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Central Valley aquifer system

Metadata also available as

Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 2000
Title: Central Valley aquifer system
Edition: Version 1.0, November 24, 1999
Geospatial_Data_Presentation_Form: vector digital data
Series_Information:
Series_Name: Ground Water Atlas of the United States
Issue_Identification: USGS HA-730
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Description:
Abstract:
This data set represents the extent of the Central Valley aquifer system in California.
Purpose:
These data delineate the areal extent of the Central Valley aquifer system as defined in the 'Ground Water Atlas of the United States' (U.S. Geological Survey HA 730). The scale of source material is 1:2,500,000 and these data are not intended for use at a larger scale.
Supplemental_Information:
The juxtaposition of regionally mapped aquifers has led to some instances where an aquifer outcrop or shallow subcrop is bounded by a State line. This is a result of the regional mapping and national categorization methods used and is not meant to imply a hydrogeologic change coincident with a State boundary.

Comments regarding the names of aquifers or the hydrogeologic interpretation of the aquifers can be directed to the U.S. Geological Survey, Water Resources Division, Office of Ground Water, ogw_webmaster@usgs.gov, (703) 648-5001.

The nationwide principal aquifers map, cited as a complete or partial source, refers to both a dataset published at 1:2,500,000 and a derived map printed at 1:5,000,000.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ARC/INFO format, this metadata file may include some ARC/INFO-specific terminology.

Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 1998
Currentness_Reference: publication date
Status:
Progress: In work
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -120.895998
East_Bounding_Coordinate: -120.337101
North_Bounding_Coordinate: 40.673437
South_Bounding_Coordinate: 34.526088
Keywords:
Theme:
Theme_Keyword: aquifer
Theme_Keyword: extent
Theme_Keyword: groundwater
Place:
Place_Keyword: United States
Place_Keyword: West
Place_Keyword: California
Access_Constraints:
None. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data.
Use_Constraints:
These data are not to be used at scales greater than 1:2,500,000.

Selection of the aquifer polygon may also result in selection of non-aquifer polygons (AQ_CODE=999) within the aquifer extent.

Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Chief, Cartography and Publishing Program
Contact_Address:
Address_Type: mailing and physical address
Address: 505 Science Dr
City: Madison
State_or_Province: WI
Postal_Code: 53711
Country: USA
Contact_Voice_Telephone: (608) 238-9333
Contact_Facsimile_Telephone: (608) 238-9334
Native_Data_Set_Environment:
Windows NT Version 4.0 (Build 1381) Service Pack 6; ESRI ArcInfo 8.1.0.415
Cross_Reference:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 1999
Title: Principal Aquifers map, Edition 1.0
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: National Atlas of the Unites States of America
Issue_Identification: National Atlas product
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage: <http://www.nationalatlas.gov/>
Cross_Reference:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 1989-99
Title: Ground Water Atlas of the United States
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: Hydrologic Investigations Atlas
Issue_Identification: HA 730
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey, Water Resources Division
Online_Linkage: <http://pubs.usgs.gov/ha/ha730/>

Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Source data was checked using standard USGS review procedures. Attributes were checked by plotting the coverage and reselecting for the different values.
Logical_Consistency_Report:
Polygon and chain-=node topology present. Every polygon has a label. This was checked using the labelerror command and the idedit command.
Completeness_Report:
The extent is based on the best available printed sources on the subject of aquifer extents. There is the potential that better data is available at the local level.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
All digitized lines when plotted at 0.05" were within the lineweight of the compilation source.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 1998
Title: Principle Aquifer Data set
Geospatial_Data_Presentation_Form: data
Series_Information:
Series_Name: National Atlas of the United States of America
Issue_Identification: National Atlas product
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Source_Scale_Denominator: 2500000
Type_of_Source_Media: digital file
Source_Contribution: Source provided location of aquifer extent line
Process_Step:
Process_Description:
a.) Aquifer names and all or part of the outcrop line shown on the Nationwide 'Principal Aquifer' map (Miller, James A., 1998), were used with the extent of each aquifer from the various chapters of the 'Ground Water Atlas of the United States' to create this coverage. The largest scale map source available was used. Where the line defining the aquifer extent is the same as the outcrop, the data were copied from the Principal Aquifers data set. Otherwise data were traced from 1:7,500,000, 1:5,000,000, or 1:2,500,000 scale map sources onto a stable base material. Where the extent was defined by a state boundary or coastline, a standard USGS digital base of the same scale state boundary or coastline was used as the source.

(The following steps were done using ARC/INFO 7.2.1 on Data General AViiON UNIX. Much of the terminology used will be specific to ARC/INFO).

b.) The aquifer extent lines were digitized into ARCEDIT using standard USGStolerances. After digitizing, a check plot was created and reviewed against the traced map. If a line was located more than a line weight (0.05") from the digitized source, it was corrected during an ARCEDIT session.

c.) Using the TRANSFORM command, the coverage containing the digitized, aquifer extent lines was combined with the coverage containing registration tics, was rubbersheeted from geographic to Albers Equal-Area Conic projection. An RMS error of less than 0.004 was accepted. If it was greater than 0.004 the location and values of the lat/long points were verified. Following this transformation, any aquifer lines from the aquifer extent coverage coincidental to aquifer lines from the 'Principal Aquifers' map data set were copied from the 'Principal Aquifers' map data set and put into the aquifer extent coverage.

The aquifer extent coverage was cleaned, the topology was built, and labels were added.

d.) Four items were added to the .PAT file: AQ_NAME (60 65 C) AQ_CODE (4 5 I), ROCK_NAME (40 45 C), ROCK_TYPE (4 5 I). ROCK_NAME comes from the Principal Aquifers Data set, 1998. The first digit of the three digit aq_code, refers to aquifer lithology.

100 series are numbers for unconsolidated sand and gravel aquifers 200 series are numbers for semiconsolidated sand aquifers 300 series are numbers for sandstone aquifers 400 series are numbers for carbonate-rock aquifers 500 series are numbers for sandstone and carbonate-rock aquifers 600 series are numbers for volcanic-rock aquifers 999 is given for non aquifer islands inside aquifer polygons

e.) The following items were verified: --Digitizing RMS error (below 0.005) --Transformation RMS error (below 0.004) --Arcs match the traced mylar (no gaps between the plot and the compilation) --Arc and polygon topology exists --Coverage has a coordinate system defined --Attributes aq_name and aq_code have been added and populated correctly --Necessary files exist to redo any step

Process_Date: 19970331
Process_Step:
Process_Description:
This step was done on an NT workstation. After plotting the extent at 1:2,000,000, the lines were checked with the documented sources. If needed, the lines were corrected to better represent the source data. This process may have included one or more of the following steps: --Reshaping the arc --Replacing the arc from the outcrop data, --Digitizing new lines polygons --Deleting polygons.
Process_Date: 19991118
Process_Step:
Process_Description:
Due to a computer problem final corrected files were lost, however hard copy plots of those files were retained. This file was recreated from those plots using a similar process to that described above. Where extent lines were equal to the outcrop, data were extracted from the Principal Aquifers Data Set. Otherwise data were digitized from the retained hard copy plots using the same tolerances and software described above. A check plot was created and compared to the hard copy plot. Significant deviations, greater than approximately a line weight (0.005"), were corrected using ARCEDIT. Data were reviewed internally to assure compliance with original sources.
Process_Date: 20000712
Process_Step:
Process_Description:
First draft of metadata created by J.M. Watermolen using FGDCMETA.AML ver.1.32 01/11/99 on ARC/INFO data set.
Process_Date: 19991118
Process_Step:
Process_Description: Documentation edited by S.M. Last, based on informal reviews.
Process_Date: 20000107
Process_Step:
Process_Description: Documentation updated by J.J. Skalet based on internal reviews.
Process_Date: 20010425

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Vector
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Complete chain
Point_and_Vector_Object_Count: 11
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Entity point
Point_and_Vector_Object_Count: 1
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains
Point_and_Vector_Object_Count: 3
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Point
Point_and_Vector_Object_Count: 2993

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Albers Conical Equal Area
Albers_Conical_Equal_Area:
Standard_Parallel: 29.500000
Standard_Parallel: 45.500000
Longitude_of_Central_Meridian: -96.000000
False_Easting: 0.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.001024
Ordinate_Resolution: 0.001024
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257222

Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: CENVALAS_EXT.AAT
Entity_Type_Definition: Line attributes
Entity_Type_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: LNTYPE
Attribute_Definition: The line category
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 1
Enumerated_Domain_Value_Definition: coastline or international boundary
Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey
Enumerated_Domain:
Enumerated_Domain_Value: 2
Enumerated_Domain_Value_Definition: interior aquifer contact line
Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey
Detailed_Description:
Entity_Type:
Entity_Type_Label: CENVALAS_EXT.PAT
Entity_Type_Definition: Polygon attributes
Entity_Type_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: ROCK_NAME
Attribute_Definition: General lithology of the rocks that make up the aquifer
Attribute_Definition_Source: Principal Aquifers Data set, 1998
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: Unconsolidated sand and gravel aquifers
Enumerated_Domain_Value_Definition_Source: Principal Aquifers Data set, 1998
Attribute:
Attribute_Label: ROCK_TYPE
Attribute_Definition: Code for rock name
Attribute_Definition_Source: Principal Aquifers Data set, 1998
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 100
Enumerated_Domain_Value_Definition: Unconsolidated sand and gravel aquifers
Enumerated_Domain_Value_Definition_Source: Principal Aquifers Data set, 1998
Attribute:
Attribute_Label: AQ_NAME
Attribute_Definition: Name of the aquifer
Attribute_Definition_Source: Principal Aquifers Data set, 1998
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: Central Valley aquifer system
Enumerated_Domain_Value_Definition_Source: Principal Aquifers Data set, 1998
Attribute:
Attribute_Label: AQ_CODE
Attribute_Definition: Numeric code for a particular aquifer
Attribute_Definition_Source:
Derived to help manage the data when numerous aquifers are aggregated
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 106
Enumerated_Domain_Value_Definition: Central Valley aquifer system
Enumerated_Domain_Value_Definition_Source: Principal Aquifers Data set, 1998
Enumerated_Domain:
Enumerated_Domain_Value: 999
Enumerated_Domain_Value_Definition: Code for aquifer absent
Enumerated_Domain_Value_Definition_Source: Principal Aquifers Data set, 1998
Overview_Description:

Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Position: Water Webserver Team
Contact_Address:
Address_Type: mailing and physical address
Address: 12201 Sunrise Valley Drive, MS 440
City: Reston
State_or_Province: VA
Postal_Code: 20192
Country: USA
Contact_Voice_Telephone: (800) 426-9000
Contact_Electronic_Mail_Address: h2oteam@usgs.gov
Distribution_Liability:
Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.

The act of distribution shall not constitue any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.

Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ARC export
File_Decompression_Technique: WinZip
Transfer_Size: 0.087
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
Access_Instructions: www

Metadata_Reference_Information:
Metadata_Date: 20010427
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Chief, Cartography and Publishing Programs
Contact_Address:
Address_Type: mailing and physical address
Address: 505 Science Dr
City: Madison
State_or_Province: WI
Postal_Code: 53711
Country: USA
Contact_Voice_Telephone: (608) 238-9333
Contact_Facsimile_Telephone: (608) 238-9334
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile

Generated by mp version 2.4.38 on Mon May 07 09:33:00 2001

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Page Last Modified: Thursday, 08-Dec-2016 13:39:54 EST