U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2006–5029

In cooperation with the City of Duluth, Minnesota

Geomorphic Characteristics and Classification of 

Duluth-Area Streams, Minnesota
Geomorphic Characteristics and 

Classification of Duluth-Area Streams, 

Minnesota

By Faith A. Fitzpatrick, Marie C. Peppler, Michele M. DePhilip, and 

Kathy E. Lee

In cooperation with the City of Duluth, Minnesota

Scientific Investigations Report 2006–5029

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2006

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iii

Contents

Conversion Factors, Vertical Datum, and Abbreviated Units of Measurement ........................ vi

Abstract .................................................................................................................................................. 1

Introduction............................................................................................................................................ 1

Purpose and Scope ..................................................................................................................... 4

Description of Study Area .......................................................................................................... 4

Methods.................................................................................................................................................. 5

Watershed Characterization ...................................................................................................... 5

Segment Characterization ........................................................................................................ 10

Reach Characterization ............................................................................................................ 10

Rapid Field Assessments ................................................................................................. 10

Intensive Field Surveys .................................................................................................... 12

Classification .............................................................................................................................. 14

Geomorphic Characteristics ............................................................................................................. 14

Watershed Characteristics ...................................................................................................... 14

Segment Characteristics .......................................................................................................... 16

Reach Characteristics and Processes ................................................................................... 32

Potential Response and Sensitivity to Disturbance ............................................................. 45

Geomorphic Segment Classification ............................................................................................... 45

Headwater Channels with Gentle Slopes .............................................................................. 49

Upper Main Stems with Moderate Slopes ............................................................................ 49

Middle Main Stems with Gentle or Moderate Slopes ......................................................... 49

Bedrock Main Stems with Steep Slopes ............................................................................... 50

Lower Main Stems with Moderate Slopes ............................................................................ 50

Aggradational Main Stems with Gentle Slopes .................................................................... 51

Tributaries with Moderate to Steep Slopes ........................................................................... 51

Summary and Conclusions ................................................................................................................ 51

Acknowledgments .............................................................................................................................. 52

References Cited................................................................................................................................. 53
iv

Figures

 1. Map showing study area and sampling sites in the Duluth, Minn., area, 

2003–2004 .............................................................................................................................. 2

 2. Plan view and longitudinal profile of geomorphic zones within a stream

network .................................................................................................................................. 3

 3. Diagram showing spatial hierarchy of watershed, stream-segment, and 

stream-reach scales ........................................................................................................... 3

 4–7. Maps showing:

 4. Bedrock geology of the Duluth, Minn., area ............................................................ 6

 5. Surficial geology and geomorphology of the Duluth, Minn., area ....................... 7

 6. Land cover in the Duluth, Minn., area ....................................................................... 8

 7. Population density in the Duluth, Minn., area, 1940 to 2000 .................................. 9

 8. Diagram showing valley development and valley types for Duluth-area 

streams, Minn. .................................................................................................................... 11

 9. Graphs showing longitudinal profiles of streams in the A, southwestern, 

and B, northeastern parts of the Duluth, Minn., area .................................................. 15

 10. Diagram showing hierarchical classification of channel types in the 

Duluth, Minn., area ............................................................................................................ 32

 11. Graphs showing longitudinal profiles for A, Lester River and B, Miller 

Creek, in the Duluth, Minn., area ..................................................................................... 42

 12. Photographs of rapid assessment sites on tributaries affected by bedrock: 

A, site 46 on Coffee Creek, B, site 2 on Stewart Creek tributary, C, site 47 

on Merritt Creek tributary, and D, site 5 on Keene Creek tributary, Duluth, 

Minn., area .......................................................................................................................... 44

 13. Maps showing geomorphic segment classification for Duluth-area streams, 

Minn., (A, northern portion and B, southern portion) .................................................. 46
v

Tables

 1. Land-cover characteristics for Duluth-area watersheds, Minn. .............................. 13

 2. Conditions at the mouths of Duluth-area streams, Minn. ........................................... 16

 3. Number of stream segments in each slope/drainage-network position 

category for Duluth-area streams, Minn. ...................................................................... 17

 4. Number of stream segments in each slope/valley type category for 

Duluth-area streams, Minn. ............................................................................................. 17

 5. Geomorphic characteristics of stream segments for Duluth-area streams, 

Minn., 2003–2004 ................................................................................................................ 18

 6. Explanation of abbreviations used in tables for segment and reach 

characteristics in this study of Duluth-area streams, Minn. ...................................... 30

 7. Reach characteristics at rapid assessment and intensive survey field sites 

for Duluth-area streams, Minn., 2003–2004 ................................................................... 34

 8. Potential channel types in each slope/valley category for Duluth-area 

streams, Minn. .................................................................................................................... 44

 9. Geomorphic segment classification scheme for streams in the Duluth, 

Minn., area based on slope, drainage-network position, geologic setting, 

and valley type ................................................................................................................... 48
vi

Conversion Factors, Vertical Datum, and Abbreviated 

Units of Measurement

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

Area

square mile (mi2

) 2.590 square kilometer (km2) 

Flow rate

cubic foot per second (ft3

/s) 0.02832 cubic meter per second (m3/s)

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as 

follows:

 °C=(°F-32)/1.8

Vertical coordinate information is referenced to the North American Vertical Datum of 1927 

(NAVD 27).

Horizontal coordinate information is referenced to the North American Datum of 1983 

(NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.
Geomorphic Characteristics and Classification of 

Duluth-Area Streams, Minnesota

By Faith A. Fitzpatrick, Marie C. Peppler, Michele M. DePhilip1, and Kathy E. Lee

Abstract

In 2003 and 2004, a geomorphic assessment of 

streams in 20 watersheds in the Duluth, Minn., area 

was conducted to identify and summarize geomorphic 

characteristics, processes, disturbance mechanisms, and 

potential responses to disturbance. Methods used to assess 

the streams included watershed characterization, descriptions of segment slopes and valley types, historical aerial 

photograph interpretation, and rapid field assessments and 

intensive field surveys of stream reaches. Geomorphic conditions were summarized into a segment-scale classification with 15 categories mainly based on drainage-network 

position and slope, and, secondarily, based on geologic 

setting, valley type, and dominant geomorphic processes. 

Main causes of geomorphic disturbance included historical logging and agriculture, and ongoing urban development, human-caused channel alterations, road and storm 

sewer drainage, ditching, hiking trails, and gravel pits or 

quarries. Geomorphic responses to these disturbances are 

dependent on a combination of drainage-network position, 

slope, and geologic setting. Geologic setting is related to 

drainage-network position because the geologic deposits 

parallel the Lake Superior shoreline. Headwater streams in 

large watersheds flow over glacial deposits above altitudes 

of about 1,200 feet (ft). Headwater tributaries and upper 

main stems have ditch-like channels with gentle slopes 

and no valleys. Urban development and road drainage 

cause increased runoff and flood peaks in these segments 

resulting in channel widening. Below about 1,200 ft, mainstem segments generally are affected by bedrock type and 

structure and have steep slopes and confined or entrenched 

valleys. Increases in flood peaks do not cause incision or 

widening in the bedrock-controlled valleys; instead, the 

flow and scour areas are expanded. Feeder tributaries to 

these main stems have steep, confined valleys and may 

be sources for sediment from urban areas, road runoff, or 

storm sewer outfalls. Main-stem segments near the glacial 

deposits/surficial bedrock contact (1,000–1,200 ft) have 

the most potential for response to disturbance because they 

tend to have narrow valleys with sandy glacial lakeshore 

deposits and moderate slopes. Increases in flood peaks 

(from upstream increases in runoff) increase the potential 

for landslides and mass wasting from valley sides as well 

as channel widening. 

Introduction

Streams in the Duluth, Minn., area (fig. 1) have been 

affected by a variety of historical land uses but remain 

highly valued for their natural resources. Streams and 

riparian areas contain important habitat for endangered or 

threatened aquatic and terrestrial species. Understanding 

the geomorphic conditions and processes of streams within 

a stream network or watershed framework is important because they relate to the overall water and aquatic 

resource quality of the stream and to the plant and animal 

communities and habitat adjacent to the stream. In 2003–

2004, the U.S. Geological Survey (USGS), in cooperation 

with the city of Duluth, studied the geomorphic characteristics and processes that affect the physical conditions of 

Duluth-area streams. 

The Duluth Natural Areas Program (DNAP) is based 

on a city ordinance designed to protect and preserve the 

natural heritage of Duluth and the surrounding area. The 

program strives to protect plant and animal communities, 

habitat for special species, natural water features, important bird habitat areas, and landscapes. Data on stream 

geomorphic conditions provide a basis for evaluating the 

rarity and quality of natural resources nominated to DNAP 

for their natural water features. An assessment of geomorphic conditions within the stream channels is important 

1

 The Nature Conservancy, Great Lakes Program, Chicago, Ill.
MINNESOTA

WISCONSIN

9

8

7

6

5

4

3

2 1

44

43

41 42

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

13 12

10

14

11

46

47

48

45

Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th to 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th to 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

Lake

Superior

MINNESOTA

WISCONSIN

Subbasin boundary

Stream

Site and identifier number

Intensive survey 

35 Rapid assessment

34

Stream basin boundary

Duluth International Airport

runway

Major road

State boundary

County boundary

City of Duluth

Study area

EXPLANATION

Base from Minnesota Department of Natural 

Resources hydrography and Wisconsin Department of 

Natural Resources hydrography: 1:24,000 digital data.

Transverse Mercator Projection, NAD 83

Interstate 35

U.S. Hwy 53

U.S. Hwy 2

St. Louis River Estuary

Carlton County

St. Louis County

Douglas County

State Route 194

Minnesota State Hwy 61

Interstate 35

U.S. Hwy 53

U.S. Hwy 2

St. Louis River Estuary

Carlton County

St. Louis County

Douglas County

State Route 194

Minnesota State Hwy 61

46°46'45"

 92°05'34"

46°50'11"

92°00'21"

0

0

4

4

2

2 KILOMETERS

MILES

Study

area

MINNESOTA

WISCONSIN

Figure 1. Study area and sampling sites in the Duluth, Minn., area, 2003–2004. Airport runway location from Minnesota 

Department of Transportation (2001).

2 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
for understanding the extent to which natural factors and 

land-use changes have affected geomorphic attributes, such 

as bed and channel configurations, and the likelihood that 

geomorphic conditions may change in the future.

A thorough stream geomorphic assessment includes 

a description of how channel, flood-plain, and valley landforms are spatially and temporally affected by regional and 

local geology, topography, climate, vegetative cover, and 

human modifications. Stream networks developed in homogeneous geologic deposits commonly consist of an erosion 

zone (where sediment and runoff are generated), a transition zone (were sediment and water are transferred through 

with no net gain or loss of material), and a deposition zone 

(where sediment from upstream erosion is dropped out of 

transport) (Schumm, 1977). A typical longitudinal profile 

of a stream illustrates how the slope of a stream typically 

changes from relatively steep in the erosion zone near 

its headwaters to gentle in the depositional zone near its 

mouth (Hack, 1960) (fig. 2). An understanding of sediment 

sources, transport, and deposition and their links to stream 

network position is key to understanding geomorphic 

responses to present and future disturbances.

Three common spatial scales used to identify geomorphic characteristics and processes are a watershed or landscape scale, a segment scale, and a reach or channel scale 

(fig. 3). The segment scale is a section of stream bounded 

Tributaries

Direction of water flow

Main stem Mouth

Erosion zone Transition zone Deposition

zone

DISTANCE UPSTREAM FROM MOUTH

ELEVATION

High gradient

Low gradient

Longitudinal profile

NOT TO SCALE

Figure 2. Plan view and longitudinal profile of geomorphic zones within a stream network (modified from Schumm, 1977)

Watershed Stream segment Stream reach/

channel

Point

bar

Rocks

Figure 3. Spatial hierarchy of watershed, stream-segment, and stream-reach scales (modified from Fitzpatrick and others, 1998).

Introduction 3
by confluences or physical or chemical discontinuities, 

such as major landforms, changes in slope, or point-source 

discharges. The reach scale is a length of stream chosen to 

illustrate a set of uniform channel features and represents 

the typical sampling unit used for field-based measurements of geomorphic characteristics. Reach-scale geomorphic conditions and processes can be used to infer conditions and processes for a given segment. 

A hierarchical channel classification system, based 

on geomorphic processes, was developed for mountain 

streams in the Pacific Northwest to help interpret channel 

morphology, assess geomorphic conditions, and predict responses to natural and human-caused disturbance 

(Montgomery and Buffington, 1993; 1997). In the Montgomery and Buffington (1997) classification, valleys were 

classified into three major types based on the predominant 

geologic materials in the valley—colluvial, bedrock, and 

alluvial (confined, moderately confined, and unconfined, 

respectively). Colluvial deposits mainly originate from 

landslides and mass wasting, whereas alluvial deposits are 

from transport and depositional processes related to modern rivers. Channels were classified into seven types—colluvial, bedrock, cascade, step-pool, plane-bed, pool-riffle, 

and dune-ripple. The channel types can be related to drainage-network position, underlying geology, and slope. The 

Montgomery and Buffington (1993; 1997) classification is 

not commonly used in the Midwest because streams have 

relatively gentle slopes compared to mountain streams. 

However, tributaries along the north shore of Lake Superior drain bedrock bluff areas and have slopes that exceed 

8 percent along some reaches. Bohle (2002) developed a 

modified version of this classification to assess geomorphic conditions for streams along the north shore of Lake 

Superior in Minnesota. Bohle (2002) classified stream 

segments into eight geomorphic map units (GMUs)—boulder/bedrock, main-stem boulder rapid, gravel-dominated 

pool-riffle, forced pool-riffle plane-bed, large woody 

debris/boulder step, tributary boulder plane-bed or rapid, 

beaver dam step-pool, and lacustrine/riverine wetland. 

The major objectives of the present geomorphic study 

of Duluth-area streams are to describe geomorphic characteristics, identify major geomorphic processes and factors 

contributing to geomorphic characteristics, identify historical changes in channel morphology and planform (plan 

view of the channel pattern), and develop a segment-scale 

classification based on similar geomorphic characteristics, 

processes, and responses to disturbance. The assessment 

and classification will provide baseline conditions and 

can be used as a tool for evaluating the quality of Duluth’s 

natural water features. Scientists, city managers, and 

citizens involved in the Duluth Natural Areas Program can 

use results from this study to help protect, preserve, and 

restore resources and help guide management activities. In 

addition to its social and conservation benefits, this study 

will advance the understanding of present and historical 

geomorphic conditions of Duluth-area streams, of other 

north- and south-shore tributaries to Lake Superior, and of 

other streams in similar hydrologic settings. 

Purpose and Scope

The purpose of this report is to provide an assessment and classification of the geomorphic characteristics, 

processes, and responses to disturbances of streams in the 

vicinity of Duluth, Minnesota. The scope of this report 

includes: 1) description of the current geomorphic characteristics, 2) identification of major geomorphic processes, 3) identification of factors contributing to current 

geomorphic characteristics and expected future trends in 

characteristics, 4) interpretations of historical changes in 

channel morphology and planform, and 5) development 

of a segment-scale classification based on geomorphic 

processes. Geomorphic characterizations and the classification system were based on watershed-, segment-, and 

reach-scale measurements and observations collected in 

2003 and 2004.

Any attempt to classify the myriad geomorphic 

characteristics and processes that can occur in urbanizing 

or urban streams with disturbed watersheds that have been 

altered by land clearing, channelization, and ditching into 

discrete categories will have limitations and problems. 

Therefore, the main goal of the classification portion of 

the study, for use with Duluth-area streams only, is to help 

show the importance of linking geomorphic characteristics 

and processes of a specific reach of stream in the context 

of its position within the landscape and geologic setting.

Description of Study Area

Streams in the Duluth area generally flow perpendicular to the shoreline of Lake Superior, from northwest 

to southeast (fig. 1). Altitudes of watersheds range from 

1,400 ft (above NAVD 27) in the headwaters to 602 ft at 

Lake Superior. Most of the altitude change occurs along 

the middle and lower main stems as streams flow over bedrock bluffs and outcrops near the shore of Lake Superior.

4 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
The climate of the Duluth area is characterized by 

cold snowy winters, cool or moderately warm summers, 

and evenly distributed precipitation (Eichenlaub, 1979). 

Large variations from average weather can occur because 

of the proximity of Duluth to Lake Superior. Average 

annual precipitation is 29–30 in., with 18 in. of average 

annual evapotranspiration and 10–12 in. of runoff (Young 

and Skinner, 1974). Mean daily maximum air temperatures 

range from 22oF in January to 78oF in July (Eichenlaub, 

1979).

Bedrock is near or at the land surface in the Duluth 

area and mainly consists of Proterozoic volcanic and igneous rocks, intrusions, and sedimentary rocks (Miller and 

others, 2002) (fig. 4). Nomenclature for geologic names 

of bedrock units follows that of the Minnesota Geological 

Survey. Bedrock type and faulting affects the pattern and 

density of the stream networks. Right-angle bends in the 

channel and stream confluences are indicative of underlying contacts between bedrock units or faulting. The Duluth 

Complex and miscellaneous other intrusive rocks form a 

prominent steep rocky bluff that parallels the shoreline of 

the St. Louis River Estuary and Lake Superior.

Quaternary surficial deposits in the Duluth area are 

generally in the upper parts of most of the watersheds but 

thin or absent from the middle main stems where bedrock 

is exposed at the land surface (fig. 5). Glacial deposits in 

the watersheds are from the Late Wisconsinan Lake Superior Lobe (Goebel and others, 1983). Glacial deposits in 

the headwaters and the upper parts of the watersheds above 

about 1,200 ft consist of supraglacial drift composed of 

sandy loamy till of the Cromwell Formation (Goebel and 

others, 1983; University of Minnesota–Duluth Geology 

Department and others, 1997; Hobbs, 2004). Later glacial 

readvances resulted in the deposition of silty loam till of 

the Lakewood Member, clay loam to silty clay loam till of 

the Moose Lake Member, and clay till of the informally 

named Knife River member, all of the Barnum Formation 

(Hobbs, 2004). In the Duluth area, the Lakewood Member 

is at altitudes from about 1,150 to 1,200 ft. The Moose 

Lake Member is at altitudes from about 1,100 to 1,150 ft. 

The Knife River member is at altitudes up to about 1,050 

ft. Shoreline features from wave action and beaches are 

present from about 1,020 to 1,100 ft and were caused by 

multiple phases of a glacial lake in the southwest part of 

Lake Superior during glacial retreats in the Late Wisconsinan and early Holocene (Leverett, 1929; Hobbs, 2004).

Land cover in the Duluth area consists of a mix of 

mainly urban land (developed/barren), forest, and shrub 

(Minnesota Department of Natural Resources, Division 

of Forestry, 2002) (fig. 6). Urban land is concentrated in 

Duluth and along transportation corridors leading into 

Duluth (fig. 1). Categories of marsh, lowland shrub, and 

lowland forest are in wetland settings.

Population density in 2000 for the area surrounding 

the studied streams ranged from greater than 5,000 people/

mi2

 near the center of Duluth to less than 250 people/ 

mi2 in rural areas (U.S. Census Bureau, 2000) (fig. 7). 

Comparison of population density maps for 1940, 1960, 

1980, and 2000 shows how urban development has spread 

through the watershed of Miller Creek and along the shore 

of Lake Superior north of Duluth over the last 20 years 

(U.S. Census Bureau, 2000; Van Riper, unpublished data). 

Methods

The methods used to assess the geomorphic characteristics of Duluth-area streams consisted of a variety of 

techniques that included data collection and interpretation 

at watershed, segment, and reach scales. 

Watershed Characterization

Drainage boundaries were delineated for the 20 

studied watersheds and also for subwatersheds of nine 

intensive survey sites to examine differences among watershed characteristics. Digital drainage boundaries from the 

USGS (Minnesota Water Science Center, written commun., 2003) were used and (or) updated based on visual 

interpretations from USGS 7.5-minute topographic maps. 

Drainage boundaries were overlaid with thematic maps of 

bedrock geology (Miller and others, 2002) (fig. 4), Quaternary deposits (University of Minnesota–Duluth Geology Department and others, 1997) (fig. 5), and land cover 

(Minnesota Department of Natural Resources, Division of 

Forestry, 2002) (fig. 6) by use of a geographic information system (GIS). These overlays were used to summarize 

differences among the watersheds for geologic setting and 

land cover (mainly the amount of urbanization). 

Longitudinal profiles were constructed for 15 mainstem streams. Stream lengths were measured with a map 

measurer between contour lines on USGS 7.5-minute 

topographic maps. Longitudinal profiles are used to identify changes in slope that are related to geologic features or 

spatial position within the stream network. 

Methods 5
Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th to 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th to 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

MINNESOTA

WISCONSIN

46°46'45"

 92°05'34"

46°50'11"

92°00'21"

Felsic series

Undifferentiated intermediate rocks

Anorthositic series

Plagioclase-rich gabbroic cumulates

MIDCONTINENT RIFT INTRUSIVE SUPERSUITE

DULUTH COMPLEX

Layered series

Troctolite and gabbro

Inclusion of magnetic rock

Bedrock not mapped

Undifferntiated volcanic rocks

Miscellaneous rock types

Rhyolite

EXPLANATION

KEWEENAWAN SUPERGROUP

NORTH SHORE VOLCANIC GROUP

Lower southwest sequence

Upper southwest sequence

Ely’s Peak basalts

Lakewood basalts

PALEOPROTEROZOIC ROCKS

OTHER

ANIMIKIE GROUP

Sillstone, shale, mudstone 

and greywacke

SEDIMENTARY ROCKS

Fond du Lac Formation

sandstone and shale

Gabbro diabase

Northland sill - gabbro

MISCELLANEOUS INTRUSIONS

Gabbro intrusion

Mafic intrusion

Virginia Formation

Stream

State boundary

Site

Intensive survey 

Rapid assessment

MESOPROTEROZOIC ROCKS

Base from Minnesota Department of Natural Resources hydrography and Wisconsin Department of 

Natural Resources hydrography: 1:24,000 digital data. Transverse Mercator Projection, NAD 83

Lake

Superior

St. Louis River

Estuary

MINNESOTA

WISCONSIN

Stream basin 

boundary

Subbasin boundary

0

0

4 MILES

4 KILOMETERS

2

2

Figure 4. Bedrock geology of the Duluth, Minn., area (from Miller and others, 2002).

6 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th to 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th to 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

MINNESOTA

WISCONSIN

St. Louis River

Estuary

MINNESOTA

WISCONSIN

MINNESOTA

WISCONSIN

St. Louis River

Estuary

46°46'45"

 92°05'34"

46°50'11"

92°00'21"

Alluvium, silt and sand with some 

gravel; hummocky

Ice contact, sand or gravel; 

hummocky or steep

Bedrock

Outwash, sand or gravel; 

rolling or steep

Organic deposits, peat; level

Supraglacial drift complex, 

loamy/sandy; steep

Till plain, clayey; rolling

Till plain, lake-modified, 

clay; rolling or undulating

Scoured bedrock uplands; rolling

Lacustrine deposits associated 

with Lake Duluth; clayey or sandy

Stream

State boundary

Site

Intensive survey 

Rapid assessment

EXPLANATION

Base from Minnesota Department of Natural Resources hydrography and Wisconsin Department of 

Natural Resources hydrography: 1:24,000 digital data. Transverse Mercator Projection, NAD 83

Lake

Superior

Holocene

Late Wisconsin

Proterozoic

Stream basin boundary

Subbasin boundary

0

0

4 MILES

4 KILOMETERS

2

2

Figure 5. Surficial geology and geomorphology of the Duluth, Minn., area (from University of Minnesota–Duluth Geology 

Department and others, 1997).

Methods 7
Lake

Superior

MINNESOTA

WISCONSIN

Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th and 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

Lester River

Lester River

Miller Creek

Mission

Creek

Kingsbury

Creek

Tischer Creek

Keene

Creek

Chester

Creek

Amity Creek

Sargent

Creek

Merritt

Creek

U.S. Steel Creek

Knowlton

Creek

Brewery & Greys Creeks

Coffee Creek

Stewart

Creek

Morgan Park

34th and 50th Avenue Creeks

62nd Avenue Creek

Buckingham Creek

Lenroot Creek

St. Louis River

Estuary

MINNESOTA

WISCONSIN

46°46'45"

 92°05'34"

46°50'11"

92°00'21" EXPLANATION

Stream

Stream basin 

boundary

Lowland shrub

Developed/barren

(urban)

Cropland

Upland shrub

Grassland

Upland forest

Lowland forest

Land cover

Water

Marsh

Base from Minnesota Department of Natural 

Resources hydrography and Wisconsin Department of 

Natural Resources hydrography: 1:24,000 digital data.

Transverse Mercator Projection, NAD 83

State boundary

Site

Intensive survey 

Rapid assessment

Subbasin boundary

0

0

4 MILES

4 KILOMETERS

2

2

Figure 6. Land cover in the Duluth, Minn., area (from Minnesota Department of Natural Resources, Division of Forestry, 2002).

8 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
1980 2000

1940 1960

Miller Creek Miller Creek

Miller Creek Miller Creek

0 4 2 MILES 8

0 4 8 KILOMETERS

1–250

251–500

501–1,000

1,001–5,000

Greater than 5,000

No tract defined

Population density in people per square mile

Stream

Stream basin 

boundary

County boundary

Census tract

boundary

EXPLANATION

Figure 7. Population density in the Duluth, Minn., area, 1940 to 2000 (U.S. Census Bureau, 2000; Van Riper, unpublished data).

Methods 9
Segment Characterization

Streams were first divided into segments with similar 

slope and valley confinement, similar to methods described 

in Montgomery and Buffington (1998). Slope and valley confinement characterizations initially were based on 

measurements and observations from USGS 7.5-minute 

topographic maps. Each segment was assigned a unique 

identification code. Segments were categorized by slope: 

less than 0.3 percent, 0.3 to 1 percent, greater than 1 to 2 

percent, greater than 2 to 4 percent, greater than 4 to 8 percent, or greater than 8 percent. Each segment was classified as confined (valley width less than 2 times the channel 

width), moderately confined (valley width between 2 and 

4 times the channel width), or unconfined (valley width 

greater than 4 times the channel width). Valley confinement was difficult to estimate from topographic maps; 

these initial characterizations were confirmed during the 

reach field surveys and changed, if necessary. Channelsegment boundaries also were confirmed in the field and 

changed if necessary.

After the field assessments were done, it was determined that valleys in the Duluth area fit into four groups 

based on modified categories assigned to valleys for Lake 

Superior tributaries in the western part of the Upper Peninsula of Michigan (Hack, 1965) (fig. 8). Headwater streams 

in the upstream parts of the watersheds have no valleys, 

are unconfined (N), and flow over glacial deposits. As 

drainage area increases and altitude decreases, the stream 

valleys are confined (C) V-shaped valleys as they cut 

through the steep, post-glacial shoreline areas, faults, or 

bedrock. Continuing downstream, the valleys become well 

developed but stream meanders follow the valley meanders 

(E). This type of valley and stream meander pattern was 

called “entrenched” by Hack (1965). The stream-meander 

pattern for this valley type tends to be irregular and determined by the intersection of the stream and valley with 

bedrock outcrops, post-glacial lake shorelines, or glacial 

meltwater valleys. In entrenched valleys, channels commonly intersect valley sides, which combined with enough 

flow and shear stress, can cause bluff and terrace erosion. 

Near the mouths, valleys tend to be wide and unconfined 

and stream-meander patterns are alluvial (A). The valleys 

are wider than the meander belt and alluvial stream meanders typically are a reflection of fluvial processes of runoff 

and sediment transport conditions. 

Aerial photographs from 1939–40, 1956, 1997, and 

2002 were used to compare historical and current channel 

and riparian conditions for the stream segments. Channel 

width, canopy pattern, type and size of riparian vegetation on each stream bank, stability and position of gravel 

bars, location of eroding banks, wood loading, and channel 

position were noted. Riparian vegetation composition was 

described as deciduous (greater than 70 percent deciduous), coniferous (greater than 70 percent coniferous) or 

mixed. Riparian vegetation age was described as young 

(less than 10 years old), mature (between 10 and 40 years 

old), or old (greater than 40 years old). Riparian vegetation 

density was described as sparse (greater than 50 percent 

open ground) or dense (greater than 50 percent forested). 

Drainage-network position was assigned to each 

segment based on the longitudinal profiles and 7.5-minute 

topographic maps. Main stems were divided into upper, 

middle, and lower categories, corresponding to main-stem 

length. Tributary categories were assigned based on the 

category assignment of the main stem at their confluence. 

Predominant categories of bedrock type, glacial 

landforms/deposits, and land cover were assigned to each 

segment based on the thematic overlays (Miller and others, 

2002; University of Minnesota–Duluth Geology Department and others, 1997; Minnesota Department of Natural 

Resources, Division of Forestry, 2002; respectively). 

Bedrock types included sedimentary, gabbro rocks, felsic 

and mafic volcanic rocks, intrusions, and bedrock buried 

by glacial deposits. In addition to thematic overlay of bedrock geology from Miller and others (2002), bedrock types 

along segments were visually checked by use of the nondigital 1:24,000-scale maps of bedrock types and outcrops 

in Schwartz (1949). Glacial landform/deposits categories 

were supraglacial drift, outwash, ice-contact, glacial lake, 

post-glacial shoreline/beach, bedrock surface, till plain, 

and undifferentiated. Dominant land cover included urban, 

developing urban, agriculture, forest, wetland, grass, 

shrubland, and roads. 

Reach Characterization

Rapid Field Assessments

Rapid assessments of geomorphic characteristics 

and processes (mainly observation-based) were done at 

48 sites from July 2003 through May 2004 (fig. 1). These 

sites were on segments with a range in slope and valley 

type. Rapid assessments were based on qualitative and 

quantitative field methods described in Thorne (1998) 

for identifying geomorphic characteristics and processes 

10 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Unconfined valley with alluvial meanders, 

stream meanders reflect fluvial processes, 

valley wider than the meander belt (wide 

flood plain) 

A

A

Unconfined valley with entrenched 

meanders; stream meanders follow valley 

meander pattern; change in valley course 

caused by change in geology; some flood 

plain; high chance for bank, terrace, and 

bluff erosion 

E

E

Confined; V-shaped valleys, headwaters, 

tributaries to main stems; no flood plain C

C

No valley development, stream unconfined 

and flows on glacial deposits N

MAJOR VALLEY TYPES

TYPICAL LANDSCAPE POSITION OF VALLEY TYPES

ALTITUDE

DISTANCE FROM HEADWATERS TO MOUTH

N

Stream

Valley side

PLAN VIEW

Figure 8. Valley development and valley types for Duluth-area streams, Minn.

Methods 11
of streams for multi-disciplinary reconnaissance studies. 

Thorne’s (1998) field methods include observations and 

measurements of riparian vegetation and geology, valley 

and flood-plain characteristics, and channel characteristics 

in relation to valley conditions. Channel morphology, bar 

formation, substrate, and controls on incision and lateral 

migration were measured and described. Bank conditions 

and interpretations also were measured and described. 

Descriptions also included type of road crossing, potential 

fish-passage problems through culverts, and any other 

potential local effects to the stream channel. Culverts are 

common in Duluth-area streams, and if inappropriately 

constructed, can be obstructions to fish migration (Gibson 

and others, 2005). Photographs of the streams were taken 

during the rapid assessments. Rapid assessment data were 

used to compare observed characteristics to predictions 

of dominant geomorphic channel processes based on the 

geomorphic segment classification.

Intensive Field Surveys

Intensive field surveys were done at nine sites in July, 

August, and October 2003. These were a subset of sites 

where rapid field assessments were done (fig. 1). The most 

common slope and valley types were selected. In addition, sites were concentrated in three watersheds—Mission 

Creek, Miller Creek, and Lester River—to describe how 

geomorphic characteristics and processes changed along 

the longitudinal profiles and also to identify upstream to 

downstream linkages in geomorphic processes. Assessments included qualitative and quantitative geomorphic 

assessment of valley, channel, and bank conditions; channel cross-section surveys, substrate measurements, cores 

of overbank sediment, and measurements of large woody 

debris (LWD) and pool area. Channel and bank measurements were based on reach-scale descriptions. Reach 

lengths were based on spacing of riffles, steps, or bedrock 

falls and ranged from 85 to 273 ft with an average reach 

length of 170 ft. Channel types were identified as bedrock, colluvial, cascade, step-pool, pool-riffle, plane-bed, 

or wetland based on definitions from Montgomery and 

Buffington (1998).

Two channel cross sections were surveyed at each 

intensive site with an automatic level (Harrelson and others, 1994). A global positioning system was used to verify 

the location of each cross section. Semi-permanent benchmarks (rebar stakes) were established at each cross section. 

The cross sections were in riffles. Water-surface and 

channel slope were measured along the stream distance 

between the two cross sections. 

Quantitative measurements of coarse substrate size 

in riffles were made by means of Wolman pebble counts 

(Wolman, 1954). One riffle was chosen (out of the two 

with cross-section surveys) to conduct the survey. Pebble 

selection techniques followed Fitzpatrick and others 

(1998) and the diameter of the b-axis of 100 pebbles were 

measured and recorded in a field book. If sand or smallersized particles were encountered, these particles were 

tallied as “sand” or “fines”. 

Overbank sedimentation was measured through 

exploratory coring with a hand-held soil probe and all 

cores were described for texture and color in the field by 

use of the U.S. Department of Agriculture textural triangle 

and color chart (Munsell Color, 1975; Soil Survey Staff, 

1951). Field grading of texture was done by rubbing soil 

between the fingers (Milfred and others, 1967). Photographs were taken in each reach. 

The number, length, and average diameter of woody 

debris were measured in each reach. Geomorphic function 

and source for the wood were recorded. Possible functions 

included pool scour, bank stability, bar stabilizer, sediment trap, or step former. Possible sources for the wood 

included side slope, upstream, or bank. All wood within 

the bankfull channel was measured that was larger than 0.1 

ft in diameter and 1 ft in length. There is no minimum size 

standard for LWD. The relatively small minimum size of 

wood counted in this study (as compared to other studies) 

was selected to maximize options for comparing LWD in 

Duluth streams to LWD surveys from other sources.

The area and depth of pools were measured in each 

reach. Pools were identified by having relatively deep, 

slow-moving water, and fine-grained bed material compared to the rest of the reach. Pool function also was 

recorded and included free, LWD, or bedrock/boulder/bank 

forced.

Channel widths recorded in Government Land Office 

(GLO) Survey notes from the Duluth area (1857, 1858, 

1868, and 1870) were compared to channel and wetted 

widths measured in cross-section surveys in 2003 to quantify potential channel-width changes at intensive sites. In 

the GLO surveys, channel widths at section line crossings 

were measured in links, and 1 link is equivalent to 0.66 

ft. It is best to compare GLO surveyed widths at multiplesection line crossings to obtain a sense of data accuracy. 

For this study, it was assumed that changes greater than 

+3 ft were appreciable. 

12 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Table 1. Land-cover characteristics for Duluth-area watersheds, Minn. (based on Minnesota Gap Analysis Program 

Classification Level 3; Minnesota Department of Natural Resources, Division of Forestry, 2002).

[<, less than]

 Watershed

Drainage

area 

(square 

miles)

Developed/

barren

(urban) 

(percent)

Cropland 

(percent)

Grassland 

(percent)

Upland 

forest 

(percent)

Lowland 

forest 

(percent)

Upland 

shrub 

(percent)

Lowland 

shrub 

(percent)

Marsh 

(percent)

Water 

(percent)

Mission Creek 10.6 21 4 2 10 46 3 12 1 <1

Sargent Creek 3.1 11 1 1 31 46 1 9 <1 0

U.S. Steel Creek 2.8 34 3 3 22 16 <1 19 2 0

Morgan Park Creek 1.3 24 1 1 43 19 0 13 0 0

Stewart Creek 1.5 16 1 1 47 25 1 9 <1 0

Lenroot Creek .4 17 <1 1 62 6 0 15 0 0

Knowlton Creek 2.2 31 3 2 24 18 5 17 <1 0

Kingsbury Creek 9.0 34 2 1 8 27 8 19 1 <1

62nd Avenue Creek 1.2 45 1 2 13 14 1 24 1 0

Keene Creek 6.0 30 1 2 11 32 6 18 <1 0

Merritt Creek 2.2 38 1 1 19 24 1 16 <1 0

Miller Creek 9.3 60 <1 1 3 21 6 8 <1 <1

Buckingham Creek 1.1 54 0 1 17 19 <1 8 <1 0

Coffee Creek 1.6 66 1 0 8 20 <1 4 0 0

Brewery and Greys 

Creeks

3.0 75 <1 0 6 16 <1 3 0 0

Chester Creek 6.7 33 1 1 9 36 7 12 1 <1

Tischer Creek 7.3 34 <1 3 11 44 2 5 <1 <1

34th to 50th Ave. 

Creeks

3.6 80 <1 <1 5 11 <1 2 <1 <1

Amity Creek 16.7 7 2 9 7 69 1 5 <1 <1

Lester River 36.0 3 2 5 7 68 2 11 <1 1

Methods 13
Classification

The segment-scale classification developed for 

Duluth-area streams was based in part on Montgomery and 

Buffington’s (1998) classification. Segments were grouped 

into 15 categories based on drainage-network position, 

slope, geologic setting (including a combination of bedrock and glacial landform features), valley type, dominant 

geomorphic processes, and potential responses to disturbance. The classification was based on results from the 

rapid field assessments and intensive field surveys. Channel types, geomorphic processes, and interpretations of 

sensitivity to disturbance summarized from the reach data 

were extrapolated to other segments with similar drainagenetwork position, slope, geologic setting, and disturbance 

mechanisms. Interpretations of potential for geomorphic 

change due to disturbance are based on observations and 

evidence for historical geomorphic change as well broad 

assumptions about the effects of slope and parent material 

on geomorphic processes.

Geomorphic Characteristics

Geomorphic characteristics of Duluth-area streams 

and the processes responsible for them are determined by 

topography and slope, drainage-network position, geologic 

setting (watershed, segment, and reach scales), valley 

type, base-level controls, vegetation, and human-caused 

alterations and disturbance. Current (2005) geomorphic 

processes reflect short- and long-term responses to disturbances. The source for the disturbance may be upstream or 

downstream of a particular segment or reach of interest. 

Watershed Characteristics

Watershed characteristics help to determine the 

amount and timing of runoff and sediment from uplands 

to channels. The 20 studied watersheds are generally 

small and range in size from less than 1 mi2 (Lenroot 

Creek) to 36 mi2 (Lester River) (fig. 1; table 1). All of 

the streams are underlain by igneous rocks except Mission Creek (fig. 4). Bedrock crops out at the land surface 

through much of the watersheds but is buried by glacial 

deposits in the upper parts of the larger watersheds (fig. 

5). There is little infiltration and potential for runoff is 

high where bedrock crops out or is thinly covered by 

glacial deposits. The Duluth Gabbro complex underlies 

many of the streams from Stewart Creek northeast to the 

upper watershed of Tischer Creek. Lester River and Amity 

Creek are underlain by felsic and mafic volcanic units 

interspersed with gabbro and mafic intrusions. These bedrock units have different rates of erosion. The sedimentary 

rocks that underlie the Mission Creek watershed are less 

resistant to erosion than the volcanics, gabbro complex, or 

the intrusions. Thus, the Mission Creek drainage pattern 

is denser and more dendritic than patterns for the other 

watersheds.

Land cover in the studied watersheds is predominantly composed of urban land (developed/barren), forest, 

or shrub (fig. 6, table 1). Percentages of urban land range 

from 3 percent in the Lester River watershed to 80 percent 

in the 34th to 50th Ave. Creeks watershed. Urban land is 

most concentrated near the mouths along the shoreline of 

the St. Louis River estuary and Lake Superior; however, 

urban land extends throughout many of the watersheds, 

especially those that are bisected by major transportation 

corridors along U.S. State Highway 53, U.S. Interstate 35, 

and U.S. State Highway 2 (figs. 1 and 6). Urban watersheds have higher potential for increased runoff rates and 

volumes and for changes in sediment inputs compared to 

forested watersheds. Watersheds with more than 50 percent 

urban land include Miller Creek, Coffee Creek, Buckingham Creek, Brewery and Greys Creeks, and 34th to 50th 

Ave. Creeks. Seven urban streams near downtown Duluth 

run underground at their mouths (table 2). Watersheds that 

are predominantly forest include Mission Creek, Sargent 

Creek, Morgan Park Creek, Stewart Creek, Lenroot Creek, 

Amity Creek, and Lester River (table 1). Watersheds that 

have had noticeable urban development from 1980 to 

2000 include Mission Creek, Morgan Park Creek, Stewart 

Creek, Lenroot Creek, Miller Creek, and Lester River (fig. 

7). Geomorphic effects from urban development are concerns for Miller Creek, Chester Creek, and Amity Creek 

(Camp Dresser and McKee, Inc., 2000).

Duluth-area main stems have complex longitudinal 

profiles (fig. 9) that are very different from the typical 

longitudinal profile shown in figure 2 for geologically old 

landscapes with homogeneous geologic deposits. Irregularities in the Duluth stream profiles are attributed to 

differences in the erodibility of geologic materials, extent 

of landforms, or changes in base level (Hack, 1965). 

Specifically, Duluth area longitudinal profiles reflect 

bedrock type and distribution of fault zones, variations 

in the texture of glacial deposits, glacial landforms (such 

14 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
600

700

800

900

1,000

1,100

1,200

1,300

1,400

1,500

18 16 14 12 10 8 6 4 2 0

RIVER MILE FROM MOUTH

ALTITUDE, IN FEET ABOVE NAVD 27

Miller Creek

Buckingham Creek

Chester Creek

Tischer Creek

Amity Creek

Lester River

B

600

700

800

900

1,000

1,100

1,200

1,300

1,400

1,500

RIVER MILE FROM MOUTH

ALTITUDE, IN FEET ABOVE NAVD 27

Mission Creek

Sargent Creek

Morgan Park

Stewart Creek

Knowlton Creek

Kingsbury Creek

62nd Ave. West Creek

Keene Creek

Merritt Creek

A

18 16 14 12 10 8 6 4 2 0

Figure 9. Longitudinal profiles of streams in the A, southwestern, and B, northeastern parts of the Duluth, Minn., area.

Geomorphic Characteristics 15
as moraines and outwash plains), postglacial landforms 

from beach ridges, shorelines or melt-water valleys, 

and the present level of Lake Superior. Reaches with 

steep slopes are prone to long-term erosional conditions, 

whereas reaches with gentle slopes are prone to long-term 

depositional conditions (Knighton, 1998). Reaches in a 

transition from steep to gentle slopes may change from 

erosional to depositional if upstream inputs of water and 

sediment change. 

The upper main stems tend to have gentle slopes 

for headwaters in glacial deposits at altitudes higher than 

about 1,200 ft. Irregularities in the longitudinal profiles 

are common from about 1,200 to 1,000 ft because of the 

boundary among glacial deposits, bedrock, and glacial 

lake shorelines. The steep slopes are on middle and lower 

main stems and tributaries indicate where the streams 

intersect bedrock (fig. 4). Streams flowing over the Duluth 

Complex gabbro intrusions have the steepest slopes. 

Below 1,100 ft, longitudinal profiles for Mission Creek 

and Sargent Creek are concave upward and less steep than 

streams to the northeast because Mission and Sargent 

Creek intersect the less resistant Animikie sedimentary 

rocks and glacial lake plain. In the northeastern part of the 

city, Lester River, Amity Creek, and a portion of Tischer 

Creek have more gentle slopes than streams in the center 

of the city but steeper slopes than Mission and Sargent 

Creeks because the streams intersect Keweenawan volcanic rocks. Only a few streams in the southwestern part of 

the study area have enough length on till plain or built-out 

land to have a gentle slope near their mouths in the St. 

Louis River estuary (fig. 1).

Segment Characteristics

Streams with gentle slopes (less than 0.3 percent) 

generally were headwater streams flowing on glacial 

deposits with no valley development with wetland vegetation (lowland shrub or forest); whereas streams with moderate to steep slopes flowed on bedrock and had confined 

or entrenched valleys (tables 3 and 4). Alluvial valleys 

Table 2. Conditions at the mouths of Duluth-area streams, Minn.

Stream Conditions

Mission Creek Channel open to the St. Louis River

Sargent Creek Channel open to the St. Louis River estuary

U.S. Steel Creek Channel open to the St. Louis River estuary

Morgan Park Creek Channel open to the St. Louis River estuary

Stewart Creek Channel open to the St. Louis River estuary

Lenroot Creek Channel open to the St. Louis River estuary

Knowlton Creek Channel open to the St. Louis River estuary

Kingsbury Creek Channel open to the St. Louis River estuary

62nd Ave. Creek Runs underground by Grand Ave.

Keene Creek Channel open to the St. Louis River estuary

Merritt Creek Channel open to the St. Louis River estuary

Miller Creek Runs underground through downtown Duluth

Buckingham Creek Runs underground through downtown Duluth

Coffee Creek Runs underground through downtown Duluth

Brewery and Greys Creeks Runs underground through downtown Duluth

Chester Creek Runs underground in downtown Duluth

Tischer Creek Channel open to Lake Superior

34th to 50th Ave. Creeks Some channels open, others run underground

Amity Creek Channel open to Lake Superior

Lester River Channel open to Lake Superior

16 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
were rare because of the small watershed sizes, bedrock 

control, and geologically young age of the streams (less 

than 10,000 years). Main-stem segments with moderate 

slopes typically were in the boundary zone between glacial 

deposits and bedrock. Tributaries to middle or lower main 

stems most commonly had 2–8 percent slopes in confined 

valleys. The combination of steep slopes and confined or 

entrenched valleys are indicative of a high potential for 

landslides along valley sides, especially if sandy glacial 

lake shoreline deposits are present. If valley sides are made 

up of unconsolidated deposits, the potential for landslides, 

mass wasting, and channel erosion increases if runoff and 

flood peaks increase (Fitzpatrick and others, 1999). 

Characteristics for all the segments are listed in 

table 5, with a list of abbreviations and definitions in 

table 6. Drainage-network position, slope, valley type, 

bedrock type, glacial landform, and dominant land cover 

are described in table 5. The table has site identification 

numbers for segments with rapid assessment or intensive survey sites. Based on field reach-scale data and air 

photos, characteristics of channel type, dominant substrate, 

mode of sediment transport, flood attenuation, observed/

expected causes for disturbance, presence of storm drains, 

and potential for geomorphic change are described for segments with field sites and extrapolated for other segments. 

Almost all of the segments have one or more observed 

or expected causes for disturbance, usually land clearing, urban development, road drainage, and inputs from 

upstream segments. The only exception is six tributary 

segments near the middle/lower main stem of Mission 

Creek that have complete forest cover and no roads.

Table 3. Number of stream segments in each slope/drainage-network position category for Duluth-area streams, Minn.

[<, less than; >, greater than]

Slope category 

(percent)

Upper 

main stem

Middle

main stem

Lower

main stem

Upper

tributary

Middle

tributary

Lower

tributary Total

<0.3 4 0 0 3 0 0 7

0.3-1 10 7 8 5 4 1 35

>1-2 4 19 6 3 9 1 42

>2-4 7 6 10 6 15 10 54

>4-8 2 4 9 3 3 10 31

>8 1 7 7 1 2 1 19

Total 28 43 40 21 33 23 188

Table 4. Number of stream segments in each slope/valley type category for Duluth-area streams, Minn. 

[<, less than; >, greater than]

Slope category 

(percent) No valley

Confined 

(origin not 

determined)

Entrenched Alluvial Bedrock

(confined) Total

<0.3 7 0 0 0 0 7

0.3-1 26 1 4 4 0 35

>1-2 17 10 12 0 3 42

>2-4 1 37 10 1 5 54

>4-8 0 15 8 0 8 31

>8 0 0 9 0 10 19

Total 51 63 43 5 26 188

Geomorphic Characteristics 17
Table 5. Geomorphic characteristics of stream segments for Duluth-area streams, Minn., 2003–2004.

[See table 6 for explanation of abbreviations. Stream segments are shown on figure 13. Data in italics are extrapolated from reach assessments of sites 

with the same segment category. Data in bold are rapid assessment or intensive survey sites. USGS, U.S. Geological Survey; ID, identification number; 

--, no detailed measurements taken; %, percent; >, greater than; <, less than]

Segment 

ID Stream name Topographic map

USGS 

reach 

ID

Drainagenetwork 

position

Slope 

%

Valley 

type

Bedrock 

type

Glacial 

landform

Dominant 

land cover

IntermittentChannel 

type

b1 Buckingham Creek Duluth -- LM >8 E GAB BED U N BE

b2 Buckingham Creek Duluth Heights 8 MM >1–2 N GAB BED U N PB

b3 Buckingham Creek Duluth Heights -- UT >2–4 C GAB BED F Y CO

c1 Chester Creek Duluth 9 LM >4–8 E VOL BED U N BE

c2 Chester Creek Duluth 43 MM >1–2 N GAB OW/BED U/F N PR/SP

c3 Chester Creek Duluth, Duluth 

Heights

-- UM 0.3–1 N GAB SD/BED S/W N WE

c4 Chester Creek Duluth -- MM <0.3 N BUR/GAB OW U N AR

c5 Chester Creek Duluth, Duluth 

Heights

-- UM >1–2 N GAB SD S/U N WE

c6 Chester Creek Duluth, Duluth 

Heights

-- UM >1–2 N GAB BED U N AR/PB

c7 Chester Creek Duluth -- LT >2–4 C VOL BED F/U Y CO

k1 Keene Creek West Duluth -- LM 0.3–1 N GAB TP U N AR

k2 Keene Creek West Duluth -- LM >2–4 C GAB BED U N BED/CA

k2a Keene Creek West Duluth 42 LM >1–2 N GAB TP U N PB/AR

k3 Keene Creek West Duluth, 

Duluth Heights

-- MM >4–8 E GAB BED U/F N CA/BE

k4 Keene Creek Duluth Heights 6 MM >1–2 E GAB BED/SH F/U N PR/SP

k5 Keene Creek Duluth Heights -- UM 0.3–1 N GAB SD/BED F/U/W N WE

k6 Keene Creek trib Duluth Heights 5 MT >4–8 B GAB BED/SH U/F N CA/CO

kg1 Kingsbury Creek West Duluth -- LM 0.3–1 A BUR TP U N AR

kg2 Kingsbury Creek West Duluth -- LM >4–8 C GAB BED/SH U N BE

kg2a Kingsbury Creek West Duluth -- LM >2–4 C GAB BED F/U N BED/CA

kg2b Kingsbury Creek West Duluth -- LM >4–8 C GAB BED U N BE

kg2c Kingsbury Creek West Duluth -- LM >8 C GAB BED U N BE

kg2d Kingsbury Creek West Duluth -- LM >2–4 C GAB BED U N BED/CA

kg3 Kingsbury Creek West Duluth 41 MM >2–4 B GAB SH/SD/

BED

U/F N SP/CA

kg4 Kingsbury Creek West Duluth -- MM 0.3–1 N GAB SD W/U N AR

kg5 Kingsbury Creek Duluth Heights -- UM <0.3 N GAB SD/BED W N AR/WE

kg6 Kingsbury Creek Duluth Heights -- UM 0.3–1 N GAB SD/BED W N AR/DW

kg7 Kingsbury Creek Duluth Heights -- UT >1–2 N GAB SD/BED W Y PR

kg8 Kingsbury Creek Duluth Heights -- UT >4–8 C GAB SD/BED F/U Y CO

kw1 Knowlton Creek West Duluth -- LM 0.3–1 N GAB TP F/U N AR

kw2 Knowlton Creek West Duluth 4 MM >4–8 E GAB BED U N BE/CA

kw2a Knowlton Creek West Duluth -- LM >8 E GAB BED F N BE

kw2b Knowlton Creek West Duluth -- MM >4–8 E GAB BED U/F N BE/CA

kw2c Knowlton Creek West Duluth -- MM >8 E GAB BED/SH S/U N BE

kw3 Knowlton Creek West Duluth -- UM >1–2 N GAB SD U N AR

l1 Lester River Duluth, Lakewood19, 31 LM >2–4 E VOL BED F N BE

18 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Dominant 

substrate

Mode of 

sediment transport

Flood 

attenuation

Dominant 

geomorphic 

processes

Observed/expected 

causes for 

disturbance

Stormdrain 

outfalls

Potential 

geomorphic 

changes

Sensitivity 

to 

disturbance

Geomorphic 

segment 

category

BE T, SIp NO EX UP, HI, UR Y Y LO B

GV SIa FP A UP, CA, UR, GV, CL N Y MOD M1

CO/BO SOi, SOw NO I, W CL, CA, RO, GV N Y MOD T2

BO/BE T, SOb NO EX, EBL UP, HI, UR Y Y LO B

GV SOi, SOw, T, SIc, 

SIp

FP I, EBA, W, LM, BF UP, UR, RO, CL Y Y HI M1

GV SOw, SOi, T, SIa WE I, W, EBA, A CL, UR, RO, CA N Y MOD W.3

FINES T, SOw NO EBA, LM, W, A UR, CA, RO, CL Y Y MOD W

GV SOw, SOi FP I, W, EBA CL, UR, RO Y Y HI U1

CO SOb, SOi, SOw, T NO I, W, EBA, LM UR, RO, CA, CL Y Y HI U1

BO SOi, SOb, SOw NO I, W, EBA, EBL, EX UR, RO, CL Y Y MOD LT

BO T, SIa NO A UP, UR, RO, CA N Y LO A

BO SOb, SOw, T NO W, EBA, EBL, EX UP, RO, UR Y Y MOD L2

BO T NO ST UP, UR, RO, CA Y Y LO L1

BO T, SOw, SOb NO W, EX, EBL, EBA UR, RO, UP, GV, CL Y Y MOD B

BO/CO T, SOw, SOi NO W, EBA, I, LM UP, GV, UR, RO, CL N Y HI M1

SA/FINES SOw, SOi, SIa WE W, EBA, I, A UR, RO, GV N Y MOD W.3

BO T NO EX UR, RO, GV N? Y MOD BT

BO T, SIa NO ST, A UP, RO, CL Y Y LO A

BE SOw, SOi, SIc, T NO W, EBA, EX, BF UR, RO, UP Y Y MOD B

BO/BE SOw, T NO W, EBA, EX, BF UP, RO, UR N Y LO L2

BE SOw, T NO W, EBA, EX, BF UR, RO, UP N Y LO B

BE SOb, SOw, T NO EX UP, UR, RO Y Y LO B

BO SOb, T, SOw, SIc NO EX, EBA, W, BF UP, UR, RO Y Y MOD L2

BO SOb, SOw, T, SIc NO EBL, EBA, LM, 

BF, W

UP, RO, UR N Y HI M2

SA/FINES SOb, T, SOw, SIc WE EBA, I, W, A UP, CA, UR, RO, CL N Y MOD M.3

FINES SOw, T, SIa WE EBA, LM, I, A CA, RO, CL N Y MOD W

SA/FINES SOw, SIa, T WE A, I, W UP, RO, CA, CL N Y LO W.3

CO SOw, SOi NO I CL, UR, RO N Y MOD/HI T1

BO SOw, SOi NO I UR, RO, CL N Y MOD/HI BT

SA/FINES T, SIa, SOb FP A UP, CA, RO Y Y MOD A

BO T, SOw, SOb NO EX, EBL, EBA UP, RO, UR, CA N Y MOD B

BE T NO EX UP, RO, UR N Y LO B

BO T NO EX UP, RO, UR N Y LO B

BE T NO EX UP, RO, UR N Y LO B

PB T, SOw NO A CA, RO, UR N Y HI U1

BE T, SIp NO EX, W, BF, EBL UP, HI Y Y LO L2

Geomorphic Characteristics 19
Table 5. Geomorphic characteristics of stream segments for Duluth-area streams, Minn., 2003–2004 —Continued

[See table 6 for explanation of abbreviations. Stream segments are shown on figure 13. Data in italics are extrapolated from reach assessments of sites 

with the same segment category. Data in bold are rapid assessment or intensive survey sites. USGS, U.S. Geological Survey; ID, identification number; 

--, no detailed measurements taken; %, percent; >, greater than; <, less than]

Segment 

ID Stream name Topographic map

USGS 

reach 

ID

Drainagenetwork 

position

Slope 

%

Valley 

type

Bedrock 

type

Glacial 

landform

Dominant 

land cover

IntermittentChannel 

type

l10 Amity Creek Arnold, Duluth -- MM 0.3–1 N GAB SD A/F N PR

l11 Amity Creek Arnold, Duluth -- MT >1–2 N GAB SD AF N PR

l12 Amity Creek Arnold -- MM >1–2 N BUR/GAB SD W N PR

l13 Amity Creek Arnold -- UM <0.3 N BUR/GAB SD W N WE

l14 Amity Creek Arnold -- UM 0.3–1 N BUR/GAB SD WF N WE/PR

l15 Amity Creek Arnold -- UT >1–2 C BUR/GAB SD F N PR

l16a Amity Creek Arnold -- UM >1–2 N BUR/GAB SD F/A/W N PR

l16b Lester River French River, 

Arnold

-- MT >2–4 C VOL/IN SD F/A N CA

l17 Amity Creek Arnold -- UT <0.3 N BUR/GAB SD W N WE

l18 Amity Creek Arnold -- UT >1–2 N BUR/GAB SD F/W Y PR

l19 Lester River French River -- MM 0.3–1 E IN TP F/A N PR

l19a Lester River French River 20 MM >1–2 E VOL/IN BED F/A N PB/SP

l2 Amity Creek Duluth 11 LM >2–4 E VOL BED F/U N BE

l20 Lester River French River, 

Arnold

23 MM 0.3–1 E BUR/IN SH F N PR

l21 Lester River French River 21 MM >2–4 B IN BED/SH F/A N PB

l22 Lester River Arnold 22 MM >1–2 N BUR/IN SD/SH F N PB

l23 Lester River Arnold -- UT 0.3–1 N BUR/IN SD W N WE

l24 Lester River Arnold -- MT >2–4 C BUR/IN SD F/A N PB

l25a Lester River Arnold -- MT 0.3–1 N BUR/IN SD W N WE/PR

l25b Lester River Arnold -- MT >1–2 N BUR/IN IC F/A N PB

l26 Lester River Arnold -- MT 0.3–1 N BUR/IN UN F/A N AR/PR

l27 Lester River Arnold -- MT 0.3–1 N BUR/GAB OW/SD FW N WE

l28 Lester River Arnold 30 MM >1–2 E IN IC AF N PB

l29 Lester River Arnold -- MT >1–2 N IN SD W N WE

l3 Amity Creek Duluth -- LM >1–2 C IN BED/SD/

SH

F N CA

l30 Lester River Arnold -- MT 0.3–1 N IN SD W N WE

l31 Lester River Arnold -- MT 0.3–1 N IN SD W N WE

l32 Lester River Arnold 24 UM 0.3–1 N BUR/GAB OW W/F N PR/PB

l33 Lester River Arnold UT 0.3–1 N BUR/GAB SD W/F N WE

l34 Lester River Arnold 25, 26, 

27, 28, 

29

UM <0.3 N BUR/GAB SD W/F N WE

l35 Lester River Arnold -- UT <0.3 N BUR/GAB SD W N WE

l36 Lester River Arnold -- UT <0.3 N BUR/GAB SD W N WE

l37 Lester River Duluth -- LT >4–8 C/E IN BED F Y CO/BE

l38 Amity Creek Duluth -- LT >2–4 C IN SD F/A Y CO

l39 Amity Creek Duluth -- LT >2–4 C IN SD F/U Y CO

20 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Dominant 

substrate

Mode of 

sediment transport

Flood 

attenuation

Dominant 

geomorphic 

processes

Observed/expected 

causes for 

disturbance

Stormdrain 

outfalls

Potential 

geomorphic 

changes

Sensitivity 

to 

disturbance

Geomorphic 

segment 

category

GV SOb, SIc FP EBA, W, LM, OS, BF UP N Y MOD/HI M.3

GV SOb FP EBA, W, LM, OS, BF CL N Y MOD/HI T1

GV Sob, SIb WE EBA, W, LM, OS UP N Y MOD M1

FINES SIa WE A CA N Y LO W

FINES SIa WE A UP, CA, CL N Y LO W.3

GV SOi, SOw NO I, EBA CL, RO N Y MOD T1

GV SOi, SOw FP/WE I, EBA RO, UR, CL N Y HI U1

BO SOi, SOw, SOb NO I, EBA, EBL, W, LM, 

BF

CL, UR, RO N Y HI T2

FINES SIa NO I, EBA UP, CA N Y LO W

GV SOi, SOw WE A CL N Y MOD T1

CO/GV T, SOb, SOw, SIc NO EBA, EBL, W, LM, 

BF

UP, CL, RO N Y MOD M.3

CO/BO T, SOb, SOw NO EBA, EBL, W, LM, 

BF

UP, CL, RO N Y MOD M1

BE T, SIp NO EX, W UP, HI Y Y LO L2

GV T, SOb, SOw NO W, EBA, EBL UP N Y HI M.3

GV T, SOb NO W, EX, EBA UP, CL, UR, RO N Y MOD M2

GV T, SIa WE A UP, CL, UR, RO N Y MOD M1

FINES SIa, SIb WE A CL, RO N Y LO W.3

BO SOw, SOi NO I, EBA, W UP, CL, UR N Y MOD M2

FINES SOw, SIa NO A CL, CA, UR N Y LO W.3

GV T, SOw NO EBA, W, LM, OS CL, GV N Y MOD T1

GV/FINES T, SOw, SIa WE W, EBA CL, RO, CA, GV N Y MOD W.3

FINES SIa WE A CL N Y LO W.3

CO/BO SOw, SOb, T NO W, EBA, EBL UP, CL N Y HI M1

FINES SIa WE A CL N Y LO T1

BO T, SIc NO EX, W, EBL, LM, BF UP N Y MOD/HI L1

FINES SIa WE A UP, CL, CA N Y LO W.3

FINES SIa WE A CL, RO N Y LO W.3

CO SIa WE ST UP, GV, CL N Y MOD W.3

FINES SIa WE ST RO, UR, CL N Y MOD W.3

FINES SOi, SIa WE I, W, EBA, A RO, UR, CL N Y LO W

FINES SIa WE I, W, EBA, A UR N Y LO W

FINES SOi, SIa WE I, W, EBA, A UR, GV N Y LO W

BO/BE T, SOw NO W, EX CL, UR, RO N Y MOD BT

CO SOi, SOw, SOb NO I, EBL, EBA CL N Y HI LT

CO SOi, SOw, SOb NO I, EBL, EBA CL N Y HI LT

Geomorphic Characteristics 21
Table 5. Geomorphic characteristics of stream segments for Duluth-area streams, Minn., 2003–2004 —Continued

[See table 6 for explanation of abbreviations. Stream segments are shown on figure 13. Data in italics are extrapolated from reach assessments of sites 

with the same segment category. Data in bold are rapid assessment or intensive survey sites. USGS, U.S. Geological Survey; ID, identification number; 

--, no detailed measurements taken; %, percent; >, greater than; <, less than]

Segment 

ID Stream name Topographic map

USGS 

reach 

ID

Drainagenetwork 

position

Slope 

%

Valley 

type

Bedrock 

type

Glacial 

landform

Dominant 

land cover

IntermittentChannel 

type

l3a Amity Creek Duluth 12, 13, 

14, 15, 

16

LM >1–2 E VOL BED F N PB/BE

L3b Amity Creek Duluth 17, 18 LM >2–4 E IN BED F N BE

l4 Amity Creek Duluth -- MM >1–2 C IN BED/SD F/A N CA

l40 Amity Creek Duluth -- LT >4–8 C IN SD F/A/U Y CO

l41 Amity Creek Duluth -- LT >4–8 C IN SD F/A Y CO

l42 Amity Creek Duluth -- LT >4–8 C VOL BED/TP F/U Y CO

l43 Amity Creek Duluth -- LT >4–8 C VOL BED/TP U/F Y CO

l44 Amity Creek Duluth -- LT >2–4 C IN SD/SH A Y CO

l45 Amity Creek Duluth -- LT >2–4 C IN BED/SD/

SH

A Y CO

l46 Amity Creek Duluth -- LT >4–8 C IN BED/SD/

SH

A/F Y CO

l47 Amity Creek Duluth -- LT >4–8 C IN BED F N CO/CA

l48 Lester River Duluth -- LT >2–4 C VOL BED/TP F/A Y CO

l49 Lester River Lakewood, Duluth -- LT >4–8 C VOL BED/SH A/F Y CO

l5 Amity Creek Duluth -- MM 0.3–1 E IN BED/SH F/U N PR

l6 Amity Creek Duluth -- MM >1–2 C GAB BED F N PB

l7 Amity Creek Duluth -- MM >2–4 C GAB BED F N CA

l8 Amity Creek Duluth, Arnold -- UM 0.3–1 N BUR/GAB SD F/A N PR/AR

l9 Lester River Duluth -- MM >1–2 E GAB SD/SH F/A N PR

m1 Miller Creek Duluth Heights 44 MM >4–8 B GAB BED/SH U N CA

m1a Miller Creek Duluth Heights 36 LM 0.3–1 E GAB TP U N PB/AR

m1b Miller Creek Duluth Heights -- LM >8 E GAB BED U N BE

m1c Miller Creek Duluth Heights -- LM >4–8 E GAB BED U N BE/CA

m1d Miller Creek Duluth Heights 7, 37 LM >8 B GAB BED U N BE

m1e Miller Creek Duluth Heights -- LM >2–4 E GAB BED U N CA/SP

m2 Miller Creek Duluth Heights 35 MM >1–2 B GAB SD/BED U N PR/SP

m3 Miller Creek Duluth Heights 34 MM 0.3–1 N GAB SD/LA F/U N PR

m4 Miller Creek Duluth Heights 32,33 UM 0.3–1 N BUR/GAB SD U/W N WE/AR

m5 Miller Creek Duluth Heights -- UT 0.3–1 N GAB SD U Y W/AR

m6 Miller Creek Duluth Heights -- UT 0.3–1 N GAB SD U Y AR

m7 Coffee Creek Duluth Heights 46 LT >8 B GAB BED U N CO/BE

m8 Miller Creek Duluth Heights -- LT >2–4 C GAB BED/SH U N CO

m8a Miller Creek Duluth Heights -- LT >1–2 C GAB BED U N CO

mp1 U.S. Steel Creek West Duluth -- LM 0.3–1 A BUR TP W/U N AR/WE

mp2 U.S. Steel Creek West Duluth -- MM >1–2 C GAB TP F/U N PR/SP

mp3 U.S. Steel Creek West Duluth, Esko -- MM >2–4 C GAB LA/SH F/U N SP

mp3a U.S. Steel Creek Esko -- UM >8 C GAB/VOL BED S/F Y BE

22 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Dominant 

substrate

Mode of 

sediment transport

Flood 

attenuation

Dominant 

geomorphic 

processes

Observed/expected 

causes for 

disturbance

Stormdrain 

outfalls

Potential 

geomorphic 

changes

Sensitivity 

to 

disturbance

Geomorphic 

segment 

category

BO/BE T, SIc NO EX, W UP, HI N Y LO L1

BE T, SIp NO EX, W UP, HI N Y LO L2

BO T, SIc, SOw, SOb NO EX, W UP, HI, RO, CL N Y HI/MOD M1

BO SOi, SOw, SOc NO I, EBL, EBA CL, UR, RO N Y HI BT

BO SOi, SOw, SOc NO I, EBL, EBA CL, UR, RO N Y MOD BT

BO SOi, SOw, SOc NO I, EBL, EBA UR, RO Y Y MOD BT

BO SOi, SOw, SOc NO I, EBL, EBA UR, RO Y Y MOD BT

CO SOw, SOi NO I, EBA, LM CL, UR, RO N Y MOD/HI LT

CO SOw, SOi NO I, EBA, LM CL, UR, RO N Y MOD/HI LT

BO SOw NO I, EBA CL N Y MOD BT

BO SOw NO EX, W CL N Y MOD BT

BO SOw, SOi, SOb NO I, EBA, LM, W CL N Y HI LT

BO/BE SOw, SOi, SOb NO I, EBA, LM, W CL N Y MOD BT

GV T, SOw, SOb FP I, EBL, EBA UP, GV N Y HI M.3

CO/BO T NO EX, EBA, W UP N Y MOD M1

BO T NO EX, EBA, W UP, CL N Y MOD M2

GV SOw NO EBA, W, LM CL, CA N Y MOD/LO W.3

GV SOw, SOb NO EBA, EBL, W, LM UP, CA N Y HI/MOD M1

BO/BE T, SOb, SOi NO EBL, W, EX, BF UP, UR, HI, RO, CL Y Y MOD B

BO T NO ST UP Y Y LO A

BE T, SOb NO EBL, EX UR, UP, HI Y Y LO B

BE/BO T, SOb NO EBL, EX UR, UP, HI Y Y LO B

BE T, SOb, SOi NO EBL, EX, I UR, UP, HI Y Y LO B

BO T, SOb NO EBL, EX UP, UR, HI Y Y LO L2

BO SOw, T, SIc NO EBA, W, LM UP, UR, RO, CL Y Y MOD M1

BO/GV SOw, T, SOi, SIc, 

SIb

NO EBA, W, LM, I, BF, 

EBL

UP, UR, RO, CA, CL Y Y HI M.3

SA/FINES SOw, SOi, SIa WE EBA, W, A, I UR, RO, CA Y Y MOD W.3

SA/FINES SOw, SOi, SIa WE EBA, W, A, I UR, RO, CA, CL N Y MOD W.3

SA/FINES SOw, SOi, SIa WE EBA, W, A, I UR, RO, CA, CL N Y MOD W.3

BE T, SOb NO EX, EBL, W UP, UR, HI Y Y LO BT

BO SOw NO EX, EBA, W, LM, 

EBL

GV, UR, RO N Y HI LT

CO SOw, T, SIp NO W, EBA, LM, BF CL, UR, CA N Y MOD LT

SA/FINES T, SIa, SOw WE/FP A, EBA, W UP, RO, UR, CA Y Y MOD A

BO/GV T, SOw, SOb NO W, EBA, EBL, LM UP, UR, RO Y Y MOD M1

BO T, SOw, SOb NO EBL, EBA, LM, BF UP, RO, GV, UR N Y HI M2

BE SOw NO EX UP, UR, RO N Y LO B

Geomorphic Characteristics 23
Table 5. Geomorphic characteristics of stream segments for Duluth-area streams, Minn., 2003–2004 —Continued

[See table 6 for explanation of abbreviations. Stream segments are shown on figure 13. Data in italics are extrapolated from reach assessments of sites 

with the same segment category. Data in bold are rapid assessment or intensive survey sites. USGS, U.S. Geological Survey; ID, identification number; 

--, no detailed measurements taken; %, percent; >, greater than; <, less than]

Segment 

ID Stream name Topographic map

USGS 

reach 

ID

Drainagenetwork 

position

Slope 

%

Valley 

type

Bedrock 

type

Glacial 

landform

Dominant 

land cover

IntermittentChannel 

type

mp4 U.S. Steel Creek West Duluth -- MT >4–8 C BUR/GAB BED S N AR

mp5 U.S. Steel Creek West Duluth 45 MM >1–2 B GAB BED U/F N PB/AR

mp6 U.S. Steel Creek West Duluth -- UT >2–4 C GAB BED F N CA/SP

mp7 U.S. Steel Creek West Duluth -- UT >4–8 C GAB BED F N CO/BE

mp8 U.S. Steel Creek West Duluth -- UM >2–4 C GAB BED F N PB

mp9 U.S. Steel Creek West Duluth -- UT >8 C VOL BED F N BE

ms1 Mission Creek Esko 38 LM 0.3–1 A SED LA G N PB/AR

ms10 Mission Creek Esko -- MT >1–2 E SED BED F Y PB

ms11 Mission Creek Esko -- MT >2–4 E SED LA/SH F/R Y CO

ms11a Mission Creek Esko -- UT >2–4 C VOL BED/SH R Y PB/AR

ms12 Mission Creek Esko -- MT >2–4 C SED SH R Y CO

ms13 Mission Creek Esko -- MT >2–4 C SED SH R Y CO

ms14 Mission Creek Esko -- MT >2–4 C SED SH F Y CO

ms15 Mission Creek Esko -- MT >2–4 C SED SH R Y CO

ms16 Mission Creek Esko -- UT >2–4 C SED SH S/R Y CO

ms17 Mission Creek Esko -- MT >2–4 E SED BED/SH F/R Y PB

ms18 Mission Creek Esko -- MT >2–4 C SED SH F/R Y CO

ms19 Mission Creek Esko -- MT >2–4 E SED BED/SH F Y PB

ms2 Mission Creek Esko -- MM >1–2 E SED BED/LA F N PB

ms20 Mission Creek Esko -- MT >2–4 C SED BED/SH F Y CO

ms21 Mission Creek Esko -- MT >2–4 C SED BED/SH F Y CO

ms22 Mission Creek Esko -- MT >4–8 C SED BED F Y CO

ms23 Mission Creek Esko -- MT >1–2 C SED BED/SH F Y CO

ms24 Mission Creek Esko -- MT >2–4 E SED BED/SH F Y PB

ms25 Mission Creek Esko -- LT >2–4 C SED BED/SH F/R Y CO

ms26 Mission Creek Esko -- LT >2–4 C SED BED F Y CO

ms27 Mission Creek Esko -- LT >2–4 C SED BED F Y CO

ms2a Mission Creek Esko -- LM >1–2 E SED BED/LA F N PR/PB

ms2b Mission Creek Esko 39 LM >2–4 A SED BED F N PB/PR

ms3 Mission Creek Esko -- MM >2–4 E SED BED F N PB/PR

ms4 Mission Creek Esko 1 MM >1–2 E SED SH//TP F/S N PR

ms5 Mission Creek Esko 40 UM 0.3–1 N BUR/SED TP R/S/F N WE

ms6 Mission Creek Esko -- UT 0.3–1 N SED TI R/S/F Y WE

ms7 Mission Creek Esko -- UT 0.3–1 N SED TI R/S/F Y WE

ms8 Mission Creek Esko -- MT >1–2 C SED SH F/S Y PB

ms9 Mission Creek Esko -- MT >1–2 E SED BED F Y PB

o1 Merritt Creek Duluth Heights -- LM >1–2 N GAB TP U N PB/AR

o2 Merritt Creek Duluth Heights -- LM >4–8 C GAB BED U N CA

o3 Merritt Creek Duluth Heights -- MM >8 E GAB BED S N BE

24 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Dominant 

substrate

Mode of 

sediment transport

Flood 

attenuation

Dominant 

geomorphic 

processes

Observed/expected 

causes for 

disturbance

Stormdrain 

outfalls

Potential 

geomorphic 

changes

Sensitivity 

to 

disturbance

Geomorphic 

segment 

category

CA/BE SOw, SOi NO EBA, I, W, BF GV, CA, UR N Y MOD BT

BE/BO T, SOw NO EX, EBA UP, RO, GV, CA N Y MOD M1

BO SOi, SOw NO EBA, I, W UR, RO N Y MOD T2

BO/BE SOi, SOw NO EX, EBA, I, W RO N Y MOD BT

BO T, SOw, SOb NO EBA, W, I, EBL RO, CL N Y MOD U2

BE SOw, SOi NO EX, EBA, W CL N Y LO BT

CO T NO W, EBA UP Y Y LO A

CO/BO SOi, SOb, SOw NO I, W, EBA, EBL CL N Y HI T1

CO SOi, SOb, SOw NO I, W, EBA, EBL CL, RO N Y HI T2

BO/CO SOi, SOb, SOw NO I, W, EBA, EBL RO N Y HI T2

CO SOi, SOb, SOw NO I, W, EBA, EBL RO N Y HI T2

CO SOi, SOb, SOw NO I, W, EBA, EBL RO N Y HI T2

CO SOi, SOb, SOw NO I, W, EBA, EBL CL, RO N Y MOD T2

CO SOi, SOb, SOw NO I, EBL, EBA CL, RO N Y HI T2

CO SOi, SOb, SOw NO I, EBL, EBA CL, RO N Y HI T2

CO SOi, SOb, SOw NO I, EBL, EBA CL, RO N Y HI T2

CO SOi, SOb, SOw NO I, EBL, EBA CL, RO N Y HI T2

CO SOi, SOb, SOw NO I, EBL, EBA UP, CL, UR N Y MOD T2

GV T NO EBL, EBA, W, LM, 

BF

UP N Y MOD M1

CO SOi, SOb, SOw NO I, EBL, EBA, LM UP, CL, RO, UR N Y HI T2

CO SOi, SOb, SOw NO I, EBL, EBA, LM CL, RO, UR N Y HI T2

BO T, SOb, SOw NO EBA, EBL NO N N MOD BT

CO/BO SOi, SOb, SOw NO EBA, EBL NO N N MOD T1

CO SOi, SOb, SOw NO I, EBA, EBL NO N N MOD T2

CO SOi, SOb, SOw NO I, EBA, EBL NO N N MOD/HI LT

CO SOi, SOb, SOw NO I, EBA, EBL NO N N MOD/HI LT

CO SOi, SOb, SOw NO I, EBA, EBL NO N N MOD/HI LT

GV T, SIc, SOw NO W, EBA, BF UP N Y MOD L1

CO/GV T, SIc FP W, EBA, BF UP N Y MOD L2

CO/GV T, SOw, SOb NO EBL, EBA, EX UP N Y HI M2

GV SOb, SOw, T FP,NO EBL, EBA, W, LM, I UP, RO N Y HI M1

GV SOi WE I, W, EBA, A CL, RO N Y MOD W.3

GV/FINES SOi WE I, W, EBA, A CL, RO N Y MOD W.3

GV/FINES SOi WE I, W, EBA, A CL, RO N Y MOD W.3

CO/BO SOi, SOb, SOw NO I, W, EBL, EBA CL, RO N Y HI T1

CO/BO SOi, SOb, SOw NO I, W, EBL, EBA CL, RO N Y HI T1

BO T NO W, EBA, EBL UP, RO, UR Y Y LO L1

BO T, SOw, SOb NO EX UP, RO, UR, CL Y Y LO B

BE T, SOw, SOb NO EX UP, RO, CL, UR Y Y LO B

Geomorphic Characteristics 25
Table 5. Geomorphic characteristics of stream segments for Duluth-area streams, Minn., 2003–2004 —Continued

[See table 6 for explanation of abbreviations. Stream segments are shown on figure 13. Data in italics are extrapolated from reach assessments of sites 

with the same segment category. Data in bold are rapid assessment or intensive survey sites. USGS, U.S. Geological Survey; ID, identification number; 

--, no detailed measurements taken; %, percent; >, greater than; <, less than]

Segment 

ID Stream name Topographic map

USGS 

reach 

ID

Drainagenetwork 

position

Slope 

%

Valley 

type

Bedrock 

type

Glacial 

landform

Dominant 

land cover

IntermittentChannel 

type

o4 Merritt Creek Duluth Heights 48 MM >8 E GAB BED U N BE

o5 Merritt Creek Duluth Heights -- UM >2–4 E GAB SH/BED U N PB

o6 Merritt Creek Duluth Heights 47 MT >8 E GAB BED F N BE

o7 Merritt Creek Duluth Heights -- UT >2–4 C GAB SH/BED F/U Y PB/SP

s1 Stewart Creek West Duluth -- LM >1–2 N GAB TP W/U N AR/PB

s2 Stewart Creek West Duluth 3 LM >8 B GAB BED/SH F/U N BE/CA

s3 Stewart Creek West Duluth -- MM >2–4 C GAB BED F N PB

s4 Stewart Creek West Duluth -- MT >2–4 C GAB BED/TP F N CO

s5 Stewart Creek West Duluth, Esko -- UM >4–8 E GAB BED/TP F N CA/AR

s5a Stewart Creek West Duluth, Esko -- UT >2–4 N VOL BED/TP U/F Y PB/SP

s6 Stewart Creek West Duluth 2 LT >4–8 B GAB BED/SH F N CO

sg1 Sargent Creek West Duluth -- LM 0.3–1 A SED LA F/U N PR

sg2 Sargeant Creek West Duluth, Esko -- MM >1–2 C SED/VOL LA/SH F N PR/SP

sg2a Sargeant Creek West Duluth, Esko -- MM >1–2 E SED LA F/U N PR

sg2b Sargent Creek West Duluth, Esko -- LM 0.3–1 C SED LA F/U N PR

sg3 Sargeant Creek Esko -- UM >2–4 C VOL LA F N PB/SP

sg4 Sargeant Creek Esko -- MT >2–4 C VOL LA F/U Y CA/SP

sg5 Sargeant Creek Esko -- MT >4–8 C VOL LA U/F Y BE/CO

sg6 Sargeant Creek Esko -- MT >8 C VOL BED/SH F Y BE

sv1a Lenroot St Creek, 

Gogebic St Creek, 

84th Ave W 

Creek, 85th Ave 

W Creek

West Duluth -- LM >2–4 C BUR TP F/U N AR/PB

sv1b Lenroot St Creek, 

Gogebic St Creek, 

84th Ave W 

Creek, 85th Ave 

W Creek

West Duluth -- MM >8 C GAB BED F/U N BE

sv2 Lenroot St Creek, 

Gogebic St Creek, 

84th Ave W 

Creek, 85th Ave 

W Creek

West Duluth -- UM >2–4 C GAB SH/BED F Y PB

sv3a Lenroot St Creek, 

Gogebic St Creek, 

84th Ave W 

Creek, 85th Ave 

W Creek

West Duluth -- LM >2–4 C BUR TP F/U N AR/PB

sv3b Lenroot St Creek, 

Gogebic St Creek, 

84th Ave W 

Creek, 85th Ave 

W Creek

West Duluth -- MM >8 C GAB BED F N BE

26 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Dominant 

substrate

Mode of 

sediment transport

Flood 

attenuation

Dominant 

geomorphic 

processes

Observed/expected 

causes for 

disturbance

Stormdrain 

outfalls

Potential 

geomorphic 

changes

Sensitivity 

to 

disturbance

Geomorphic 

segment 

category

BE T, SOw NO EX, W, EBA, EBL UP, UR, RO, HI N Y LO B

BO SOi, SOw NO I, W, EBA, EBF UR, RO N Y MOD U2

BE T, SOw NO EX, W, EBA, EBL UP, UR, RO, HI N Y LO BT

BO/CO SOw, SOi, SOb NO W, EBA, EBF, I, A UR, RO Y Y MOD T2

BO/CO T, A NO EX, A, W UP, RO, CA Y Y LO L1

BE/BO T, SOb NO EBL, EX UP, RO N Y LO B

CO T, SOw, SOb WE EBL, EBA, EX UP, CL N Y MOD M2

CO SOw, SOi WE EX, I, W, EBA UR, RO N Y MOD T2

BO T, SOw, SOb WE EX, EBA, EBF UP, RO, CL N Y MOD B

BO SOi, SOw, SOb WE I, A, W, EBA, EBL UR, RO N Y HI T2

BO none NO ST NO N N MOD BT

GV T, SOw, SIb, SIa FP W, I, EBA, LM, OS, A UP, RO, GV, UR Y Y HI A

CO SOi, SOb, SOw, 

T, SIc

NO I, EBL, EBA, W, LM, 

BF

UP, RO, GV N Y HI M1

CO/GV SOb, SOw, T FP EBA, EBL, W, LM, 

BF

UP, RO, GV N Y HI M1

GV SOb, SOw, T NO EBL, EBA, W, LM, 

BF

UP, RO, GV, UR N Y HI A

CO T, SOw, SIc NO EBA, W, LM, BF RO, GV, UR N Y MOD U2

CO T, SOw NO EBA, W, I RO, GV N Y MOD T2

BO T, SOw, SOi NO I, EBA, W GV, RO, CL N Y MOD BT

BE/BO SOi NO I, EX GV, CL N Y LO BT

CO T, SOw NO EBA, W UP, RO, UR N Y MOD L2

BE T, SOb NO EX, EBL UP, RO N Y LO B

BO SOi, SOw, SOb NO I, EBA, EBL CL, RO, HI N Y MOD U2

CO T, SOw NO EBA, W UP, RO, CL N Y MOD L2

BE T NO EX, EBL UP, RO, HI N Y LO B

Geomorphic Characteristics 27
Table 5. Geomorphic characteristics of stream segments for Duluth-area streams, Minn., 2003–2004 —Continued

[See table 6 for explanation of abbreviations. Stream segments are shown on figure 13. Data in italics are extrapolated from reach assessments of sites 

with the same segment category. Data in bold are rapid assessment or intensive survey sites. USGS, U.S. Geological Survey; ID, identification number; 

--, no detailed measurements taken; %, percent; >, greater than; <, less than]

Segment 

ID Stream name Topographic map

USGS 

reach 

ID

Drainagenetwork 

position

Slope 

%

Valley 

type

Bedrock 

type

Glacial 

landform

Dominant 

land cover

IntermittentChannel 

type

sv4 Lenroot St Creek, 

Gogebic St Creek, 

84th Ave W 

Creek, 85th Ave 

W Creek

West Duluth -- MM >8 C GAB BED/SH F N BE

sv5 Lenroot St Creek, 

Gogebic St Creek, 

84th Ave W 

Creek, 85th Ave 

W Creek

West Duluth -- UM >4–8 C GAB BED/SH F N CA/BE

t1 Tischer Creek Duluth -- LM >4–8 E IN BED/TP U N BE

t2 Tischer Creek Duluth -- MM >1–2 N IN BED U N PR

t3 Tischer Creek Duluth -- MM >1–2 C GAB BED U N PR

t4 Tischer Creek Duluth -- MM 0.3–1 N GAB BED S N AR

t5 Tischer Creek Duluth -- MM >2–4 C GAB BED U N PB

t6 Tischer Creek Duluth -- UM 0.3–1 N GAB BED F/S/U N AR

t7 Tischer Creek Duluth -- MT >1–2 C GAB BED U/F Y PB

t8 Tischer Creek Duluth -- MT >1–2 E VOL BED U/F N AR/PR

t9 Tischer Creek Duluth 10 LM >8 E IN BED U N BE

u1 34th Ave E Creek Duluth -- LM >4–8 E IN BED U N BE

u2 38th Ave E Creek Duluth -- LM >4–8 C VOL BED U N BE

u3 43rd Ave E Creek Duluth -- LM >4–8 C VOL BED U N BE

u4 43rd Ave E Creek Duluth -- MM >8 E VOL BED U N BE

u5 43rd Ave E Creek Duluth -- UM >2–4 C VOL/IN BED U N AR

u6 50th Ave E Creek Duluth -- MT >2–4 C VOL BED U Y CA

u7 40th Ave E Creek Duluth -- UT >4–8 C VOL/IN BED U Y CO

28 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Dominant 

substrate

Mode of 

sediment transport

Flood 

attenuation

Dominant 

geomorphic 

processes

Observed/expected 

causes for 

disturbance

Stormdrain 

outfalls

Potential 

geomorphic 

changes

Sensitivity 

to 

disturbance

Geomorphic 

segment 

category

BE T NO EX, EBL UP, RO, HI N Y LO B

BE/BO SOw NO ST RO, CL, HI N Y LO B

BE/BO T, SOb NO EX, EBL HI, UP, RO Y Y LO B

GV SOi, SOw, T NO W, EBA, LM UP, UR, RO Y Y HI M1

GV SOi, SOw, SIc, T NO W, EBA, LM, BF UP, UR, RO Y Y HI M1

FINES SIa FP/WE A UP, UR, CA Y Y LO M.3

BO/CO SOi, SOw, T, SIc NO W, EBA, I, LM, BF UP, UR, CL Y Y HI M2

GV/FINES SOi, SOw WE/NO W, EBA, A, I CA, UR, RO, CL N Y MOD W.3

CO SOi, SOw, SIc NO W, EBA, I, BF CL, CA, UR Y Y HI T1

GV/CO SOi, SOw, T NO W, EBA, I CL, A, UR, RO Y Y HI T1

BE/BO T, SOb NO EX, EBL HI, UP Y Y LO B

BE/BO T, SOi, SOb, SOw NO EX, I, EBL UR Y Y MOD B

BE/BO T, SOi, SOb, SOw NO EX, I, EBL UR Y Y LO B

BE/BO T, SOi, SOb, SOw NO EX, I, EBL UR Y Y LO B

BE/BO T, SOi, SOb, SOw NO EX, I, EBL UR Y Y LO B

CO SOi, SOw FP W, I, EBL, A CA, UR, CL Y Y MOD U2

BO T, SOi, SOb, SOw NO W, EX, I UR N Y MOD T2

BE/BO T, SOi, SOb, SOw NO EX, I, LM, W UR, CL Y Y MOD BT

Geomorphic Characteristics 29
Table 6. Explanation of abbreviations used in tables for segment and reach characteristics in this study of Duluth-area streams, 

Minn.

Drainage-network position

UM Upper main stem

MM Middle main stem

LM Lower main stem

UT Upper main-stem tributary

MT Middle main-stem tributary

LT lower main-stem tributary

Valley type/stream meandering

N No valley development, stream unconfined and flows 

on glacial deposits

C Confined, V-shaped valleys with no flood plain, bedrock, or colluvial

E Unconfined valley, entrenched meanders; stream meanders follow valley course, affected by geologic 

setting; some flood plain

A Unconfined valley with alluvial meanders, stream 

meanders reflect fluvial processes; valley wider 

than meander belt, wide flood plain

B Confined valley formed in bedrock, no flood plain

Dominant bedrock type for segment

SED Slate/sedimentary

GAB Duluth gabbro complex

VOL Felsic and mafic volcanics

IN Intrusions

BUR Bedrock buried by glacial deposits

Glacial landform/deposits

SD Supraglacial drift

OW Outwash

IC Ice contact

LA Glacial lake

SH Post-glacial shoreline/beach

BED Bedrock surface

TP Till plain

UN Undifferentiated

Dominant watershed land cover

U Urban

D Developing urban

A Agriculture

F Forest

W Wetland

G Grass

S Shrubland

R Roads

Channel type

CO Colluvial

BE Bedrock

CA Cascade

SP Step-pool

PB Plane-bed

PR Pool-riffle

AR Artificial

WE Wetland

Dominant substrate

BD Bedrock

BO Boulder

CO Cobble

GV Gravel

SA Sand

FINES Fines/Organic debris

AR Artificial – concrete and others

30 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
Table 6. Explanation of abbreviations used in tables for segment and reach characteristics in this study of Duluth-area streams, 

Minn.—Continued.

Mode of sediment transport

SOi Source—incision

SOb Source—bluff erosion

SOw Source—bank erosion, widening

T Transfer

SIc Sink—lateral and mid-channel sand/gravel bars

SIb Sink—overbank sedimentation

SIa Sink—aggradation

SIp Sink—fines in pools

Flood attenuation

NO None

FP Flood-plain attenuation

WE Wetland storage

Dominant geomorphic processes

H Headcutting

I Incision

EBL Bluff/terrace erosion

EBA Bank erosion

W Widening

LM Lateral migration

OS Overbank sedimentation/levee formation

BF Mid-channel/lateral bar formation

A Aggradation

EX Expansion of flow area

ST Stable

Causes for geomorphic disturbance

CL Logging, agriculture, clearing

UP Upstream changes in sediment/water inputs

UR Urban development

CA Man-made channel alterations

RO Road drainage

DI Ditching

HI Hiking trails

GV Gravel pits

NO None

Potential changes in sediment/water inputs

Y Yes

N No

Potential sensitivity to change

LO Low—little or no change in overall channel morphology expected

MO Moderate—minor changes in substrate size, width, 

pool depth

HI High—substantial, readily detectable changes in 

channel morphology with a change in an important 

factor

Geomorphic Characteristics 31
Reach Characteristics and Processes

Reach characteristics for the 48 rapid assessment and 

intensive survey sites are summarized in table 7. The table 

contains a list of the dominant geomorphic processes at 

each site; modes of sediment erosion, transport, and deposition; geomorphic sensitivity to change; and remarks on 

pool and LWD source and function. The rapid assessment 

and intensive survey sites were in a variety of segment 

categories of slope, drainage-network position, and valley 

types (table 5). All but four sites were on main stems and 

all but one had perennial streamflow. 

The intensive sites mainly were in two of the largest 

watersheds in the Duluth area—Miller Creek (9.3 mi2) and 

Lester River (36 mi2). This design allowed for an understanding of the downstream progression of geomorphic 

conditions and processes, including linkages among sediment erosion, transport, and deposition. Miller Creek was 

chosen for more detailed study because of past and ongoing urban development in its upper watershed and erosion-resistant gabbro bedrock. The Lester River watershed 

had mainly rural land and contained volcanic and intrusive 

rocks. An intensive site was measured along Mission 

Creek in a transitional reach near a glacial lake shoreline 

between glacial deposits and bedrock (site 1), which has 

urban development upstream and future potential for valley side failures. An intensive site also was in a transitional 

reach along Chester Creek (site 43) between glacial deposits and bedrock. Both of these sites are in reaches near 

the upstream boundary between glacial deposits, glacial 

lake shorelines, and bedrock. These two sites had similar 

geologic settings to site 23 on the Lester River and site 34 

on Miller Creek (figs. 1, 4, and 5).

Most of the channel types described by Montgomery and Buffington (1998) were present in Duluth-area 

streams except for dune-ripple types (fig. 10, table 8). 

Fitting possible channel characteristics into categories 

for the segments was sometimes difficult for reaches in 

slope transition zones where channel conditions changed 

rapidly. Also, it was difficult to distinguish whether some 

streams were flowing on alluvium, colluvium, or glacial 

outwash deposits. Wetland channels and artificial ditches 

most commonly had slopes of less than 0.3 percent but 

some had slopes of 0.3 to 1 percent. Wetland ditches 

contained fine-grained deposits of organic-rich material 

during low flow that was most likely transported downstream during runoff events. Plane-bed channels were in 

middle main-stem transition areas between glacial deposits 

and exposed bedrock, in lower main-stem transition areas 

where streams flowed from steep bedrock to gentle till 

Figure 10. Hierarchical classification of channel types in the Duluth, Minn., area (modified from Montgomery and Buffington, 

1993; 1998). (%, percent; >, greater than; <, less than)

32 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
plain or landfill. Plane-bed channels generally had slopes 

from about 1 to 4 percent. Pool-riffle channels had slopes 

of about 1 to 2 percent and generally were in streams intersecting glacial deposits. Step-pool channels were mainly 

in middle main stems with slopes greater than 2 percent 

where glacial deposits transitioned to bedrock at the land 

surface. At slopes greater than 4 percent, channel types 

on main stems were cascade or bedrock and on tributaries 

were colluvial or bedrock. 

Geomorphic characteristics plotted on longitudinal 

profiles for Lester River (fig. 11A) and Miller Creek (fig. 

11B) illustrate how segment and reach characteristics 

progressively change from upstream to downstream. In 

the Lester River watershed, the upper main stem flows 

through wetlands, with gentle slopes and ditches (site 

25). Progressing downstream at site 24, the slope remains 

gentle as the stream flows across supraglacial drift. At 

site 24, there is no valley, runoff and sediment inputs are 

low, and LWD is rare. Farther downstream, the entrenched 

valley is cut into glacial outwash and ice contact deposits 

and the slope increases (site 30). Evidence of valley side 

failures or landslides is present (accentuated by the narrow 

valley and erodible glacial deposits) and bank erosion is 

common along straight stretches and bends, indicating 

channel widening. It is likely that, at about this point along 

the main stem, tributaries become sediment sources to 

the main stem. Overbank sedimentation is occurring on 

the flood plain. Farther downstream at site 23 (fig. 1), the 

slope lessens where the bedrock changes from a gabbro 

intrusion to volcanic rocks. Sediment deposition in the 

channel and in overbank areas is more common than at 

site 30, along with LWD jams. The channel shows signs 

of widening and bank erosion is common but there is less 

lateral migration and valley side failures are less common 

than upstream. At site 20, the slope increases where the 

stream intersects a gabbro intrusion and the channel type is 

step-pool. Farther downstream at site 31, the steep bedrock 

channel shows scour along channel margins, an indication 

of channel expansion. Bank erosion is more likely to occur 

where banks are composed of alluvium instead of bedrock 

or colluvium. The reach at site 31 functions as a transfer 

zone, and sediment and LWD are transported through 

the reach and downstream. There is little or no overbank 

sedimentation. LWD originating from tree-lined banks or 

valley side slopes is transported downstream. Falls or rapids are at intersections with erosion-resistant felsic rocks, 

or rocks with less jointing or air pockets, whereas pools or 

cascades are at intersections with mafic rocks, which are 

less resistant to erosion. Pools are free-formed below falls; 

pool levels are sometimes raised by human modification 

(stacking rocks at the lower end) for swimming. Bluff and 

gully erosion is common along hiking trails and near storm 

drain outfalls that run along the valley top because they 

tend to concentrate runoff. Landslides also are frequent 

where runoff becomes concentrated. Feeder tributaries 

in this reach are prone to gully erosion and provide local 

sources of sediment to the main stem.

Similar to Lester River, the upper main stem of Miller 

Creek begins with wetland ditches with gentle slopes (site 

33, fig. 11B). Site 34 is downstream of an area with extensive shopping development and upstream of the transition 

from glacial deposits to bedrock at the land surface. The 

channel type at site 34 is pool-riffle with evidence for 

recent (within 5 years) channel widening, avulsion (sudden 

channel movement), and flood scour. The flood plain has 

about 1.5 ft of post-settlement alluvium. LWD is common 

and provides some habitat and pools. Downstream, in the 

steep reach affected by the Duluth-complex gabbro rocks 

(site 44), the cascade-type channel shows signs of channel expansion in areas with no flood plain or widening in 

areas with flood plain. There is minimal to no overbank 

sedimentation through the reach at site 34. This site functions as a transfer zone for upstream sources of sediment 

and upstream or bank-derived LWD. Site 37 downstream 

is an example of a bedrock channel with a slope of greater 

than 8 percent. Similar to Lester River, bedrock channels on Miller Creek show evidence of channel expansion 

(scoured bedrock along channel margins and trees toppling 

into the channel) and sediment inputs from landslides and 

gully development along the tops of valley sides related to 

storm drains and hiking trails. Downstream of the bedrock-controlled zone, the channel is an artificial plane-bed 

at site 36.

No intensive sites were on tributaries, but observations and photographs from tributaries or small main stems 

with rapid assessments indicated that middle and lower 

tributaries with relatively steep slopes had colluvial, cascade, or bedrock channel types (fig. 12). For example, site 

46 on Coffee Creek (considered a tributary to the lower 

main stem of Miller Creek), was ephemeral and had a mix 

of colluvial/bedrock channel types (fig. 12A). Tributaries 

to Merritt, Stewart, and Keene Creeks were perennial (figs. 

12B–D). The Stewart Creek tributary (site 2) had a small 

colluvial channel that was hidden by vegetation. The Merritt Creek tributary (site 47) had a bedrock channel. The 

Keene Creek tributary (site 5) had a cascade channel. The 

amount of scour in the channels was attributed to upstream 

land cover and effects on runoff and flood peaks. Coffee 

Creek had an urban watershed; Stewart Creek had a forested watershed. Merritt Creek was forested at the site but 

Geomorphic Characteristics 33
Table 7. Reach characteristics at rapid assessment and intensive survey field sites for Duluth-area streams, Minn., 2003–2004.

[USGS, U.S. Geological Survey; mi, mile; ft, foot; LWD, large woody debris; cfs, cubic foot per second; °, degree; '. minute; ", second; mi2, square mile; 

%, percent; gv, gravel; co, cobble; FP, flood plain; m, medium; c, coarse; ns, not sampled; bf, bankfull; w, width; d, depth; bo, boulder; ds, downstream; 

us, upstream; ~, approximately; sed, sediment; <, less than; occas., occasional; ns, not surveyed; accum, accumulation; trib, tributary]

USGS 

field 

number

Stream

name Latitude Longitude

Drainage

area

(mi2)

Measured 

reach

slope (%)

Channel geomorphic setting Pool notes

1 Mission Creek at 

Stenman Rd.

46°41'43" 92°18'42" 2.12 1.6 Slightly incised? Widening. Large gv/co load 

carried by stream, bars mobilized during 

floods, accumulations around LWD; large 

trees on bank falling in. Boulder zones may 

be related to glacial lake shoreline or road 

construction.

Pool habitat caused 

by three main 

sources.

2 Stewart Creek 

Tributary at 

Skyline Rd.

46°42'07" 92°13'43" ns no Bedrock controlled channel, no evidence of 

incision or widening.

ns

3 Stewart Creek at 

Skyline Rd.

46°42'13" 92°13’41" ns no Bedrock controlled channel, increases in bf 

w and d due to increased flow, no apparent 

incision or widening.

ns

4 Knowlton Creek 

at South 

Boundary Access Rd.

46°43'30" 92°13'20" ns no Bedrock controlled channel, increases in bf 

w and d due to increased flow, no incision 

or widening, human hardening of channel 

location.

Pools caused by 

scour at base of 

falls.

5 Keene Creek 

Tributary at 

Skyline Rd./

Getchell Rd.

46°45'01" 92°11'17" ns no Rocks scoured, bo/gr banks are stable, road 

runoff a problem from Skyline Rd. 

Pools rare.

6 Keene Creek at 

Skyline Rd.

46°45'21" 92°11'21" ns no ns ns

7 Miller Creek at 

Skyline Rd.

46°46'25" 92°08'35" ns no ns ns

8 Buckingham 

Creek at 

Skyline Rd.

46°46'43" 92°07'23" ns no ns ns

9 Chester Creek at 

Skyline Rd.

46°48'46" 92°05’30" ns no ns ns

10 Tischer Cr. at 

Skyline Rd./ 

Vermillion Rd.

46°50'48" 92°03'57" ns no ns ns

11 Amity Creek at 

Occidnetal 

Rd., Lester 

Park

46°50'39" 92°00'37" ns no Bedrock channel, rocks scoured, evidence of 

increased bankfull width and depth.

Pools caused by 

scour at base of 

falls.

12 Amity Creek at 

Occidental 

Rd., Amity 

Creek Park, 

# 1

46°50'56" 92°00'41" ns no Bedrock controlled channel. ns

13 Amity Creek at 

Occidental 

Rd., Amity 

Creek Park, 

# 2

46°51'14" 92°00'41" ns no Bedrock controlled channel. ns

34 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
LWD notes Overbank

sedimentation

Estimate of 

streamflow 

(cfs)

Sensitivity to change Additional notes

Large trees in flood plain are 

source for LWD. Fallen trees 

starting to hang up on banks 

above water surface. Channel 

avulsion occurring, LWD may 

not stay in place. 

FP on inside of bend has 

1–1.5 ft organic rich m/c 

sandy loam to sand over 

gv/co. The surficial A 

horizon is about 1 ft thick. 

Sediment accum. is slow.

0.5 High—increases in runoff or sediment 

loads will affect habitat. Reach affected 

by Highway 35 runoff. Potential to 

migrate into valley sides. Potential loss 

of LWD function and pools. Sensitive to 

road runoff, gullying from road runoff, 

ditch construction, and landslides.

Anecdotal evidence that the 

reach previously had brook 

trout, which disappeared after 

Highway 35 was built. Culvert 

at Stenman Rd. blocks fish 

passage.

ns ns <.25 Sensitive to road runoff-related 

landslides, and ditching.

Boulder bottom, moss-covered 

rocks, minimal bank erosion, incipient channel flowing around 

boulders, occas. exposed roots.

ns ns 2–3 Sensitive to road runoff-related 

landslides, ditch construction.

Air photos show landslides in 

the vicinity.

LWD absent, any wood would 

have to come from us and is 

likely transported through this 

reach.

ns .25–.5 Sensitivity to road runoff, increases in 

bankfull width/depth.

S. Boundary Rd. culvert blocks 

fish passage and is grade control, site near transition in slope.

LWD absent. ns .5 Sensitivity to road runoff, increases in 

bankfull width/depth.

Culvert blocks fish passage, 

marked as ephemeral on topographic map but has base flow.

ns ns ns ns none

ns ns ns ns none

ns ns ns ns Between Twin Lakes. Quarries 

common. Golf course us. Upper 

valley runs between ridges of 

gabbro.

ns ns ns ns Narrow, confined valley in park.

ns ns ns ns none

LWD rare, most transported 

through reach.

None, outcrop. 4 Sensitivity to road runoff, increases in 

bankfull width/depth, local erosion from 

hiking trail.

Lester Park is heavily used, 

erosion coincident with trails.

ns ns ns ns none

ns ns ns ns none

Geomorphic Characteristics 35
Table 7. Reach characteristics at rapid assessment and intensive survey field sites for Duluth-area streams, Minn., 2003–2004

—Continued.

[USGS, U.S. Geological Survey; mi, mile; ft, foot; LWD, large woody debris; cfs, cubic foot per second; °, degree; '. minute; ", second; mi2, square mile; 

%, percent; gv, gravel; co, cobble; FP, flood plain; m, medium; c, coarse; ns, not sampled; bf, bankfull; w, width; d, depth; bo, boulder; ds, downstream; 

us, upstream; ~, approximately; sed, sediment; <, less than; occas., occasional; ns, not surveyed; accum, accumulation; trib, tributary]

USGS 

field 

number

Stream

name Latitude Longitude

Drainage

area

(mi2)

Measured 

reach

slope (%)

Channel geomorphic setting Pool notes

14 Amity Creek at 

Occidental 

Rd., Amity 

Creek Park, 

# 3

46°51'25" 92°00'48" ns no ns ns

15 Amity Creek at 

Occidental 

Rd., Amity 

Creek Park, 

# 4

46°51'29" 92°00'47" ns no ns ns

16 Amity Creek at 

Occidental 

Rd., Amity 

Creek Park, 

# 5

46°51'35" 92°00'51" ns no Bedrock controlled channel. ns

17 Amity Creek at 

Occidental 

Rd., Amity 

Creek Park, 

# 6

46°51'39" 92°00'53" ns no Bedrock controlled channel. Pools caused by 

scour at base of 

falls.

18 Amity Creek at 

Skyline Rd.

46°51'40" 92°00'59" ns no Bedrock controlled channel. ns

19 Lester River at 

Superior St.

46°50'21" 92°00'25" ns no Bedrock controlled channel. Pools caused by 

scour at base of 

falls.

20 Lester River at 

Strand Rd.

46°53'16" 91°59'29" ns no Channel appears entrenched but also has some 

depositional features.

ns

21 Lester River 

Tributary at 

Strand Rd.

46°53'16" 91°59'42" ns no ns ns

22 Lester River 

Tributary at 

Beyer Rd.

46°53'41" 92°00'21" ns no Ditch-like, transitional/depositional? ns

23 Lester River at 

North Tischer 

Rd.

46°54'27" 92°00'20" 28.51 yes Bluffs/valley sides are currently stable, 

widening a problem, accum. of fines in pools, 

unstable banks but some toe protection from 

co/bo in terrace deposits (glacial meltwater 

related); pre-settlement tree trunks exposed 

along banks. Sediment accumulation around 

fallen trees.

Fine sediment 

accumulation.

24 Lester River 

at Hwy 43, 

Lismore Rd.

46°56'18" 92°04'26" ns no Stable grassy banks, base flow driven flow. Pool on ds side 

culvert.

25 Lester River at 

Arnold Rd., 

#1

46°58'40" 92°05'26" 2.94 no Depositional, organic debris accumulation 

during low flow, but scour down to clay during 

floods.

Scour pool at tributary confluence.

36 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
LWD notes Overbank

sedimentation

Estimate of 

streamflow 

(cfs)

Sensitivity to change Additional notes

ns ns ns ns Local erosion, potential for 

landslides.

ns ns ns ns Local erosion, potential for 

landslides.

ns ns ns ns none

ns ns ns ns none

ns ns ns ns none

LWD rare. None, outcrop. ns Local human activity—rearranging 

rocks to deepen pools.

Park/trails along both sides, 

local erosion from trail runoff, 

potential landslides.

LWD occas. ns ns Bank erosion, bluff erosion. none

ns ns ns ns Alder thicket.

ns ns <.25 ns Alder thicket.

Us source for LWD. Large 

log jam ds of bridge and 

above sampled reach—some 

of it hanging above channel. Source for LWD in 

reach from trees falling in 

from banks from widening. 

Appears that most LWD is 

transported ds during floods.

Abandoned channel at or 

slightly lower in elevation 

than modern channel. 

Abandoned channel 

filled with wood and 4 ft 

loam/fines. Buried soil at 

about 3 ft below surface. 

On FP, 1 ft sand/loam 

over gravel.

4–5 High—potential to migrate or widen 

into valley sides and increase erosion/

sediment input.

Bridge is not blocking fish 

passage.

None apparent. ns 3–4 ns Culvert does not block fish 

passage.

LWD from snags on banks, 

some sediment trapping 

function.

2 ft organic muck over 

1 ft peat over glacial lake 

clay.

0 Us changes in runoff promotes channel 

scour. Deposition of organic debris 

during low flow. No source observed 

for gravel.

Old culvert does not block fish 

passage.

Geomorphic Characteristics 37
Table 7. Reach characteristics at rapid assessment and intensive survey field sites for Duluth-area streams, Minn., 2003–2004

—Continued.

[USGS, U.S. Geological Survey; mi, mile; ft, foot; LWD, large woody debris; cfs, cubic foot per second; °, degree; '. minute; ", second; mi2, square mile; 

%, percent; gv, gravel; co, cobble; FP, flood plain; m, medium; c, coarse; ns, not sampled; bf, bankfull; w, width; d, depth; bo, boulder; ds, downstream; 

us, upstream; ~, approximately; sed, sediment; <, less than; occas., occasional; ns, not surveyed; accum, accumulation; trib, tributary]

USGS 

field 

number

Stream

name Latitude Longitude

Drainage

area

(mi2)

Measured 

reach

slope (%)

Channel geomorphic setting Pool notes

26 Lester River at 

Arnold Rd. 

#2

46°56'54" 92°05'26" ns no Depositional? Natural levees of muck. Pooled at cement 

box culvert.

27 Lester River at 

Emerson Rd.

46°57'10" 92°05'44" ns no Same as site 25 and 26. Scour pool ds of 

road culvert.

28 Lester River at 

Howard Gnesen Rd., #1

46°57'45" 92°06'42" ns no Lowland setting, more riparian woody vegetation than sites 25–27, organic deposits in channel bottom, evidence of minor downcutting.ns

29 Lester River at 

Howard Gnesen Rd., #2

46°58'36" 92°06'43" ns no Similar to site 28, maybe a little less erosion. ns

30 Lester River at 

Hwy 37, Jean 

Duluth Rd.

46°55'18" 92°02'54" 19.28 yes Occasional landslides, widening, no evidence 

of incision, not as unstable as site 23, undercut 

banks.

Formed by riffles, 

enhanced by LWD.

31 Lester River near 

Lester River 

Rd.

46°50'32" 92°00'21" 36.45 yes Bedrock controlled channel, rocks scoured, increases in bankfull width/depth, fine sediment 

accum. in pools, channel widening with local 

increases in valley width (bedrock controlled).

Pools caused by 

scour at base of 

falls, levels raised 

by humans.

32 Miller Creek at 

Ridgeview Rd.

46°51'04" 92°09'45" ns no ns ns

33 Miller Creek at 

Swan Lake 

Rd.

46°49'43" 92°10'34" ns no Evidence of incision and widening, organic 

debris deposition common (peat eroded from 

us reaches).

Silt accumulation 

in scour hole ds of 

culvert.

34 Miller Creek 

upstream of 

Chambersberg Ave.

46°47'46" 92°09'37" 7.44 yes Massive erosion problem, new scour channels, 

widening, incision due to large increases in 

runoff volume from shopping area.

Pools from 

riffle/pool complex, 

LWD, and boulder. 

Siltation in large 

pool between 

bottom of reach 

and driveway 

crossing.

35 Miller Creek at 

Anderson Rd.

46°47'36" 92°09'26" ns yes Signs of widening, more so downstream of 

culvert, upstream banks reinforced with riprap, 

no indications of siltation.

1 step pool.

36 Miller Creek between 2nd and 

3rd St. and 

26th Ave.

46°45'51" 92°07'58" ns no Stable, wide short cascade between underground segments.none

37 Miller Creek at 

10th St.

46°46'15" 92°08'23" ns no Somewhat stable because of bedrock, increase 

in side scour because of increase in flood size, 

also some indication of incision under bridge 

(1927), maybe a bit of plucking going on.

Pools at bottom of 

falls.

38 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
LWD notes Overbank

sedimentation

Estimate of 

streamflow 

(cfs)

Sensitivity to change Additional notes

LWD from snags on banks, 

water-table changes related to 

road construction.

ns 0 Similar to site 25. Cement box culvert does not 

block fish passage.

LWD from snags on banks, 

water-table changes related to 

road construction.

Appears similar to site 25. <0.25 Similar to site 25. No notes on culvert condition.

ns ns 1.5 Similar to sites 25–27. Culvert does not block fish 

passage.

ns ns ns Similar to site 25–28. No notes on culvert condition.

Mainly from bank widening, 

occas. carried in from us.

On FP, 1 ft sand over 0.45 

ft organic-rich sand with 

common wood/organic 

debris over co/gv. Common woody debris at 1 ft 

below FP surface, related 

probably to European 

settlement.

4 Terrace and valley side cuts source of 

sediment to ds reaches, sensitive to us 

sources of sediment, also additional 

runoff from us may cause widening/ 

meandering and more terrace/ valley 

side cuts, no evidence of incision.

Half culvert in not blocking fish 

passage. No signs of erosion. 

Painted rocks in stream.

Lack of LWD. None, outcrop. ns Gullying from tributaries intersecting 

valley sides, landslides from trail runoff, 

us inputs from flood/scour, sediment 

flushed through reach, occasional gravel 

bars.

Thick algae on rocks, heavily 

used trails.

ns ns ns Potential effects from us landfill. none

Abundant LWD from banks, 

helps to stabilize banks.

ns ~1 Us inputs of sediment and runoff. Oil slick on surface, water odor, 

receives runoff from airport 

parking lot, abundant algae, culvert does not block fish passage.

Abundant, coming from 

banks, causing local scour/

bank erosion, probably source 

of LWD to downstream 

reaches.

Center of island between 

channels: 1–1.5 ft sandy 

loam over gravel. Buried 

logs, wood common at 

1.5 ft, observed eroding 

from bank toe as well.

~4 High—runoff, sediment source for 

downstream reaches.

Bridge does not block fish 

passage; landowner said no fish 

spawning in 2003 because of 

fish kill last winter and dry summer. Landowner thought stream 

change happened after commercial development on north 

side of highway. Some springs 

downstream of bridge.

Occas. LWD from alder along 

banks, some sediment trapping, some bank stabilization.

ns, residential backyards. ~4 High—runoff, sediment source for 

downstream reaches, human alterations 

to control channel changes.

Culvert does not block fish passage, erosion around upstream 

side of culvert.

Minimal. ns ns Highly altered and reinforced. No fish passage through culvert, 

short open section between 

underground segments.

Occas LWD from valley 

sides, transported out during 

floods.

None, outcrop. 4? Valley side failures from road/trail runoff, and entrance of storm sewers/tribs. 

road washouts common.

none 

Geomorphic Characteristics 39
Table 7. Reach characteristics at rapid assessment and intensive survey field sites for Duluth-area streams, Minn., 2003–2004

—Continued.

[USGS, U.S. Geological Survey; mi, mile; ft, foot; LWD, large woody debris; cfs, cubic foot per second; °, degree; '. minute; ", second; mi2, square mile; 

%, percent; gv, gravel; co, cobble; FP, flood plain; m, medium; c, coarse; ns, not sampled; bf, bankfull; w, width; d, depth; bo, boulder; ds, downstream; 

us, upstream; ~, approximately; sed, sediment; <, less than; occas., occasional; ns, not surveyed; accum, accumulation; trib, tributary]

USGS 

field 

number

Stream

name Latitude Longitude

Drainage

area

(mi2)

Measured 

reach

slope (%)

Channel geomorphic setting Pool notes

38 Mission Creek at 

Hwy 23

46°39'39" 92°16'32" ns no Maybe some widening, no signs of incision, 

man made channel oversized.

Rare or absent.

39 Mission Creek 

at 131st Ave. 

West

46°40'13" 92°16'37" ns no Impoundment collected about 1–2 feet gravel 

disturbed by dam.

ns

40 Mission Creek at 

Helburg Rd.

46°42'11" 92°20'02" ns no ns None present.

41 Kingsbury Creek 

south of Alice 

St and 1st 

Ave. North

46°44'13" 92°13'12" ns no Widening—alders falling, exposed roots 

common, grassy banks are undercut, fine sed 

deposition between boulders and in pools.

Pools related to 

step/pool channel 

units.

42 Keene Creek at 

Bristol St. 

46°44'15" 92°10'35" ns no Stable, artificial hardening from willows and 

boulder riprap on banks, drop structure at end 

of park.

None except for 

at bottom of drop 

structure.

43 Chester Creek at 

Triggs Rd.

46°49'12" 92°06'40" 3.00 yes Unstable, multiple channels, similar to site 34 

except maybe a little more incised. Degrading 

and widening, flood channels common.

Pools related to 

riffle/pool sequences and LWD.

44 Miller Creek at 

Lake Superior 

College

46°47'06" 92°08'52" 8.26 yes Signs of widening in areas without bank 

protection and some slight incision.

No pools in reach.

45 U.S. Steel Creek 

upstream of 

Hwy. 23

46°40'30" 92°13'15" ns no Extensive bank erosion along railroad track. ns

46 Coffee Creek at 

North 19 1/2 

Ave. West

46°46'20" 92°08'04" ns no Bedrock channel, possible enlargement. ns

47 Merritt Creek 

tributary at 

Skyline Drive

46°45'45" 92°09'38" ns no Bedrock channel, possible widening. Step pools—

garbage, rare.

48 Merritt Creek at 

Skyline Drive

46°45'35" 92°09'54" ns no Bedrock channel, possible enlargement. ns

40 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
LWD notes Overbank

sedimentation

Estimate of 

streamflow 

(cfs)

Sensitivity to change Additional notes

Rare LWD, from bank, no 

function.

None? 3? Low—human alterations, reinforcements.Bridge area looks stable, no 

signs of erosion, does not block 

fish passage.

ns ns ns Unknown. Dam has been out for some 

time, 1997 air photo shows 

disturbance at site as well. Not 

very good location.

LWD from bank. ns 0 Runoff from interstate, road crossings. Road crossing interfering with 

drainage.

LWD from bank, alders falling in, some hanging above 

channel ds, no function.

ns 2? High—if runoff increases will widen 

more.

none 

LWD rare, maybe from 

upstream, no function.

ns 2? Low—human alterations, reinforcements.3 foot drop in drop structure is 

fish barrier?

LWD common from banks 

and upstream, provides 

multiple functions.

0.5–1.5 ft sand loam over 

gv/co.

<1/4 High—widening/downcutting—provides sediment to ds reaches.Bedrock geologic map (1949) 

shows gridwork of streets in 

the section, not there today. Old 

building foundation on right 

bank of cross section 2, maybe 

more houses there 50 years ago 

than now?

LWD mainly from banks/ 

valley side slope.

Minimal on right side, 

1.5 ft sand w/ boulder. 

No left FP; all riprap on 

left side.

4? Slight to moderate—hardened banks 

and bottom, subject to side scour from 

increases in flood size.

Artificial hardening of left side 

where storm sewer parallels 

creek for long distance, probably down to STP at lake.

ns ns ns Subject to widening. Recent rebuilding of banks, no 

veg, silt fence failing.

ns none ns Subject to enlargement. Disturbed land cover.

Rare, us side of bridge. none 2? Subject to widening, urban development 

upstream.

Trails along stream, new 

residential development us, 

wetlands common us.

ns none ns Subject to enlargement, urban development upstream.Cannot access from roads, no 

parking.

Geomorphic Characteristics 41
RIVER MILE FROM MOUTH AT LAKE SUPERIOR

ALTITUDE, IN FEET ABOVE NAVD 27

600

700

800

900

1,000

1,100

1,200

1,300

1,400

20 15 10 5 0

Site 31

BE

2–4

E

LM

L2

Site 30

PR

1–2

E

MM

M1

Site 25

WE

<0.3

N

UM

W

Site 23

PR/PB

0.3–1

E

MM

M.3

Site 20

PR/SP

1–2

E

MM

M1

Site 24

PR/PB

0.3–1

N

UM

U.3

U.S. Geological Survey site number (fig. 1)

Channel type

Slope category, in percent

Valley type

Drainage network position

Geomorphic Segment Category (GSC)

EXPLANATION

A

Figure 11. Longitudinal profiles for A, Lester River and B, Miller Creek, in the Duluth, Minn., area. See table 6 for explanation of 

abbreviations. (<, less than)

42 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
600

700

800

900

1,000

1,100

1,200

1,300

1,400

9 8 7 6 5 4 3 2 1 0

RIVER MILE FROM MOUTH AT LAKE SUPERIOR

ALTITUDE, IN FEET ABOVE NAVD 27

Site 33

WE/AR

0.3–1

N

UM

U.3

Site 36

PB/AR

0.3–1

E

LM

A

Site 37

BE

>8

B

LM

B

Site 34

PR

0.3–1

N

MM

M.3

Site 44

CA

4–8

B

MM

B

B

EXPLANATION

Site 30

PR

1–2

E

MM

M1

U.S. Geological Survey site number (fig. 1)

Channel type

Slope category, in percent

Valley type

Drainage network position

Geomorphic Segment Category (GSC)

Figure 11. Longitudinal profiles for A, Lester River and B, Miller Creek, in the Duluth, Minn., area. See table 6 for explanation of 

abbreviations—Continued. (<, less than)

Geomorphic Characteristics 43
A

B D

C

Coffee Creek

Site 46

Merritt Creek tributary

Site 47

Stewart Creek tributary

Site 2

Keene Creek tributary

Site 5

Figure 12. Photographs of rapid assessment sites on tributaries affected by bedrock: A, site 46 on Coffee Creek, B, site 2 on 

Stewart Creek tributary, C, site 47 on Merritt Creek tributary, and D, site 5 on Keene Creek tributary, Duluth, Minn., area.

Table 8. Potential channel types in each slope/valley category for Duluth-area streams, Minn.

[<, less than; >, greater than; channel types: WE, wetland; PR, pool-riffle; PB, plane-bed; SP, step-pool; BE, bedrock; CA, cascade; CO, colluvial; na, not 

applicable]

Slope category 

(percent) No valley Confined Entrenched Alluvial Bedrock

<0.3 WE na na na na

0.3-1 WE/PR na na PB/PR na

>1-2 PR PB PB na PB/SP/BE

>2-4 PB SP/CA/CO SP/CA/BE/CO na SP/CA/BE/CO

>4-8 na CA/BE/CO CA/BE/CO na BE/CA/CO

>8 na BE BE na BE

44 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
had urban development in the upper half of its watershed, 

and the Keene Creek tributary had a mix of forest and 

shrubland but local erosion problems from road drainage.

Potential Response and Sensitivity to 

Disturbance

Human activities affect geomorphic processes in 

Duluth-area streams at multiple spatial scales (tables 5 and 

7). Activities include watershed-scale forest clearing for 

logging, agriculture, or urban development; segment-scale 

clearing of riparian vegetation for similar purposes, road 

construction and drainage, and ditching; and reach-scale or 

local features, such as human-caused channel alterations 

(straightening, dredging, damming), gravel pits or quarries, 

road crossings, and hiking trails. Geomorphic conditions 

in each segment may be affected by upstream changes 

in the flow regime or sediment inputs, or downstream 

disturbances such as changes in base level (creation of a 

reservoir) or straightening (increases slope). Geomorphic 

processes also may be affected by past activities for which 

there may be little modern evidence, such as forest clearing, logging, log dams, and log drives following European 

settlement in the late 1800s. 

Each segment has a known or extrapolated set of 

geomorphic processes that are presently occurring (table 

5). For Lake Superior tributaries in Wisconsin, watershedscale removal of forest vegetation has increased the size of 

flood peaks and caused increased erosion and sedimentation rates compared to pre-European settlement conditions 

(Fitzpatrick and others, 1999). Streams in the Duluth area 

are geologically young and very few are alluvial; thus the 

textbook concepts of geomorphic stability and potential 

responses or sensitivity to disturbance that are based on 

geologically old stream systems in well-developed alluvial 

valleys may not be applicable (such as development of 

concave upward profiles described by Hack (1960)). 

Example streams that illustrate how geomorphic 

processes are affected by human activities and disturbance 

are middle or lower main stems in the Duluth area with 

entrenched valleys. If their watersheds are completely 

forested, landslides and bluff erosion would occur episodically where stream meanders intersected valley sides. If 

a watershed is cleared for urban development, increased 

runoff and flood peaks would increase stream power, 

which in turn would increase the erosive potential of the 

channel, potentially contributing to bank erosion and 

landslides. Segments with steep slopes and narrow, deep 

valleys developed in glacial deposits have the most potential for lateral movement and landslides if upstream runoff 

contributions are increased. Landslide and bluff erosion 

also can be increased by the creation of gullies from hiking 

paths, storm drains, and road drainage that concentrate 

runoff onto erosive or unstable slopes. If a channel is in a 

bedrock-controlled valley, the likelihood of the occurrence 

of a landslide is less or minimal during human time scales, 

but still would be possible in areas that have glacial deposits overlying bedrock. Also, the sensitivity of bedrock 

channels to disturbance will be less than alluvial channels 

or channels that flow through glacial deposits.

Another example of geomorphic response to disturbance are middle main stems that flow through glacial 

deposits but are close to the transition to exposed bedrock, 

such as at Mission Creek (site 1), Miller Creek (site 34), 

Chester Creek (site 43), and Lester River (site 23) (figs. 

1, 4, and 5). At these sites, Miller and Chester Creeks do 

not have developed valleys but Mission Creek and Lester River are larger rivers with less resistive bedrock and 

entrenched valleys. Upstream inputs of water and sediment 

have changed for all these sites because of land clearing 

and wetland drainage, most dramatically for Miller Creek 

because of extensive commercial development in its upper 

watershed. Downstream, bedrock is a local base-level control, inhibiting incision as a possible geomorphic response 

to upstream increases in runoff and changes in sediment 

sources and inputs. The most ubiquitous response in these 

middle main stems to upstream increases in runoff is 

channel widening, lateral migration, and avulsion. If the 

streams have developed valleys, then migration into valley 

sides causes landslides. Slopes and banks are low enough 

that overbank sedimentation can result. These streams do 

not have lateral bedrock controls, and old glacial shorelines and ancient beaches are common in this transition 

area and deposits from them are easily eroded if they 

occur along valley sides. Thus, these segments have a high 

potential for geomorphic change from upstream increases 

in runoff volumes and flood peaks.

Geomorphic Segment Classification

Based on the compilation and interpretation of watershed-, segment-, and reach-scale data, the segments were 

grouped into 15 geomorphic segment categories (GSCs) 

with similar geomorphic characteristics and processes 

(fig. 13 and table 9). The categories are primarily based 

on slope and drainage-network position and secondarily 

on geologic setting and valley type. Dominant geomorphic 

processes are summarized for each category. As stated 

earlier, the classification is based on reach, segment, and 

Geomorphic Segment Classification 45
A

Lake

Superior

L8

L33

L1

M4

L34

L20

C3

L5

L9

C1

C5

L27

T2

T6

L6

L22

C4

L10

C6

T8

L30

L32

U4

L2

L11

L3

L4

L16a

T4

U1

M5

U3

L23

M6

L28

L38

L48

U6

L45

U7

T9

L26

T1

T3

L35

L12

L16b

T5

L41

L3a

C2

C7

L29

L42

U2

L18

L19

L43

L36

L21

L39

L25b

L19a

L46

U5

L13

L47

L31

L7

L14

L25a

L15

L17

T7

L40

L44

L49

L24

L37

L3b

W - wetland,< 3%W.3 - wetland, 0.3–1%U1 - upper main stem, 1–2%U2 - upper main stem, 2–4%

M.3 - middle main stem, 0.3–1%M1 - middle main stem, 1–2%M2 - middle main stem, 2–4% B - bedrock main stem, > 4%L1 - lower main stem, 1–2%L2 - lower main stem, 2–4%A - lower main stem, 0.3–1%T1 - upper/middle tributary, 1–2%T2 - upper/middle tributary, 2–4%BT - bedrock tributary, > 4%LT - lower tributary, 2–4%

Geomorphic Segment Classification

Stream segment IDStream basin boundarySubbasin boundaryStream

MS1a

EXPLANATION

Base from Minnesota Department of Natural Resources hydrography and Wisconsin Department of Natural Resources hydrography: 1:24,000 digital data. Transverse Mercator Projection, NAD 83

A

Lake

Superior

MINNESOTA

Study

area

WISCONSIN

B

Figure 13. Geomorphic segment classification for Duluth-area streams, Minn. (

A, northern portion and 

B, southern portion). Categories mainly based on drainage-network 

position and slope. (%, percent; >, greater than; <, less than; ID, identification code)

46 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
B

Lake

Superior

M4

K5

K1

C1

C5

K4

T2

O1

B1

C4

C6

T8

KG5

M1a

U4

K3

MS5

KG1

M8

O7

KG4

MP1

T4

U1

B3

M5

U3

M6

O4

SG1

U6

U7

T9

MS8

T1

T3

KW1

S5

SG2

S1 S2

SG3

C2

C7

MS11a

MS4

U2

MS11

M1

M3

MS2

SG2a

S3

O5

M2

B2

MP2

KG6

MS10

MS7

O6

MS20

U5

MP3

SV4

M1d

MS1

KG2c

S5a

KG3

KG7

MS24

MP5

SG6

K2

MP9

MS16

SV3a

KW2c

SG2b

M1e

MS2B

KW3

SV2

KG8

MS3

S4

MS9

MS13

MS17

MS26

MS15

SV1b

M7

MS27

MS18

MS19

O2

SG5

4 SG

SV3b

MS22

MP8

MS6

MS12

MS2a

M8a

MP3a

SV1a

MS25

MS21

KW2

MS14

MP6

MP4

MP7 MS23

KW2b

K2a

KG2b

O3

SV5

M1c

KG2

M1b

KW2a

KG2a

KG2d

S6

MINNESOTA

WISCONSIN

St. Louis Estuary St. Louis River Estuary

W - wetland,< 3%W.3 - wetland, 0.3–1%U1 - upper main stem, 1–2%U2 - upper main stem, 2–4%

M.3 - middle main stem, 0.3–1%M1 - middle main stem, 1–2%M2 - middle main stem, 2–4% B - bedrock main stem, > 4%L1 - lower main stem, 1–2%L2 - lower main stem, 2–4%A - lower main stem, 0.3–1%T1 - upper/middle tributary, 1–2%T2 - upper/middle tributary, 2–4%BT - bedrock tributary, > 4%LT - lower tributary, 2–4%

Geomorphic Segment Classification

Stream segment IDStream basin boundarySubbasin boundaryStreams

MS1a

EXPLANATION

Base from Minnesota Department of Natural Resources hydrography and Wisconsin Department of Natural Resources hydrography: 1:24,000 digital data. Transverse Mercator Projection, NAD 83

A

Lake

Superior

MINNESOTA

Study

area

WISCONSIN

B

Figure 13. Geomorphic segment classification for Duluth-area streams, Minn.—Continued (

A, northern portion and 

B, southern portion). Categories mainly based on drainagenetwork position and slope. (%, percent; >, greater than; <, less than; ID, identification code)

Geomorphic Segment Classification 47
Table 9. Geomorphic segment classification scheme for streams in the Duluth, Minn., area based on slope, drainage-network position, geologic setting, and valley type. 

Potential channel type, dominant geomorphic processes, pre-European settlement conditions, and potential sensitivity to disturbance also are summarized.[<, less than; >, greater than; LWD, large woody debris. See table 6 for definitions of abbreviations for drainage-network position, geologic setting, valley type, and potential channel type.]

Segment 

Slope

(percent)

Drainage 

network 

position

Geologic 

setting

Valley 

type

Potential 

channel 

type

Dominant geomorphic 

processes in 2003

Likely pre-European 

settlement conditions

Potential 

sensitivity to 

disturbance

Number of 

segments

W <0.3 UM, UT SD N WE Incision during floods, aggradation 

during low flow, runoff source

Channels poorly defined or absent Low/Moderate 7

W.3 0.3–1 UM, UT, 

MT

SD N WE Incision during floods, aggradation 

during low flow, runoff source

Channels poorly defined Moderate 19

U1 >1–2 UM SD N PR? Incision, bank erosion Not known High 4U2 >2–4 UM SD/BED/SH C PB/SP? Incision, bluff erosion, bank erosion Not known Moderate 7

M.3 0.3–1 MM SD/SH N/E PR Bank erosion, bluff erosion, lateral 

migration, bar formation, overbank sedimentation

Meandering pool/riffle channels 

dominated by gravel with bank erosion limited to outside bends, abundant LWD

Moderate/high 7

M1 >1–2 MM BED/SH 

transition

C/E/N PR/SP Bank erosion, bluff erosion, lateral 

migration, bar formation, overbank sedimentation

Meandering pool riffle or step pool 

channels depending on proximity to bedrock

Moderate/high 19

M2 >2–4 MM BED/SH C SP/PB Bank erosion, bluff erosion, lateral 

migration, bar formation

Possibly step-pool channels with 

gravel, cobble, boulder beds

Moderate/high 6

B >4–8+ MM, LM BED C/E BE/CA Channel expansion, bluff erosion Bedrock or step/pool channels, possibly abundant large woody debris Low 30

L1 >1–2 LM TP/LA C/E PB Channel expansion, widening Potentially meandering pool/riffle 

channels with abundant large woody debris

Low/moderate 6

L2 >2–4 LM BED/TP 

transition

C/E PB/BE Channel expansion, widening, bank 

erosion, bar formation

Potentially step/pool channels with 

abundant large woody debris

Low/moderate 10

A 0.3–1 LM TP/LA A/N PR/AR Aggradation Meandering, avulsing sand channels 

in estuary setting

Low/high 9

T1 >1–2 UT, MT SD/BED 

transition

E/C/N PR? Incision, widening, bank erosion, 

gully erosion

Unknown Moderate/high 12

T2 >2–4 UT, MT BED/SH C/E PB? Incision, gully erosion, bank erosion Unknown Moderate/high 21

BT >4–8+ MT, LT BED C CO/CA Channel expansion, incision, gully 

erosion

Poorly defined colluvial channels Moderate 19

LT >2–4 LT SD/BED/ 

SH

C PB/CO/BE Incision, gully erosion, bank erosion, 

lateral migration

Poorly defined colluvial channels Moderate/high 11

48 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
watershed characteristics specific to Duluth-area streams. 

There may be unknown local disturbance mechanisms that 

have affected geomorphic processes for some segments 

that were not field surveyed. This classification is only 

directly applicable for Duluth-area streams and is useful 

for showing the importance of linking geomorphic features 

of a specific reach to drainage-network scale processes. 

In the Duluth area, streams generally flow perpendicular 

to their base-level control (Lake Superior or St. Louis 

River estuary). The boundary between glacial deposits 

and exposed bedrock, and glacial lake shorelines also run 

parallel to Lake Superior. Thus, drainage-network position, 

geologic setting, topography, and valley type are closely 

related for Duluth-area streams, making the potential 

sources for and transport of sediment ultimately linked to 

their position within the drainage network. 

Headwater Channels with Gentle Slopes

Headwater segments with slopes less than 0.3 percent 

(W) or from 0.3 to 1 percent (W.3) are mainly upper main 

stems or tributaries to upper main stems in wetlands and 

lowland areas in the larger watersheds (table 9). The channels are commonly altered by ditching (table 5). Ditching helps speed up runoff to downstream segments with 

steeper slopes. Many of the channels are bisected by roads 

and receive runoff from large transportation corridors. 

Many channels have culvert placement-related problems 

at road crossings. Channels have water in them and low 

banks but have little flow between runoff events. Finegrained, organic-rich material accumulates during low flow 

within the channels; however, the beds of the channels are 

on parent material, such as glacial lake clay, which gives 

the appearance that the fine-grained material is flushed out 

during runoff events. 

Headwater streams tend to respond to increases in 

runoff by widening rather than incision. There is evidence 

from the GLO notes that the wetland channels are wider 

now than they were in the mid-1800s, probably from a 

combination of ditching, road runoff, and historical upland 

clearing. For example, at site 25 on Lester River, the channel in 1858 was 3 ft wide compared to 18–22 ft wide in 

2003. Occasional LWD from banks provides local habitat 

and sediment trapping but floods are generally not powerful enough to transport large debris. 

Presently (2005), these headwater segments generally 

have low to moderate sensitivity to disturbance because 

of gentle slopes, but they have some potential to widen 

with further increases in runoff. Segments with slopes of 

0.3–1 percent are distinguished in the classification from 

segments with less than 0.3 percent because the potential 

sensitivity to disturbance may be higher in the channels 

with greater than 0.3 percent slopes. If runoff is increased 

through urban development or road drainage, there is a 

potential that the channels will widen and become greater 

sources of runoff and fine-grained sediment to downstream 

segments.

Upper Main Stems with Moderate Slopes

A small number of upper main stems have greater 

than 1–2 percent or greater than 2–4 percent slopes (U1 

and U2 categories, respectively; table 9). These segments 

are at the upper end of some of the small watersheds that 

begin at or near the transition zone between glacial deposits and bedrock, such as Chester Creek (greater than 1–2 

percent slopes with no valley development), or in bedrock, 

such as Merritt Creek (greater than 2–4 percent slopes with 

confined valleys). Potential causes for geomorphic change 

include urban development or vegetation clearing, road 

drainage, and channel alterations. The bedrock segments 

have higher slopes; however, segments in glacial deposits 

have a greater potential to respond to increases in runoff 

through incision or widening. Riparian land cover along 

the segments varies from urban to forest. If forested, segments may be a source for LWD from the banks. 

Middle Main Stems with Gentle or Moderate 

Slopes

Middle main stems are divided into three groups 

based on their slope category (M.3, M1, and M2) (table 9). 

Middle main stems with greater than 1 to 2 percent slopes 

are the most common in watersheds within the study area. 

Middle main stems with gentle slopes (M.3) are 

in larger watersheds on supraglacial drift upstream of 

the bedrock outcrops with no valley development or 

entrenched valleys. Site 23 on Lester River and site 34 on 

Miller Creek fall into this category. These segments generally have pool-riffle channel types and are large enough to 

have some alluvium in channel and overbank areas. The 

main potential cause for disturbance is upstream increases 

in runoff. Local disturbances, such as channel alteration 

and road drainage, also may affect geomorphic conditions. 

Segments function as sediment source zones through bank 

erosion, widening and possibly increasing bluff erosion 

where valleys are developed, zones of sediment transfer, 

and also zones of sediment accumulation in overbank 

areas and bar formation. Potential for geomorphic condiGeomorphic Segment Classification 49
tions to change because of upstream increases in runoff is 

moderate to high. Riparian areas tend to be forested and 

are a source for LWD, but LWD has a high potential to be 

transported downstream during floods or form large log 

jams at bends.

Middle main stems with greater than 1 to 2 percent 

slopes (M1) are at the transition zone between bedrock 

and glacial deposits and have confined or entrenched valleys. These segments mainly function as sediment sources 

and transfer zones, with local storage of sediment in bars 

downstream of large eroding banks. Similar to M.3 segments, increased runoff from upstream segments is the 

main potential cause for disturbance, as well as road and 

storm drainage. There is more potential for landslides 

and bank erosion than for M.3 segments because of the 

steeper slopes and more developed valleys. The M1 segments generally have high sensitivity to disturbance unless 

developed in bedrock. There is no evidence for historical 

width changes for M1 segments. Forested riparian areas 

and upstream segments are sources for LWD. At site 43 

on Chester Creek, LWD is providing some bank and bar 

stabilization and sediment trapping, and, occasionally, 

some pool scour. 

Middle main stems with greater than 2 to 4 percent slopes (M2) have confined valleys and are typically 

developed in transition zones between glacial deposits, 

bedrock or glacial shorelines. These segments are generally zones of sediment transfer, with some segments also 

functioning as sediment sources. Potential disturbances are 

upstream increases in runoff, and local effects of urbanization and road drainage. Possible geomorphic changes 

from upstream increases in runoff include widening, bank 

erosion, landslides, lateral migration, and bar formation. 

Potential for geomorphic change from disturbances ranges 

from moderate to high, depending on parent material and 

valley type. Segments with gabbro bedrock have moderate potential, whereas segments with glacial deposits or 

sedimentary rocks have high potential.

Bedrock Main Stems with Steep Slopes

Bedrock channels with steep slopes (greater than 4 

percent slope) (B) are common and are on steep middle 

to lower main stems with mainly gabbro bedrock (figs. 

4 and 13). The valleys contain little or no alluvium, have 

little or no flood plain, and channel sides and bottom are 

composed of bedrock. These segments are mainly source 

and transport zones for water and sediment. Potential 

disturbances include increased runoff from upstream 

segments and feeder tributaries, and local landslides and 

mass wasting from hiking trails, road drainage, and storm 

sewers. Most of the sediment from the failures is transported downstream. Increases in runoff and flood peaks 

result in the expansion of the flow area and scour zone 

but the channel morphology typically remains the same 

because of the vertical and horizontal bedrock control. 

Instead, channel erosion may increase through waterfall 

recession and knickpoint migration (Tinkler and Wohl, 

1998). Pools temporarily fill with fine sediment between 

floods. A comparison of GLO survey notes and 2003 channel surveys from site 44 on Miller Creek indicates that in 

2003 the channel possibly was 3–5 ft wider than in 1858. 

Potential for geomorphic change in these segments is low 

to moderate because the channel morphology is controlled 

by bedrock. 

Presently, the effect of LWD on channel morphology 

in these reaches is negligible because most of the wood 

is not large enough to remain stationary during floods. 

However, LWD may have had more effect on channel 

morphology prior to European settlement when the size 

of the LWD was much larger because trees in the immediate riparian zone and upstream segments were larger. It 

is possible that some cascade or bedrock channels were 

step/pool prior to European settlement. Bank-derived LWD 

may alter channel morphology by providing local and 

temporary scour or lateral migration caused by temporary 

steps or log jams. A study of LWD in Washington streams 

suggested that woody debris affects channel morphology, 

planform, and flood-plain topography (Abbe and Montgomery, 2002); however, woody debris shorter than half 

the channel width is unstable and provides only temporary 

storage of sediment (Montgomery and Buffington, 1993). 

Lower Main Stems with Moderate Slopes

Lower main stems with slopes from greater than 1 

to 4 percent (L1 and L2) are in Lester River and Mission 

Creeks and other watersheds in the southwestern part of 

the study area (fig. 13). These segments generally have 

entrenched or confined valleys developed in a range of 

geologic materials (table 5). Many of the channels have 

human-caused channel alterations and have been straightened or have extensive bank stabilization and grade 

control. These channels function as zones of sediment 

transport. Causes for disturbance include increased runoff 

and sediment from upstream segments, road drainage, 

concentrated drainage and landslides from storm sewers 

and hiking trails. Segments that are bedrock controlled 

have flow expansion from increased runoff. Widening and 

lateral migration may occur in alluvial channels that have 

50 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
not been artificially stabilized. A comparison of channel 

widths at site 31 on Lester River for 1858 and 2003 indicates that the channel has widened by 5 ft or more. Potential for geomorphic change generally is low to moderate 

depending on parent material and slope. 

Aggradational Main Stems with Gentle 

Slopes

Aggradational lower main stems (A) are uncommon 

in the study area (fig. 13). These segments are on till or 

lake plain and drain to the St. Louis River estuary (fig. 1). 

Channels typically are artificially constructed plane-bed 

channels, such as those at site 38 on Mission Creek. The 

lower main stem of Sargent Creek potentially is the least 

affected by human-caused channel alterations. The gentle 

slopes are conducive to sediment accumulation in overbank areas and in channels. Potential causes for disturbance to these channels include increases in runoff and 

sediment from upstream areas and concentrated drainage 

from roads. These streams also are naturally affected by 

slowly rising water levels in Lake Superior due to regional 

differences in crustal rebound after glacial ice melted from 

the region about 10,000 years ago (Larsen, 1994). Potential 

sensitivity to disturbance ranges from low to high, depending on how channel alteration and hardening has occurred. 

The source and function of LWD in these segments is 

unknown. At site 38 on Mission Creek (fig. 1), LWD was 

rare, with some trees falling in from the banks.

Tributaries with Moderate to Steep Slopes

As mentioned previously, less time, effort, and field 

checking was spent on tributaries, especially those that are 

ephemeral. The majority of the approximately 70 tributary 

segments are ephemeral and 4 of the 15 GSCs are based 

on tributaries (T1, T2, BT, and LT; table 9). The divisions 

for the four categories mainly reflect the potential for the 

tributaries to incise or form gullies. All four categories are 

considered source areas for sediment and runoff to main 

stems. Major causes for disturbances are land clearing, 

urbanization, concentrated drainage from roads or storm 

sewers, and gravel pits and quarries. Forested riparian 

zones provide LWD sources; LWD function likely varies 

depending on slope.

 Tributaries with greater than 1–2 percent slopes 

(T1) generally flow on glacial deposits and tributaries with greater than 2–4 percent slopes (T2) flow on 

bedrock or glacial lake shoreline deposits. Valley types 

for T1 segments include undeveloped, confined, and 

entrenched, whereas valleys for T2 segments are confined 

or entrenched. Many of the T1 and T2 segments are in the 

Mission Creek watershed, with T2 segments on the eastern 

side of the watershed because there is more relief coming 

off of the Duluth gabbro complex and T1 segments on the 

western side because there is less relief related to the lake 

plain/till plain and sedimentary bedrock. Both T1 and T2 

segments have moderate to high potential for incision, 

bank erosion, and landslides. Steeper segments have more 

potential for erosion unless they are bedrock controlled. 

Steep segments that intersect glacial lake shoreline deposits have the highest potential for erosion.

Tributaries with confined bedrock valleys (BT) have 

steep slopes and are also sources of runoff and some sediment to bedrock main stems. Many tributaries are in urban 

areas. Even though slopes are steep, potential sensitivity to 

disturbance is moderate because incision and widening are 

limited by the presence of bedrock in channel margins. 

Tributaries to lower main stems (mainly Amity and 

Mission Creeks) with 2–4 percent slopes are colluvial 

channels in confined valleys (LT) and are sources for 

runoff and sediment. These segments have moderate to 

high potential to incise, widen, and produce gullies and 

landslides because of their proximity to main stems with 

entrenched valleys. 

Summary and Conclusions

Streams in 20 watersheds in the Duluth, Minn. area 

were studied by the USGS in cooperation with the city 

of Duluth in 2003–04 to identify channel geomorphic 

characteristics and processes, identify potential causes for 

geomorphic changes related to disturbance, and develop a 

classification reflective of characteristics, processes, and 

potential for geomorphic change. These goals were accomplished by collecting watershed-, segment-, and reachscale geomorphic data from digital maps, historical maps 

and notes, aerial photographs, and rapid assessments and 

intensive surveys. Understanding the geomorphic conditions and processes of these streams is important because 

they relate to overall water and aquatic-resource quality 

and adjacent plant and animal habitat. 

Streams in the Duluth area have been affected by 

a variety of historical land uses. Main causes of historical and present geomorphic disturbance include logging, 

agriculture, ongoing urban development, human-caused 

channel alterations, road and storm sewer drainage, ditching, hiking trails, and gravel pits or quarries. Geomorphic 

Summary and Conclusions 51
responses to these disturbances are dependent on a combination of drainage-network position, slope, and geologic 

setting. Almost all of the channel segments have undergone some geomorphic changes from past human-related 

disturbances.

Segments were classified into 15 unique geomorphicsegment categories primarily based on differences in drainage-network position and slope, and, secondarily, based 

on geologic setting, valley type, and dominant geomorphic 

processes. The categories accounted for major differences 

in geology and valley types because stream networks 

generally are perpendicular to the Lake Superior shoreline, 

and a major contact between glacial deposits and exposed 

bedrock parallels the Lake Superior shoreline. The three 

major bedrock types in the Duluth area have a range in 

erosion resistance; the least resistant are the Animikie 

Group sedimentary rocks in the Mission Creek watershed, the most resistant are the Duluth Complex gabbro 

intrusions in the center of the city; and the Keweenawan 

volcanic rocks in the Lester and Amity River watersheds 

are moderately resistive.

Because of insufficient slope or bedrock control, 

most of the drainage networks in the Duluth area have 

low to moderate potential for channel change from future 

disturbance. Some channels cannot incise further because 

bedrock acts as grade control, but channels can be sediment sources from widening, bank erosion, and landslides (in confined or entrenched valleys). Most of the 

headwaters segments with gentle slopes at altitudes about 

1,200 ft above NAVD27 have been ditched or channelized. Combined with urban development and concentrated 

road drainage, these segments are primary sources for 

runoff and secondary sources of sediment to downstream 

segments. Middle main-stem segments are at altitudes 

from about 1,200 to 1,000 ft and have moderate slopes 

in confined or entrenched valleys that are in the contact 

zone between glacial deposits, bedrock, and glacial-lake 

shorelines. These segments have a high potential for channel change and are primary sediment sources because they 

have confined or entrenched valleys with sandy glaciallakeshore deposits.

Below about 1,000 ft, main-stem segments and tributaries generally are affected by bedrock type and structure 

and have steep slopes and confined or entrenched valleys. 

Increases in flood peaks usually do not cause incision or 

widening in bedrock-controlled valleys; instead, the flow 

and scour area is expanded into riparian zones along the 

channel boundaries. Feeder tributaries to these main stems 

have steep, confined valleys and may be sources for runoff 

and sediment from urban areas or road and storm sewer 

drainage. Tributaries with glacial deposits overlying colluvium have a high potential for incision, widening, and 

landslides and mass wasting from valley sides. Aggradational or gentle-sloped lower main stems are in flat areas 

of till plains or fill between the bedrock bluffs and Lake 

Superior or the St. Louis River. These channels are mainly 

artificially constructed or stabilized. 

The segment-scale classification developed for this 

study can be used as a screening tool to distinguish channels that may require extra attention and care in preventing 

landslides and bank erosion. The classification is an initial 

step toward a better understanding of the spatial distribution of channels with similar geomorphic processes. The 

classification can be refined as more reach-scale geomorphic data are collected, especially for tributary segments. 

The classification could be improved and verified through 

quantitative geomorphic measurements at additional 

intensive survey sites and further monitoring at established 

intensive survey sites.

Acknowledgments

Todd Bohle (Seattle Public Utilities–Washington) 

assisted with initial stream characterization and review 

of historical aerial photos. Kyle Deming (city of Duluth) 

helped to guide study goals and approach and provided 

digital maps of Duluth urban features. Meghan Hannon 

(USGS Minnesota Water Science Center) assisted with 

field surveys and historical aerial photography interpretation. Christopher Sanocki, Andrea Bergman, and Paul 

Oduro (USGS Minnesota Water Science Center) provided 

digital maps of drainage boundaries, bedrock, glacial 

deposits, land cover, and population density. Jacqueline Hamilton (USGS Minnesota Water Science Center) 

obtained Government Land Office Survey notes. Meredith Cornett, Brian Schreurs, Thomas Duffus, and Daryl 

Peterson, all of The Nature Conservancy (Minnesota), are 

thanked for assistance with digital maps, input on study 

design, and technical insights. Todd Bohle, Daryl Peterson, David Montgomery (University of Washington), and 

Timothy Diehl (USGS Tennessee Water Science Center) 

provided technical reviews. Editorial review was completed by Angel Martin (USGS Illinois Water Science 

Center). Michelle Greenwood and Jennifer Bruce (USGS 

Wisconsin Water Science Center) created publication-quality graphics and did the layout design. 

52 Geomorphic Characteristics and Classification of Duluth-Area Streams, Minnesota
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