floodplain issues in transportation design training seminar

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Floodplain Issues In Transportation Design

Training Seminar

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Before we start…...• Restrooms

• Fire Exits

• Water/soda machines

• Discussion/Comments/Questions

• Lunch

• Accreditation

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Presenters InformationBill Jenkins, ADWR

Phone: (602) 417-2445Email: [email protected]

Chuck Williams, CL Williams ConsultingPhone: (928) 368-2248Email: [email protected]

Jon Fuller, JE Fuller Hydrology & GeomorphologyPhone: (480) 752-2124Email: [email protected]

John Wise, Stantec ConsultingPhone: (520) 750-7474Email: [email protected]

LTAP (Local Technical Assistance Program)Annie Parris

Phone: (602) 712-7157Email: [email protected]

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Course Outline8:00 am – Start

I. Introduction – (15 minutes)

II. Overview of Regulations – (30 minutes)

IV. Overview of State Standards - (15 minutes)

V. Flood Hydrology and Floodplain Hydraulics – (30 minutes)

9:45 am – Break (15 minutes)

V. Flood Hydrology and Floodplain Hydraulics Continued – (40 minutes)

VI. River Engineering and Geomorphology – (60 minutes)

11:40-12:50 pm – Lunch (70 minutes)

VII. Effects of Transportation Structures on Fluvial Systems – (30 minutes)

VIII. Overview of Design Guidelines – (30 minutes)

3:00 pm – Break (15 minutes)

X. Illustrated Examples Continued – (90 minutes)4:45 pm – Open Discussion/Comments/Questions (15 minutes)

III. Overview of ADWR/ADEM Roles – (15 minutes)

IX. Design Process – (55 minutes)

X. Illustrated Examples – (15 minutes)

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I. IntroductionA.Purpose of Course

1. Introduce Floodplain Concepts in Transportation Design

2. Familiarize Students with Floodplain Regulations Important for Transportation Design

3. Introduce Technical References for Design and Analysis of Transportation Structures in Floodplains

4. Review Design Examples of Transportation Structures in Floodplains

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Mississippi River Channel near Commerce, Missouri.

The river’s surface area was reduced by 50% in this area from 1884 to 1968 due to both natural reasons and development work reasons. HDS6-01 (Sections 1.2.1).

I. IntroductionB.General Description of Floodplain

Issues in Transportation Design1. Rivers are Naturally Dynamic

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River changes can affect transportation structures. Rivers may change due to:

Shortened flow paths (cutoffs) making rivers less “curvy” and increase streambed slopes and velocities.

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The river may no longer “want” to cross under an existing bridge, but would “prefer” a crossing elsewhere causing

erosion and scour of upstream abutments and embankments.

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Structural projects, such as transportation construction projects, may induce river changes.

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I. Introduction 1. Rivers Are Naturally Dynamic

River changes may be induced by human activities including: channel alterations (i.e.,straightening, dredging, clearing) land use changes (i.e., urbanization, agriculture, mining,

and logging) streambed mining/excavationconstruction of dams or reservoirs

River changes can propagate upstream or downstream, sometimes quickly, sometimes over long periods.

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Examples of Watercourse Straightening

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Examples of Watercourse Changes with Time

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Structural projects, such as transportation construction projects, may induce river changes.

Also: hydrologic change, geological shifting (such as uplift or warping of earth’s surface), climatic fluctuations (droughts, floods), erosion and deposition at bends, or in some cases even sea level changes.

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In summary, archaeological, botanical, geological, and geomorphic evidence supports the conclusion that:most rivers are subject to constant change as a normal part of their morphologic evolution.

“Therefore, stable or static channels are the exception in nature.”

HDS6-01 (Sections 1.2.1)

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Issues in Transportation Design1. Rivers are Naturally Dynamic2. Example of Bridge Crossing Effects:

Bridge crossings are among the most common types of river encroachments.

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I. IntroductionB.General Description of Floodplain Issues in

Transportation Design1. Rivers are Naturally Dynamic2. Example of Bridge Crossing Effects:

Bridge crossings are among the most common types of river encroachments.Some Possible Immediate Responses: Bridge construction may cause a contraction leading to local scour, water level changes (backwater), lateral instability, bank erosion, abutment scour erosion, and deposition downstream.

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This watercourse may be shifting to accommodate the available flow path under the bridge.

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Scour Protection for the Abutmentwas necessary to protect the bridge.

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I. IntroductionB.General Description of Floodplain Issues in Transportation

Design1. Rivers are Naturally Dynamic2. Example of Bridge Crossing Effects:

Bridge crossings are among the most common types of river encroachments.Some Possible Immediate Responses: Bridge construction may cause a contraction leading to: local scour, water level changes (backwater), lateral instability, bank erosion, abutment scour erosion, and deposition downstream.Some Possible Delayed Responses: Constrictions may cause higher local velocities, which may affect tributaries, the main channel, and other transportation crossings.

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Resulting erosion and soil degradation in channels may adversely affect other transportation crossings

of the tributaries or main channel.

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Some Worst Case Results For Bridges

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Some Worst Case Results For Bridges

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[Handout 16 Pictures from Table 9.1 of HDS6-01]

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Transportation Design1. Rivers are Naturally Dynamic2. Example of Bridge Crossing Effects:3. Example of Culvert and Dip Crossing Effects:

Culverts and dip crossings may not be of such grand scale as a bridge, but are a far more common type of roadway crossing improvement.

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Example of Culverts

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Transportation Design1. Rivers are Naturally Dynamic2. Example of Bridge Crossing Effects:3. Example of Culvert and Dip Crossing Effects:

Culverts and dip crossings may not be of such grand scale as a bridge, but are a far more common type of roadway crossing improvement.Some Possible Responses to culvert and dip section designs may include sedimentation, streambed degradation, increased magnitudes and frequencies of flooding upstream, or undermining of roadway foundations.

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Some Worst Case Results For Culverts

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Some Worst Case Results For Culverts

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C.Examples of cases that demonstrate floodplain issues, problems and constraints Nowood River near

Ten Sleep, Wyoming

I. Introduction

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C.Examples of cases that demonstrate floodplain issues, problems and constraints Nowood River near Ten Sleep, Wyoming Lee Moore Wash near Sahuarita, Arizona

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Lee Moore Wash Crossing – After

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I. IntroductionD.Design Process Preview

(a.k.a. An ounce of prevention, is worth a pound of cure!) Overview of Design Guidelines

A. Bridge DesignB. Culvert DesignC. Dip Crossing DesignD. Low-Flow Channel Crossing Design

Overview of Design ProcessA. Project InitiationB. Principal Factors to be Considered in DesignC. Resources (Data checklists and sources)

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I. IntroductionE. FITD Class CD Preview

Class CD provides a searchable data base of reference literature

Interactive browser (Electronic Navigator) assists learning about key issues in the design of roadways and other transportation structures in floodplain environments Issues are arranged by topicDirect links open relevant documents listed under each

topicCD suggests websites to monitor for document updates

floodplain issues in transportation design training seminar

Documents

transportation design1

transportation design2

floodplain hydraulics

floodplain concepts

dynamic river changes

dynamicriver changes

rivers surface area

reservoirsriver changes