Rain Draining Strategies

When rainstorms come pouring through California each winter, think about this: Where is all that water going when it lands in your backyard? Here are some tips to protect your house, pool cover and prized outdoor plants located in low lying areas:

• Enjoy the rain...from indoors. Do as little as possible in the garden during a downpour. Working in wet soil causes compaction. 

 

• Add gutter extensions to move water away from the house. These sections of flexible pipe allow you to divert water several feet away from plants that don't like wet feet. And, it may keep your house foundation drier, too.

A better system for draining water away from house gutters or garden beds that habitually have slow water percolation: a hard pipe drain system. Surface drains lead to three-inch PVC pipe, buried beneath the soil and sloping down towards the lowest part of the property or to an outlet.
 Be sure to slope the drain pipe, allowing at least a one foot drop for each 100 feet of length (one quarter-inch per foot). Dig backwards from where the water will exit the pipe, trenching back towards the source of flooding to help determine how deep to lay the drain pipe. Line the trench with a few inches of gravel, both above and below the pipe. For a lawn area, try to lay the pipe at least two feet below the surface.

 

• Get a submersible sump pump to move water in a hurry from pool covers and planted areas that flood. Some models are water activated (they automatically come on when the water level rises an inch or so). Place the sump pump on a board to keep dirt from clogging the filtration screen.

• Dig a hole. A hole (also called a sump) that is dug in the lowest portion of your yard, a hole that penetrates through all the layers of hardpan (usually 2-4 feet below the surface), can help drain away storm water. Line the hole with a non-porous material (hard plastic sheeting, for example) to keep the surrounding dirt from falling back into the hole. Fill the hole with small rocks, about one inch in diameter.

• Construct an underground hard drain or a French drain (perforated drain pipe or gravel creek bed). If it's the lawn area that's flooding, dig a trench and lay a drain line in the lowest area of the lawn. Don't do any digging immediately after a heavy rain, though; wait until the soil dries enough to avoid unnecessary soil compaction. Be sure to slope the perforated drain pipe, allowing at least a one foot drop for each 100 feet of length (one quarter-inch per foot). Dig backwards from where the water will exit the pipe, trenching back towards the source of flooding to help determine how deep to lay the drain pipe. Line the trench with a few inches of gravel, both above and below the pipe. For a lawn area, try to lay the pipe at least two feet below the surface.

• If it's the garden bed that's flooding, consider building raised beds this fall, lining the bed with 2X8, 2X10 or 2X12 redwood planks. Capping off the top of these boards with 2X6 redwood will give you a comfortable place to sit while harvesting vegetables and pulling weeds.

 

• If you haven't planted in a flooded area yet, consider creating mounds first, planting trees and shrubs on the top of the mounds.

 If you're still stuck with pools of standing water after heavy rains despite your best efforts, consider planting trees and shrubs that can take "wet feet". Water-tolerant trees for many areas of Northern and Central California include sweet gum, magnolia, and tupelo. Shrubs for wet areas include thuja and red twig dogwood.