OC Watersheds Central OC Watershed Management Area
The COC WMA encompasses the entire Newport Bay Watershed and the northern portion
of the adjacent Newport Coast Watershed that lies within the jurisdiction of the
Santa Ana Regional Water Board. This region includes three Critical Coastal Areas
(CCAs), two Areas of Special Biological Significance(ASBS), nine miles of coastline,
and a functioning estuary designated as a State Ecological Reserve. The planning
area, located approximately 40 miles south of Los Angeles and 70 miles north of
San Diego, is highly urbanized, with a current estimated population of 705,000 residents
expected to reach 787,000 by 2030. There are currently five Total Maximum Daily
Loads (TMDLs) in the watershed, with more pending. The entire area within the WMA
drains to the CCAs and ASBS, which means conditions in the WMA significantly impact
the coastal ecosystem. Water supplies are diverse including groundwater, desalted
groundwater, recycled water, and imported water.
The COC WMA encompasses an area of approximately 154 square miles with overland
flows draining toward the Pacific Coast into Newport Bay. Major cities within the
watershed include Irvine, Newport Beach, Tustin, and portions of Costa Mesa, Laguna
Hills, Laguna Woods, Lake Forest, Orange, and Santa Ana. The principal watercourse
of the Newport Bay watershed is San Diego Creek, with a drainage area that covers
approximately 122 square miles of the Newport Bay Watershed. The main tributary
to San Diego Creek is Peters Canyon Wash; smaller tributaries include Serrano Creek,
Borrego Canyon Wash, Agua Chinon Wash, Bee Canyon Wash, Sand Canyon Wash, and Bonita
Canyon Creek. The Santa Ana-Delhi Channel subwatershed covers approximately 17 square
miles. The channel is an artificial drainage that conveys water from the city of
Santa Ana into Upper Newport Bay. The San Diego Creek and Santa Ana-Delhi Channel
are the major inputs into Upper Newport Bay. The San Diego Creek Watershed generates
roughly 80-percent and the Santa Ana Delhi Channel generates about 15-percent of
the discharges into Upper Newport Bay, with the balance from other small tributaries.
Central OC Integrated Regional Water Management Plan (COC IRWMP) Efforts
The County of Orange led the first Integrated Regional Water Management effort for
the COC WMA which culminated in the production of the Phase I Central Orange County
IRWM Plan (IRWMP). The Phase I IRWMP was undertaken to provide a bridge between
existing and developing watershed planning efforts, allowing for more effective
collaboration and greater opportunity to leverage agency resources across jurisdictions.
It had a strong emphasis on the sensitive coastal resources, Areas of Special Biological
Significance and Critical Coastal Areas (CCAs) that are located within the Central
Orange County WMA. The Phase I IRWMP was also developed to meet Proposition 50 priorities.
The Phase I IRWMP was integral to subsequent watershed planning efforts led by the
City of Newport Beach. In January 2006, the City of Newport Beach was awarded a
planning grant by the State Water Board through Proposition 40 for preparation of
an Integrated Coastal Watershed Management Plan (ICWMP) to address ASBS and CCA
issues along Newport Coast. Much of the material in the ICWMP was used during the
preparation of the Phase I Central Orange County IRWMP.
In May 2006, the City of Newport Beach was awarded a planning grant by the California
Department of Water Resources through Proposition 50 for the preparation of an IRWMP
for the Newport Bay Watershed including data collection, analysis, and formulation
of policy and guidelines. Though building on some new elements, this Phase II effort
incorporated the Phase I Central Orange County IRWMP. The County of Orange is currently
leading an effort to complete a third phase of the Central Orange County IRWMP.
Phase III will be a compilation and revision of the first two IRWMPs; the information
contained in the Phase I and Phase II plans will form the basis of the Phase III
plan.
In addition to the COC IRWMP efforts, stakeholders will participate in applying
for Proposition 84 grant funding with other Santa Ana River Watershed funding area
partners with the Santa Ana Watershed Project Authority (SAWPA.
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