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Central Valley aquifer system

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

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