Presentation Abstract
The Swinomish agricultural area, along the Swinomish Channel, is part of the Skagit River Delta, a major agrarian region in Puget Sound. Historically a complex system of tidal channels serving as salmon habitat, the tidelands have since been diked and drained. In 2005, the Swinomish Indian Tribal Community (SITC) began restoration to demonstrate compatibility of fish habitat and agriculture. Muted tidal regulators (MTRs) operated to optimize tidal inundation and fish passage, replaced traditional tidegates, and prompted a study to evaluate soil conductivity impacts on agriculture. Objectives included electromagnetic (EM) surveying of soil conductivity, qualitatively assessing EM results utilizing two additional methods, and assessing local crop suitability and restoration effectiveness for fish habitat and agriculture compatibility. All methods showed low conductivity throughout the majority of the area with isolated elevated levels adjacent to drainage ditches, the main Channel dike, and in low-lying depressional areas. Designed for periodic inundation, a restoration area yielded some of the highest conductivity levels. Using conversion formulas applicable to each conductivity measurement method, conductivity values were converted to salinity classes to evaluate potential adverse crop effects. The areas described above ranged from primarily ‘slightly saline’ and ‘moderately saline’ (many crop yields restricted), to ‘strongly saline’, with marginal ‘very strongly saline’ areas along the main dike and in the restoration area. However, the vast majority of the agricultural area could be categorized as ‘non-saline’, with negligible crop effects. These results indicate that the restoration designed to enhance fish habitat resulted in limited salinity intrusion to the adjacent cropland. This study, along with concurrent projects in the Swinomish agricultural area, suggests that fish and farming, two economically and culturally significant symbols of the region, may not only survive, but thrive in the same space.
Session Title
Posters: Habitat Restoration & Protection
Keywords
Soil conductivity, Soil salinity, Agriculture, Electromagnetic surveys, Muted tidal regulators, Tide gates, Fish habitat
Conference Track
SSE18: Posters
Conference Name
Salish Sea Ecosystem Conference (2018 : Seattle, Wash.)
Document Type
Event
SSEC Identifier
SSE18-81
Start Date
5-4-2018 11:30 AM
End Date
5-4-2018 1:30 PM
Type of Presentation
Poster
Genre/Form
conference proceedings; presentations (communicative events); posters
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Salmondae--Conservation--Washington (State)--Skagit River Delta; Agricultural chemicals--Environmental aspects--Washington (State)--Skagit River Delta; Fish habitat improvement--Washington (State)--Skagit River Delta; Soil salinization--Control--Washington (State)--Skagit River Delta; Water quality--Washington (State)--Skagit River Delta
Subjects – Names (LCNAF)
Swinomish Indians of the Swinomish Reservation, Washington
Geographic Coverage
Salish Sea (B.C. and Wash.); Skagit River Delta (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Included in
Fresh Water Studies Commons, Marine Biology Commons, Natural Resources and Conservation Commons, Terrestrial and Aquatic Ecology Commons
Soil conductivity study and implications for fish and farming compatibility in the Swinomish agricultural area
The Swinomish agricultural area, along the Swinomish Channel, is part of the Skagit River Delta, a major agrarian region in Puget Sound. Historically a complex system of tidal channels serving as salmon habitat, the tidelands have since been diked and drained. In 2005, the Swinomish Indian Tribal Community (SITC) began restoration to demonstrate compatibility of fish habitat and agriculture. Muted tidal regulators (MTRs) operated to optimize tidal inundation and fish passage, replaced traditional tidegates, and prompted a study to evaluate soil conductivity impacts on agriculture. Objectives included electromagnetic (EM) surveying of soil conductivity, qualitatively assessing EM results utilizing two additional methods, and assessing local crop suitability and restoration effectiveness for fish habitat and agriculture compatibility. All methods showed low conductivity throughout the majority of the area with isolated elevated levels adjacent to drainage ditches, the main Channel dike, and in low-lying depressional areas. Designed for periodic inundation, a restoration area yielded some of the highest conductivity levels. Using conversion formulas applicable to each conductivity measurement method, conductivity values were converted to salinity classes to evaluate potential adverse crop effects. The areas described above ranged from primarily ‘slightly saline’ and ‘moderately saline’ (many crop yields restricted), to ‘strongly saline’, with marginal ‘very strongly saline’ areas along the main dike and in the restoration area. However, the vast majority of the agricultural area could be categorized as ‘non-saline’, with negligible crop effects. These results indicate that the restoration designed to enhance fish habitat resulted in limited salinity intrusion to the adjacent cropland. This study, along with concurrent projects in the Swinomish agricultural area, suggests that fish and farming, two economically and culturally significant symbols of the region, may not only survive, but thrive in the same space.
