Sediment Budget for Salmonid Spawning Habitat Rehabilitation in a Regulated River
Document Type
Article
Journal/Book Title/Conference
Geomorphology
Volume
76
Issue
1
Publisher
Elsevier
Publication Date
2006
Keywords
geomorphology, habitat rehabilitation, sediment budget
First Page
207
Last Page
228
Abstract
Bed elevation, feature adjustments, and spawning use were monitored at three Chinook salmon (Oncorhynchus tschawytscha) spawning habitat rehabilitation sites to measure project longevity in a regulated river. Sites enhanced with 649–1323 m3 of gravel lost from 3–20% of remaining gravel volume annually during controlled flows of 8–70 m3/s and 2.6–4.6% of placed material during a short-duration (19 days) release of 57 m3/s. The oldest site lost ∼50% of enhancement volume over 4 years. Of the mechanisms monitored, gravel deflation was the greatest contributor to volumetric reductions, followed by hydraulic scour. Spawning, local scour around placed features, and oversteepened slopes contributed to volumetric changes. As sites matured, volumetric reductions decreased. Sites captured as much large woody debris as was lost. While complexity is an extremely important aspect of ecological function, artificial production of highly diverse and complex habitat features may lead to limited longevity without natural rejuvenation.
Recommended Citation
2006. Merz, JE, Pasternack, GB† and Wheaton, JM. Sediment budget for salmonid spawning habitat rehabilitation in a regulated river. Geomorphology. 76(1‐2): 207‐228. DOI: 10.1016/j.geomorph.2005.11.004.
