Flycasters Little Arthur Creek Fish Ladder Project
After many years of surveying south bay fisheries the FFF and San Jose Flycasters located a high dam on the important Little Arthur Creek tributary of the Pajaro River in Gilroy that predated the 1924 California Water Code. There were no minimum flow requirements and the dam was silted in, completely blocking steelhead migration. Under the leadership of one of our members, the late Fred Houwink, we found that the very cooperative ranch owner, Edward Pickells, had attempted to build fishways in the canyon only to have them destroyed twice by flood-stage flows. Mr. Pickells had a flashboard portal in the dam that he opened in winter to flush out accumulated rubbish and was very receptive to our project.
Our involvement with the Federation of Fly Fishers thorough Marty Seldon, who then the FFF Conservation Vice President, showed us the potential of the Alaska Steep-Pass Fish Ladder. CDF&G engineers and biologists visited the site and were also very enthusiastic. Fred and another club member, Jerry Hensley, who became the formal project contractor used the data, surveyed the site, and then designed a four-section, forty-foot long ladder system. With agency participation and agreement, a formal proposal was later made to the CDF&G for Bosco-Keene funds that resulted in a grant of $31,500 for the project.
The project came to fruition in the summer of 1986. There were numbers of vendors, our contractor, and club volunteers providing most of the labor. About 500 tons of riprap rock were purchased and placed in the canyon to form a 40-foot ramp up to the portal of the dam, 10 foot above the streambed. Flycaster’s work teams muscled the riprap into a trough for the fishway sections that were fabricated in Gilroy. Each section had a two-foot wide bottom and side sections with complex interior welded baffle plates. Dozens of angle-iron straps braced the open top and hundreds of 1/2x1 inch bolts held them all together. The bulldozer and shovel crane used to handle the riprap were inadequate to handle the fishway and a 45-ton crane was brought in to lift the fishway and reach out 75 feet to lower it into the riprap trough. A two-foot high concrete weir was built across the end of the ledge with openings for the fishway and rubbish exhaust port. The last construction phase of the project pumped 32 cubic yards of concrete to consolidate the rip-rap and tie it all together with reinforcing bars set in holes drilled in the sheer canyon wall. CDF&G monitored all phases of construction and we passed every inspection with flying colors.
The photos below show the dam prior to construction of the ladder, one photo of the ladder under construction and one photo looking down the creek from the top of dam after completion.