Land Cover of Alluvial Areas: Russian River Main Stem, Alexander Valley Reach, Sonoma County, California, 1942
Abstract/Contents
- Abstract
- This polygon shapefile describes the landuse and landcover of the Alexander Valley reach of the Russian River in 1942. The Alexander Valley Reach extent is defined by the Jimtown Bridge and Cloverdale, Sonoma Co. This dataset is one of six datasets that together, form the GIS data for the Russian River Resource Enhancement Plan and Public Access Plan (Enhancement Plan).Each of the .shp files listed above is intended to be linked to a .dbf using the 'ACADTEXT' attribute column. The .dbf files were created as a part of the original Enhancement Plan, not the Russian River Watershed GIS.Link this file with hab2_42.dbf for landuse/landcover information.
- Purpose
- This layer can be used for land use analysis and planning in the Russian River region of California.
Description
Type of resource | cartographic, software, multimedia |
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Form | Shapefile |
Extent | 0.466 |
Place | Windsor, California, US |
Publisher | Circuit Rider Productions |
Date valid | 1942 |
Publication date | 2002 |
Language | English |
Digital origin | born digital |
Map data | Scale not given. ; EPSG::26910 W 123°1ʹ25ʺ--W 122°49ʹ10ʺ/N 38°49ʹ49ʺ--N 38°39ʹ11ʺW 123°1ʹ25ʺ--W 122°49ʹ11ʺ/N 38°49ʹ49ʺ--N 38°39ʹ11ʺ, Scale not given ; EPSG::4326 |
Creators/Contributors
Creator | Circuit Rider Productions |
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Subjects
Subject | Land cover |
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Subject | Alluvial plains |
Subject | Alluvial streams |
Subject | Sonoma County (Calif.) |
Subject | Mendocino County (Calif.) |
Subject | Russian River Watershed (Calif.) |
Subject | 1942 |
Subject | Inland Waters |
Subject | Farming |
Genre | Geospatial data |
Genre | Cartographic dataset |
Bibliographic information
Supplemental information |
Data Set Source: Sonoma County Planning Department (1990 aerial photos); American Digital Cartography, Inc. (digital base maps); U.S. Soil Conservation Service (1942 aerial photos - now archived at Sonoma State University). Data Source Form: 1:6,000-scale enlargements of rectified 1990 photos, printed on blueprint-quality paper and traced on stable mylar base; 1:8,286-scale enlargements of 1942 photos printed on heavy photo paper and traced on stable mylar base; digital maps based on USGS 1:100,000-scale DLGs; ground-truth of areas covered by riparian vegetation from 1992 ground surveys and 1:2,400-scale unrectified 1991 photos. METHODOLOGY:
DATA DICTIONARY: Item definitions, codes, and explanatory notes for the Russian River Resource Enhancement Plan Databases I. INTRODUCTION: The purpose of this data dictionary is to document the contents of the GIS attribute databases that were developed for the Russian River Resource Enhancement Plan, including information on GIS data set file names, item names in each database file, item definitions, data sources, and codes. Since a data dictionary must change and grow along with the database itself, the code changes that are inevitable in any on-going project have also been recorded here. The project's three study areas (Mendocino Study Area, Alexander Valley Study Area, and Middle Reach Study Area) were assigned codes of 100000, 200000, and 300000, respectively. Two attribute databases (Land Use and Habitat, Riparian Vegetation and Gravel Bar) were developed for each study area. These attribute databases were originally created in Lotus 1-2-3 spreadsheet format, then translated into dBase III+ format ("dbf" filename extension) for use with the ArcCAD GIS program. The database filenames for each study area consist of abbreviations referring to the type of data, the first digit of the study area code, the year of aerial photography; and a filename extension designating the file format. For example, Hab3_42.dbf is the name of the file containing habitat data for Study Area 300000 (Middle Reach), based on 1942 aerial photos, and stored in dbf file format. Each individual map polygon or sub-polygon in the database was assigned a composite ID number derived by summing up the values of the codes for Decade, Study Area, Zone, Bank, Polygon, and Sub-Polygon, as given below. For example, the ID number 9358159.1 designates a specific 1990-decade Middle Reach polygon in the Channel Zone on the Right-hand side, with Polygon Number 159 and Sub-Polygon Number 0.1. DECADE
STUDY_AREA
ZONE
Code 60000 = Zone "U": Upper or "historical" floodplain terraces along the main stem; i.e., all lowland areas between the outer limit of the main stem riparian vegetation and the study area boundaries, including the channels, riparian areas, and floodplains of tributary creeks. The relatively level terrace areas are nevertheless high enough that they are assumed to be only rarely subject to flooding by the river (as mapped in the present study this zone may include some small areas that are actually within the river's active floodplains and some other small areas that are actually above the historical flood elevations). Code 70000 = Zone "K": Uplands within the study area boundaries that are higher than the general level of the upper floodplain terraces along the main stem or its major tributaries, and which are separated from the floodplains by a distinct break in slope. It is assumed for the purposes of the present study that these upland areas are never subject to flooding by streamwaters. BANK
POLYGON
SUB_POLYGON
Note: On the field sheets the sub-polygons were originally designated by lower-case letters. In the present decimal-number system, sub-polygon 0.1 corresponds to the former sub-polygon a, sub-polygon 0.2 to the former sub-polygon b, etc. A "missing data" code of either "xxxx" (for text fields) or "9999" (for numerical fields) was assigned when data for a given map polygon was unavailable, in order to differentiate such cases from legitimate "blank" fields in the database.
II. RIPARIAN VEGETATION AND GRAVEL BAR DATABASES dBASE III+ filenames: RIP1_90.dbf, RIP2_90.dbf, RIP3_90.dbf Item (1). Item Name: ACAD_TEXT\Field Width: 14\Data Type: Number
Item (2). Item Name: R_MILE\Field Width: 7\Data Type: Number
Item (3). Item Name: AREA_HA\Field Width: 12\Data Type: Number
Item (4). Item Name: AREA_AC\Field Width: 12\Data Type: Number
Item (5). Item Name: N_SIZE_CL\Field Width: 10\Data Type: Number
Code 1 = Seedlings: <1" dbh
Note: Although Northen's dbh class names are different from those used in the WHR system, his categories nevertheless correspond exactly to the first five WHR size classes (i.e., seedling, sapling, pole tree, small tree, medium/large tree). Item (6). Item Name: AV_HEIGHT\Field Width: 9\Data Type: Number
Code 1 = <3'
Item (7). Item Name: N_COVER\Field Width: 9\Data Type: Character
Code u = "unvegetated" (<10% cover)
Item (8). Item Name: N_VEGTYPE\Field Width: 10\Data Type: Character
Code f = Forbs, Grasses, and/or "Shrubs" (interpreted here as woody plants 3'-15' tall)
Item (9). Item Name: AV_DBH\Field Width: 10\Data Type: Character
Code A = Seedling to Sapling size (<1"-6"; WHR codes 1 and 2)
Note: On our field sheets the "Size" category originally contained dbh size class information according to the standard WHR definitions (Mayer and Laudenslayer 1988). We subsequently modified our classification by lumping the five WHR size classes into the above three categories, and changing the name of this item to Av_dbh. Av_dbh differs from Item 2 above (N_Size_Class) in that the latter refers only to the dbh of "the stand's largest trees" (Northen 1991; 1992). Item (10). Item Name: N_SPPTYPE\Field Width: 12\Data Type: Character
Cottonwood = (fc) = PF
Note: The species codes shown in parentheses above are taken from Northen (1991; 1992). We originally used these codes on our fieldsheets, but they were later changed to upper-case letters matching the codes used in Items (13) and (14) below. Item (11). Item Name: N_STATUS\Field Width: 8\Data Type: Number
Code 0.1 = Vegetation either "absent" or largely so (less than 10% cover) or "sparse" (less than or equal to 50% cover).
Note: In his previous work in the riparian zone of the Russian River, Northen (1991; 1992) designated "... Hind's Black Walnut and Box Elder, and to a lesser extent Oregon Ash", as the late successional or "climax" species in this plant community. He noted that he "... did not include White Alder as such, even though it may be when adjacent to an old, stable channel". Note: Northen did not specify what he meant by "evident numbers" in the above classification scheme; we interpreted it to mean "Individuals of late successional species abundant enough to be seen frequently without having to make a special search for them". Note: The "sub-status" category originally appearing on our field sheets was subsequently discarded. Item (12). Item Name: N_BARTYPE\Field Width: 12\Data Type: Character
Code lgr = Level or rounded cross-section; mainly gravel
Item (13). Item Name: OVERSTORY\Field Width: 36\Data Type: Character
Code, Tree Species, Common Name
Item (14). Item Name: UNDERSTORY\Field Width: 36\Data Type: Character
Item (15). Item Name: VINES\Field Width: 21\Data Type: Character
Item (16). Item Name: SHRUBS\Field Width: 36\Data Type: Character
Code, Shrub/Vine/Gd.Cover/Aquatic, Common Name:
Item (17). Item Name: GR_COVER\Field Width: 62\Data Type: Character
Item (18). Item Name: PC_GR_COV\Field Width: 10\Data Type: Number
Code 1 = 0% - 25%
III. LAND USE AND HABITAT DATABASES dBASE III+ filenames: HAB2_42.dbf, HAB3_42.dbf, HAB1_90.dbf, HAB2_90.dbf, HAB3_90.dbf Item (1). Item Name: Acad_Text; Data Type: Number; Field Width: 14
Item (2). Item Name: R_MILE\Field Width: 7\Data Type: Number
Item (3). Item Name: AREA_HA\Field Width: 12\Data Type: Number
Item (4). Item Name: AREA_AC\Field Width: 12\Data Type: Number
Item (5). Item Name: LANDFORM\Field Width: 10\Data Type: Character
Zone "U": Upper Terraces and Tributary Streams
Note: Ground truth was not obtained for the tributary streams, hence these habitats were not subdivided further into bar types or vegetation types. Zone "C": Main Stem River Channel
Item (6). Item Name: LANDUSE\Field Width: 9\Data Type: Character
Code A (Land Use) = Agricultural Land
Code G (Land Use) = Gravel Extraction Pit (excluding pit margin)
Code Gmo (Land Use) = Gravel Pit Margin, "open" (i.e., <10% cover) Code Gmv (Land Use) = Gravel Pit Margin, "vegetated" (i.e., >10% cover)
Code Ig (Land Use) = Industrial Land (gravel processing facilities; mainly un-vegetated) Code Iot (Land Use) = Industrial Land (all other types of heavy industrial facilities; mainly un-vegetated) Code Iw (Land Use) = industrial-related water features (e.g. sewage treatment ponds) Code R (Land Use) = Rural Residential, Rural Public Facilities (e.g. schools), Rural Commercial Land, or Rural Golf Courses and other landscaped areas with 10-75% tree and/or grass cover
Code U (Land Use) = Urban Residential, Urban Public Facilities, Urban Commercial Land, Urban Parks
Code C (Land Use) = Major Transportation Infrastructure (e.g., multi-lane freeways or other limited-access highways; airport runways and facilities - including pavement and rights-of-way). Smaller roads (whether paved or unpaved) are not shown unless they form part of a polygon boundary. Code O (Land Use) = Open Land (i.e., mainly unvegetated land that is not presently in agricultural, industrial, residential, commercial, transportation, or urban use, with <10% cover by herbs, shrubs, and/or trees).
Code N (Land Use) = Non-Cultivated Vegetated Land (i.e., cultural, semi-natural, or natural vegetation - see definitions in report glossary), with >10% cover by herbs, shrubs, and/or trees.
Note: The land form/land use/land cover classification scheme given in the preceding three items is a greatly modified and expanded version of a system developed by Philip Northen (see Northen 1991; 1992). CRP initially attempted to use a classification scheme identical to Northen's, but this turned out not to be feasible due to the smaller scale of our aerial photos (i.e., 1:6,000 instead of 1:2,400). For example, Northen's "Outer Bank" landform category was not mapped at our photo scale because its narrow width made it very difficult to interpret; it is included in our category of "In-channel Terrace". We also did not find it feasible to map dry secondary channels occurring on point bars as separate units, therefore Northen's "Open Secondary Channel" landform category was not used. If a wet secondary channel was connected to the main river channel at both ends and surface water was visible throughout its length, then it was mapped as a side loop of the main wetted channel. Backwater ponds (isolated wet areas in an otherwise dry secondary channel) or "lagoons" (wet, shallow embayments located where an otherwise dry secondary channel meets the main stem) were also mapped as wetted channel. Note: Urban forest was originally coded w (for "woods") in the data entry sheets, and the artificial reservoir category was not at first used for urban areas. Note: It sometimes happened that ground truth personnel estimated the cover in some polygons of the Open land use category to be greater than 10%. In such cases the ground truth estimate was given more weight than the airphoto estimate, because: a) a scattered cover of grasses, forbs and/or shrubs was often difficult to detect on the imagery used in this project, and b) the ground truth data was acquired more recently than the photo data. ******************************************************************************
Item (8). Item Name: CNDDB\Field Width: 12\Data Type: Number
-----------------------------------------------------------------------------------------------------------Land Cover Units Used in this Study, and Their Approximate Correspondence to Units in the WHR
Forbs and Shrubs (successional)*2, CSC, Coastal Scrub, 32100
Wetted Channel of Stream, RIV, Riverine, None
*1 CNDDB codes are generally based on R. F. Holland (1986), and R. F. Holland's WHR-CNDDB correlations in the "Crosswalk Table" on pp. 23-39 in Mayer and Laudenslayer (1988). WHR Habitat names and codes are those listed in Mayer and Laudenslayer (1988) and the California Department of Fish and Game's WHR Computer Database (version 5.0). Since the intention of the WHR system is to classify major vegetative complexes at a scale sufficient to predict wildlife habitat relationships, most of its categories are at the association level of a vegetation classification or higher. A WHR habitat is generally broader than a "natural Community" type in the CNDDB system; i.e., a WHR habitat often encompasses more than one CNDDB community type. Where disturbance has removed a pre-existing tree cover and tree species have not yet re-colonized a site to any significant degree, the WHR system allows the coding of such units as the "seedling stage" of a tree-dominated habitat. In this project we preferred not to make assumptions regarding potential vegetation development; all such units were coded on the basis of their presently existing cover (e.g., "Open", "Grassland", or "Forbs and Shrubs"). *2 Areas of forbs and shrubs that represent early successional stages of tree-dominated habitats in this part of Sonoma County frequently include dominants (e.g., Baccharis pilularis) typical of WHR Coastal Scrub habitat (CNDDB Northern [Franciscan] Coastal Scrub, 32100). Since the study areas are at the inland fringes of the distribution of Coastal Scrub, this habitat was used as an approximation of early successional stands. *3 All Grassland/Savanna cover units were assumed to be WHR Annual Grassland, unless determined by ground truth to be Perennial Grassland. *4 In the CNDDB system, Riparian Forest is 61400 and Riparian Scrub is 63400, but only the 61400 code was used here. *5 "Oak/Hardwood Woodlands" in this geographic area are very variable in composition and structure. The CNDDB code 71100 refers to all vegetation types dominated by oaks and other hardwoods, but unfortunately the WHR system does not contain a comparably general designation. The WHR code VOW (Valley Oak Woodland) was therefore used to represent all oak woodlands in the lower-elevation parts of the study area and COW (Coastal Oak Woodland) was used for all hillside oak woodlands, since those appeared to be the most common types. However, in any area where ground-truth data was not obtained it should be realized that stands labeled VOW or COW may actually comprise some of the other oak-and hardwood-dominated types listed in this table. *6 "Mixed Upland Forest" is a complex mixture of subtypes, most of which contain some percentage of Douglas-Fir. These subtypes vary from mixed hardwood woodlands with California Bay or oaks, to Mixed Evergreen and Redwood Forests, to forests strongly dominated by Douglas Fir. The WHR Douglas-Fir Habitat type (DFR) is broad enough to include all these local variants, but the CNDDB types are more restrictive. It should be noted that the CNDDB type called Douglas-Fir Forest (82400) actually refers to a Douglas-Fir/Sitka Spruce/Western Hemlock assemblage that does not occur within the project area. Most mixed upland forests containing Douglas-Fir in this area were therefore classified in the more general CNDDB category of "Broad-Leaved Upland Forest" (81000), and were correlated to WHR Montane Hardwood-Conifer Habitat (MHC). However, when the estimated canopy cover by Douglas-Fir exceeded 50% the stand was assigned to CNDDB Mixed North Slope Forest (81500) and correlated to WHR Douglas-Fir Habitat (DFR). *7 On the western side of the river basin in our study areas, the general distribution of Douglas-Fir Habitat given in Mayer and Laudenslayer (1988) completely overlaps that of Redwood Habitat. Where ground truth was lacking it was not always feasible to separate the two types on our aerial imagery. In doubtful cases, alluvial stands that appeared to be dominated by conifers were coded as WHR Redwood Habitat (RDW) and CNDDB Alluvial Redwood Forest (61120/82310); or as CNDDB Upland Redwood Forest (82320) if they occurred in canyon or moist upland sites. On the eastern side of the river basin, the overlap in Douglas-Fir and Redwood distributions is much smaller; any upland conifer-dominated stands in this area would be coded as WHR Douglas-Fir Habitat (DFR) and CNDDB Mixed North Slope Forest (81500), unless they were located in canyon sites judged to be more appropriate for CNDDB Upland Redwood Forest (82320). *8 Although Eucalyptus Forest is listed as a habitat type in Mayer and Laudenslayer (1988), iot is not included as a habitat type in version 5.0 of the CWHR database. For lack of a better designation, the few stands of Eucalyptus that were mapped in the present project were coded as VOW on the assumption that their wildlife habitat values are somewhat similar to oaks (although they do not provide the same food resources). Item (10). Item Name: P_CLOSE\Field Width: 10\Data Type: Character
Code L = Low; from "10"% (i.e., 5-15%) up to "40"% (i.e., 35-45%)
Note: The standard WHR system uses four classes for percent canopy closure (i.e., 10-24%, 25-39%, 40-59%, 60-100%). In the present project it was not feasible to distinguish such narrowly-defined categories because of the less-than-optimum quality of the available aerial photos; we therefore used the three broad classes defined above. In effect our scheme combined the first two WHR categories ("Sparse" and "Open") into a single class, while retaining classes similar to the WHR's "Moderate" and "Dense" categories. Note: Our class boundaries for percent canopy closure were deliberately "fuzzy"; i.e., instead of a class boundary being a single percentage value, our threshold criteria spanned a range of values. The dividing line between canopy closure classes was drawn by eye where there was a "noticeable change" in canopy density that fell within these ranges on the photos; the actual location of the line was therefore a matter of the judgement of the photo-interpreter. According to Thompson (1987) a similar procedure is used by USGS to produce vegetation cover information on 7.5 minute quad maps. Note: Within Zone C in Sonoma County, percent closure of the riparian vegetation canopy was visually estimated from 1:2,400 (1" = 200') prints of aerial photos flown in 1991 for the County Planning Department's Aggregate Monitoring Program. Aerial photos at 1:2,400-scale were not available outside Zone C in Sonoma County or for any part of the study area in Mendocino County; 1:6,000-scale photos were used in these areas to make canopy closure estimates. Item (11). Item Name: CROWN_SIZE\Field Width: 12\Data Type: Character
Code A = Seedling to Sapling size (<15'; WHR codes 1 and 2)
The use of these three broad size classes was a deliberate tradeoff, intended to improve the accuracy of classification by accepting some loss of precision. Note: The WHR system assumes that there is a consistent relationship between crown diameter and dbh which can be applied to all species of conifers on the one hand and all species of hardwoods on the other. No doubt this is an over-simplification, but it enables the user of the WHR system to obtain a rough estimate of average tree dbh from aerial photos in areas or time periods for which ground truth data may be unavailable. The table below gives the correspondences among size class, conifer crown diameter, hardwood crown diameter, and dbh class that are assumed in the WHR system (Mayer and Laudenslayer 1988). Also shown are the actual sizes of tree crown images as they appear on aerial photos at the scales which were used in this project: WHR Code, WHR Size Class, WHR Conifer Crown Diam., WHR Hardwood Crown Diam., WHR dbh Class, Hdwood Crown Diam. on 1:6,000 Aerial Photos, Hdwood Crown Diam. on 1:2,400 Aerial Photos 1, Seedling, n/a, n/a, < 1", n/a, n/a
Note: The structural condition of an entire stand, i.e., its particular combination of average tree size and canopy closure, is called the "habitat stage" in WHR terminology. A concept similar to that of the WHR habitat stage (albeit at a coarser resolution) can be expressed in our system by combining the codes for our three crown size classes with the codes for our three canopy closure classes. For example, in our terminology the single habitat stage "BL" (consisting of "Pole to Small" size class trees with "Low" canopy closure) could include up to four of the WHR habitat stages: Pole/Sparse (3S), Pole/Open (3P), Small/Sparse (4S), and Small/Open (4P). Item (12). Item Name: ELEMENTS\Field Width: 160\Data Type: Character
Physical Elements:
Dead or Decadent Vegetation Elements:
Live Vegetation Elements:
Food Resources:
Code be = berries
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WGS84 Cartographics | This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection. |
Location | https://purl.stanford.edu/gy818dp6867 |
Access conditions
- Use and reproduction
- These data are licensed by Stanford Libraries and are available to Stanford University affiliates only. Affiliates are limited to current faculty, staff and students. Non affiliates seeking access should contact the publisher directly. These data may not be reproduced or used for any purpose without permission.
- Copyright
- Copyright ownership resides with the originator.
Preferred citation
- Preferred citation
- Circuit Rider Productions and National Oceanic and Atmospheric Administration (2002). Land Cover of Alluvial Areas: Russian River Main Stem, Alexander Valley Reach, Sonoma County, California, 1942. Circuit Rider Productions. Available at: http://purl.stanford.edu/gy818dp6867
Collection
Russian River watershed GIS
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