Posts tagged California drought

Photo by Michael Chen (CC BY-NC-ND 2.0)

Photo by Michael Chen (CC BY-NC-ND 2.0)

“In the last 10 water years, eight have been dry, one wet, one average. Although this year may end up being wet, we can’t say whether it’s just going to be one wet year in another string of dry ones.” – Nancy Vogel, spokeswoman for the Natural Resources Agency.

The observation above seem to represent a bit of a Debbie Downer moment in light of the general relief Californians are celebrating after enduring years of warm and dry winters, inundated by a weekly parade of significant rain and snowfall up and down the Golden State. But indeed, Vogel’s words aren’t intended to “dampen” spirits,  but to remind us all of the dangers of complacency, mistaking short term changes in weather versus the long term patterns of climate.


Xeriscape garden; Creative Commons photo: Jeremy Levine

Xeriscape garden; Creative Commons photo: Jeremy Levine

Want to do the environmentally responsible thing and install a drought tolerant landscape? The first thing you could do is rip out your lawn and install trees, shrubs and ground cover. Generally, this act alone will save you about a third of your monthly water use. The caveat being is that you must not water your newly planted trees, shrubs, and groundcover the same amount as your newly removed lawn or you will not save any water at all.

However, you must give your new landscape some water to keep it alive and healthy. How much? Therein lies the rub. I don’t know. I have over 25 years experience as a landscape architect and I’m regarded as one of the many experts in exterior water conservation in California, yet I cannot guarantee the water usage of any landscape I design for you.

Why? Because no one really knows.

How can this be? Because the mixed-bed landscape ecosystems – trees, shrubs, and ground cover – from around the world are very complex, and there’s never been any funded field research to determine averages and amounts. The closest thing we have is a study called WUCOLS.

In the early ’90s, the University of California Cooperative Extension and the California Department of Water Resources teamed to create what eventually became the definitive reference for plant water usage in California: the Water Use Classification of Landscape Species study – or WUCOLS for short.

Autumn planting at the UC Davis Arboretum and Public Garden. Creative Commons photo: Katie Hetrick

Autumn planting at the UC Davis Arboretum and Public Garden. Creative Commons photo: Katie Hetrick

Climate and growing regions, chart from the WUCOLS IV User Manual

Climate and growing regions, chart from the WUCOLS IV User Manual

WUCOLS is comprised of two parts: it’s a formula for calculating plant water use in California with a fairly comprehensive list, rating plants from “very low” to “high” water requirements. In the last 25 years since it was published, WUCOLS has been updated 4 times. The list has become an integral part of the State’s landscape water conservation efforts, as well as an integral part of major sustainable scoring systems like LEED, SITES, and the Living Building Challenge. The study’s authors never imagined their creation would be used to define plant water conservation not only in California, but around the world.

WUCOLS was originally meant to be just a guide. As such, the study is beginning to show signs of not being able to hold up to the scrutiny necessary to be the basis for water conservation laws in the State and around the Country.

This is not to say that the original study was not valid or rigorous. With a limited budget, the authors worked with what they had. They convened with experts from five different bio-regions around the state to evaluate nursery-available plants. They also used existing field studies wherever possible to help guide their evaluations.

Still, most of the plants on the WUCOLS list are rated based on anecdotal evidence rather than true field research data. This has become a problem as most of the water districts and municipalities write into their ordinances requirements that only plants rated by WUCOLS as “very low” and “low” can be planted within their jurisdiction.

In an attempt to finally add a more rigorous data to WUCOLS, the UC Cooperative Extension and the Department of Water Resources has been conducting a survey of 1,500 ornamental landscape sites around the state. They will announce their findings at a meeting on December 6th at the Metropolitan Water District Headquarters, adjacent to LA Union Station.

If we are serious about wanting to use our water resources responsibly while still maintaining the beauty of our state, we must be able to give landowners and designers the tools to be able to make the best decisions benefitting landscapes. The only way to accomplish this lofty goal is to provide the people of California with vetted research that generates hard and reliable data.

WUCOLS will now be moving forward to becoming that tool. AHBE Landscape Architects is proud to be the sponsor for this event. Please look for more information about this event in this space, and through announcements with our partner organizations: USGBC, Living Building Challenge, and ASLA.

"Lake Recession" Lake Tahoe, Nevada May 17, 2015 Photo by Calvin Abe

“Lake Recession” – Lake Tahoe, NevadaMay 17, 2015.  Photo by Calvin Abe.

With El Niño now gone, Californians now move onto the strong possibility of a La Niña – “the positive phase of the El Niño Southern Oscillation and is associated with cooler than average sea surface temperatures in the central and eastern tropical Pacific Ocean” – a weather system which will likely exacerbate drought conditions as temperatures climb and humidity drops across the state. Let us hope the Sierra Nevada snowpack can hold out as long as possible…


Lake Tahoe. Photo by Calvin Abe.


Lake Tahoe. Photo by Calvin Abe.

Buffalo Grass at Monrovia project

“Which turf substitute – beside gravel or other paving – provides a green ground cover that people can sit upon, tolerates moderate foot traffic, and requires less water?”

As a practicing landscape architect, this is the inquiry I’m most frequently asked by friends, clients, and other design colleagues. I tell them one alternative is a California native turf grass species known as Buffalo Grass (Bouteloua dactyloides), a species of native grass bred by UC researchers at Davis and Riverside in 2003, the very same that can be seen planted in a fire lane at the AHBE project Monrovia Gold Line Station [shown above].

According to one vendor’s website, one of the varieties of this plant developed for the precipitation scarce and hot temperatures of Southern California and Arizona, UC Verde, can use up to 75% less water than a traditional fescue lawn, grows to a maximum height of 6”, and can be mowed approximately every month for a more manicured look (or not at all for more of a meadow appearance).

UC Verde Buffalograss In Santa Monica, CA. Creative Commons photo by Tom Engelman.

UC Verde Buffalograss in Santa Monica, CA. Creative Commons photo by Tom Engelman.

Buffalo Grass is a perennial grass that spreads by stolons, or running roots. One notable physical trait characterizing UC Verde grass is that it goes dormant in the winter months with less sunlight and cooler temperatures. This process slows both vertical and horizontal growth, and the grass changes from green to tan or straw during this dormant phase. Specific recommendations for addressing this color change on the website state:

The duration of this color change may be reduced by combining a late fall fertilization with mowing UC Verde to about 1 inch height when you begin to see the change in color. This will allow the sun to keep the soil warmer reducing these changes. In the late winter, repeat the fertilization to encourage the grass to begin growing again. If you want to have your lawn totally green during the winter months, an organic based turf colorant can be applied.

But is the constant green color so important from an aesthetic perspective? Brown turf grass can certainly indicate a dead or dying traditional lawn, but what if it’s a natural part of the life cycle of the Buffalo Grass, a plant that will return to its green and growing cycle once again when more hours of light become available? Straw, cream, golden, decomposed granite, and blue-grays of agaves and cactus are all colors too. I believe as concerned occupants of this region acclimating to the new norm – drought – we need to embrace these colors as part of our long-term landscape palette.

Click image for full size image.

Click image for full size image.

If you haven’t noticed, this month at AHBE Lab has been dedicated to water conservation and sustainability – ranging from posts about city and state infrastructure, to those revolving around personal household habits, to offering “how-to” instructions for saving and reusing water. We even brought a little levity to what is a pretty serious challenge. I thought I’d chime in with a diagram illustrating how collecting and using water at home can be utilized for creating a sustainable ecosystem at the residential level.

There are essentially 2 parts to the water collection system shown above: 1. the exterior rain water collection and, 2. the interior grey water system (kitchen, bathroom and laundry). Both systems can be as extensive (adding a new grey water piping system) or as simple (bucketing out clean shower water) as you want to make it. Three steps are required for both interior and exterior systems:

  • Monitoring current water use
  • Developing the infrastructure to use water efficiently
  • Create and implement these new integrated systems into daily habits
Designers everywhere are looking to add water sustainability features into communities, including grey water systems, like this one for Eco Village.

Designers everywhere are looking to add water sustainability features into communities, including grey water systems, like this one for Eco Village.

Our plans above recommend integrating exterior features like permeable paving, rain barrels, and irrigation to maximize water use when availability is limited while also aiding in replenishing local aquifers. Inside, our proposed home is equipped with a grey water system, partnered with biodegradable laundry detergents and soaps which won’t harm soil, alongside buckets strategically placed to capture water at drains and sinks to be reused for gardening or landscaping purposes.

Though these propositions may seem difficult to implement, they do have recent precedent. Other countries like Australia and Israel have already integrated these solutions on a city, state, and country wide basis. There is research being done about the Los Angeles River and urban drainage which may help us use the water normally washed away into the ocean. No matter how small or large, bringing these different ideas to the table can help alleviate many of the water related issues we’re facing as a city and as a state.