Watershed Management Areas

*** Please visit www.northocirwm.org for the most up-to-date information on Integrated Regional Water Management (IRWM) efforts in North and Central Orange County. ***

*** Please visit www.southocirwm.org for the most up-to-date information on Integrated Regional Water Management (IRWM) efforts in South Orange County. ***

Integrated Regional Water Management Plans (IRWM Plans)

IRWM Plans for the North, Central, and South Watershed Management Areas (WMAs) have been updated to meet State standards. Goals and solutions specific to each WMA are formulated through consensus with participating stakeholders. Likewise, a custom slate of projects and programs is developed to address the water resource needs of the WMAs. In the future the ability to fund water resource projects will be challenging. With the collaborative process, Orange County continues to be a leader in meeting those challenges. Watershed Management Areas and Integrated Regional Water Management Plans are key tools to accessing federal, state and local grant opportunities to help offset the investment necessary to sustain the water resource needs of the region.

Water Needs Assessment Results Workshop

Over the past few months, we’ve been conducting outreach to characterize the needs of disadvantaged and underrepresented communities in the Region. Our findings have been summarized into a draft Water Needs Assessment report for Orange County which is now available for public comment on the County website (https://ocgov.box.com/s/05x9sxpzfukzmskp5db3loi6z6qaxmi4 ).

South Orange County was also included in the San Diego Funding Area  (San Diego IRWM Region, Upper Santa Margarita Watershed IRWM Region, and South Orange County IRWM Region) which is now available for public comment on the San Diego IRWM website (http://sdirwmp.org/2019-irwm-plan-update). The summarized information for South Orange County water challenges and needs is the same in both reports. 


In June 2003, per direction from the Board of Supervisors, the County of Orange led a multi-agency task force to develop a countywide Water Quality Strategic Plan. As a result, a new structure for water resource management evolved based on a new concept of Watershed Management Areas (WMAs). The eleven watersheds in Orange County are grouped by similar characteristics into three Watershed Management Areas: North, Central, and South. 

At its essence, the Watershed Management Area is a collaborative framework for municipalities and special purpose agencies to work collaboratively and find synergies across water resource disciplines. Its purpose is to bring together a wide variety of water resource managers in order to achieve more comprehensive and cost effective solutions to Orange County’s water resources needs. Regular stakeholder forums are held to involve the public and share information across organizations within each Watershed Management Area.  As of 2017, the North and Central WMA Integrated Regional Water Management Plans (IRWM Plans) have been merged and planning efforts combined to provide the greatest benefits to the region. The North/Central and South WMA groups meet on a regular basis to collaborate on water resource issues, including water supply, surface water quality, flood management, wastewater, and natural resource protection. The table below shows the Watershed Management Areas in Orange County that have an existing cooperative agreement in place with a link to the governing body for each WMA.

Area Governing Body

Central Orange County Watershed Management Area
Newport Bay Watershed Executive Committee

South Orange County Watershed Management Area
South Watershed Management Area Executive Committee