Locally Sponsored Research

Guam Hydrologic Survey

Data Availability Report

Chapter 6: Distribution System Data
by: David Vann

Guam Waterworks Authority, US Navy Public Works Center (PWC), and the US Air Force 36th Civil Engineering Squadron are the three principle agencies responsible for the production and distribution of potable water on the island of Guam. Each maintains a division responsible for mapping and archiving water distribution data. GWA currently has a contract with Earth Tech Environmental (formerly W.B. Flores Engineers) for distribution system modifications. Earth Tech maintains its own data archive for GWA’s distribution system.

Between January and June 1998 the Guam Hydrologic Survey visited with each organization to establish a point of contact and obtain copies of maps and files describing distribution systems. Agencies, points of contact, and observations are listed below.



Guam Water Authority (GWA)
Map Utilities
PO Box 3010
Agana, Guam 96910

Point of Contact:
Quirino Bas Bas
Chief Engineer
Ph: 649-7880


Data format and archiving

Maps are kept in hard copy only. GWA relies mainly on a 1997 1:400 scale map set, “Existing Islandwide Water Facilities System Maps,” prepared by Barrett, Harris, and Associates, Inc. in association with Arizala, Costinianio, Villereal, and Associates. Drawings of any additions to the system are in blueprint form (“as-builts”). As-builts are provided to GWA by the contractors with each distribution system modification, and are archived at Map Utilities.

Data evaluation

Evaluation of the accuracy and completeness of the current distribution maps will require an exhaustive long-term field investigation by GWA. WERI recommends digitization of the existing maps be accomplished as quickly as possible and that steps should be taken to ensure maps are subsequently kept current. GHS can keep copies of the maps and plans in the GHS Data Library at WERI, but revision and proper archiving of the source documents can only be done by the organization responsible for installation, maintenance, repair, and modification of the distribution system.

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Earth Tech Environmental
790 S. Marine Drive Suite 2
Tamuning, Guam 96931
Mailing Address: PO Box 12346
Tamuning, Guam 96931

Point of contact:
Mark Cramer
Chief Engineer
Ph: 647-6083
Fax: 647-6086


Data format and archiving

Maps and drawings are in multiple formats. Earth Tech maintains ad-ons to the GWA system in AutoCAD files. Hard copies of the main GWA distribution system are kept as standard maps in a 1:400 scale (Barrett, 1977).

Data Evaluation

Base maps and digital files of the distribution system are updated regularly. All digital files are in a common format.

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US Navy

US Navy Public Works Center
PSC 455, Box 195
FPO, AP 96540-2937

Director of Engineering Fena Reservoir and Lab
Ph: 339-7181 or 339-3220
Fax: 333-2035


Data format and archiving

Maps of the US Navy distribution system are stored in multiple formats. Hard copy maps are available in varying scale and are kept at both PWC-Piti and PWC-Sumay. AutoCAD drawings on CD are maintained at the Piti-PWC in 1: 200 scale. Unrestricted maps and files may be obtained with a written request. Transfer of this information is limited to federal and local agencies and professionals in the private sector.

Data evaluation

Large-scale studies of the Navy water distribution are done on a contractual basis, roughly at five-year intervals. The quality of the data is excellent. With each new study, data files are upgraded to reflect changes. Modifications to the system done in the interim are added to the existing AutoCAD files. All digital files are in a common format.

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AAFB Environmental Division
Unit 14007

Point of contact:
MSgt David Martin
Utilities Superintendent
Ph: 366-4305


Data format and archiving

Maps of the USAF water distribution system are archived in multiple formats. Hard copy maps in varying scale and AutoCAD drawings are available at the 36th Civil Engineering Office. The transfer of this information is limited to federal and local agencies and professionals in the private sector.

Data evaluation

Physical evaluation and modification of the distribution system is performed internally by USAF engineers. As the system is upgraded, data files are revised to reflect any changes to the existing system. Digital maps are maintained in an AutoCAD format.


General Recommendation

Current data collection efforts by the federal government and the private sector are of high quality, but more important, are in a common format. WERI recommends GWA data to be standardized into the same format. This will greatly facilitate engineering analysis.

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