Watershed Management Areas

Update on the South IRWM Plan                    
Projects can be submitted via the South IRWM website/Data Management System (DMS).

The OC Plan for Integrated Regional Water Management in North and Central Orange County was completed in March 2018 and is available here.

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. 


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 

Integrated Regional Water Management Plans (IRWM Plans)

IRWM Plans for North/Central and South WMAs are currently being updated to meet State standards and to update local planning initiatives discussed within the plans. 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.

North/Central WMAs

For more information about the North/Central WMAs, IRWM Plan (OC Plan), project submittal and selection processes, and opportunities for stakeholder involvement, please visit the North/Central IRWM website and data management system.