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Watershed rehabilitation in redwood national park and other pacific coastal areas. R. W. Coats (Ed.). Centre for natural resource studies of JMI, inc. and national park service
Author(s) -
McDonald Adrian
Publication year - 1983
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3290080215
Subject(s) - national park , library science , service (business) , citation , natural resource , watershed , resource (disambiguation) , natural (archaeology) , geography , archaeology , political science , business , computer science , computer network , marketing , machine learning , law
The Carmel River Basin of 670 km2 was dammed in the 1920's. Prior to that. the lower 24 km alluvial reach had been a high-gradient braided largelyephemeral arroyo typical of chaparral-dominated central coastal watersheds. Fire suppression. reservoir sedimentation. and a sequence of low-flood magnitude years led to channel incision. narrowing. and growth of a major riparian vegetation community. Loss of riparian vegetation in some sites. coupled with moderate magnitude flood flows caused destabilization of the channel locally and a return to conditions more typical of those prior to 1920. A management plan has been developed to attempt to achieve the conditions of quasistability to which the residents had become accustomed by the mid-1960's when riparian vegetation began to die back. INTRODUCTION The Carmel River drains a 670 km2 (255 mi 2) basin. Rising in the rugged Santa Lucia Mountains and passing through the 24 km (15 mi) long. alluviated Carmel Valley. it ultimately discharges into the Pacific near Carmel, Calif. (fig. 1). This alluvial reach is sub-divided by a bedrock constriction and narrowing of the valley (the "Narrows") into a lower 16 km (10 mi) reach (the "Lower Carmel") and a middle 8 km (5 mi) reach (the "Middle Carmel"). The "Upper Carmel" refers to the segment above San Clemente Dam (fig. 2). Average annual rainfall in the mountainous headwaters with elevations to 2133 m (7000 ft) is 1040 mID (41 in) but decreases to 430 mID (Ii in) in the lower valley. While the upper river is perennial, the lower river is intermittent, with surface flow typically from December through June. Near the river's mouth, average discharge is 2.7 ems (97 cfs), and the bankfull discharge (here, the 2.4 yr flow) is 79.2 ems (2800 cfs). Two water supply dams. the Los Padres and San Clemente Dams. together impound about 3000 ac-ft (fig. 1). The Carmel basin supplies most of the water for the Monterey Peninsula cities of Monterey. Pacific Grove. Seaside. and Carmel. As these areas have grown. demand for water has risen substantially. To meet demand, California-American Water Company (Cal-Am), a private utility, has drawn increasingly upon water supply wells in the alluvium along the lower and middle Carmel valley over the past two decades. Of the 13,000 ac1 Professor, Environmental Geology, University of California, Santa Cruz, Calif. 95064 2 Graduate Student, Fluvial Geomorphology, Earth Sciences Board, University of California. Santa Cruz, Calif. 95064 191 f~~!:! ~,.~ ..;-~'1;; .•.. '. i! I:' .• ' ') !t .. ~ ::