Little Shasta River Cone Screen

Little Shasta River Cone Screen


The Little Shasta River watershed is fed by rain and snowmelt from Mount Shasta, the Klamath Mountains, and the Cascade Range. California Department of Fish and Wildlife (CDFW) manages the Shasta Valley Wildlife Area (SVWA) which is located on Little Shasta River. The SVWA is managed to protect, enhance, and restore riparian and wetland habitats to support protected species including Chinook and Coho Salmon. CDFW’s diversion ditch is located in SVWA and was retrofitted with an ISI cone screen to meet state and federal fish protection criteria at this irrigation diversion.

The ISI cone screen is located in a protected cement alcove in a reach of the river where a bioengineered grade control structure consisting of interwoven woody debris and boulders maintains water level. The water is delivered to the irrigation diversion through the ISI C168-48HA cone screen, which measures 14 feet (4.3 m) in diameter and 4-feet (1.2 m) high, into a 36-inch (0.9 m) siphon. The screen is equipped with 1.75-mm slot openings and a hydraulic drive brush cleaning system and includes baffles inside the screen to create uniform flow over the screen surface. The screen has a capacity of 58 cfs (37.5 MGD; 5,913 m3/h) at a 0.33 fps approach velocity at full submergence and therefore meets the diversion flow of 30 cfs (19.4 MGD; 3,058 m3/h) with just 21 inches (0.53 m) of water depth.

Benefit of ISI System

The following are the key benefits of the ISI screen system design at this site:

  1. The conical screen shape maximizes diversion capacities during low water elevations while maintaining compliance with stringent fish protection requirements.
  2. The placement of the screens offset from the river in a cove reduces the total project footprint and keeps the screens out of the path of flood waters when they occur.
  3. ISI’s mechanical brush-cleaning system maintains a clean screen surface which ensures compliance with fish protection requirements and reliable diversion of water.


Shasta Valley Wildlife Area


Cascade Stream Solutions, LLC

General Contractor:

Gary Black


Little Shasta River, Montague, CA

Year Installed:


Slot Size:


Screen Model:


Drive System:




Water Body:


Flow Rate:

58 cfs (37.5 MGD; 5,913 m3/h)

Screen Type:

Cone Screens (conical)

Retrieval Systems:

Fixed Flange Connection

Number of Screens:


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