Fish Habitat Enhancement Project

Proposal:

The Game and Fish Department (Region VI- Mesa) proposes to take advantage of an opportunity to install fish habitat at Canyon Lake in November and December, 2007 during a planned 50 foot drawdown of the lake. The plan is to use natural and artificial materials that will be anchored on the dry lakebed. These types of habitat enhancement opportunities rarely occur within the chain of lakes due to the extreme demand of water delivery that the (SRP) provides to its downstream customers.

Why:

Woody fish habitat particularly underwater trees and natural structure are lacking at Canyon Lake due to its age (75 plus years). This type of environment serves as hiding cover and shelter for structure-seeking fish species such as bass, crappie, bluegill sunfish and catfish. Increased recruitment of young-of-year fish will be realized for years to come, as those cohorts will continue to benefit from the placement of these structures. The cover will also concentrate fish and should increase angler success rates.

When:

Drawing of the lake water will begin in late August 2007 to lower the lake 50 vertical feet to an elevation of 1610’ msl (mean sea level) for inspection and maintenance of Mormon Flat dam. Water levels will begin to drop rapidly after the beginning of September and will be at the 50’ level by early November. Planned refilling will begin mid December and by mid January 2008, the lake will be at its level of 1660’ msl. Activities to transport and construct habitat devices in- place along designated shorelines will probably not begin until mid November after which time the lakebed should be dry enough to walk upon. Timeframe of habitat installation phase (construction period) will be about 5 weeks.

Where:

There are 7 pre-selected sites on Canyon Lake that were chosen due to their topography as ledges close to deep water or sloping bare shorelines that offer enhancement opportunities (see Attachment Maps 1 & 2). Habitat devices should be constructed at a depth of 25 feet below the high water maximum and not be over 10 feet in height. This will insure that there will not be conflicts with the boating public during normal varying water levels when pump-back operations are occurring. Total acreage of enhancement will be approximately 5 to 6 acres.

What:

Juniper trees and wooden pallets are the materials of choice as they are readily available, durable and are cost-effective. These materials have been proven as successful components in fish habitat enhancements in other central Arizona reservoirs such as Apache, Bartlett and Saguaro lakes and several urban lakes in the Phoenix area (Cortez, Chaparral, and Town Lake). The materials will be tied together using UV stabilized three foot zip-ties to form pyramids and will be anchored with cement blocks (see picture). There will be no degradation of water quality due to the use of natural/stabilized construction materials. A synergistic effect of the wooden pallet frames and natural cover within juniper trees has proven to be an effective design to attract a wide variety of fish species and sizes. Groups of devices will be clumped together rather than constructed in lines or rows to optimize this effect.

How:

Juniper trees will be acquired from thinning projects on the U.S.Forest Service lands or vegetation clearing under APS power lines in the Prescott area. They will then be transported to holding areas near the Palo Verde launch ramp and the Main Marina beginning in October 2007, where they will be stored in a secure fenced yard. Pallets will similarly be hauled from the Phoenix metro area and placed in the secure yards. When the installation phase of the project begins, pontoon boats will haul trees, pallets, connecting materials and weight construction materials to designated sites. For more inaccessible sites, airlifting structures by helicopter will be explored. Volunteers will help in the loading, unloading and construction of devices under the direction of a project foreman.

Monitoring:

Evaluation of the stability of the habitat structures will commence once the lake refills, and every other month for one year thereafter to check for floaters and resink devices in place. Effectiveness of the habitat as fish attractors will begin during April 2008 as water temperatures climb and fish activity increases. Visual surveys will be conducted using SCUBA, and capture surveys will utilize gill nets and electrofishing.

Resource Cooperators:

AGFD- Lead (Region VI), Special Services Development Branch, SRP, APS, BOR, Canyon Lake Marina, Luke Air Force Base, Angler/Sportsman’s Groups

Picture of habitat structures:

Submitted by: Jim Warnecke Region VI Fish Program Manager Attachment 1. Vicinity map of Canyon Lake, Maricopa County, Arizona.

Canyon Lake

Attachment 2. Designated fish habitat development sites in channel and basin areas of Canyon Lake.

Nemo Cove Beer Can Pt.

Teddy Bear Pt.

Beaver Landing Pt.

Tortilla Cove

Mormon Flat

LaBarge Cove