| Water Wells of Loudoun County, VA (2010) | |
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Data format: SDE Feature Class File or table name: GISDBB.GISBROW.V_WELLPOLL Coordinate system: Lambert Conformal Conic Theme keywords: health, environment, well, groundwater, yield, transmissivity, storativity |
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Abstract:
V_WELLPOLL is a data set of water wells only in the county that have been identified and assigned a unique SITE-ID number. The majority of wells are individual potable water wells.
Information for wells comes primarily from State Groundwater Well Completion (GW2) forms completed by well drilling contractors and varies in accuracy and completeness. This layer is maintained and administered by the Health Department and Department of Building and Development.
There are a couple of Individual Wells that are designated as a pollution source type. |
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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.
V_WELLPOLL is a data set of water wells only in the county that have been identified and assigned a unique SITE-ID number. The majority of wells are individual potable water wells.
Information for wells comes primarily from State Groundwater Well Completion (GW2) forms completed by well drilling contractors and varies in accuracy and completeness. This layer is maintained and administered by the Health Department and Department of Building and Development.
There are a couple of Individual Wells that are designated as a pollution source type.
V_WELLPOLL was created to provide an easily accessed record of wells and to link these sites to other geographic data within the GIS. For most records, specific construction information and other physical characteristics are available from the County. This information may be used to aid in the evaluation of the groundwater resource in the case of wells, or of certain types of observed or potential pollution problems in the case of pollution sources.
V_WELLPOLL was created in March 2010 to provide an easily accessiable spatial database of water wells only. It also provides additional attribute information on Status, Depth, etc.
The original WELLPOLL layer, of both wells and pollution sources, was developed in 1988 by the County's Environmental Health Department. Records were entered into a database from 40 years of historical paper files, which exhibited a wide range of completeness and accuracy. This was an on-going process until early 1996 at which time the layer was no longer maintained. In late 2000, the Department of Building and Development began a process of updating the layer by entering data from the permit files, which had accumulated since 1996.
Data are stored in the corporate ArcSDE Geodatabase as a point feature class. The coordinate system is Virginia State Plane (North), Zone 4501, datum NAD83 HARN (vertical datum, if applicable, NAVD88), US Survey foot units.
publication date
Every reasonable effort has been made to assure the accuracy of these data. Loudoun County, Virginia does not assume any liability arising from the use of these data. These data are provided without warranty of any kind, expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular service. Reliance on these data is at the risk of the user. These data were generated for use by Loudoun County and are available to the public. These data are intended for use at 1:2400 scale or smaller. Acknowledgement of Loudoun County would be appreciated in products derived from this data.
1 Harrison Street SE, 2nd Floor
MS 68
Retention of attribute accuracy throughout the coverage to geodatabase feature class coversion process was ensured by a QA/QC programmatic check. To meet satisfactory QA/QC requirements the input coverage and output feature class must have, on a record by record basis, identical attribution when comparing all concatenated fields to all the user-defined attribution.
Topologically clean
Features may have been eliminated or generalized due to scale and intended use. To assist Loudoun County, Virginia in the maintenance of the data, please provide any information concerning discovered errors, omissions, or other discrepancies found in the data.
Retention of coordinate accuracy throughout the coverage to geodatabase feature class conversion process was ensured by a QA/QC programmatic check. To meet satisfactory QA/QC requirements the input coverage and output feature class must have the same record total, and on a record by record basis, area, perimeter, and length differential of less than +/- 0.5%.
Loudoun County Health Department decision to develop original WELLPOLL coverage in 1998. Loudoun County Health Department & Building and Development decision to develop & publish new Water Wells data layer for public viewing and staff use on County's Weblogis mapping site
Records were entered into a database from 40 years of historical paper files, including State Ground Water Well Completion Forms and Health Department permits, inspections, and field checks. They exhibited a wide range of completeness and accuracy. This was an on-going process until early 1996 at which time the layer was no longer maintained.
The Department of Building and Development began a process of updating the existing layer by entering data from the permit files, which had accumulated since 1996.
This data set was part of a batch process that converted legacy data from ArcInfo coverage in Librarian to a single-tiled ArcInfo coverage in preparation for a final coversion to ArcSDE Geodatabase Feature Classes. Data were extracted from Librarian using the EXTRACT TOPOLOGICAL command. Multi-tiled data sets were extracted into multiple coverages and then combined based on the feature type(s). Layers with both polygon and arc feature classes were processed with the Arc commands, MAPJOIN and DISSOLVE. Arc feature classes alone were processed with the Arc commands, APPEND and DISSOLVE. Layers with both arc and point feature classes and point feature classes alone were processed with the Arc command, APPEND. When used, the Arc command, DISSOLVE, was given with the <#all> option. All coverages were then reprojected to HARN 83 using the following .prj file specifications: INPUT PROJECTION STATEPLANE UNITS FEET ZONE 5551 DATUM NAD27 NADCON PARAMETERS OUTPUT PROJECTION STATEPLANE UNITS FEET FIPSZONE 4501 DATUM HPGN NADCON PARAMETERS END This dataset was then converted to a feature class in a geodatabase in ArcSDE.
In March 2010, a new data layer of water wells only, called (V_WELLPOLL), was created from the orginial pollution source and water well database (WELLPOLL). This was to provide a layer of water wells only and provide additional well information, like status, depth, etc.
Internal feature number.
ESRI
ID number of well
Loudoun County
A unique alphanumeric identifier for each well or pollution source. Composed of the four-letter ID-CODE (what the item is), the four-digit year of completion, and a four digit sequential cataloging number.
Loudoun County
Same as the SITE-ID except it uses a two-digit year of completion or date of discovery from field verification identifier.
Loudoun County
Describes if the item is a well or pollution source
Loudoun County
A four-letter code categorizing the type of well or pollution source
Loudoun County
The year the well or pollution source was completed or date of discovery from field verification identifier.
Loudoun County
A sequential cataloging number to create unique SITE-ID numbers when multiple sites of the same TYPE and ID-CODE are completed during the same year.
Loudoun County
Source that created or edited feature class
Loudoun County
Date that feature class was created or modified
Loudoun County
Not for public distribution. Internal User ID of editor creating or modifying feature class
ID number of well in Water Resources Information System
Loudoun County Building and Development
The construction permit number assigned
Loudoun County Environmental Health Department
Depth of the well measured in feet
Loudoun County Environmental Health Department
The operational status of the well
Loudoun County Environmental Health Department
Type of well; full text description
Loudoun County Environmental Health Department
Production of the well measured in gallons per minute (GPM)
Loudoun County Environmental Health Department
Feature geometry.
ESRI
WE_TYPE_HP: Describes if the item is a well or pollution source
Type Definition P Pollution Source W Well
WE_ID_CODE: A four-letter code categorizing the type of well or pollution source
Code Definition WWCO Community well WWCS Community spring WWDH Dry well WWDU Dug well WWHP Heat pump well WWID Industrial well WWIN Individual well WWIR Irrigation well WWMN Monitor well WWNC Non-community well WWOB Observation well WWQM Water quality monitoring well WWSP Spring WWTS Test well WWUN Unknown well
WE_UPD_SOURCE: Source that created or edited feature class
Source Definition 0 Undetermined 1 Legacy (pre 2002) 2 County 3 Contract
1 Harrison Street SE, 2nd Floor
MS 65
Every reasonable effort has been made to assure the accuracy of these data. Loudoun County, Virginia does not assume any liability arising from the use of these data. These data are provided without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular service. Reliance on these data is at the risk of the user.
ESRI Personal Geodatabase Feature Class
ESRI Shapefile
AutoCad Digital Exchange File
Size limit: 4.5 GB. Visit our website at: http://www.loudoun.gov/omagi, click on "Loudoun County Mapping Documents & Order Forms." The "Forms" directory will lead you to custom & standard (countywide) data order forms. Hardcopy maps may also be available; please contact the Mapping Office Public Information Counter for more information regarding all data requests.
1 Harrison Street SE, 2nd Floor
MS 65