Drought to Deluge, Preparing for El Nino

Drought to Deluge, Preparing for El Niño

Drought to Deluge? Preparing for El Niño!

By Master Gardener Sue Ridgeway

According to the National Weather Service, there is a 90 percent likelihood that the United States will experience a strong El Niño season this winter—one that could conceivably last until the summer of 2016. Historically, the effects of El Niño are greater in Southern California, but this year Northern California may expect to see some drought relief as well. Should we, in Sonoma County, be cautiously optimistic that the extra rain will help ease our drought concerns, or, based on our prior experience with very strong El Niño events, should we be prepared for the challenges, and possibly disastrous effects, of a deluge? 

 

If Sonoma County’s past experience, such as in 1997, with strong El Niños is any indication, we should prepare for the worst: wide-spread flooding, landslides, debris flows, downed trees, erosion and property damage. We need to be proactive, secure our homes and gardens now, not wait to do it during powerful, drenching rainstorms. [Graphic courtesy of NASA, Earth Observatory] 

The primary purpose of this article is to address preparations to protect your gardens, not actions to protect your home. There is significant Internet guidance on measures that homeowners can take to protect their property as well as emergency supplies to have on hand. Inquire as to whether or not there is a COPE program in your neighborhood and review online FEMA flood guidance. 

What measures can Sonoma County home gardeners take to prepare and to protect their gardens from possible flooding rains? Consider the following (a walk around your property may suggest additional actions): 

1. Prepare soil to absorb the water, prevent run off and erosion - “slow it, spread it, sink it!”

• Prevent erosion and encourage water percolation; cover bare soil or areas where water will collect, with 3 to 4 inches of organic mulch, or plant with low-water natives and other beneficial vegetation.
• If practical, capture and collect storm water in rain barrels, rain gardens, bio-swales and retention ponds.
• If you have replaced your lawn, confirm that the new landscaping does not interfere with grade and drainage, especially if you have newly installed impervious surfaces and retaining walls.
• When directing water runoff, be aware of the requirements of the recently established Sonoma County Riparian Ordinance.
• Take advantage of free online resources like “A Homeowner’s & Landowners Guide to Beneficial Stormwater Management.”
• There are several techniques useful for minimizing runoff where landscape design is concerned. Most focus on using permeable rather than impermeable hardscapes to allow water penetration, rather than diversion to drains. For more information see the SCMG article on “Landscape Design to Minimize Runoff.”

2. Remember to turn off your automatic lawn and drip watering systems; with luck you won't need them again until the late spring.

 3. Secure your yard against the rain and high winds: if necessary repair or reinforce fencing, store or tie down and cover outdoor furniture, overturn or protect potted plants in a sheltered area (plants can “drown” in poorly drained pots).

4. Confirm the health of your trees. The drought has weakened or killed many trees; shallow rooted and weakened trees may not withstand heavy winds or the weight of too much water.

• If you are concerned about tree safety, a certified arborist can conduct a risk assessment.
• Trim or remove diseased or dead tree branches that could endanger your home and property.
• Use three or four sturdy stakes to secure newly planted trees and large shrubs.

5. Take special steps in order to food garden during a rainy period (for more detail, see “Food Gardening and El Niño”). 

• Prepare your soil to absorb water and hold it. Reduce top soil loss, run off and improve soil structure by digging in or adding three to four inches of compost, or plant a cover crop. Add a top layer of organic mulch.
• Prepare your plant beds for good drainage either by elevating the soil in boxes or raising the soil level and mounding the beds.
• Cover the garden beds of smaller plants with securely-fixed floating row covers or plastic low tunnels to protect plants and soil.
• Do not consume your produce if any edible parts, above or below ground, are submerged, splashed by or near flood waters. Flood-borne contaminants are a danger.

6. Be alert for the symptoms of “Sudden Oak Death,” a disease that is killing California’s oak trees. It is caused by an invasive plant pathogen,Phytophthora ramorum, that is water loving and produces plentiful spores in moist or humid conditions. It has been fairly dormant in the drought, but El Niño could change that. For more information, see the UC pest note.

Many officials predict El Niño's rains will ease California’s drought conditions, but will not end them. In fact, a dry La Niña could follow close on its heels. Hydrologist Alan Haynes, of the National Oceanic and Atmospheric Administration, stated: “…if the wettest year were to occur, we still wouldn't erase the deficit that's built up in the last four years.” This year being “water wise” takes on an additional meaning; we must continue planning for a continued drought while also preparing for a possible deluge.