Soil Survey of Anchorage Area, Alaska - Natural Resources

307 Pages·2001·2.76 MB·English

Soil Survey of
United States In cooperation with the
Department of Anchorage Soil and
Agriculture Water Conservation
Anchorage Area,
District; Chugach State
Natural Resources Park; Cook Inlet
Conservation Region Inc.; Eklutna Alaska
Service Inc.; Municipality of
Anchorage; U.S.
Department of the
Interior, Bureau of
Land Management;
University of Alaska
Fairbanks, Agricultural
and Forestry
Experiment Station;
U.S. Department of the
Army; and the U.S. Air
Force

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How To Use This Soil Survey
Detailed Soil Maps
The detailed soil maps can be useful in planning the use and
management of small areas.
To find information about your area
of interest, locate that area on the
Index to Map Sheets. Note the
number of the map sheet and turn
to that sheet.
Locate your area of interest on
the map sheet. Note the map unit
symbols that are in that area. Turn
to the Contents, which lists the
map units by symbol and name
and shows the page where each
map unit is described.
The Contents shows which table
has data on a specific land use for
each detailed soil map unit. Also
see the Contents for sections of
this publication that may address
your specific needs.
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This soil survey is a publication of the National Cooperative Soil Survey, a joint effort of
the United States Department of Agriculture and other Federal agencies, State agencies
including the Agricultural and Forestry Experiment Station, and local agencies. The
Natural Resources Conservation Service (formerly the Soil Conservation Service) has
leadership for the Federal part of the National Cooperative Soil Survey.
Major fieldwork for this soil survey was completed in 2000. Soil names and descriptions
were approved in 2001. Unless otherwise indicated, statements in this publication refer to
conditions in the survey area in 2001. This survey was made cooperatively by the Natural
Resources Conservation Service; the Anchorage Soil and Water Conservation District;
Chugach State Park; Cook Inlet Region Inc.; Eklutna Inc.; Municipality of Anchorage;
U.S. Department of the Interior, Bureau of Land Management; University of Alaska
Fairbanks, Agricultural and Forestry Experiment Station; U.S. Department of the Army;
and the U.S. Air Force. This survey is part of the technical assistance furnished through
the Anchorage Soil and Water Conservation District.
Soil maps in this survey may be copied without permission. Enlargement of these
maps, however, could cause misunderstanding of the detail of mapping. If enlarged,
maps do not show the small areas of contrasting soils that could have been shown at a
larger scale.
The United States Department of Agriculture (USDA) prohibits discrimination in all of its
programs and activities on the basis of race, color, national origin, sex, religion, age,
disability, political beliefs, sexual orientation, and marital or family status. (Not all
prohibited bases apply to all programs.) Persons with disabilities who require alternative
means for communication of program information (Braille, large print, audio tape, etc.)
should contact the USDA’s TARGET Center at 202-720-2600 (voice and TDD).
To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room
326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C., 20250-
9410, or call 202-720-5964 (voice and TDD). USDA is an equal opportunity provider and
employer.
Cover: The city of Anchorage, Alaska surrounded by the Cook Inlet and the
Chugach Mountains. Typic Cryaquents soils occur on the vegetated tidal flats in
the foreground. Talkeetna, Chugach, and Deneka soils, and rock outcrop occur on
the Chugach Mountains in the background.
Additional information about the nation’s natural resources is available on the
Natural Resources Conservation Service home page on the World Wide Web.
The address is http://www.nrcs.usda.gov.
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Contents
How To Use This Soil Survey..............................3 419—Eklutna very cobbly sand, 0 to 3
Foreword................................................................8 percent slopes.........................................31
General Nature of the Survey Area......................11 420—Haplocryods, 20 to 50 percent slopes....31
Landforms and Geologic Deposits..................11 421—Histic Cryaquepts, 0 to 15 percent
Water Resources.............................................12 slopes......................................................32
Native Vegetation............................................12 422—Histic Cryaquepts-Hurdygurdy
Climate.............................................................12 association, 3 to 25 percent slopes.........32
How This Survey Was Made................................13 423—Hurdygurdy-Siwash-Rock outcrop
Detailed Soil Map Units......................................15 association, 10 to 70 percent slopes.......33
400—Anchorpark loamy very fine sand, 30 424—Icknuun peat, 0 to 3 percent slopes.......34
to 85 percent slopes................................16 425—Jacobsen-Disappear-Doroshin
401—Andic Humicryods-Rock outcrop complex, 0 to 3 percent slopes................34
association, 25 to 85 percent slopes.......16 426—Jacobsen-Disappear-Doroshin
402—Clam Gulch silt loam, 0 to 7 percent complex, 3 to 7 percent slopes................36
slopes......................................................17 427—Jacobsen-Disappear-Doroshin
403—Clam Gulch-Doroshin-Jacobsen complex, 7 to 12 percent slopes..............37
complex, 0 to 15 percent slopes..............17 428—Kashwitna-Kichatna complex, 0 to 3
404—Cryosaprists, 0 to 1 percent slopes........19 percent slopes.........................................38
405—Cryorthents, silty, 5 to 65 percent 429—Kashwitna-Kichatna complex, 12 to
slopes......................................................19 20 percent slopes....................................39
406—Cryorthents and Urban land, 0 to 5 430—Kashwitna-Kichatna complex, 30 to
percent slopes.........................................19 85 percent slopes....................................40
407—Cryorthents and Urban land, 5 to 20 431—Kashwitna-Kichatna complex,
percent slopes.........................................20 undulating................................................41
408—Deception-Cryorthents complex, 45 432—Kashwitna-Kichatna complex,
to 90 percent slopes................................20 undulating and hilly..................................42
409—Deception-Disappear complex, 433—Kashwitna-Kichatna complex,
undulating and hilly..................................21 undulating and steep...............................46
410—Deception-Estelle-Kichatna complex, 434—Kichatna-Pioneer Peak-Jacobsen
0 to 7 percent slopes...............................22 complex, 0 to 15 percent slopes..............47
411—Deception-Estelle-Kichatna complex, 435—Matsu silt loam, 0 to 3 percent slopes....48
12 to 20 percent slopes...........................23 436—Matsu silt loam, 3 to 7 percent slopes....48
412—Deception-Estelle-Kichatna complex, 437—Moose River-Niklason complex,
20 to 45 percent slopes...........................24 frequently flooded, 0 to 3 percent
413—Deception-Estelle-Kichatna complex, slopes......................................................49
45 to 85 percent slopes...........................26 438—Moose River-Niklason complex,
414—Deception-Estelle-Kichatna complex, occasionally flooded, 0 to 3 percent
undulating and hilly..................................27 slopes......................................................50
415—Deception-Estelle-Kichatna complex, 439—Nakochna-Rock outcrop association,
undulating and steep...............................28 20 to 85 percent slopes...........................51
416—Disappear-Pioneer Peak complex, 0 440—Pioneer Peak silt loam, 0 to 3
to 7 percent slopes..................................29 percent slopes.........................................51
417—Doroshin peat, 0 to 7 percent slopes.....30 441—Pioneer Peak silt loam, 3 to 7
418—Dumps, landfill........................................31 percent slopes.........................................52
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442—Pioneer Peak-Jacobsen-Doroshin 465—Whitsol silt loam, 0 to 3 percent
complex, 12 to 20 percent slopes............52 slopes.......................................................69
443—Pits, gravel..............................................54 466—Whitsol silt loam, 3 to 7 percent
444—Riverwash and Niklavar soils, 0 to 2 slopes.......................................................70
percent slopes..........................................54 467—Whitsol silt loam, 7 to 12 percent
445—Rock outcrop..........................................54 slopes.......................................................70
446—Salamatof peat, 0 to 3 percent slopes....55 468—Whitsol silt loam, 12 to 20 percent
447—Smithfha loamy very fine sand, 0 to 3 slopes.......................................................71
percent slopes..........................................55 469—Whitsol silt loam, 20 to 45 percent
448—Smithfha loamy very fine sand, 3 to 7 slopes.......................................................71
percent slopes..........................................56 Soil Properties.....................................................73
449—Smithfha loamy very fine sand, 30 to Engineering Index Properties...........................73
45 percent slopes.....................................56 Physical Properties...........................................74
450—Smithfha loamy very fine sand, Chemical Properties.........................................75
undulating and steep................................57 Water Features.................................................76
451—Smithfha-Anchorpark complex, Soil Features....................................................77
undulating and hilly..................................57 Use and Management of the Soil.......................79
452—Susitna silt loam, 0 to 2 percent Horticulture.......................................................79
slopes.......................................................58 Climate........................................................79
453—Susivar and Niklavar fine sandy Soil..............................................................79
loams........................................................59 Soil Temperature....................................79
454—Susivar-Moose River complex, 0 to 2 Soil pH....................................................80
percent slopes..........................................59 Fertilizer Requirements and Soil
455—Talkeetna-Chugach-Deneka Amendments......................................80
complex, 12 to 20 percent slopes............60 Surface Runoff, Water Infiltration, and
456—Talkeetna-Chugach-Deneka Drainage............................................80
complex, 20 to 45 percent slopes............61 Irrigation and Water Management..........80
457—Talkeetna-Chugach-Deneka Growing and Using Native Plants...............81
complex, 45 to 85 percent slopes............62 Land Capability Classification..........................81
458—Talkeetna-Chugach-Deneka Interpretive Ratings..........................................82
complex, undulating and hilly...................64 Rating Class Terms....................................82
459—Talkeetna-Chugach-Histic Numerical Ratings.......................................82
Cryaquepts association, 10 to 70 Recreation........................................................82
percent slopes..........................................65 Engineering......................................................83
460—Talkeetna-Chugach-Histic Building Site Development..........................84
Cryaquepts association, cool, 10 to 70 Sanitary Facilities........................................85
percent slopes..........................................66 Construction Materials................................87
461—Talkeetna-Deneka-Rock outcrop Hydric Soils......................................................87
complex, 30 to 85 percent slopes............67 Key To Hydric Soil Criteria..........................88
462—Typic Cryaquent and Typic Classification of the Soils...................................91
Cryaquept soils, 0 to 2 percent slopes.....68 Taxonomic Units and Their Morphology................91
463—Water, fresh............................................69 Anchorpark Series............................................92
464—Water, saline...........................................69 Andic Humicryods............................................92
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Chugach Series...............................................93 Plains and Hills.........................................122
Clam Gulch Series...........................................94 Stream Terraces.......................................123
Cryorthents......................................................95 Flood Plains..............................................123
Cryosaprists.....................................................95 Depressions..............................................123
Deception Series.............................................96 References.........................................................125
Deneka Series.................................................97 Glossary.............................................................127
Disappear Series.............................................98 Tables.................................................................135
Doroshin Series...............................................99 Table 1.—Temperatureand Precipitation at
Eklutna Series..................................................99 Anchorage, Alaska................................136
Estelle Series.................................................101 Table 2.—Probability of frost at Anchorage,
Haplocryods...................................................102 Alaska....................................................137
Histic Cryaquepts...........................................103 Table 3.—Growing Season at Anchorage,
Hurdygurdy Series.........................................103 Alaska....................................................137
Icknuun Series...............................................104 Table 4.—Acreage and Proportionate
Jacobsen Series............................................105 Extent of the Soils..................................138
Kashwitna Series...........................................105 Table 5.—Engineering Index Properties........139
Kichatna Series..............................................106 Table 6.—Engineering Particle Size Data.....153
Matsu Series..................................................108 Table 7.—Physical Properties of the Soils....176
Moose River Series.......................................108 Table 8.—Chemical Properties of the Soils...187
Nakochna Series...........................................109 Table 9.—Water Features.............................198
Niklason Series..............................................110 Table 10.—Soil Features...............................207
Niklavar Series...............................................111 Table 11.—Land Capability...........................212
Pioneer Peak Series......................................112 Table 12.—Recreation: Camp and Picnic
Salamatof Series...........................................113 Areas, Playgrounds, Foot and ATV
Siwash Series................................................113 Trails......................................................216
Smithfha Series.............................................114 Table 13.—Building Site Development:
Susitna Series................................................115 Structures..............................................230
Susivar Series................................................116 Table 14.—Building Site Development: Site
Talkeetna Series............................................117 Improvements........................................238
Typic Cryaquents...........................................118 Table 15.—Sanitary Facilities: Sewage
Typic Cryaquepts...........................................119 Treatment..............................................249
Whitsol Series................................................119 Table 16.—Sanitary Facilities: Landfill..........261
Formation of the Soils......................................121 Table 17.—Construction Materials: Gravel
Climate...........................................................121 and Sand...............................................273
Lowlands..................................................121 Table 18.—Construction Materials: Topsoil
Mountains.................................................121 and Roadfill............................................282
Soil-Landform Relationships..........................122 Table 19.—Hydric Soils List..........................295
Mountains.................................................122 Table 20.—Classification of the Soils............306
Issued 2001
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Foreword
The USDA Natural Resources Conservation Service is proud to present the
following soil survey, which covers much of the land area in Anchorage, Alaska.
This soil survey contains information that can be used in land-planning programs
in the Anchorage Area, Alaska. It contains predictions of soil behavior for selected
land uses. The survey also highlights limitations and hazards inherent in the soil,
improvements needed to overcome the limitations, and the impact of selected land
uses on the environment.
This soil survey is designed for many different users. Government agencies, the
Soil and Water Conservation District, community officials, Alaska Native tribes,
engineers, developers, builders, and home buyers can use the survey to plan land
use, select sites for construction, and identify special land practices.
Conservationists, teachers, students, and specialists in recreation, wildlife
management, waste disposal, and pollution control can use the survey to help
them understand, protect, and enhance the environment.
The information in this report is intended to identify soil properties that are used
in making various land use or land treatment decisions. Statements made in this
report are intended to help the land users identify and reduce the effects of soil
limitations on land uses. Land use regulations of Federal, State, and local
governments may impose special restrictions on land use or land treatment. The
landowner or user is responsible for identifying and complying with existing laws
and regulations. The Natural Resources Conservation Service and the Anchorage
Soil and Water Conservation District can provide helpful information.
Great differences in soil properties can occur within short distances. Some soils
are seasonally wet or subject to flooding. Some are shallow to bedrock. Some are
too unstable to be used as a foundation for buildings or roads. Wet soils are poorly
suited for waste treatment systems. A high water table makes a soil poorly suited
for basements or underground installations.
Many soil properties that affect land use are described in this soil survey. The
location of each soil is shown on the detailed soil maps. Each soil in the survey
area is described. Information on specific uses is given for each soil. Help in using
this publication and additional information are available at the Anchorage office of
the Natural Resources Conservation Service or Alaska Cooperative Extension.
Chuck Bell
State Conservationist
Natural Resources Conservation Service
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Location of the survey area in Alaska.