Hydrology

By Special Contributing Author: Dennis Jackson, Hydrologist

Hydrology is the science of the circulation and distribution of water from the moment it falls as precipitation until it is returned to the atmosphere by evaporation or transpiration. Studying the hydrology of a watershed can help resource managers understand the flow of water within stream systems and beneath the earth's surface. Water is critical for salmonid survival with each life stage requiring different hydrological conditions. For example, adults migrate during winter storms to ensure access to upstream spawning habitat, while rearing juveniles grow quickly during times of moderate flow, with both high winter floods and summer droughts creating potentially hazardous environments. This section discusses basic hydrologic processes including how water moves, its chemical and physical properties, and interaction with living things, to provide an understanding of how certain stream conditions are formed that may affect salmonid survival in San Mateo and Santa Cruz Counties.

Hydrologic Cycle – describes the movement of water through the environment.

Stream Morphology – examines the processes that shape streams.

Environmental Extremes – discusses the effects of floods and droughts on salmonid habitat and how human actions may influence these natural processes.

General References

Bates, R.L., J.A. Jackson, and American Geological Institute. 1984. Dictionary of Geological Terms. 3rd ed. Garden City, New York: Anchor Press/Doubleday.

Jacobson, R.B., S.R. Femmer, and R.A. McKenney. 2001. "Land-use Changes and the Physical Habitat of Streams: A Review with Emphasis on Studies within the U.S. Geological Survey Federal-State Cooperative." USGS. Circular 1175. View on-line source.

Ruel, J.C., D. Pin, and K. Cooper. 2001. Windthrow in riparian buffer strips: Effect of wind exposure, thinning and strip width. Forest Ecology and Management 143:105-113.