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Introduction to Floodplain Analysis


CU
Enrollment in this course is by invitation only

Problem Statement

Water resources engineers are frequently required to protect people and property from the impacts of flooding. In order to determine the depth of flood waters and to determine the size or width of floodplains, engineers must first examine both the hydrology and hydraulics of the watershed to determine the amount of water that will reach a stream and how it will be propogated down the channel and across the floodplain.

When making decisions about the best ways to prevent flood damages, government officials, engineers, and community residents need to know the water elevation to plan for, essentially asking how high will the river rise during a flood? In this module, a case study will consider Darlington, WI, a town that experienced significant flooding in the spring of 2019, along with many parts of the Upper Midwest and states bordering the Mississippi River.

Module Overview

This module addresses fundamental topics in hydrology and hydraulics through a real-world application of floodplain analysis on the Pecatonica River near Darlington, WI. These key water resources topics include the application of the principles of watershed hydrology (where does water go in the watershed, by what pathway, and for how long), where to find data required for floodplain analysis, the theoretical underpinnings used to analyze gradually varied flow conditions, and the development of a HEC-RAS model to simulate flood extents for different return period discharges.

This will be accomplished through learning activities within each section. Results from each activity will be recorded in results templates. The results templates for each activity can be found at the beginning of each activity.

Topics Covered

  • watershed delineation
  • streamflow data acquistion and analysis
  • streamflow frequency analysis
  • fundamentals of open channel flow
  • analysis of gradually varied flow
  • floodplain analysis using HEC-RAS

Prerequisites

N/A

Learning Objectives

At the end of this module, students will be able to:

  • delineate a watershed
  • acquire and analyze streamflow data
  • perform frequency analysis to determine streamflow return period / magnitude
  • apply fundamental principles of open channel hydraulics (Manning's equation, Standard Step method)
  • perform a floodplain analysis using HEC-RAS

This will be accomplished through activities within each section. Results from each activity will be recorded in results templates. The results templates for each activity can be found at the beginning of each activity.

Course Authors

Austin Polebitski

Austin Polebitski

Assoc. Professor, Civil and Environmental Engineering, University of Wisconsin Platteville

polebitskia@uwplatt.edu
Tyler Smith

Tyler Smith

Assoc. Professor, Civil and Environmental Engineering, Clarkson University

tsmith@clarkson.edu

Target Audience

Junior/Senior Hydrology and Water Resources Engineering Courses

Tools Needed

Computer with access to Internet, Excel, and HEC-RAS software [free]

Course Citation

Polebitski, A. and Smith, T. (2020). Introduction to Floodplain Analysis. HydroLearn. https://edx.hydrolearn.org/courses/course-v1:UW_Platteville+CEE4300+F2020/about

Expected Effort

A student could expect to complete this module with approximately 25 work hours.