Water Quality Data Model in GIS for the Rio
Bravo/Grande basin
Prepared by Carlos Patino-Gomez, Daene
C. McKinney and David R. Maidment
June 2007
Abstract
In
previous research, the Center for Research in Water Resources (CRWR) of The
University of Texas at Austin, and the National Water Commission (CNA) of
Mexico cooperated to develop the Rio Grande/Bravo a database in which most of
the data are referenced geographically (i.e., a geodatabase). The geodatabase
consists of a Geographic Information System (GIS) and a relational database
containing hydrologic, hydraulic and related data for the basin. ArcHydro was
used as the basis of the geodatabase since it allows the river basin to be
represented in a realistic network of upstream to downstream connections. The ArcHydro data model defines attributes,
relationships, and connectivity between hydrologic features in a GIS database.
Now that the Rio Grande/Bravo geodatabase has been created, it is available for
use in various water management agencies within the U.S.
and Mexico,
and these agencies have shown great interest in its use. In this project, CRWR and CNA have cooperated
to build on the results of the previous project to accomplish three tasks: (1)
add water quality data to the Rio Grande/Bravo geodatabase; (2) add water
related infrastructure data to the Rio Grande/Bravo geodatabase; and (3)
determine the main river segments in this basin to be used in the water quality
modeling. This project assists in
developing bi-national cooperation between Mexico
and the United States
concerning water in the Rio Grande/Bravo basin, providing accurate and reliable
data necessary for analysis and resolution of water resources issues.
Contents
Section
1 Statement of problem..
4
2 Objective.
5
3 Introduction and background.
5
3.1 Past Activities.
7
3.2 Brief introduction to the Rio
Grande/Bravo basin.
9
4 Methodology.
13
4.1 Data collection.
13
4.2 Developing the schema of the
Water Quality Data Model (WQDM)
17
4.3 Spatial reference information.
21
4.4 Developing the Geodatabase.
21
4.5 Clipping and Merging Data Sets.
23
4.6 Creating Feature Datasets.
24
4.6.1 ArcHydro Feature dataset
25
4.6.2 Main Rivers Feature
Dataset
26
4.6.3 Schematic Diagram Feature
Dataset
26
4.6.4 Water Quality Original
Data Feature Dataset
26
4.7 Processing.
26
4.7.1 Creating HydroEdges.
26
4.7.2 Creating Monitoring Points.
28
4.7.3 Feature Class: Waterbody.
30
4.7.4 Feature Class: Watershed.
31
4.7.5 Feature Class:
HydroJunction.
32
4.7.6 Creating the
SnapControlPoint feature class.
33
4.7.7 Creating a geometric
network.
33
4.7.8 Assigning Regional
HydroIDs.
33
4.7.9 Water Quality Parameters.
34
4.7.10 TSGroup table.
35
4.7.11 TSType table.
35
4.7.12 Impaired Code Table.
35
4.7.13 Agency responsible table.
35
4.7.14 Topology and relationships
among the feature classes.
35
4.7.15 Regionalization process.
36
4.7.16 DISCREPANCY OF THE
HYDROLOGIC DATA..
38
4.8 Entity and attribute information.
40
4.8.1 Attributes of the
HydroEdge feature class.
40
5 Results.
43
5.1 River segments.
43
5.2 Monitoring Point
44
5.3
Digital Orthophoto Quadrangles (DOQ)
44
6 Conclusions.
47
7 Acknowledgements.
47
8 References.
48
The Rio
Grande/Rio Bravo River is a transboundary water source shared by the United States and Mexico. The river is the lifeblood for much of the
economic activity in the Rio Grande/Bravo valley on both sides of the
border. A continually increasing
population, serious problems related to lack of sanitation and clean water, as
well as regular high investments in infrastructures which are not achieving
their objectives, are likely to force governments at various levels to search
for alternative approaches, other than relying only on engineering solutions
through supply management alone. The institutions concerned are aware that
successful water resources management requires a long term planning process
from technical, economic, political, social, and environmental viewpoints.
Recently, the basin’s highly developed water resources and decade-long drought
conditions have created tensions over water sharing in the basin. Areas of conflict and several possible
negotiated remedies are being identified, but access to reliable data for
analysis of alternative solutions to these problems is lacking. For this reason
the development of watershed-scale databases including both water quantity and
water quality information for the Rio Grande/Bravo basin is of critical
importance. Minute 308 of the International Boundary and Waters Commission
(IBWC), June 28, 2002, states that it is very important to support projects
that increase data exchange related to the management of hydrological
information systems. These systems
should include information from both sides of the basin in a timely manner to
enable the IBWC to adopt principles and understandings under which both
Governments provide the highest priority to fulfilling their respective
obligations under the 1944 Water Treaty.
This
project helps to solve the fundamental problem of making accurate data
available for decision makers in the basin.
These data are being provided in the industry-standard ArcHydro
geographic information system (GIS) which provides ready access to data for
hydrologic and policy analysis using a wide variety of hydrologic, water
quality, economic, and environmental models.
ArcHydro makes it possible to store information about a river basin in a
way that resembles the physical geography of the real basin, so that you can
analyze effects from upstream or on downstream in a connected manner.
The main
goal of this project is the development of a Water Quality Data Model (WQDM)
for the whole Rio Grande/Bravo basin, based on a framework developed in Visio
2000 and exported as a schema into an access file. This data model is implemented
following criteria and parameters from the International Boundary Water
Commission (IBWC), Texas Commission on Environmental Quality (TCEQ), United
States Geological Survey (USGS), Environmental Protection Agency (EPA), and Mexican
National Water Commission (CNA). This georeferenced database includes spatial
and temporal information related with water quality, as well as water related
infrastructure data to the Rio Grande/Bravo, being implemented in a Geographic
Information System (ArcGIS) following the ArcHydro data model structure
developed at the Center for Research in Water Resources of the University of
Texas at Austin (CRWR-UT). This relational database is related to the Water
Quantity Data Model for the Rio Grande/Bravo basin already developed in a
previous project by the CRWR and CNA.