Cullinan Ranch Diversion

Cullinan Ranch Diversion


The San Pablo Bay National Wildlife Refuge is part of the U.S. National Wildlife Refuge System whose mission is to conserve and restore protected species populations and their habitat. The Cullinan Ranch Restoration Project is a part of the larger San Pablo Bay National Wildlife Refuge and involves reclamation of diked agricultural land to restore it to estuarine tidal marsh. A tidal intake which includes an ISI cone screen was included in the project to avoid entrapping federally protected salmonids within the reclaimed area when flooding events would have otherwise resulted in potential levee breeching. The intake was retrofitted with a 12-ft (4.3-m) diameter, 41-inch (1.0 m) high cone screen to reduce potential impacts to fish at the point of diversion. This solar power brush-cleaned screen includes 1.75-mm slot openings and has a capacity of 50.8 cfs (7,136 m3/h) at a 0.4 fps (cm/s) approach velocity. The 500 Watt solar powered system includes 6 deep cell batteries, cabinet, and charging system.

Benefit of ISI System

ISI's conical shaped screen enables this shallow water diversion to meet fish protection criteria by placing a large screen surface area in a relatively small project footprint. The brush-cleaning system maintains a clean screen surface and therefore maintains the regulatory required approach velocity during water diversion. Use of 316L stainless steel for screen construction provides protection against the estuarine salinities which range from 5-33 ppt. The solar power system allowed the project to be completed without the need to run power to the site.


U.S. Fish and Wildlife Service


Ducks Unlimited

General Contractor:

Great Lakes Environmental and Infrastructure


Pablo Bay, California

Year Installed:


Slot Size:


Screen Model:


Drive System:




Water Body:


Flow Rate:

50.8 cfs (7,136 m3/h)

Screen Type:

Cone Screens (conical)

Retrieval Systems:

Fixed Flange Connection

Number of Screens:


©1996-2021 Intake Screens, Inc. All Rights Reserved.