May 29, 2015
To: California Department of Water Resources
From: Global Green USA
Subject: Comments on 2009 MWELO for Integration Into 2015 Revision
Global Green USA is a 501(c)3 non-profit organization dedicated to identifying smart solutions to climate change through catalytic projects, research, and advocacy. In particular, we support water, energy, and waste efficiency in urban areas through these activities.
The Model Water Efficient Landscape Ordinance came to our attention as an excellent, if underutilized, tool for encouraging water efficiency in urban and suburban areas, as well as helping to support the purchase and use of post-consumer materials (specifically compost made from food scraps and yard wastes) to encourages oil health as well as water efficiency.
Our comments concerning the document are based on the following assumptions:
- Water use reduction and soil health are top priorities for the DWR, and the State of California.
- oil organic matter is of paramount importance when it comes to water retention. For every 1% organic matter content, the soil can hold 16,500 gallons of plant available water per acre of soil down to one depth - about 1.5 quarts of water per cubic foot of soil for each percent of organic matter.1
- Compost has attributes that are unique among “mulches” – because it is very permeable, it is superior to inorganic materials as well as more compacted organic materials such as wood chips in terms of achieving water retention and soil health.2
- Compost is appropriate for use in nearly all ecosystems in California, and is already the preferred soil amendment and erosion control method used statewide by CalTrans. It supports native plant species and reduces irrigation needs as well as erosion and runoff.3
- There is abundant supply of compost in the State of California, but that supply is also poised to grow as more cities divert food scraps from landfill in accordance with AB 341. Increased use of compost containing post-consumer food scraps and yard waste for landscaping projects will help to support achieving the Statewide goal of 75% diversion, and reduce greenhouse gas emissions.4
§ 491. (pp) – Definition of “mulch.” We recommend that this definition indicate that organic materials should take precedence, where ecologically possible, over inorganic materials, and that composted organic material, in particular that which includes post- consumer material, should take precedence over more compacted products such as bark, wood chips, etc.
§ 492.6 Soil Management Report – Section (2) We recommend that the project applicant be required to meet a minimum soil organic matter content of 5% unless there is a compelling ecological reason why this would be harmful.
§ 492.6 Landscape Design Plan – Section 3(A)We recommend that the “Mulch and Amendments” section indicate that organic materials should take precedence, where ecologically possible, over inorganic materials, and that composted organic material, in particular that which includes post-consumer material, should take precedence over more compacted products such as bark, wood chips, etc.
§ 492.6 Landscape Design Plan – Section 10
We recommend that the application of composted organic material, in particular that which includes post-consumer material, be listed as a best management practice for storm water control.
§ 492.4 Water Efficient Landscape Worksheet
Global Green's experience with certifying multiple LEED for Homes and LEED for Neighborhood Development projects across the State of California suggests that nearly all competently designed landscapes that use climatically appropriate plantings and irrigation strategies achieve water reductions well above 50% of baseline. This trend suggests that the State's water usage baseline is likely too weak and should be made more stringent, in turn yielding increased landscape irrigation savings. We suggest a re-examination and possible reduction of the values assigned to the ETAF and the Additional Water Allowance for SLA.
Examples of Other Ordinances That Promote Water Retention and Soil Health
Denver, Colorado Water Service:
“Before a newly constructed premise may be landscaped, property owners must amend their soil with compost so the soil more efficiently retains water. This rule applies to all new residential, commercial, government and industrial properties within Denver Water’s service area.”
“14.02.4 Soil Amendment for Irrigation of Turf at Newly Licensed Premises. Proof of proper soil preparation is required before installation of plant material. Penalties may apply if soil amendment is not completed prior to the installation of plant material. Proper soil amendment is the equivalent of adding approved compost at a rate of four cubic yards per 1,000 square feet of permeable area, incorporated (roto tilled) to a depth of six inches.” http://www.denverwater.org/OperatingRules/OperRules14/
Chapter 14, Article VI, Section 1(c)(12-13) address the mandatory use of compost for both new residential and non-residential landscapes.
“All new landscapes are required to have a minimum 6 inches of soil depth in areas planted with turfgrass. The six inch soil depth will consist of 75 percent soil blend with 25 percent compost.”
http://www .leandertx.gov/sites/default/files/fileattachments/Planning/page/ 338/waterconservationordinan ce03.15.2007.pdf
We hope that these comments and resources are useful to you as you revise the Model Water Efficient Landscape Ordinance for the State of California. Please feel free to reach out to us if you have any further questions.
Laura “Lily” Kelly
Senior Program Associate
San Francisco Office and Coalition for Resource Recovery
Global Green USA
645 Harrison Street #200
San Francisco, CA 94107
1 Sullivan, Preston "Drought Resistant Soil" (2002) Appropriate Technology Transfer for Rural Areas. https://attra.ncat.org/attra- pub/summaries/summary.php?pub=118
2Shaw, David A., Pittenger, Dennis R., McMaster, Mark “Water Retention and Evaporative Properties of Landscape Mulches” Proc. 26th Annl. Irrigation Show, Phoenix, AZ, Nov. 6-8, 2005. Irrigation Assoc., Falls Church, VA. http://ucanr.edu/sites/UrbanHort/files/80238.pdf
3 California Department of Transportation "Erosion Control Toolbox - Compost"
4 CalRecycle "Climate Change and Solid Waste Management - Organics" http://www.calrecycle.ca.gov/Climate/Organics/