Skagit River General Investigation

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Skagit River General Investigation

What is a General Investigation or GI?

The Skagit River Flood Risk Management General Investigation ended in 2015. The letters below, dated April 1, 2015 and June 17, 2015, state the County's position in response to the Corps' request for a budget and timeline waiver.

What were the stages of the GI Study?

Reconnaissance Phase

  • Determine Problem(s)
  • Define Federal Interest
  • Prepare a Project Management Plan
  • Negotiate a Federal Cost Sharing Agreement
Feasibility Phase
  • Identify, evaluate, and recommend an appropriate, coordinated, and implementable solution
  • Resulting Report: Feasibility Report and Environment Impact Statement
Pre-Construction Engineering and Design Phase
  • First phase of construction
    This phase is complete when the first construction contract is ready to award
Construction Phase
  • Constructed in response to a completed feasibility study with a Chief of Engineer's report
  • Needs congressional authorization
Operations and Maintenance Phase
  • Usually the responsibility of the local sponsor

What is the purpose and status of the Skagit River GI Study?

The Skagit River GI is currently in the Feasibility Phase, also referred to as the Skagit River Flood Risk Management Feasibility Study. The Reconnaissance Study was complete in 1993. The primary intent of the flood risk management feasibility study is to evaluate flooding problems in the Skagit River basin from the Ross Dam reservoir (Ross Lake) to Skagit Bay; to formulate, evaluate, and screen potential solutions to these problems; and to recommend an alternative that has a federal interest and is supported by the local entities.The Feasibility Phase includes the following milestones:

  • Existing and Without Project Conditions
    • Research existing data and identify gaps
    • Collect data (e.g. economic, environmental, geotechnical)
    • Develop and analyze future without any projects
  • Alternatives Formulation
    • Develop measures (A measure is a feature (structural) or activity (nonstructural) that can be implemented at a specific geographic site to address one or more planning objectives)
    • Develop screening criteria (e.g. completeness, effectiveness, efficiency, and acceptability)
    • Preliminary Screening of Measures
    • Refine Measures
    • Develop Conceptual Alternatives
    • Develop Screening Criteria
    • Preliminary Screening of Alternatives
    • Refine Alternatives, bring to 10% Design
    • Final Screening of Alternatives and Selection of Preferred Alternative
    • Detailed Analysis of Selected Alternative (35% Design)
  • Selection of Recommended Plan (Current Status of Skagit River GI)
  • Final Feasibility Report/Environmental Impact Statement
  • Congressional Authorization of Project
The public, resources agencies, tribes, and advisory committees are engaged at all stages of the GI. There are formal avenues for commenting, including the National Environmental Policy Act (NEPA) stages and the Feasibility Scoping Meeting.
What are the opportunities associated with the Skagit River GI?
  • Reduce the risk of flooding and flood damages in urban areas through the least environmentally damaging structural or non-structural methods that are acceptable, cost effective, complete, and efficient.
  • Improve public safety and reduce life risks during flood events.
  • Provide flood risk management projects that support continued agricultural production.
  • Preserve and protect historic, cultural, and tribal resources.
  • Reduce flood risk to major transportation corridors.
  • Improve existing habitat within the river corridor.
  • Reduce operation and maintenance costs of the existing levee system to local and federal governments.

Related Resources:



Letter to Army Corps of Engineers June 17, 2015


Letter to Army Corps of Engineers April 1, 2015


Army Corps of Engineers: Waiver: Janicki
Army Corps of Engineers: Waiver: Dahlstedt
Army Corps of Engineers: Waiver: Wesen
Concurrent Review Summary & Scope/Schedule/Budget for Study Completion
Feasibilty Schedule
Larsen / DelBene Letter


Skagit River General Investigation NEPA Public Meeting presentation June, 2014
Status Update Presentation to the Board of County Commissioners June, 2014
Status Update Presentation to the Board of County Commissioners May, 2014

Draft Feasibility Report and Environmental Impact Statement May, 2014


Skagit River Hydrology Technical Documentaion August, 2013
US Army Corps of Engineers: SMART Planning Milestones July 15, 2013
G.I. Status Update Presentation November 12 2013
G.I. Status Update Presentation May 15 2013
USACE Approach to Climate Change and Sea Level Rise May 7 2013
Project Status Summary: May 6, 2013
Project Status Summary: February 26, 2013


Spring 2012: Preliminary Alternatives Outreach Summary Report
September 26, 2012: Public outreach Comments Received
September 17, 2012: Status Update Flood Control Zone District Advisory Committee
February 2012, U.S. Army Corps of Engineers Civil Works Feasibility Study Program Execution and Delivery
May 4, 2012 Public Outreach on Preliminary Range of Alternatives | Comment Form
April 25, 2012 Preliminary Alternatives Presentation Read-Ahead
March 13, 2012 Feasibility Scoping Meeting Agenda
January 31, 2012 Skagit Review Plan


January 31, 2011 Basin Levees
January 31, 2011 Levee Risk and Reliability Report
August 31, 2011 Skagit Revised Measures
September 1, 2011 Flood Narrative
September 1, 2011 Revised Economics
September 20, 2011 Skagit FSM Transmittal
September 1, 2011 Alternatives Formulation Strategy
November 23, 2011 Skagit HQUSACE Comments
2011 USACE NEPA Scoping Report


June 18, 2010 Geotechnical and Hydrogeologic Report
December 23, 2010 Skagit Environmental Baseline

Resource Links:

US Army Corps of Engineers: Seattle District