Southern California Branch Meeting


Subsurface Intakes for Desalination Feed water Supply: Current Lessons from the On-Going MPWSP Test Slant Well Long-Term Pumping Test Program located near the City of Marina, Central Coast of California


Presentation by:

Brian Villalobos

OCWD Facility Tour Led By:

Adam Hutchinson



The tour of the Groundwater Replenishment System (GWRS) includes an overview of the project, which is the world’s largest Indirect Potable Reuse (IPR) project, and a tour of the various treatment processes used to purify sewer water into water this is distilled quality.


With on-going need to develop new water supplies in California, ocean desalination has moved up on the list of priorities for water supply agencies. New and innovative approaches to extract seawater include near shore subsurface intakes. These are engineered structures which collect groundwater from beneath the ocean floor. Subsurface intakes are favored among regulatory agencies because of:

  1. no ocean construction impacts,
  2. avoidance of entrainment and impingement impacts to marine organisms, and
  3. no permanent visual impacts to coastal areas.

Additionally, subsurface intakes are beneficial to plant operations by:

  1. elimination or reduction of costly pretreatment,
  2. protection from high turbidity storm surge and red tide events by natural filtration and pretreatment from ocean floor sediments, and
  3. minimal growth of marine organisms that occurs inside the intake pipeline

California-American Water Company (CalAm) is developing new water supplies to replace groundwater supplies that have historically come from the Carmel River and groundwater pumping from the Seaside Groundwater Basin. A new innovative project, the Monterey Peninsula Water Supply Project (MPWSP) includes constructing a subsurface subsea seawater intake system and a 9.6MGD or 6.4MGD desalination plant. CalAm commissioned construction of a test slant (angled) well, 724 feet in length, and at an angle of 19 degrees below the horizontal constructed at the CEMEX sand and gravel mine site near Marina, California.


Facility Tour - 6:00 - 7:00 p.m.
Break - 7:00 - 7:30 p.m.
Presentation - 7:30 p.m.

(Vegetarian Option Available)

  • Pizza 


Members: $15.00
Non-Members: $20.00
Students: Free
*students still have to register on the GRA website



Scholastic Sponsorship Program -  The Southern California Branch continues its ongoing scholastic sponsorship program, which involves local sponsors supporting our annual scholarship fund for students who are engaged in groundwater studies. If your organization is interested in participating as a sponsor for a future event, please contact a Branch Officer.

Email List -  Visit the GRA mailing list sign up page to confirm your interest in getting emails on branch events, webinars and state-level events.


Tue, Oct. 10, 2017
6:00 p.m. - 8:45 p.m.

Event has ended


Orange County Water District Boardroom
18700 Ward Street
Fountain Valley, California 92708