Sustainable Water Management in the Megacity of Los Angeles

Mark Gold, D.Env.

Director of Water Scarcity Solutions at NRDC

Adjunct Professor at UCLA Institute of the Environment and Sustainability

mgold@nrdc.org

Major Water �Projects in California

• Federal – Central Valley Project (CVP)

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• State – State Water Project (SWP)

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• Local – Many other projects throughout state, including Colorado River system, Hetch Hetchy, EBMUD, Owens Valley

Source: Water Environment Foundation

Achieving Integrated Water Resources Management

• Water Quality Standards Compliance
• Maximize Stormwater Capture
• Maximize Flood Control
• Provide additional open space and habitat benefits
• Maximize Water Recycling
• Maximize Water Conservation
• Sustainable Funding for programs and O+M

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Example - City of Los Angeles – One Water Plan

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INTEGRATED WATER MANAGEMENT

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State Water Bond Measures�General obligation bonds (State pays them back through general fund).

• Propositions 13, 40, 50, 84 and 1
• Prop 13 – 2000 - 65% approval - $2 Billion
• Prop 40 – March 2002 – 57% approval - $2.6 Billion
• Prop 50 – November 2002 – 55% approval - $3.4 Billion
• Prop 84 – 2006 – 54% approval - $5.4 Billion
• Prop 1 -– 67% approval - $7.5 Billion
• Prop 68 – June, 2018 - $1.6B for water.

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• Can only pay for capital costs. Not for Operations and maintenance or programs.
• 2020-2022 - $190B budget surplus. Over $1B in nature based solution funds. More for stormwater infiltration as well. Some funding in jeoparfy this year.

Proposition O

• $500 million bond measure for Los Angeles
• Passed with over 76% of the vote in 2004
• Primary focus – To enable L.A. to comply with the County stormwater permit and local TMDLs by reducing runoff pollution
• Secondary – multi-use benefits including water supply, flood control, recreation and habitat
• Bond measures only pay for capital costs

Green Streets and LID

Proposition O – Machado Lake and Wilmington Drain Nature Based Solution project

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Vegetative Swale

Aeration System

Measure W – Safe Clean Water Program

• Countywide measure - $83/household annually. $280 M/yr
• 9 watershed jurisdictions
• Approximately 40% for the cities, 50% for watershed groups. 10% for monitoring and administration.
• 2018 – LA County Measure W. Resiliency approach. Passed with 69.5% of the vote!!! Not just stormwater for water quality, but IWM. Safe, Clean Water Program. Goal of $328M a year in perpetuity. Parcel tax.
• Now in implementation phase. Most of the focus has been on municipal stormwater permit compliance within each watershed. Not much on regional multi-benefit projects. No bonding.

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Water Recycling

• Tertiary Treatment (filtration and disinfection – Title 22 – bacteria 2.2 total coliforms cfu per 100 ml and turbidity not to exceed 10 NTU (nephlometric turbidity units))
• Advanced treatment – MF-RO, nitrification/denitrification (NDN), UV-peroxide – NDMA removal
• Non-potable uses – irrigation and industry
• Indirect Potable Reuse – mixing – groundwater or reservoirs – purple pipe
• Direct Potable Reuse – use existing infrastructure. California – regulations in 2024.

West Basin – Ed Little Water Recycling Plant

Desalination – pros and cons

• Pros – reliable source of water supply. Very important in areas highly vulnerable to drought.

At small scale, can be done with greatly reduced environmental impacts – subsurface intakes, colocation of brine discharge, state of the art diffusers. Wonderful technology for brackish groundwater and wastewater recycling.

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• Cons – Very expensive compared to local (stormwater capture, groundwater) and imported water supplies. Also, considerably more expensive than wastewater recycling.

Ocean intakes detrimental to marine life – impingement and entrainment. Brine can be toxic to marine life, especially undiluted. Difficult to develop adequate mitigation plans for projects that cause ongoing harm over long time periods (30-50 years).

Water Conservation: Turf Replacement – A $350 Million+ Social Engineering Conservation Experiment in Southern California

UCLA Grand Challenge: �Sustainable LA

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GOAL: 100% renewable energy, 100% locally sourced water, & enhanced ecosystem health by 2050

Sustainable LA Water Research Objectives

• Objective 1: Maximize Local Water Supplies
• Quantify and characterize existing water supplies
• Expand available water supplies
• Encourage adoption of local water sources
• Enhance water supply resilience and sustainability
• Objective 2: Reduce Water Consumption
• Objective 3: Improve Local Water Resource Management
• Improve water management infrastructure and technology
• Improve water governance and policy

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Sources of Water for LA City

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Data source: https://data.lacity.org/A-Livable-and-Sustainable-City/LADWP-Water-Supply-in-Acre-Feet/qyvz-diiw

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In 2019-2020 – LA Aqueduct = 48%, MWD = 41%, Recycled water = 2% and GW = 9%. Less than the local water figure of 15% often cited.

Also, annual water use in the city is less than 500K AFY.

L.A. Sustainable Water Supply Research Approach

• UCLA/CSM team (Mika, Hogue, Pincetl, Gallo, Porse, Reed, Edgley, Gold) summarized existing City of LA water plans – DWP integrated water plan, IRP, Water Quality Compliance Master Plan, County IRWMP, TMDL Compliance Plans, pertinent salt and nutrient management plans, etc..
• Use of watershed stormwater flow/land use pollutant concentration models to determine appropriate suite of BMPs to attain receiving water quality standards.
• Ballona Creek, Dominguez Channel and Los Angeles River watersheds
• Estimated dry and wet weather volumes of stormwater infiltrated or captured with various alternatives

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Ballona Creek and Dominguez Channel Watersheds – and adjacent groundwater basins

• Water Quality Standards
• Capturing runoff from sig. portion of drainage area & putting thru BMPs approaches compliance
• Potential Local Water Supply
• Est. recharge in our scenarios 20,000 to 60,000 afy
• Fewer or different BMPs = less recharge potential
• How much becomes water supply?

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Low Impact Development Effects

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The City of LA LID Ordinance, which became effective in 2012, requires all development

and redevelopment projects that create, add, or replace 500 ft² or more of impervious

area to capture the three-quarter inch rain event for infiltration or reuse on site.

Looked at impacts of implementing across whole watershed. These numbers

could be greatly expanded by expanding ordinance to include resale, and by

establishing partnerships with NGOs to increase voluntary implementation.

L.A. Sustainable Water Supply Approach

• Watershed approach to maximizing water recycling – Dominguez Channel and Terminal Island Treatment Plant. L.A. River and Tillman and Glendale. Ballona area and Hyperion.
• Use of groundwater maps to determine aquifer capacity, recharge potential and estimate maximum sustainable yield.
• Determine flood control, open space/recreation and habitat benefits of various alternatives
• Cost/benefit alternatives of various alternatives

BMPs reduce LA River flows

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CFS: cubic feet per second, MGD: million gallons per day, AFY acre-feet per year

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Modeled median seasonal flows at Wardlow Gage with and without BMPs.

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Flow reduction after BMP implementation of 53 to 71%

Energy requirements can vary within treatments & agencies

https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=4927b55bc77760db738b958720721852f66338bf

GHG emissions 2014 & 2035

https://escholarship.org/uc/sustainable_la_rw

City of Los Angeles Water Use Scenarios (Is Self Sufficiency Possible?

• Assessed three water portfolios
• 2013-2014 drought year,
• City-based, building on Urban Water Management Plan and pLAn (sustainable city plan) goals
• Maximize local water scenario
• 98 gpcd, projected population of 4.35 million people yields demand of 479.1K afy
• Eliminate imported water (125.6K afy) and Increase SW capture or water recycling by 33.2K afy and decrease consumption to 75 gpcd (365.6K afy)= self sufficiency!!

UCLA Sustainable LA Water Project: Los Angeles Citywide Overview 2017 – Mika, K, , E. Gallo, E. Porse, T. Hogue, S. Pincetl, and M. Gold.

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City of LA Approach:�Mayor Garcetti’s Green New Deal Goal = 70% local water by 2035

• Transformation of Hyperion Treatment Plant to an Advanced Water Recycling Plant. Operation Next. Up to 240K AFY. 2035 goal of 100% beneficial reuse of wastewater.
• LA County Sanitation Districts and MWD are doing the same at the Carson wastewater Treatment Plant – Pure water Southern California would serve LA County and the region. Up to 170K AFY.
• Pump and treat of contaminated groundwater in the eastern San Fernando Valley – up to 85K AFY.
• Stormwater capture – infiltration in the San Fernando Valley. Tujunga spreading grounds now 16K AFY. Less elsewhere, but Measure W makes it possible. 2035 goal of 150K AFY SW captured.
• Need for even greater conservation. Outdoor irrigation and washing machines are great opportunities. Water neutrality ordinance possibility. Current water use = about 105 gpcd (total water use/population.

City of Santa Monica Approach to Water Self Sufficiency

• SM will achieve near self sufficiency (over 90%) by the end of 2023. They imported all of their water in the late 1990s due to groundwater contamination.
• Santa Monica Urban Runoff Reuse Facility (stormwater reuse).
• Enhanced water conservation. Water neutrality ordinance. Ex: New development can not increase water demand for a given parcel. Also, advanced metering infrastructure for leak prevention and assessment of conservation efforts.
• Sustainable Groundwater Management Plan – local permitting for all new uses.
• Expand groundwater pump and treat efforts.
• Sustainable Water Infrastructure Project – sewer mining and wastewater recycling, stormwater storage and increased treatment capacity. Just completed!!

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