The 2015 update to California’s Model Water Efficient Landscape Ordinance (MWELO) applies to all landscape projects requiring a building or landscape permit, plan check or design review for new construction with an aggregate landscape area equal to or greater than 500 sq. ft. and to rehabilitated landscape projects with an aggregate landscape area equal to or greater than 2,500 sq. ft. The reach is purposely broad to encourage watershed-sensitive landscapes that deploy the state’s limited water resources wisely. According to the California Department of Water Resources (CADWR), about half of the state’s urban water is used for landscape irrigation.
CA’s MWELO is the kind of effort likely to take hold in other states that face futures of limited water resources.
CADWR has begun the process to update MWELO by 2020 as mandated by law. Their first stakeholder listening session was held in Pomona on January 30 in conjunction with the California Association of Nurseries and Garden Centers (CANGC).
While MWELO doesn’t restrict the type of plants that may be used in the landscape, it clearly states that the entire landscape must meet the Maximum Applied Water Allowance (MAWA) for the space. Language pushes local, native and adapted plant species while being cognizant of local tree ordinances and fire potential. MWELO mandates the use of compost, mulch and use of irrigation hydrozones. Over time as MWELO’s full effects play out, it will drastically affect the types of plants that California’s nursery and greenhouse growers produce and that designers/landscapers/landscape architects specify. Water hogs will not be allowed.
The 2015 update made several important changes from the 2010 version: Mandating that landscape projects more than 2,500 sq. ft. have to use a Performance Compliance Approach and must include a soil management report, landscape design plan, irrigation design plan and a grading design plan. It also provides that new and rehabilitated landscapes less than 2,500 sq. ft. are eligible for streamlined Prescriptive Compliance Approach (a checklist of standards) that are documented in a Landscape Plan.
Comments from industry stakeholders at the January 30 meeting tended to pragmatic, encouraging CADWR to keep it simple so that implementation by both industry and the jurisdiction (city, county) will work. Employees that may be charged with the responsibility to enforce rules do not know how to identify specific plants. For that matter, most homeowners or business owners likewise don’t know plant material.
Discussion about Evapotranspiration (ETo) calculations (see Appendix A) centered on the need to develop precise calculations for landscapes. The need to better understand the science of complex plant communities in managed landscapes arose a number of times during conversations. Focusing on a watershed approach encourages ecosystems approaches to the landscape rather than rigid prescriptive mandates.
Current ETo calculations originated in the agricultural industry. Concerns were also expressed about how outdoor landscape and water use budgets would be meshed with MWELO at the city/water agency level, especially regarding pushing existing landscapes (exempted from MWELO) to perform at levels that enable the city/water agency to meet their numbers.
The very real need to overlay MWELO to the state’s Low Impact Development ordinances for stormwater management was also pervasive. Which plants are able to handle water inundation and drought? It’s a small list.
Pushing construction project contractors to become educated or even certified will help take pressure off of overly simple project cost concerns and place the emphasis on project outcome/results. Engineers were also targeted in this regard.
At one point, ideas of expanding MWELO to include energy and carbon footprint were floated. Others suggested pulling recycled water out of use equations to encourage more use since the state is underutilizing “purple pipe” water.
MWELO references Water Use Classification of Landscape Services (WUCOLS) , a database developed by horticulture and landscape professionals who served on committees that represented various regions in the state. A recent recommendation to the state legislature includes mandatory labeling of plants by their water use.
- Achieving a New Normal in California Landscapes, a watershed-based approach to urban landscapes by the California Urban Water Conservation Council.
- Plantopolis: Drought Tolerant Landscapes
- Climate-Appropriate, Drought Tolerant, or Native Plant Lists as Advertised by California Agencies and Organizations (Draft)
- Categorical Benefits: The of Landscapes
- The Watershed Approach to Landscaping
February 15, 2017 NewTerrain