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Geological characterization and sedimentary processes of nearshore habitats in Kachemak Bay, Alaska

Overview

The ultimate goal of this project is to quantify the linkages between the dynamic sedimentary system and marine benthos of Kachemak Bay at a variety of temporal and spatial scales. In particular we aim to test the hypotheses that the amount of exposed rocky habitat on the north shore of Kachemak Bay is a function of periodic and episodic sand wave migration and that the variability of sand wave migration rates is a function of storm magnitude and frequency (as opposed to tidal currents). Kachemak Bay is an ideal location for this effort as it currently features one of the most diverse instrument arrays within the Gulf of Alaska.

Start/End Dates 10/1/2003 - 9/30/2008 Location Kachemak Bay and Western Kenai Peninsula, AK Investigators Peter Ruggiero, Project Chief Guy Gelfenbaum, Project Chief

Location of study area. Click map for larger version.

Objectives

• Understand and quantify the short- and long-term coastal change rates along the western shore of the Kenai Peninsula as a function of wave energy, sediment supply, and coastal land level change.
• Develop modeling tools to identify sediment pathways and to ultimately predict coastal change, with and without human intervention.
• Since a number of recent studies have linked ecosystem dynamics, and specifically population declines, to sediment and nearshore dynamics we will develop an understanding of the interrelations between coastal processes, sediment transport, and nearshore ecosystem health.
• Translate data to assist policy makers within the Kenai Peninsula in identifying cost-effective solutions to reduce erosion, flood related property losses, and the associated financial hardships of Kenai Peninsula coastal property owners.

Approach

Under a pilot study begun in February 2003, the USGS and partners at the Kachemak Bay Research Reserve, the City of Homer, and Northwest Research Associates, Inc. initiated a video monitoring program along the Kachemak Bay, Alaska nearshore to assess the impact of sediment dynamics on nearshore marine ecosystems. Our approach will be to continue this partnership, extend the time series of video monitoring, collect additional ground truthing data, and add a biological monitoring component to selected cross-shore transects.

Tasks and SubTasks

Quantify the Linkages Between Dynamic Sedimentary Systems and Marine Benthos

Sunset at Halibut Cove.

Products

Northwest Research Associates and USGS, Homer Alaska Argus Beach Monitoring System
http://zuma.nwra.com/homer/
http://www.planetargus.com/homer/

Adams, P.N., Ruggiero, P., Gelfenbaum, G., Schoch, C., and Oltman-Shay, J., Nearshore sediment transport along the mixed grain size beaches of Kachemak Bay, Alaska. Abstract, Ocean Sciences Meeting, Portland, OR., AGU

Adams, P.N., and Ruggiero, P., Intertidal Sand Waves on a Mixed Sediment Beach: Are They Effective Wave Energy Dissipators? 2005 Coastal Dynamics Conference, Barcelona Spain

Peter Ruggiero, Guy Gelfenbaum, and Pete Adams, Kenai Peninsula Coastal Dynamics Workshop in Homer, Alaska, Kachemak Bay Research Reserve

Cooperators

• Kachemak Bay Research Reserve
• City of Homer
• University of California Santa Cruz