyed Susans, Inkberry shrub for sun; Agarista Populifolia for shade.

A rain garden is not for every site, however. If your site retains pooled water for several days after rain, or has heavy clay soil that is gray in color with ribbons of brown in the first foot of the surface, you should select another option because the area does not drain well. Sandy soils work better.

Since you mentioned a perc test, I assume you have a septic system. If so, be aware that rain gardens should be constructed at least 25 feet away from septic drainage lines. Depending on the size of your area, a water feature such as a small pond may work.

Another possibility, similar to a rain garden, is a wetland or bog garden. Unlike rain gardens, bogs do not drain and dry out, so plants are those that don’t mind wet feet, like Pitcher Plants and cypress trees or beautiful Delta Swamp Lily, Hymenocallis liriosme.

UPCOMING: (Free and open to the public)
When: April 18, noon to 1 p.m.
Where: Jon Archer Center, 1070 Schillinger Road N., Mobile
What: Topic: Propagating Camellias by Layering by Rick Crow

When: May 5, 10-11:30 a.m.
Where: Jon Archer Center, 1070 Schillinger Road N., Mobile
What: Topic: Whole Foods: Local Food Sourcing and Sustainable Living, by Whole Foods representative

Master Gardener Helpline: Call 1-877-252-4769, or send your gardening questions to coastalalabamagardening@gmail.com.

Regional Agent Ellen Huckabay will write a column for the May 12 Lagniappe all about the particulars of the Master Gardener Course, which begins on Wednesday, Aug. 10. Here’s a preview:
Deadline to apply: June 8
Classes: Aug. 10 – Nov. 16 (9 a.m. to 2:30 p.m.)
For more information: Call Diane at 251-574-8445 or email jda0002@aces.edu

What: Farm to Table Event presented by Alabama Cooperative Extension System
When: Monday, June 6, 6-8 p.m.
Where: Sessions Farm Market, Grand Bay
Cost: $60 per person  
Reservations required by May 27.