The Rio de las Vacas originates in the Jemez Mountains on the Santa Fe National Forest (SFNF). The river flows east of the Valles Caldera for 21 miles before joining the Rio Cebolla to form the Rio Guadalupe. The upper reaches of this river contain one of 13 remaining core populations of Rio Grande cutthroat trout (Oncorhynchus clarki virginalis), according to US Fish and Wildlife Service. The Rio de Las Vacas has been identified as a priority recovery area for Rio Grande cutthroat trout by both the FS and the New Mexico Department of Game and Fish. Historically unmanaged cattle use that damaged habitat and introduction of exotic trout species (rainbows and browns) in the lower watershed reduced the native cutthroat population.
To address these problems, the USDA Forest Service (FS) and Trout Unlimited (TU) formed a partnership to protect and restore the Rio Grande cutthroat trout populations in the Rio de las Vacas watershed. The long term goal of the Rio de las Vacas Rio Grande Cutthroat Restoration Partnership is to add 11 miles of native fish waters to the upper 10 miles of Rio Grande cutthroat trout waters that already exist. The objectives of this initial project are to improve an existing man-made fish barrier that protects the upper 10 miles of native fish assemblage and restore stream habitat in a critical reach of the 11 mile restoration area.
The first objective involved securing a man-made fish barrier on the FS wilderness boundary that protects the upper 10 miles of the watershed from encroachment by non-native rainbow and brown trout. While the existing barrier was still functional, it was on the verge of failure and was in need of immediate maintenance and repair. It was imperative that the existing native fish assemblage be protected from exotic species as the first step in the overall recovery program. Barrier repair was relatively simple. Large boulders were placed at the base of the structure that both filled the plunge pool and reinforced the toe of the dam. Without deep water to build swimming speed, exotic trout cannot jump the barrier during high water events.
The primary aims of the stream restoration project were to reduce summer and fall water temperatures and improve the condition and shape of the stream channel. The main stream habitat problem in the first reach to be addressed was a road crossing directly through the stream channel. Continual vehicle use had obliterated the channel. The road was closed and livestock grazing was eliminated so that willows had started to re-colonize riparian areas. However, the stream channel had become so damaged that natural recovery was unlikely. Specific tasks to improve stream riparian and channel areas included closing the road crossings and restoring the stream channel; adding large woody debris to increasing pool habitat, help reduce the average width of stream channel, and decrease fine sediment in riffles; increasing the average amount of stream shade with riparian plantings; and obliterating and seeding two miles of the old road.