Los Angeles River environmental flows: Balancing water reuse and ecological support goals in an effluent dominated, urban river - USA

Description

Location

Sketch

Location: Lat:34.01609143076131 Long: -118.2214281905257

Information about lithology/geochemistry:

The LA River watershed is in Los Angeles County, CA, USA and is 2,160 km2. Approximately 32% of the watershed is impervious and dominant land uses include residential, open space, and commercial. The upper tributaries of the watershed are in steeply sloped mountains where much of the landscape is forested and unaltered. The lower portions of the watershed, which drain to the mainstem and other tributaries, are highly urbanized on quaternary young alluvial fan deposits, marine and nonmarine sedimentary rocks. The lower portion of the watershed is highly altered for water supply and flood control; most of the mainstem of the river is channelized except for two key soft-bottom reaches, Glendale Narrows and Sepulveda Basin. The majority of non-storm flows in the lower watershed derive from discharge of treated effluent from three water reclamation plants (WRPs).

Main Description

Conserve Ecohydrological processes in natural ecosystem

NO

Enhance ecohydrological processes in novel ecosystem

YES

Apply complementary Ecohydrological processes in high impacted system

YES

This table presents the different categories of ecosystem services that ecosystem can provide, divided in:

Provisioning services
Regulating services
Habitat or supporting services
Cultural Services

Provisioning Services are ecosystem services that describe the material or energy outputs from ecosystems. They include food, water and other resources.

Regulating Services are the services that ecosystems provide by acting as regulators eg. regulating the quality of air and soil or by providing flood and disease control.

Ecosystem services "that are necessary for the production of all other ecosystem services". These include services such as nutrient recycling, primary production and soil formation.

Cultural Services corresponds nonmaterial benefits people obtain from ecosystems through spiritual enrichment, cognitive development, reflection, recreation, and aesthetic experiences.

EH Principles

Quantification of the hydrological processes at catchment scale and mapping the impacts

Ecological engineering (integration, dual regulation and biotechnologies in catchment scale for enhancement of ecological potential)

ECOHYDROLOGY ENGINEERING SOLUTIONS

Watershed management plans have established conservative and aggressive plans to implement low impact design and best management practices (BMPs) to capture and treat stormwater in the Los Angeles River watershed. Many BMPs have already been constructed with the focus on water quality treatment and groundwater recharge. The effect of these BMPs on instream habitats and species was evaluated using the developed flow-ecology curves

Ecohydrological Infrastructure

Treated wastewater effluent is discharged directly into the Los Angeles River from three water reclamation plants (WRPs; also called wastewater treatment plants) and is the primary source of streamflow during the dry season.

Hydrological Flow

Major Issues

Which: Flow alteration is a major concern in the LA River watershed and future flow management actions are expected to change streamflow conditions further.

Social ecohydrological system

EH Objectives

Water:

Biodiversity

Services

Resilience

Cultural Heritage

EH Methodology

Catchment Ecohydrological sub-system

Objectives

Culture, Previous studies have documented that numerous outdoor recreational activities occur on the LA River. In various reaches of the LA River, depending on flows and condition of the river bed and bank, recreational activities include kayaking, wading, fishing, horseback riding etc.

Education, The LA River provides many educational opportunities to the local primary, middle, and high schools, as well as universities. For example, in Compton, CA, a disadvantaged community that has limited access to green space and nature, local schools have the opportunity to sample water and evaluate conditions of Compton Creek, a major tributary to the LA River.

Law, The LA River is protected via the Federal Clean Water Act, the State Porter Cologne Water Quality Act, and the State Fish and Game Code.

Policy, Through California Water Code Section 1211 (1211 wastewater change petitions), all wastewater treatment plants that intend to recycle some or all of their effluent must submit a petition illustrating that proposed changes will not adversely affect beneficial uses of receiving waters and ultimately gain approval from the State Water Board.

Governance, The LA River is managed collectively by the County of Los Angeles and the US Army Corps of Engineers for selected reaches. The Cities of Los Angeles, Burbank, and Glendale manage treated effluent discharge into the river. Discharges are regulated via permits from the Regional Water Quality Control Board.

Stakeholders

University of California, Los Angeles, Colorado School of Mines, University of Portland, University of California Extension, California State University Chico

California Department of Fish and Wildlife, US Fish and Wildlife Service, State Water Resources Control Board –Division of Water Quality, State Water Resources Control Board – Division of Water Rights, Long Beach Water Department, LA Mayor – LA River Works, City of Los Angeles, RCD Santa Monica Mountains, Santa Monica Mountains Conservancy, LA Regional Water Quality Control Board, Watershed Conservation Authority, Mountains Recreation Conservation Authority, US Bureau of Reclamation, Upper LA River Water Master, LA Department of Water and Power, LA County Public Works, LA County Sanitation District, Southern California Coastal Water Research Project, Calleguas Municipal Water District, Rivers and Mountains Conservancy, Burbank Water and Power, City of Los Angeles, Bureau of Sanitation, Glendale Water & Power, City of Los Angeles LA Sanitation and Environment, LA County Flood Control District, Glendale Water & Power, US National Center for Atmospheric Research.

Council for Watershed Health, The Nature Conservancy, Los Angeles Waterkeeper, The River Project, Heal the Bay, Friends of the Los Angeles River

Environmental Science Association Consultants, Stillwater Sciences, MBC Aquatics, Studio-MLA, Brown and Caldwell

The Environmental Flows Workgroup – subcommittee of the California Water Quality Monitoring Council, the California Environmental Flows Framework Technical Team, the Southern California Stormwater Monitoring Coalition

Catchment Sociological sub-system

Activities

Key ecohydrology related activities in the LA River demosite operate on three key dimensions:

1) Data and information collection: this includes monitoring of physical and biological conditions in the river, collection of empirical data to fill key data gaps (i.e., continuous stream temperature data and habitat surveys), and identifying key limiting factors in addition to changes in streamflow that may affect ecology.

2) Knowledge: development of conceptual and computation models that describe key physical and biological processes and future management scenarios being contemplated. These models serve as important tools that can form the basis for flow management and stream restoration decisions in the future that are grounded in science and integrate key processes.

3) Wisdom: a primary goal of this study is to provide user-friendly management tools that take the complicated models and outputs and develop actionable and clear recommendations based on a suite of user-defined priorities. This study included quarterly stakeholder and technical advisory group meetings including scoping meetings from the project inception and meetings focused on the technical approach to the final data products produced. The goal is to ensure that the tools produced are sound and will ultimately be useful for the end users (i.e., stakeholder community, regulators, and managers). Providing useful management tools will help create more rapid implementation.