Historical changes in anadromous fish habitat in the Upper Grande Ronde River, Oregon, 1941-1990 Public Deposited

Analytics
http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/2801pk427

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • The U.S. Bureau of Fisheries (now National Marine Fisheries Service) conducted stream habitat surveys in the Upper Grande Ronde River Basin in 1941. This survey was part of an extensive inventory of stream habitat conditions for anadromous salmonids (Oncorhynchus spp.) throughout the Columbia River Basin. The survey systematically inventoried 158 km of streams within the 3000 km2 watershed. Stream habitat was degraded from land-use activities (riparian timber harvest, splash dams, stream channelization, livestock grazing, and mining) prior to the 1941 survey. A 1990 resurvey determined how stream habitat conditions had continued to change. The historical survey and the 1990 resurvey inventoried streams according to pool and substrate characteristics. Pools were classified by size and depth criteria, while substrate was divided into size-classes. Losses in total pools/km (> 20m2 area and > 0.5 m depth) ranged from 43 to 83% (mean = 65%, 12.2 to 4.31km), while the loss in large pools/km (> 20m2 and > 1.0 m depth) ranged from 20 to 89% (mean = 68%, 6.2 to 2.0/1cm) for individual streams. The loss of variability in pool frequencies from 1941 to 1990 (total pools/km a2 = 43.9 to 2.8, large pools/km a2 = 23.2 to 3.2) demonstrates that stream channels have become less diverse. Classifying streams by reach types indicated that the decline in pool frequencies was not significantly related to geomorphic constraints. Substrate composition appears to have shifted toward smaller size-classes, with an increase in fine sediments (< 6mm) in the headwaters. Livestock grazing declined 78% (229,000 to 51,000 aum) from 1911 to 1990, while annual timber harvest increased 172% (36 to 98 mmbf) from the pre-survey period (1896-1940) to the post-survey period (1940-1990). Road densities have increased concurrent with timber harvest, currently averaging 4 miles/mile2. Base discharge has increased 51% (18.5 to 28.0 cfs), while there has been a 27% decrease in annual precipitation (22.0" to 16.0") and snowpack (April 1 water equivalent) (15.0" to 10.5") from 1941 to 1990. In an era of presumably improving management (1941-1990), large-scale losses in the fish habitat necessary for the continued viability of resident and anadromous fish populations continued to occur.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Language
Digitization Specifications
  • Master files scanned at 600 ppi (256 Grayscale, 24-bit Color) using Capture Perfect 3.0 on a Canon DR-9080C in TIF format. PDF derivative scanned at 300 ppi (256 B&W, 256 Grayscale, 24-bit Color), using Capture Perfect 3.0, on a Canon DR-9080C. CVista PdfCompressor 3.1 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Linda Kathman(linda.kathman@oregonstate.edu) on 2008-08-21T12:57:47Z (GMT) No. of bitstreams: 1 McIntosh_Bruce_A_1992.pdf: 2797720 bytes, checksum: 8025109d207146388ae2b75d60fa5ae8 (MD5)
  • description.provenance : Approved for entry into archive by Linda Kathman(linda.kathman@oregonstate.edu) on 2008-08-21T12:55:41Z (GMT) No. of bitstreams: 1 McIntosh_Bruce_A_1992.pdf: 2797720 bytes, checksum: 8025109d207146388ae2b75d60fa5ae8 (MD5)
  • description.provenance : Submitted by Anna Opoien (aoscanner@gmail.com) on 2008-08-20T18:40:09Z No. of bitstreams: 1 McIntosh_Bruce_A_1992.pdf: 2797720 bytes, checksum: 8025109d207146388ae2b75d60fa5ae8 (MD5)
  • description.provenance : Made available in DSpace on 2008-08-21T12:57:48Z (GMT). No. of bitstreams: 1 McIntosh_Bruce_A_1992.pdf: 2797720 bytes, checksum: 8025109d207146388ae2b75d60fa5ae8 (MD5)

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items

Thumbnail Title Date Uploaded Visibility Actions
Default McIntosh_Bruce_A_1992.pdf 2017-08-14 Public