Historically, the Carmel River south of Monterey, CA supported runs of steelhead that could make many on the current list of the world’s best steelhead streams blush. In the 1850’s, the river saw annual returns of between 12,000 and 20,000 adult fish. Rapid expansion and urbanization of the Monterey area, however, set into motion a sequence of events that greatly degraded the river’s habitat.
Dams, surface water diversions, ground water extraction, urban development, levees, culverts, road crossings and channelization have all contributed to the dramatic decline of Carmel River steelhead runs.
During the period from 1964 to 1975, an average of 821 adult steelhead ascended the fish passage facilities at San Clemente Dam. In 1994, only 91 steelhead made the trip. During the 2012-2013 season, 249 adults were reported at San Clemente Dam and 65 adults were reported and Los Padres Dam.
In 1997, Carmel River steelhead were listed as a threatened species and in 1999, the Carmel was named as one of the nation’s 10 most endangered rivers.
The first major blow to the Carmel’s anadramous fish populations occurred in 1880, when Old Carmel River Dam was built. Then in 1921, San Clemente Dam was completed 18 river miles above the mouth. Though equipped with fish passage, the dams posed substantial impediment to both up and downstream migration of adult and juvenile steelhead.
More significantly, the dams restricted new gravel recruitment into the lower river, which lead to bank erosion, bottom substrate armored with large cobbles and boulders (and a lack of spawning gravel), channelization, reduction in flood plain habitat and general degradation of spawning and rearing areas.
As the human population of the basin grew and San Clemente Dam filled with sediment, demand for more water storage resulted in the building of Los Padres dam in 1948. Located approximately 7 miles upstream of San Clemente Dam, Los Padres Dam affected the habitat in the reach between the two reservoirs very much the same way that the original structures affected the lower river.
Predation upon out-migrating juvenile steelhead by non-native warm water species in the reservoirs can also be significant at times.
In addition to the dams, surface water diversions and groundwater extractions have had extremely damaging effects on steelhead populations. Drawdowns often leave sections of the mainstem below San Clemente Dam completely dry — or a series of isolated stagnant pools. In either case, fish migration (adult and juvenile) is greatly restricted or impossible at times.
Another huge factor in the decline of the Carmel’s steelhead populations is the lack of over-summering habitat in the sections below the dams. Young steelhead spend up to a year in freshwater before migrating out to the ocean and thus require cold, clean water – which is often not available in the summer and fall due to the water use practices here.
Reduced flows also diminish the viability of the Carmel River estuary as an important rearing zone for juvenile steelhead. Surface water diversions and groundwater extraction also artificially modify the pattern of sandbar formation and natural breaching at the estuary, which can block access to the ocean for in-bound adult fish and out-migrating juveniles.
Lack of water can also keep potentially anadramous juvenile O. mykiss from emigrating out of the watershed and force them to complete their lifecycle within the river. Artificially low flows can also turn minor barriers to fish migration into impassible obstacles.
The lower Carmel River below San Clemente Dam flows through developed residential and commercial land, so the mainstem and surrounding floodplain and riparian habitats have been altered by bank protection and flood control projects. Road construction resulting in the silting in of spawning gravels and impassible dams and culverts on smaller spawning tributaries also reduce the carrying capacity of the Carmel River.
The mandated reduction of water withdrawals by 2016 should increase the river’s viability as a steelhead producer. The ongoing removal of San Clemente Dam and ingenious rerouting of the river channel should also greatly enhance fish habitat and passage in the lower 18 miles of river. Habitat enhancement of the new channel is getting close to being finished and the drawdown of the reservoir began in April.
The section of the mainstem Carmel below Los Padres Dam will still suffer from the ill effects of the barrier, however.
The river upstream of Los Padres is generally in better condition than the reaches below the dams. The upper reaches and tributaries like the Miller Fork are mainly perennial and feature some excellent stretches of quality spawning and rearing habitat. Increased flows in the lower river and removal of San Clemente Dam should allow more adult steelhead to reach those areas, though the dam at Los Padres still remains an issue for passage.
Additional spawning habitat could potentially be added to the drainage by altering/removing manmade and natural barriers on tributaries such as San Clemente Creek, Cachagua Creek and Tularcitas Creek — and adding passage to the dam on Black Rock Creek.
The Carmel will never regain its former glory as a top-notch steelhead stream, but with projects in the work, things seem to be headed in the right direction. Stay tuned…