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In cooperation with the U.S. Air Force, Aeronautical Systems Center, Environmental Management Directorate, Wright-Patterson Air Force Base, Ohio

Development of a Geodatabase and Conceptual Model of the Hydrogeologic Units Beneath Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

By Sachin D. Shah

U.S. Geological Survey
Scientific Investigations Report 2004–5062


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pdf (9.21 MB)


Contents

Abstract

Introduction

Purpose and Scope

Description of the Study Area

Acknowledgments

Hydrogeologic Units and Contaminant History

Alluvial Aquifer

Goodland-Walnut Confining Unit

Paluxy Aquifer

Trichloroethene (TCE) Contamination

Geodatabase

Conceptual Model

Alluvial Aquifer

Goodland-Walnut Confining Unit

Paluxy Aquifer

Composite of Hydrogeologic Units

Summary

References

Appendix—Data on Structural Surfaces of Goodland-Walnut Confining Unit and Paluxy Aquifer

Figures

1.  
Map showing location of Air Force Plant 4 (AFP4) and Naval Air Station-Joint Reserve Base Carswell Field (NAS–JRB) study area, Fort Worth, Texas
2.  
Photograph showing erosional contact between the alluvial aquifer and the Goodland-Walnut confining unit, AFP4 and NAS–JRB study area, Fort Worth, Texas
3.  
Map showing water table (potentiometric surface) of the alluvial aquifer and general directions of ground-water flow, AFP4 and NAS–JRB study area, Fort Worth, Texas, fall 2002
4.  
Map showing extent of trichloroethene (TCE) plume in the alluvial aquifer, AFP4 and NAS–JRB study area, Fort Worth, Texas, October 2002
5.  
Map showing static features contained in the base layer of the geodatabase, AFP4 and NAS–JRB study area, Fort Worth, Texas
6.  
Map showing reference points for environmental data collected during 1993–2002 and contained in the location layer of the geodatabase, AFP4 and NAS–JRB study area, Fort Worth, Texas
7.  
Block diagram showing the altitude of the top of the alluvial aquifer, AFP4 and NAS–JRB study area, Fort Worth, Texas, created from a U.S. Geological Survey 10-meter digital elevation model
8.  
Map showing thickness of the alluvial aquifer, AFP4 and NAS–JRB study area, Fort Worth, Texas
9.  
Map showing locations and sources of data used to construct the altitude of the top of the Goodland-Walnut confining unit, AFP4 and NAS–JRB study area, Fort Worth, Texas
10.  
Block diagram showing the altitude of the top of the Goodland-Walnut confining unit, AFP4 and NAS–JRB study area, Fort Worth, Texas
11.  
Map showing thickness of the Goodland-Walnut confining unit, AFP4 and NAS–JRB study area, Fort Worth, Texas
12.  
Map showing altitude of the top of the Paluxy aquifer and sources of data, AFP4 and NAS–JRB study area, Fort Worth, Texas
13.  
Block diagram showing the altitude of the top of the Paluxy aquifer, AFP4 and NAS–JRB study area, Fort Worth, Texas
14.  
Block-diagram composite of hydrogeologic units (three-dimensional conceptual model), AFP4 and NAS–JRB study area, Fort Worth, Texas

Tables

1.  
Stratigraphic units at Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas
2.  
Relational tables within the location layer of the geodatabase that depict data used for spatial analysis

VERTICAL AND HORIZONTAL DATUMS

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83)


Abstract

Air Force Plant 4 and adjacent Naval Air Station-Joint Reserve Base Carswell Field at Fort Worth, Texas, constitute a government-owned, contractor-operated facility that has been in operation since 1942. Contaminants from AFP4, primarily volatile organic compounds and metals, have entered the ground-water-flow system through leakage from waste-disposal sites and from manufacturing processes. The U.S. Geological Survey developed a comprehensive geodatabase of temporal and spatial environmental information associated with the hydrogeologic units (alluvial aquifer, Goodland-Walnut confining unit, and Paluxy aquifer) beneath the facility and a three-dimensional conceptual model of the hydrogeologic units integrally linked to the geodatabase. The geodatabase design uses a thematic layer approach to create layers of feature data using a geographic information system. The various features are separated into relational tables in the geodatabase on the basis of how they interact and correspond to one another. Using the geodatabase, geographic data at the site are manipulated to produce maps, allow interactive queries, and perform spatial analyses. The conceptual model for the study area comprises computer-generated, three-dimensional block diagrams of the hydrogeologic units. The conceptual model provides a platform for visualization of hydrogeologic-unit sections and surfaces and for subsurface environmental analyses. The conceptual model is based on three structural surfaces and two thickness configurations of the study area. The three structural surfaces depict the altitudes of the tops of the three hydrogeologic units. The two thickness configurations are those of the alluvial aquifer and the Goodland-Walnut confining unit. The surface of the alluvial aquifer was created using a U.S. Geological Survey 10-meter digital elevation model. The 2,130 point altitudes of the top of the Goodland-Walnut unit were compiled from lithologic logs from existing wells, available soil-boring logs, and previous studies. Data from 120 wells, primarily from existing reports, were used to create a map of the approximate altitude of the Paluxy aquifer.

 


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