Floodplain ManagementSESSION 2

Stream Systems on

Dynamic Earth

Geologic Framework

Prepared By

Donald R. Reichmuth, PhD.

Geologic Framework

Objectives:Define FloodplainsDescribe Stream System FunctionsExplain Tectonic PlatesExplain Vertical Plate MotionIdentify Tectonic DomainsSummarize Glacial BehaviorCompare Erosion Related Processes

River Basin Definition

A region or area

bounded by a topographic divide

that contributes water

to a particular stream channel (corridor)

or other water body.

Floodplain Definition

That portion of a Drainage Basin

that is covered by Transported Sediment

that was deposited in or near a stream channel.

FUCTIONS OF RIVER SYSTEMS

• Removes Erosional Debris– Most Important– Acts Over Long Periods

• Removes Excess Water– Importance Secondary– Acts Sporadically Over Short Periods

• Provides Fresh Water Supply– Necessary To Sustain Life

• Transports Chemicals & Nutrients

Geologic Framework• Tectonics

• Passive Margins• Stable Platforms• Active Margins• Hot Spots

• Glaciation• Alpine Glaciers• Continental Glaciers

• Geomorphology• Surface Forming Processes

– Water– Ice– Gravity– Wind

Present Plate Boundaries

BASIC TYPES OF PLATE INTERACTION

Stream Systems on

Dynamic Earth

North America

Structure– Craton

• Shield• Stable Platform

– Mobile Belts

Tectonic Activity– Active Margin– Passive Margin

Karst TopographyExample

• Solution Cavities In Limestone

• Streams Have Subsurface Connections

Cretaceous Inland Sea100 Million Years Ago

Vertical Plate Motion

Causes:Tectonic/Earthquake Activity

Erosion & Sediment Loading

Glaciation

Human Activities

Uplift Example

Himalayan Data

Present Height --- 30,000 Ft (9,500 m)

Tectonic Uplift Rate ---More Than 1 cm/yr

Erosion Rate ---Now Equals Uplift Rate

Sediment Yields Highest Known

Worldwide Erosion Rates

Oceanic-Continental Convergence

Oceanic Crust SubductsOcean Trench Forms

Lighter Melted Material RisesVolcanoes Form

Lithosphere Plunges Into Asthenosphere

Effects Of Plate Locking

Effects Of Erosion

Man Induced Vertical Movement

Ongoing Elevation Changes

Active MarginNote:• Aleutian Trench

• Canada– Strike-Slip Faulting

• Mobile Belt Deposits

• California– Strike-Slip Faulting

Active Margin

• Ocean-Continent Subduction

• Strike Slip Faulting

Hot Spot Locations

Hawaiian Hotspot

Passive Margin

• Coastline Sinking– Drowned River

Valleys– Numerous Near-

shore Islands– Shoreline Migrating

Landward

Northern Hemispheric Glacial Areas

16,000 B.P.

NOTE:

Portions Of Alaska

Are Ice Free

Pleistocene Glaciation

Note:• Alpine Glaciers• Continental

Glaciers• Ice Marginal Rivers• Alaska Ice Free

Area

Glacial Impact Areas

Preglacial Teays Basin

Teays BasinOverrun By Ice

Channel Buried

Ohio RiverForms

Drains Basin

Western Glacial Lakes

15,000 B.P.

– Climate Much Wetter Than Present

– Large Basins Had Internal Drainage

Loess

Wind Blown Silt

From GlaciersRock Flour

Stream Banks Stand Vertical

When Stable

Glacial ReboundContours In Meters Uplift

Great Lakes Glacial ReboundContours – Uplift per 100 Yrs.

Sea Level Changes

16,000 Years BP -- 120 Meters Lower

6,000 Years BP – Reached Present Level

Near Future – Expected To Rise

Holocene Sea Level Changes

Primarily Cause --- Glacial Melting

In The

Northern Hemisphere

Erosion In River Basins

Controlling Factors:• Chemical vs. Mechanical Weathering

– Temperature– Precipitation

• Basin Gradient

• Basin Soil/Bedrock Type

• Tectonic Activity

Chemical & Mechanical Weathering

Erosion Processes

Erosion Processes

Mass Movements

Class Handout

CASE STUDIES

• Columbia River

• Mississippi River

• Ohio River

• Potomac River

• Red River of the North

• Rio Grande River

• Santa Ana River

Geologic Setting

Tectonic Glacial Water Sediment Outlet

COLUMBIA RIVER (INCLUDING ROCKY MTN. TRENCH,

SNAKE RIVER, WILLAMETTE RIVER, COLUMBIA RIVER BAR &

LONG BEACH)

Active Margin, Subducting Plate, Flood Basalts Shifted Channel

Alpine Glaciation, Lake Missoula Floods, Bonneville Flood

Significant Snow-pack, Dryer Summers

Considerable Bedrock Control, Average

Sediment Production

Pacific Ocean, Glacial Flood Deposits Off Coast, Northern Shore Current

Dominant

MISSISSIPPI RIVER (INCLUDING MISSOURI RIVER &

LOUISIANA DELTA)

Passive Margin, Stable Mid-continent Shelf, Coastal Zone

Sinking

Major Glacial Meltwater Channel, Strong Impact From Low Glacial

Sea Level

Heavy Lowland Spring Runoff, Heavy

Rainfall At Times

Large Quantities Of Fine Sediment And Dissolved

Solids

Gulf Of Mexico, Large Marine Fan-delta, Westward Coastal

Circulation

OHIO RIVER (INCLUDING TEAYS RIVER, MONONGAHELA RIVER &

ALLEGHENY RIVER)

Stable Mid-continent, Heads In Old Eroded Allegheny Mtns., Crosses Stable Mid-continent

Sedimentary Shelf

Ice Marginal Channel Built From Pieces Of Numerous Drainages

Significant Spring Runoff, Above

Average Precipitation

Below Average Because Of Low Elevation And

Good Vegetative Cover

Flows Into Mississippi River, Can Have Flood

Synchronization Problems

POTOMAC RIVER (INCLUDING CHESAPEAKE BAY &

DELMARA PENINSULA)

Passive Margin, Heads In Old Eroded Allegheny Mtns., Crosses

Into Sinking Sedimentary Coastal Shelf, Impacted By A

Meteor

Originally Graded To Low Glacial Sea level

Above Average Precipitation

Below Average Because Of Low Elevation And

Good Vegetative Cover

Atlantic Ocean, Submerged River Valley,

Northern Coastal Circulation.

RED RIVER OF THE NORTH (INCLUDING LAKE WINNIPEG &

HUDSON BAY)

Stable Mid-continent, Flows From Sedimentary Shelf OnTo

Continental Craton

Originates In Glacial Lake Agassiz, Flows North Against

Glacially Induced Crustal Rebound Centered Near Hudson Bay, Stream Gradient Lowering

Rapid Spring Lowland Snowmelt Occasionally Mixed

With Rain

Fine Grained Derived From Old Glacial Lake

Bed

Hudson Bay That Has Uplifted Over 100 Meters

Since The Last Glaciation

RIO GRANDE RIVER (INCLUDING ELEPHANT BUTTE

RESERVOIR, RIO PUERCO & PADRE ISLAND)

Active Uplift At Head (Mtn. Building), Mouth Sinking At

Passive Margin

No Significant Glacial Impacts, Small Amount Of Alpine

Glaciation At Head

Area Arid, Significantly Higher Precipitation During

Glacial Periods

High Fine Sediment Production Caused By

Occasional High Intensity Storms And Scant Vegetative Cover

Gulf Of Mexico, Northeast Coastal Circulation

Strongly Influences The Stability Of Padre Island

SANTA ANA RIVER (INCLUDING SAN BERNARDINO

MTNS., PRADO WETLANDS, LOS ANGLES BASIN & HUNTINGTON

BEACH)

Active Margin, Strike-slip Faulting Very Active

No Significant Glacial Impacts

Area Arid, Significantly Higher Precipitation During

Glacial Periods,Water

Imported Into Basin

High Fine Sediment Production Caused By

Occasional High Intensity Storms And Scant Vegetative Cover

Pacific Ocean, Southern Coastal Circulation

Influences Huntington Beach

GEOLOGIC SETTINGRIVER BASIN

JURISDICTION & CONCERNS

Habitat Pollution Development

COLUMBIA RIVER (INCLUDING ROCKY MTN. TRENCH, SNAKE RIVER, WILLAMETTE RIVER,

COLUMBIA RIVER BAR & LONG BEACH)

Washington, Oregon, British Columbia &

Indian Nations

Declining Salmon Populations

Cominco Smelter (Canada)Numerous Large Dams,

Hanford Nuclear Facility, Barge Traffic

Conflict Developing Between Indian Nations & Newer Arrivals

MISSISSIPPI RIVER (INCLUDING MISSOURI RIVER &

LOUISIANA DELTA)

Midwestern States & Montana

Loss Of Channel Length, Disruption Of Sediment Transport

Agricultural Chemicals Entering River, Gulf Of Mexico

"Dead Zone"

Levee Construction, Barge Traffic, Large Dams, Oil & Gas

Drilling/Production

Conflict Developing Between Upper River States (Especially Along The Missouri) & Lower

River States

OHIO RIVER (INCLUDING TEAYS RIVER, MONONGAHELA RIVER &

ALLEGHENY RIVER)

Pennsylvania, Ohio, West Virginia, Kentucky, Indiana

& Illinois

Impacted By Industrial Use

Industrial Discharges, Acid Rain From Power Plant

Emissions

Change In Vegetative Cover, Major Urban Growth In Valleys

Original Teays River Partially Buried During Glaciation

POTOMAC RIVER (INCLUDING CHESAPEAKE BAY &

DELMARA PENINSULA)

West Virginia, Virginia, Washington D.C. & Maryland

Bay Contains 160 Nonindigenous Species

Industrial Discharges, Urban Runoff, Salt Water Intrusion In

Groundwater

Expanding Urbanization, Shoreline Construction

Demand For Domestic Water Supplies Becoming Critical

RED RIVER OF THE NORTH (INCLUDING LAKE WINNIPEG &

HUDSON BAY)

North Dakota, Minnesota, & Manitoba

Degraded By Agriculture

Agricultural Chemicals Entering River

Construction On The Floodplain, Levee Construction Near Towns

Management Requires Cooperaton Between Canada &

The U.S.

RIO GRANDE RIVER (INCLUDING ELEPHANT BUTTE

RESERVOIR, RIO PUERCO & PADRE ISLAND)

Colorado, New Mexico, Texas, Chihuahua, Coahuila,

Nuevo Leon & Tamaulipas

Loss Of Fresh Water Access For Marine

Species

Channel Heavily Dewatered Particularly In Lower Reaches

Dam Construction, Water Withdrawal For Agriculture,

Sediment Filling Channel In Some Sections

Requires Water Allocation Between The United States &

Mexico

SANTA ANA RIVER (INCLUDING SAN BERNARDINO MTNS.,

PRADO WETLANDS, LOS ANGLES BASIN & HUNTINGTON BEACH)

California (Containing Cities & Counties Of

The Los Angles Basin)

Channel Concrete Lined, Total Loss Of

Cover

Sewer Outfalls Discharge Into River, Salt Water Intrusion Into Groundwater, Fires In

Upper Watershed

Massive Urban Development In Lowlands, Construction On Steep

Erosive Hillsides

Water Imported From The Colorado River

RIVER BASIN JURISDICTION RECENT CONCERNS COMMENTS

Slide Presentation Prepared By

Geomax, P.C.Dr. Donald R. Reichmuth, President

1023 W. 30th Ave.Spokane, WA 99203-1324

Phone & FAX – 509-838-6390E-mail – geomax@comcast.net