IIAB/Overview

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Assessing the Impact of Federal Navigation Projects on Adjacent Beaches:
Methods to Conduct Section 111 Studies

by Julie D. Rosati


PURPOSE: This Wiki-Technical Note presents an overview of the Section 111 Authority, presents methods that can be applied in Section 111 studies, and provides a reference list to previous Section 111 studies. The Wiki-TN concludes with recommendations for a systematic, defensible Section 111 analysis.

CITATION:

 Rosati, J.D., 2011, Assessing the Impact of Federal Navigation Projects on Adjacent Beaches:  
Methods to Conduct Section 111 Studies, Wiki-TN, Vicksburg, MS: U.S. Army Engineer Research and Development Center.

INTRODUCTION: Section 111 of the 1968 Rivers and Harbors Act, Public Law 90-483 gives the Federal government the authority to study, plan, and prevent or mitigate damages to shores caused by navigation projects. Since the 1970s, there have been numerous Section 111 studies that have estimated the erosion caused by navigation channels, jetties, and dredging and placement activities over the lifetime of the project. The goal of a Section 111 study is to estimate the percentage of damages caused by the Federal navigation project, which will then be cost-shared with a local partner at the same percentage as the original project to mitigate for the navigation project. Section 111 studies have applied a range of methods, including an assessment of processes (waves, currents, sediment transport) with and without the project, analysis of historical shoreline position and beach profile data, and formulation of sediment budgets.

TYPES OF DATA FOR ANALYSIS:

Condition Data

  • Shoreline position
  • Beach profiles
  • Topography and bathymetry

Processes

  • Long-term sea level change
  • Offshore (and nearshore, if available) wave and wind climatology
  • Tidal data

Anthropogenic Activities

  • Dredging and placement history
  • Construction of jetties, seawalls, groins, and other structures
  • Mining activities