Technical Memo: Hydrologic Hazard Assessment
Publication Date
2-2025
Publisher
Cal Poly Humboldt
Abstract
This technical memorandum outlines the development of a 2-Dimensional hydraulic model constructed to simulate a range of fluvial and coastal event conditions in the Hwy 101 corridor to support the Comprehensive Climate Adaptation and Implementation Plan (CAIP) for the Eureka-Arcata Corridor. The goal of this phase of the modeling exercise was to simulate existing conditions to characterize in-channel and floodplain hydraulics within the project area. The results will help guide the formulation of adaptation strategies and establish a baseline for comparison for forthcoming vulnerability assessments and future conditions scenarios. The following sections provide a detailed overview of the hydrologic analyses used to define boundary conditions and develop the hydraulic model, including data inputs, assumptions, and methodologies. Additionally, salient model results are presented, highlighting key in-channel, floodplain and infrastructure hydraulic characteristics. All values provided in this memo are in English units and vertical elevations are referenced to the North American Vertical Datum of 1988 (NAVD88), unless otherwise noted. All geospatial data associated with the 2D hydraulic model were projected in the NAD 1983 NSRS 2007 State Plane California I FIPS 0401 (US Feet) following coordinate.