Land Use and Land Cover: Pajaro River and San Benito River Watershed, California, 2012
Abstract/Contents
- Abstract
- This polygon shapefile represents land use and land cover for the Pajaro River and San Benito River Watershed in San Benito, Santa Clara, and Santa Cruz counties of California for 2012. This shapefile was extracted from a generalized land use/land cover database of the Salinas-Pajaro region. Map unit categories were based on a modified Anderson Level II hierarchy. Mapping generally adhered to a 0.5 acre Minimum Mapping Unit (MMU) for riparian and agriculture types and 1 acre MMU for all upland, urban, or other land use types. Vegetation percent cover classes were assigned to the tree and shrub layers for each stand. Herbaceous vegetation was not assigned a cover class. All density values are measured in absolute cover, not relative cover. If tree cover is equal to or greater than 40% then the shrub cover is assigned a Not Assessed value of 9. The minimum mapping unit resolution size of the land use/land cover polygons is twofold. In the intense agricultural region and for wetland and riparian areas the polygons have a 0.5 acre MMU. In the remainder of the study area, composed of non-agricultural areas, upland vegetation, and urban areas, the MMU is 1 acre. For thin linear-shaped polygons the MMU for width is one half the width of a full MMU square. Because of the agricultural emphasis of the project, large urban developed areas, such as cities, towns, and villages, were not typically further subdivided other than for agricultural uses within their extents. The MMU size for these agricultural uses within urban areas is 0.5 acres. As noted above, the study area overlaps with the 2005 mapping of the Salinas River and San Benito river major riparian corridors that Aerial Information Systems, Inc. conducted for the Nature Conservancy. The MMU for the original projects was <0.5 acres. Where those units had not changed for 2005 and 2012 mapping, the map units were kept at the original polygon size. The 0.5 acre MMU is used for new mapping of riparian and wetland map units. Other Mapping Criteria includes photo interpretation of land cover is based on state-wide criteria for vegetation mapping. The Salinas Valley mapping area encompasses 412,508 acres along the entire width of the valley, including the lower foothill toeslopes, from the San Ardo Oil Field in the south, to the Monterey Bay shoreline in the north between Marina and Castroville. The valley lies entirely within the outer coastal ranges; its western edge is bounded by the Sierra de Salinas and Santa Lucia Range with the eastern extent defined by the western slopes of the Gabilan Range.
- Purpose
- The Nature Conservancy (TNC) and Stanford University contracted Aerial Information Systems, Inc. to develop a 2005 and 2012 Anderson Level II terrestrial Land Use/Land Cover map for a portion of the Salinas Valley in Monterey County and portions of several valleys in the greater Pajaro River and San Benito River watershed in San Benito, Santa Clara, and Santa Cruz Counties, to support research and future modeling efforts in the area.
Description
Type of resource | cartographic, software, multimedia |
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Form | Shapefile |
Extent | 2.745 |
Date valid | 2012 |
Publication date | 2014 |
Language | English |
Digital origin | born digital |
Map data | Scale not given. ; Custom projection W 121°48ʹ22ʺ--W 121°14ʹ49ʺ/N 37°27ʺ--N 36°39ʹ53ʺW 121°48ʹ4ʺ--W 121°15ʹ15ʺ/N 37°26ʺ--N 36°39ʹ55ʺ, Scale not given ; EPSG::4326 |
Creators/Contributors
Creator | Aerial Information Systems, Inc | |
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Creator | Nature Conservancy (U.S.) | |
Creator | Danny Karp | |
Creator | Sasha Gennet |
Subjects
Subject | Land use |
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Subject | Land cover |
Subject | Vegetation classification |
Subject | Pajaro River Valley (Calif.) |
Subject | Pajaro (Calif.) |
Subject | San Benito County (Calif.) |
Subject | Santa Clara County (Calif.) |
Subject | Santa Cruz County (Calif.) |
Subject | Pajaro River Watershed (Calif.) |
Subject | Pajaro River (Calif.) |
Subject | 2012 |
Subject | Environment |
Subject | Biology and Ecology |
Genre | Geospatial data |
Genre | Cartographic dataset |
Bibliographic information
Supplemental information |
MAPPING CLASSIFICATION DESCRIPTIONS/CRITERIA The Land Use/Land Cover mapping classification is a simple life form classification representing trees, shrubs, herbs, agriculture, urban. Note that there is correlation to some of the upper level hierarchy (Formation to Macrogroup) of the National Vegetation Classification Hierarchy as Applied to California Vegetation in the Manual of California Vegetation, 2nd Edition, Appendix 3. Land Use/Land Cover
10 = Forest & Woodlands (Trees)
Where natural trees are the overstory to agriculture or orchards/vineyards, the trees will take precedence in mapping and the Comment field will note trees over agriculture. If the trees are scattered or sparse then the agriculture or orchards/vineyards will take precedence and the Comment field will note the tree presence. 12 = Riparian Forest & Woodland (Wetland Native Trees)
Since the majority of the major riparian zones of the 2005 Salinas River and 2007 San Benito River projects were previously mapped, these databases were used as the starting point of the new mapping for this project. The MMU of the original map units was <0.5 acre. For this project, the map units within those areas were left even if they were below the current project MMU. However for the 2012 mapping if there was a change, then the 0.5 acre MMU was used. If wetland tree or shrub vegetation was predominant, those took precedence over the Water Feature Class. 13 = Exotic Trees (Dry Upland Exotic Trees)
Single rows of planted trees are not mapped unless the crowns are so large that they meet the MMU width. 20 = Shrublands
Since the majority of the major riparian zones of the 2005 Salinas River and 2007 San Benito River projects were previously mapped, these databases were used as the starting point of the new mapping for this project. The MMU of the original map units was <0.5 acre. For this project, the map units within those areas were left even if they were below the current project MMU. However for the 2012 mapping if there was a change, then the 0.5 acre MMU was used. If wetland tree or shrub vegetation was predominant, those took precedence over the Water Feature Class. 22 = Upland Scrub (Chaparral, California Coastal Scrub & Pacific Coast Scrub)
30 = Herbaceous Vegetation
Dry upland herbaceous (grass) map units range from small parcels of land that have been vacant for years, to large expanses of open or fenced land which is also referred to as rangeland. Rangeland can take the form of woodlands, shrublands, or herbaceous as the predominant vegetation. From a land use point of view they can be considered not in any use, or used for grazing of domesticated animals. For this project the vegetation takes precedence over the grazing aspect of land use. However, smaller fields that are typically improved, and periodically or often maintained and associated with a farmstead or animal operation/ranch (horses, cows, small animals), are mapped as Pasturelands. Remnant foundations of buildings that have been removed are included with the surrounding vegetation. Large ditches that predominantly contain the weeds/grass/ruderal vegetation are included in the Water Feature class. Instances of stand-alone small corrals within a large area of grass in an agricultural area or in the outer rangeland area, with no buildings present, are mapped as Urban/Built-up, with a “Corrals” note in the Comment field. If the corrals within the grassland are below MMU, then the grassland polygon is noted for the presence of corrals in the Comment field. Otherwise, small corrals adjacent to buildings or other urban uses are mapped as part of the Urban/Built-Up. If corrals are associated with confined feeding operations, then they are mapped with those uses. 32 = Meadow & Marsh (Wetland/Wet Herbaceous)
Where a dammed wetland feature occurs in a “natural environment”, that is, occurring along a drainage and not impounded on all sides, the Water Feature is separated from the wetland herbaceous where possible. Large mappable ditches whose delineations may contain wet herbs are mapped as Water Feature. Since the majority of the major riparian zones of the Salinas and San Benito Rivers were previously mapped in 2005, these databases were used as the starting point of the map. 40 = Little or No Vegetative Cover
42 = Human Caused Unvegetated
Strips of cleared land along the riparian corridor edge may be mapped as Human Caused Unvegetated if it meets the minimum MMU width. There may be a dirt road within the cleared area, and agriculture adjacent to the cleared area. Orchards/Vineyards that had been recently cut down and the land cleared may be called as Human Caused Unvegetated if the current temporal and future imagery shows that the land has not returned to Orchard/Vineyards. If the imagery shows the land as grassy, then it is mapped as Mediterranean Grasslands & Forbs. 50 = Agriculture
Fallow agricultural land is coded as Active and Recently Active Agriculture. It can appear grassy, weedy, or scraped. If the supplemental imagery shows that the land appears to have active agriculture within the last 5 years of the base image then it is coded as Active and Recently Active Agriculture. If it appears to not have been in production during that time, then it is coded as its current state of cover. If an area was mapped as Agriculture, but looked grassy/weedy on 2012 image, then the comment field will note that map unit was grassy in 2012, but had agriculture within 5-year cycle. It is difficult to differentiate heavily disked/mowed grass areas from agricultural grain field crops. Therefore a general guideline was established for mowed features within the intensive agricultural areas. These features were typically classified as Active or Recently Active Agriculture. However, similar features occurring in the rangeland areas were categorized as Mediterranean Grassland & Forbs. In both cases a note in the Comment field was used to address this discrepancy. Raspberry fields are bush/vine crops whose photo signature is difficult to differentiate from row crops. They appear to have very narrow rows and tend to be low growing with very little shadow. Often they are covered by plastic hoop covers in the field. Because of the narrow rows and inconsistent cover by plastic hoops, it is very difficult to distinguish the raspberry fields from row crops. Therefore they are included within the Active or Recently Active Agriculture class. Where natural trees are the overstory to agriculture, the trees will take precedence in mapping and the Comment field will note trees over agriculture. If the trees are scattered or sparse, the agriculture will take precedence and the Comment field will note the tree presence. Wide strips of cleared land along the edges of agricultural fields or orchards/vineyards may be mapped as Human Caused Unvegetated if they met the minimum MMU width. There may be a dirt road within the cleared area. Some of these cleared areas are narrow slopes or embankments. 52 = Pasturelands
This category does not include large open or fenced rangeland, which is typically mapped as natural vegetation. 53 = Orchards/Vineyards
Orchards/Vineyards that have been cleared completely are coded as Human Caused Unvegetated. However if rows or hummock are present, but the vines are not discernible or are very small, then the map unit is still mapped as Orchard/Vineyard. Raspberry fields are bush/vine crops whose photo signature is difficult to differentiate from row crops. They appear to have very narrow rows and tend to be low growing with very little shadow. Often they are covered by plastic hoop covers in the field. Because of the narrow rows and inconsistent cover by plastic hoops, it is very difficult to distinguish the raspberry fields from row crops. Therefore they area included within the Active or Recently Active Agriculture class. Where natural trees are the overstory to an orchard or vineyard, the trees will take precedence in mapping and the Comment field will note trees over agriculture. If the trees are scattered or sparse then the Orchard/Vineyard will take precedence and the Comment field will note the tree presence. Wide strips of cleared land along the edges of agricultural fields or orchards/vineyards may be mapped as Human Caused Unvegetated if they meet the minimum MMU width. There may be a dirt road within the cleared area. Some of these cleared areas are narrow slopes or embankments. 54 = Dairy, and Other Bovine Confined Feeding Operations
55 = Poultry and Other Small Animal Confined Feeding Operations
60 = Urban/Built-Up
Note that nursery greenhouses are mapped as Active and Recently Active Agriculture, but other building structures, parking areas, and small weed/disturbed areas within the nursery complex are included in Urban/Built-Up. Small corrals and backyard pens associated with adjacent farmsteads/residences/ranchettes are also included as Urban/Built-up. Mappable major highways are typically divided with a center median and have four lanes of traffic. The vegetated edge right-of-way is mapped separately if it is greater than the 0.5 acre MMU in the intense agricultural region. If the vegetation in the right-of-way is the same as the adjacent vegetated polygon, then it is included there. In transportation corridors where a paved road was situated adjacent to a railroad right-of-way and the width of the corridor was above MMU, the corridor was mapped as Urban/Built-Up. Note that riparian vegetation and river Water Feature take precedence over a highway bridge when they overlap. This category also includes intensive areas of urban development include cities, small towns, and isolated farmsteads/ranchettes and associated buildings. Single or clusters of agricultural buildings sometimes occur on small parcels of otherwise cleared land within the intensive agricultural area. Cleared parcels of land within the agricultural areas that contain stored equipment (irrigation, vehicles, equipment, etc.) and no buildings are mapped as Human Caused Unvegetated. Instances of stand-alone small corrals within a large area of grass in an agricultural area or in the outer rangeland area, with no buildings present, are mapped as Urban/Built-up, with a “Corrals” note in the Comment field. If the corrals within the grassland are below MMU, then the grassland polygon is noted for the presence of corrals in the Comment field. Otherwise, small corrals adjacent to buildings or other urban uses are mapped as part of the Urban/Built-Up. If corrals are associated with confined feeding operations, then they are mapped with those uses. Where a disturbance corridor containing a paved road occurs within the intense agricultural area, and is >0.5 ac MMU full side width, then the corridor is mapped as Urban/Built-Up. Because of the agricultural emphasis of the project, large urban developed areas were not typically further subdivided other than for agricultural uses (0.5 acre MMU) within their extents. Grass (Mediterranean Grassland & Forbs) and Water Features were also mapped if they were greater than or equal to 10 acres.
The Pacific Ocean is also mapped as Water Feature. The shoreline is represented by the extreme high waterline (Upland-Littoral interface). This interface is normally not affected by the fluctuation of the tides. The demarcation was photo interpreted and mapped as best as could be done with the 2005 imagery as part of the original 2005 Salinas River project. Since 2009 Salinas River update retained the 2005 database shoreline, then the 2012 mapping also retained the 2005 shoreline. Cover Density – Tree and Shrub only
Other Mapping Criteria Photo interpretation of land cover is based on state-wide criteria for vegetation mapping. However, as mapping progressed there was a slight change in perspective on the mapping of grasslands/pastures. Typically the vegetation type would take precedence over the land use. Thus, large areas of “rangeland’ grasses could also be extensively used for grazing. Mowed grasslands were sometimes difficult to distinguish from agricultural lands and may have been called cropland rather than grass, especially if the area is frequently mowed and otherwise maintained. An attempt was made to add a note in the Comment field for the mapped unit when this situation was noticed.
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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/jp529sh7785 |
Access conditions
- Use and reproduction
- This item is in the public domain. There are no restrictions on use.
- Copyright
- This work is in the Public Domain, meaning that it is not subject to copyright.
Preferred citation
- Preferred citation
- Karp, D. and Gennet, S. (2014) Land Use and Land Cover: Pajaro River and San Benito River Watershed, California, 2012. Available at: http://purl.stanford.edu/jp529sh7785
Collection
Salinas-Parajo Generalized Land Use/Land Cover Mapping
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