Preparing for EL NINO in LA

Thinking Sustainably and Preparing for El Nino
by Mike Garcia, Enviroscape LA

Mitigate the storm’s effect on our home and garden – AND – Divert and capture storm water to help our severe drought

  • We are in a severe prolonged drought yet if El Niño comes this year an estimated 114 billion gallons of water we could be capturing is lost.
  • Even with El Niño – we are still in a drought.
  • El Niño is predicted to bring 30” of rain or more to Southern California.
  • For every inch of rain, 3.8 billion gals. of rainwater is estimated to go into

paved surfaces and streets straight to the ocean depleting our ground water. (source:


Even in a drought year with only 7 inches of rain, the average homeowner could capture

approx. 4,000 gallons of water!!  (source: treepeople)

Rainwater Storage

Stores rainwater to use during drought months in the garden!

RAIN BARRELSrain-barrels

Install rain barrels at your downspouts – link them together – average rain barrel holds 55 gal.

Have a plan for directing the overflow water after the barrels fill up

Often a great way to water a specific thirsty area in your drought tolerant garden, i.e. veggies.

Drip irrigation is the best way to utilize the water


— Underground storage to be used later in the garden via a pump system

TIP: DIY ONLY if you know what you are doing with drainage! This is often best left to the pros.

Rainwater Diversion

Diverting water replenishes our depleted aquifer -it slows down or stores the rainwater briefly so it can percolate into the ground.


“is an underground structure that disposes of unwanted water, most commonly storm water runoff, by dissipating it into the ground, where it merges with the local groundwater.” Dry Well Wikipedia

— Can be located to areas in the garden with trees to help give them the deep watering they need

— Tip: In many cases you can direct your roof’s downspout to a buried pipe that leads to the dry well

— DIY ONLY if you know what you are doing with drainage! This is often best left to the pros.


— using water redirected from your roof to seasonal dry creek beds

— Make sure to conduct a soil percolation test if you are installing a rain garden or swale:

  • Dig a hole 18” x 18”
  • Fill with water and if the water drains AT LEAST 1” per hour the soil can support a rain garden


Check out your garden’s drainage patterns – Low or pooling areas? Standing water that can seep into your home or basement garage etc?

sump pump   … if you have a sump pump – make sure it’s in ship-shape order

water diversion system


— Keep gutters cleaned out.  If they are broken or weak – consider replacing.

— No gutters and soil splashing challenges? Temporary fix: In these areas under the roofline you may be able to use gravel to slow the energy of the water hitting the surface and cutting a trough in the surface.

— Keep mulch, pebbles, seed balls or pods or leaves away from your garden drains.


Built planters are often designed along your garden perimeter, against your home or patio, or around trees.

— Test your planters to see if they have proper drainage holes and that the exit holes are not clogged.

Trees, mulch and compacted soil


— Pruning now – yes, by a qualified contractor

– Be careful of over-pruning right now – many of our big trees are drought weakened – Take the end weight off and dead wood only

— Leaning trees – keep an eye on the tree! If the tree is cracked or the roots are lifting on one side? it’s time to call in an arborist

— When in doubt for a large mature tree – especially near or over your home – call in an expert

— Wind is a big issue: Dry and unhealthy trees falling over or losing large branches

Note on Trees and how they affect our eco-system

Trees affect water systems worldwide and their removal can contribute to ground water

depletion, flooding and in many cases environmental disasters. They are key elements in your landscape.


— In our city, we have removed trees and poured concrete, making our landscape impervious to water.

— leaves aka mulch are hauled to the landfill.

— But trees are part of the water system. When rain falls on leaves and branches, it slows down and filters? into the earth. Leaves should fall and be left to form mulch. Mulch on the ground protects the tree and enables it to act like a giant sponge, helping water absorb into the aquifer that we use for drinking.

— One mature tree can capture tens of thousands of gallons of water in a large rainstorm. Our native landscape isn’t a desert. In the olden days of our city, the early explorers wrote that they could move from one end of the San Fernando Valley to the other without leaving the shade of an oak tree. Now we have cut and removed the trees, and we have to replant trees and find other solutions.

— Billions of dollars are spent on solutions. Planting a tree and keeping our existing trees healthy is fairly cheap

Permeable surface

Impervious surfaces prevent rain from soaking into the ground and instead direct polluted runoff to the ocean. Create new spaces for water to seep through to your garden!!

– Cutting into concrete, breaking up pavement areas,

– Permeable concrete, grass Crete, softset flagstones, concrete pavers, etc. etc. Lots of ideas!!

– Softer materials for paths:  decomposed granite (DG) or pea gravel from sustainable sources.

TIP: Place gravel or DG where it has a buffer in-between it and hardscape so it stays in place.

Should I landscape now?

– Not on slopes

If you have a hill:

– Large Tarps – anchored in an emergency

Free Sandbags from LA County Fire Dept., check locations:

Use drought tolerant and native plants – limit conventional lawn – native lawns are best

  • Native and Drought Tolerant plant roots help the ground prepare for rain by acting as a sponge. They are designed to capture as much rain as possible!
  • SIDE BENEFIT: Native plants create biological diversity for backyard urban habitat without pesticides? and fertilizers. BIRDS — BEES — BUTTERFLIES — Beneficial Insects — Humans — FUN

– MULCH now thickly. This can help stop erosion and mulch is an essential part of your garden’s healthy soil.

– Place around the plants on top of the soil. Mulch IS KEY TO healthy soil. LEAVE the leaves!

– Use local free tree trimming mulch when you can – chop /shred tree trimmings from your own yard

– Make sure mulch cannot slide into drains and clog them.

Rainwater roof analysis:

1000 square feet of roof yield 623 gallons of water per inch of rain.

Calculation goes like this- Roof area (ft square) X rainfall (ft. ) X 7.48 gal/ft.+ total rainwater ( gal ).

For example, if you want to calculate how much rainwater in gallons falls on your 55-by-80-foot (4400-square-foot) lot in a normal year where rain fall averages 12 inches, the calculation would look like this;

4,400-square-foot catchment area X 1 foot of average rainfall X 7.48 gallons per cubic foot = 32,912 gallons of rain falling

on the site in an average year rain.  Source:

Plant Sources:


  • Deep Roots, Manhattan Beach, CA – Natives, etc.
  • Marina del Rey Nursery, MDL, CA – Drought tolerant and good veggie section, some natives

– Tree Of Life San Juan Capistrano, CA Natives – Theodore Payne Foundation, Sun Valley, CA Natives – call for hours (818) 768-1802 – Marina Del Rey Nursery, in MDR – Water wise plants and succulents

Books, classes and online sources:

California Native Plants for the Garden, Carol Bornstein, David Fross, Bart O’Brien, Cachuma Press, 2005 SNPS – California Native Plant Society online, Tree of Life website (above), Theodore Payne, MBBG online. Tree People

Mike Garcia,
Landscape Design Contractor  & Certified Pond Builder
Founder of Enviroscape LA  Landscaping

Phone: (310) 374-1199


PDF File: Preparing for EL NINO.pages