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Marin IJ Articles

Conserve Water, Our Liquid Gold

  • Dave Phelps
  • “Whiskey is for drinking but water is worth fighting over!”

    What Mark Twain said has been true since wells were dug and rivers dammed.   It will likely be a big problem in the near future.  The movie “Blue Gold” brought to our attention the recent and on-going acquisitions and consolidations of the world’s fresh water supplies by a small number of multi-national corporations and select private investors.  It also pointed towards price setting and profiteering similar to what we’ve started to see with oil, a similar, non-renewable, and very precious resource.  The web site www.PeakWater.org follows current events.

    Did you know that new landscapes are not allowed to use overhead irrigation within two feet of a sidewalk or driveway?  Or on areas less than 8 feet wide? Or on slopes exceeding 15%?  Did you know that those old impact sprinklers will not meet new irrigation efficiency requirements? These and other new rules are better ways to manage water in the landscape.

    By the time Governor Schwarzenegger declared drought in June of 2008 after the driest spring in 88 years, and sent SBX7-7 or the “20 by 2020” Water Conservation Plan to legislation, water conservation in California had already been in full swing.  Assembly bills AB 325, 2717, and 1881, the Water Efficient Landscape Ordinance, were being developed and implemented.  Finally, in 2010, after local water agencies were given a year to come up with a better plan to meet local conditions, the ordinance was approved and became effective as law in September of that year.

    The population of California is growing by roughly a person a minute with about half of urban water being used as irrigation, with and estimated 20 % of that being wasted. While many people in California understand these issues, few appreciate the brilliance, holistic nature and thoroughness of the current legislation. Many don't even know there are new rules.  A big part of the performance metrics of “20 by 2020” was to get all water users metered.  Now many areas in California whose water use was never even measured are seeing metered water bills and a future of dramatic rate increases.  Times have changed.

    The details of MMWD’s Ordinance 421 can be found on their web site at www.marinwater.org; look for the ”Landscape Plan Review Requirements: Users Guide” in the Conservation section. It should be noted that this ordinance, being a locally improved version of AB 1881, mandates a wonderful blend of education and outreach, conservation incentives, pollution prevention, addressing soil and the use of compost and mulch, as well as watering to a water budget set by the present, local climate.  It mandates weather-based controllers among other requirements and has raised the bar for the landscaping industry.  It has and will save us a lot of water.

    As with anything official these days, there are a few acronyms to get accustomed to.  The first is ETo; this is “reference evapotranspiration,” and is the combination of the evaporation and transpiration of water vapor from a cool season grass in a particular climate and day of the year.  The next are MAWA and ETWU; they are, respectively, the “maximum applied water allowance” and “estimated total water use”.  Simply put, they refer to how much water you are allowed, given your climate, and how much your landscape is estimated to use, given your landscape plan.  Together, these concepts allow for water to be applied as part of a water budget that is set as a percent of what it would take to keep a cool season grass healthy.

    Another important acronym is WUCOLS.  This is the “water use classification of landscape species” and gives a value of how different plants grown in different climate zones use differing amounts of water.  When plants are grouped onto irrigation valves or stations where the plants all have the same WUCOLS rating, that is called hydrozoning.  This allows for both very efficient programming of the irrigation system, but also allows designers free reign to use whatever plants they want—so long as when the square footage of the different hydrozones are added up, the total does not exceed the MAWA.  Brilliant.

    The Water Efficient Landscape Ordinance sets the standard for irrigation system efficiency by setting a minimum “distribution uniformity” that can be easily tested.  It minimizes the chance of invasive plants or fire prone plants being used, and even promotes the use of non-potable water such as reclaimed water, grey water and rainwater.  The ordinance also mandates a drainage plan be included so that water that falls on the site is encouraged to stay on site.  Turning our old drainage systems into infiltration systems helps to recharge our aquifers, protect our storm water systems, and ultimately, our creeks and bay.

    Many other requirements minimize the loss of water through leaks and breaks.  Separate irrigation or sub meters are also mandatory on most landscapes.  This allows for water use monitoring and is another tool to catch leaks quickly.

    Old water regulations used to tell you which days you could water your lawn.  These regulations tell you how much mulch you need to use and promote more appropriate plants.  The comprehensive and holistic approach that is climate driven is exactly what is needed to promote both the conservation of our most precious resources, as well as good land stewardship and respect for our climate and our environment.  While some complain about more rules, this legislation should be embraced.  Hopefully the days of seeing potable water going down the storm drain will be a thing of the past.  It’s about time.