Cumulative impact assessment in coastal wetland watersheds: Jacoby Creek, Humboldt County, California

Thesis/Dissertation · Mon Dec 31 23:00:00 EST 1984

OSTI ID:5151976

Tuttle, A E

This work tests the transferability of a model cumulative impact assessment method - developed for an agricultural/residential watershed in central California - to a forested/residential watershed in northern California. The method focuses on coastal wetland sedimentation caused by development in the surrounding watershed. The premise of the method is that future wetland impacts will resemble those of the past if future anthropogenic disturbances and natural processes occur at the same intensity as those experienced over the historical record. The method quantifies historic land-use disturbance and wetland change, and establishes a recommended upper limit for future land-use intensity based on historic site disturbance. Indices of site disturbance are keyed to local erosional processes. Measures include impervious surface coverage, bare ground disturbance, location of mass-movement features, and intersections of roads with streams. For Jacoby Creek it was found that the creek-mouth delta grew nearly 18 acres between 1931 and 1978 due to deposition of sediment from the 17 sq. mi. watershed. Approximately 8 acres of the delta have become vegetated; established salt marsh remains unchanged. The method is potentially transferable to other cumulative impact problems where land-use intensity is an important variable.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 5151976
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
290300 -- Energy Planning & Policy-- Environment
Health
& Safety
510200 -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AQUATIC ECOSYSTEMS
CALIFORNIA
COASTAL REGIONS
ECOSYSTEMS
ENVIRONMENTAL IMPACTS
FEDERAL REGION IX
LAND USE
NORTH AMERICA
RIVER DELTAS
SEDIMENTATION
USA
WATERSHEDS
WETLANDS