Translate this page

MWD approves Diamond Valley Lake fish screen replacement design

Friday, March 7th, 2014
Issue 10, Volume 18.
Joe Naiman
Valley News Correspondent

The Metropolitan Water District of Southern California board authorized the final design to replace the fish screens on the inlet/outlet tower at Diamond Valley Lake.

The MWD board’s February 11 action also appropriated $380,000 for the work while finding the project categorically exempt from California Environmental Quality Act review.

Diamond Valley Lake has a maximum storage capacity of 810,000 acre-feet and provides emergency storage in the event of a major earthquake, carryover storage in periods of drought, and seasonal storage to meet member agency demands. The inlet/outlet tower east of the lake’s Owen Dam is 266 feet high; nine tiers of twin ports spaced 25 feet apart allow water to enter or exit from different lake elevations.

A hydraulically-operated butterfly valve controls flow through each port, which is seven feet in diameter. The ports open into a wet well which rises the full height of the tower above the pressure tunnel at its base. The lake water passing through the tower into the pressure tunnel can be diverted either to the Wadsworth pumping plant or to the adjacent pressure control


When water is being withdrawn from the lake, fish screens are placed in front of the ports to prevent debris from entering the tower. In addition to protecting the fish, the screens also protect the valves at the tower and at the pressure control structure and the pump turbines at the Wadsworth pumping plant. The four fish screens Advertisement
Advertisement for Temecula Valley Chamber of Commerce
[ Temecula Valley Chamber of Commerce ]
are each 26 feet wide by 19 feet tall. The fish screens are raised and lowered to the desired elevation by a pulley system operated by a gantry crane mounted on top of the tower.

The fish screens, like other parts of Diamond Valley Lake, are inspected periodically. An inspection of the fish screens identified extensive corrosion damage in the coated carbon steel structure elements including the hoist beam eye bars, the support beams, and the retaining pins. The corrosion was likely caused by galvanic action between the screens’ stainless steel and carbon steel components.

In November 2012 the MWD board authorized the preliminary design phase to replace the fish screens with units which would not be susceptible to galvanic corrosion.  The preliminary design phase is now complete. The final design activities include engineering design, preparation of drawings and specifications, receipt of competitive bids, and refinement of estimated construction costs. The actual project will replace the fish screens using stainless steel components while refurbishing corroded lifting blocks, screen supports, and other structural elements.

The total construction cost is estimated at between $1.7 million and $1.9 million.  MWD staff will return to the board with a request to award a construction contract after the final design is completed. The $380,000 for the final design covers $256,000 to prepare drawings and specifications, $72,000 for project management and receipt of bids, and $52,000 for contingency. MWD staff will perform all final design work.



arrow Be the first to share your opinion on this article!

Add your Comment


Images, Formatting, or HTML is not allowed : plain text only. You may post up to 5 website addresses within your comment.


The Valley News has tightened its' policy regarding comments.
While we invite you to contribute your opinions and thoughts, we request that you refrain from using vulgar or obscene words and post only comments that directly pertain to the specific topic of the story or article.
Comments that are derogatory in nature have a high likelihood for editing or non-approval if they carry the possibility of being libelous.
The comment system is not intended as a forum for individuals or groups to air personal grievances against other individuals or groups.
Please, no advertising or trolling.
In posting a comment for consideration, users understand that their posts may be edited as necessary to meet system parameters, or the post may not be approved at all. By submitting a comment, you agree to all the rules and guidelines described here.
Most comments are approved or disregarded within one business day.

RSS FeedFacebookTwitter

Advertisement for Stellar Solar


Most Commented

Reach Local Customers

The Valley News The Valley News
760-723-7319 - 1588 S. Mission Rd. Suite 200, Fallbrook CA 92028
All contents copyright ©2015
About Us
Earthquake Information
Business Listings
Contact Us
Letter to the Editor
Report a website error
Online Digital Edition
RSS Feeds