| DNR Forest Practices Wetland Layer | |
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Data format: Personal GeoDatabase Feature Class File or table name: WET Coordinate system: Lambert Conformal Conic Theme keywords: inlandWaters, wetlands, vegetation, soils, hydrology, hydrography |
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Abstract:
The DNR Forest Practices Wetlands Geographic Information System (GIS) Layer is based on the National Wetlands Inventory (NWI). In cooperation with the Washington State Department of Ecology, DNR Forest Practices developed a systematic reclassification of the original USFWS wetlands codes into WAC 222-16-035 types. The reclassification was done in 1995 according to the Forest Practice Rules in place at the time. The WAC's for defining wetlands are 222-16-035 and 222-16-050. |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
The DNR Forest Practices Wetlands Geographic Information System (GIS) Layer is based on the National Wetlands Inventory (NWI). In cooperation with the Washington State Department of Ecology, DNR Forest Practices developed a systematic reclassification of the original USFWS wetlands codes into WAC 222-16-035 types. The reclassification was done in 1995 according to the Forest Practice Rules in place at the time. The WAC's for defining wetlands are 222-16-035 and 222-16-050.
It is intended that these data be only a first step in determining whether or not wetland issues have been or need to be addressed in an area. The DNR Forest Practices Division and the Department of Ecology strongly supports the additional use of hydric soils (from the GIS soils layer) to add weight to the call of 'wetland'. Reports from the Department of Ecology indicate that these data may substantially underestimate the extent of forested wetlands. Various studies show the NWI data is 25-80% accurate in forested areas. Most of these data were collected from stereopaired aerial photos at a scale of 1:58,000. The stated accuracy is that of a 1:24,000 map, or plus or minus 40 feet. In addition, some parts of the state have data that are 30 years old and only a small percentage have been field checked. Thus, for regulatory purposes, the user should not rely solely on these data. On-the-ground checking must accompany any regulatory call based on these data.
The reclassification is based on the USFWS FWS_CODE. The FWS_CODE is a concatenation of three subcomponents: Wetland system, class, and water regime. Forest Practices further divided the components into system, subsystem, class, subclass, water regime, special modifiers, xclass, subxclass, and xsystem. The last three items (xsomething) are for wetland areas which do not easily lend themselves to one class alone. The resulting classification system uses two fields: WLND_CLASS and WLND_TYPE. WLND_CLASS indicates whether the polygon is a forested wetland (F), open water (O), or a vegetated wetland (W). WLND_TYPE, indicates whether the wetland is a type A (1), type B (2), or a generic wetland (3) that doesn't fit the categories for A or B type wetlands. WLND_TYPE = 0 (zero) is used where WLND_CLASS = O (letter "O").
The wetland polygon is classified as F, forested wetland; O, open water; or W, vegetated wetland depending on the following FWS_CODE categories:
F O W
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Forested Open Vegetated
Wetland Water Wetland
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PFO* POW PUB5
E2FO PRB* PML2
PUB1-4 PEM*
PAB* L2US5
PUS1-4 L2EM2
PFL* PSS*
L1RB* PML1
L1UB*
L1AB*
L1OW
L2RB*
L2UB*
L2AB*
L2RS*
L2US1-4
L2OW
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* indicates inclusion of the subcategory (ie. PEM* includes PEM1F, PEM1FB, etc.).
DNR FOREST PRACTICES WETLANDS DATASET ON FPARS Internet Mapping Website:
The FPARS Resource Map and Water Type Map display Forested, Type A, Type B, and "other" wetlands. Open water polygons are not displayed on the FPARS Resource Map and Water Type Map in an attempt to minimize clutter.
The following code combinations are found in the DNR Forest Practices wetlands dataset:
WLND_CLASS WLND_TYPE wetland polygon classification
F 3 Forested wetland as defined in WAC 222-16-035
O 0 *NWI open water (not displayed on FPARS Resource or Water Type Maps)
W 1 Type A Wetland as defined in WAC 222-16-035
W 2 Type B Wetland as defined in WAC 222-16-035
W 3 other wetland
* NWI open water polygons are indicated by WLND_CLASS = O and WLND_TYPE = 0. Open water is used in the USFWS and WAC 222-16-035 classification system. These open water polygons are not included in the FPARS Resource Map and Water Type Map views of this dataset in an attempt to minimize clutter on the FPARS maps.
publication date
See DNR Agency Data License Agreement at: http://www.dnr.wa.gov/dataandmaps/nfoaov12-09-03.html The user must be aware of the limitations of these data. It is intended that these data be only a first step in determining whether or not wetland issues have been or need to be addressed in an area. The DNR Forest Practices Division and the Department of Ecology strongly supports the additional use of hydric soils (from the GIS soils layer) to add weight to the call of 'wetland'. Reports from the Department of Ecology indicate that these data may substantially underestimate the extent of forested wetlands. Various studies show the NWI data is 25-80% accurate in forested areas. Most of these data were collected from stereopaired aerial photos at a scale of 1:58,000. The stated accuracy is that of a 1:24,000 map, or plus or minus 40 feet. In addition, some parts of the state have data that are 30 years old and only a small percentage have been field checked. Thus, for regulatory purposes, the user should not rely solely on these data. On-the-ground checking must accompany any regulatory call based on these data.
1111 Washington St SE
PO Box 47012
This is a reselect of NWI data by Laura Vaugeois, DNR Forest Practices Division, c. 1995
The Forest Practices wetlands GIS data layer has passed initial testing in a subset of DNR Regions, conducted by field foresters. The field verification concluded that: (1) A high percentage of the wetlands depicted, especially larger wetlands, do exist on the ground; 2) The lumping of NWI codes into categories fitting the wetland typing system in WAC 222-16-035 is largely accurate. The Forest Practices wetlands layer was determined to be of sufficient quality to be included in the Risk Assessment mapping system, an internal mapping program used by DNR Forest Practices staff to review Forest Practice Applications (FPA). This layer is also currently included in the new Risk Assessment ArcIMS site, a internal DNR mapping tool that replaced the paper risk assessment mapping system. Problems with the dataset include: (1) The extent of forested wetlands may be substantially underestimated. Various studies show the NWI data are 25-80% accurate in forested areas. (2) Some parts of the state use data layers that were developed using rudimentary techniques and have not been updated significantly in 30 years. Many of these techniques have since been refined. (3) Bogs, a Type A wetland with additional restrictions on road construction and timber harvest, are not depicted as separate from other Type A or forested wetlands. The Forest Practices wetlands layer is considered appropriate for use as a first step in determining whether or not wetland issues need to be evaluated in an area. Field checking is essential; no regulatory decision should be based solely on these data.
Reports of positional errors have not been investigated or resolved as of December 2007.
Washington State Department of Ecology supplied the USFWS NWI data.
Metadata imported.
Dataset copied.
Internal feature number.
ESRI
USFWS National Wetlands Inventory (NWI) codes. See http://wetlandsfws.er.usgs.gov/NWI/index.html
USFWS NWI. See the Wetlands and Deepwater Habitats Classification and NWI Map Codes Legend at http://wetlandsfws.er.usgs.gov/NWI/webatx/atx.html
WLND_CLASS is one of two fields used to classify polygons. WLND_CLASS and WLND_TYPE classify polygons into five (5) categories: F3, forested wetland; O0, open water; W1 Type A Wetland; W2, Type B Wetland; and W3, other vegetated wetland. WAC 222-16-035 defines forested wetland (F3), Type A Wetland (W1), and Type B Wetland (W2). WAC 222-16-035 distinguishes Type A wetlands by size and amount of open water. Open water is indicated by WLND_CLASS = O (letter "O"). * indicates inclusion of the subcategory (ie. PEM* includes PEM1F, PEM1FB, etc.).
Forested wetlands. All forested wetlands have WLND_CLASS = F and WLND_TYPE = 3 (other wetland).
If FWS_CODE is in {PFO*, E2FO}, then WLND_CLASS = F, forested wetland, and WLND_TYPE = 3, other wetland.
Open water. All open water polygons have WLND_CLASS = O (letter "O") and WLND_TYPE = 0 (zero).
If FWS_CODE is in {POW, PRB*, PUB1-4, PAB*, PUS1-4, PFL*, L1RB, L1UB, L1AB, L1OW, L2RB*, L2UB*, L2AB*, L2RS*, L2US1-4, L2OW}, then WLND_CLASS = O, open water, and WLND_TYPE = 0, no type.
Vegetated wetlands. Where WLND_CLASS = W, WLND_TYPE is in {1, 2, 3}.
If FWS_CODE is in {PUB5, PML2, PEM*, L2US5, L2EM2, PSS*, PML1}, then WLND_CLASS = W, vegetated wetland, and WLND_TYPE is in {1, 2, 3}.
WLND_TYPE is the second of the two fields used to classify polygons. WLND_CLASS and WLND_TYPE classify polygons into five (5) categories: F3, forested wetland; O0, open water; W1 Type A Wetland; W2, Type B Wetland; and W3, other vegetated wetland. WAC 222-16-035 defines forested wetland (F3), Type A Wetland (W1), and Type B Wetland (W2). WAC 222-16-035 distinguishes Type A wetlands by size and amount of open water. Open water is indicated by WLND_CLASS = O (letter "O"). * indicates inclusion of the subcategory (ie. PEM* includes PEM1F, PEM1FB, etc.).
Type A vegetated wetland.
Type B vegetated wetland.
Other wetland. May be forested or other wetland.
Open water polygons are assigned WLND_TYPE = 0 (zero). WAC 222-16-035 distinguishes Type A wetlands by size and amount of open water. Open water is indicated by WLND_CLASS = O (letter "O").
Feature geometry.
ESRI
Length of feature in internal units.
ESRI
Area of feature in internal units squared.
ESRI
DNR Licensing Agreement required. Go to: http://www3.wadnr.gov/dnrapp6/dataweb/dmmatrix.html
download from the Forest Practices Spatial Data Sets web page, http://www.dnr.wa.gov/forestpractices/data/.
download from the Forest Practices Spatial Data Sets web page, http://www.dnr.wa.gov/forestpractices/data/
1111 Washington St SE
PO Box 47012