NAWQA GIS Resources
For internal use only

Winter 2007 National Data Request

Guidelines for Preparing Ground Water GIS Coverages for National Data Aggregation

02/23/2007

Purpose

This document describes how to prepare the ground water GIS coverages requested for national aggregation.

Timetable

The response date for sending the GW GIS data to Kerie Hitt is May 18, 2007. Check the status log for a list of responses to date.

Scope

This data request applies to 11 study units (GAFL, HDSN, LINJ, MISE, PUGT, RIOG, SACR, SANT, SCTX, SPLT, UMIS) and covers two items:
  1. boundaries for new LUSs and MASs completed since FY05; and
  2. depending on the circumstances outlined below, boundaries or metadata for cycle 1 LUSs and MASs that were resampled in their entirety during cycle 2.

We are requesting the following:

GUIDELINES FOR SUBMITTING LUS AND MAS BOUNDARY POLYGON COVERAGE(S)

The study unit Ground Water Specialist and GIS specialist should work together to complete this request. The study unit Ground Water Specialist should prepare the metadata with the help of the GIS Specialist.

Circular 1112 by Gilliom and others contains a description of cycle 1 ground water study design, the selection of agricultural land use studies, and well selection strategy, which still apply to cycle 2 design.

The urban land use study plan contains information about the urban land use design.

Please prepare boundary coverages for:

  1. OVERALL HYDROLOGIC UNIT DEFINED FOR STUDY - MAS BOUNDARY

    2. This is the polygon coverage that delineates the ENTIRE AREAL EXTENT OF THE HYDROGEOLOGIC UNIT DEFINED FOR STUDY, which is, in most cases, the major aquifer study boundary (MAS). This boundary includes the full range of land uses, not only the targeted land use.

    a) For example, for a major aquifer study (sus1), an agricultural land-use study of vineyards (lusor1a), and an agricultural land-use study of almonds (lusor2a) in the eastern San Joaquin Valley alluvial fans, the SANJ study unit would first prepare a coverage that represents the boundary of the eastern San Joaquin Valley alluvial fans. This boundary also would be the overall boundary for LUS studies because it defines the areal extent of the ground water being sampled.

    Although the same polygon represents the overall boundary of the MAS and both LUSs, SANJ would provide one coverage for each network: 1) one for the MAS, 2) one for the vineyard LUS, and 3) one for the almond LUS. Each coverage would have a customized metadata file that describes how the wells were selected for that network.

    In this example, these coverages would result: 

    OVERALL BOUNDARY      SUCODE
1.  SUS1_BND          xxxxsus1
2.  LUSOR1A_BND       xxxxlusor1  (same as SUS1_BND)
3.  LUSOR2A_BND       xxxxlusor2  (same as SUS1_BND)
    b) If a land-use study was not nested within one of the major aquifer studies, submit a separate coverage representing the overall boundary of the hydrolgeologic unit within which the LUS is located and metadata for that coverage. 
    OVERALL BOUNDARY     SUCODE
1.  LUSCR1_BND       xxxxluscr1

  2. LAND USE TARGETED FOR STUDY - LUS BOUNDARY

    3. This is the polygon coverage that delineates the TARGETED LAND USE (LUS) within the overall area described in #1. The targeted land use coverage is derived from the intersection of the hydrogeologic unit to be sampled with the land use targeted for the particular LUS. This defines the area within which well sampling locations were selected.

    Each time a network is sampled, the associated targeted land use area should be clear. If the targeted area changes, it should be updated, but the original coverage, which was relevant to previous sampling, will be retained.

    Most of the time, we would expect the targeted area to be stable from cycle 1 to cycle 2, with any replacement wells falling within the original area.

    Continuing the example from #1a, the targeted land use for the vineyard LUS would be the intersection of the vineyards land use with the San Joaquin Valley alluvial fans and the targeted land use for the almonds LUS would be the intersection of the almonds land use with the San Joaquin Valley alluvial fans. Each targeted land use LUS coverage would be nested within the corresponding overall boundary coverage.

    SANJ would submit a metadata file for each targeted land use coverage. The coverage metadata should describe the relation of the LUS to the overall boundary coverage and how the wells were selected. 

    TARGETED LAND USE     OVERALL BOUNDARY                          SUCODE      
1. LUSOR1A_TRG         1.  LUSOR1A_BND  (same as SUS1_BND)      xxxxlusor1a  
2. LUSOR2A_TRG         2.  LUSOR2A_BND  (same as SUS1_BND)      xxxxlusor2a
    In the second example #1b, one coverage of targeted land use would result: 
    TARGETED LAND USE     OVERALL BOUNDARY                        SUCODE      
1. LUSCR1_TRG         1.  LUSCR1_BND  (not an SUS)            xxxxluscr1
    Here is an illustration showing the concept of LUS boundaries being nested within the MAS boundary. (This example contains three gif files, each about 6 KB.) (See also the map showing the location of ground-water chemistry sites in Circular 1159, p.24, for a similar example.)

    The "targeted" coverage for the urban land-use studies should be the coverage that results from the intersection of the areal extent of the aquifer being studied with the residential/commercial land use (minus transportation and industrial land use), provided that the wells were located to achieve at least 75 percent new residential/commercial land use. The "targeted" coverage should be the same one used for random selection of drilling sites. If you have questions as to which coverage to submit, please consult the urban land use study plan or contact Curtis Price (cprice).