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Geographic Information Systems
Definition:
Geographic Information Systems, or GIS, is an extremely useful tool
for answering fish population questions and for displaying the result
in a visual and intuitive way. Multiple layers of geographically
referenced data can be used to find locations of features, recognize
patterns, map quantities and densities, or visualize change over time.
Uses:
- Fish distribution and density
- Habitat status assessment
- Habitat restoration suitability
- Geomorphology classification
- Change-over-time analysis
Capabilities:
- Data conversion, acquisition, and creation
- Aerial photo interpretation and remote sensing
- Spatial and 3D analysis
- Map and graphic creation
Clients:
Question: Which areas along the Clackamas River
would be suitable for habitat restoration to improve salmon habitat?
Answer: Using aerial photo interpretation, we found relic side channels
suitable for reconnectivity. We assessed suitability of these side
channels for salmon habitat restoration based on geomorphology,
land ownership and floodplain connectivity.
Question: How has Clackamas River channel morphology
and complexity changed over time due to changes in flow created by
dam operations?
Answer: We digitized the river channel from historic
aerial photos, then quantified the area of braided reaches in each
time period and made a comparison to determine the change over time.
Question: Did creeks in the Yakima River basin,
now used as irrigation ditches, have historic populations of
fish?
Answer: We used GIS to find watersheds of study creeks. We then assessed the possible range of historic fish populations using elevation, geology, and hydrology data, by comparing study creek watersheds to watersheds of creeks with known fish populations.
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