Arc Hydro Groundwater Data Model
GIS in Water Resources
Fall 2009
With contributions from Norm Jones (BYU), Gil Strassberg
(Aquaveo), David Maidment (UT Austin), Tim Whiteaker (UT
Austin), Steve Grise (ESRI), Steve Kopp (ESRI)
Learning Objectives:
By the end of this class you should be able to:
• Understand how we describe subsurface features in GIS using
the Arc Hydro Groundwater Data Model
• Understand the linkages from one subsurface feature to
another, and to time series or hydrostratigraphic data
Outline
• Background
• Arc Hydro Framework
• Arc Hydro Groundwater Components
Linking GIS and Water Resources
GIS
Water
Resources
Arc Hydro: GIS for Water Resources
Published in 2002, now in revision for Arc Hydro II
• Arc Hydro
– An ArcGIS data model for
water resources
– Arc Hydro toolset for
implementation
– Framework for linking
hydrologic simulation
models
The Arc Hydro data model and
application tools are in the public
domain
Challenges in developing Arc Hydro
• ArcGIS is a very successful static, 2D or 2.5D system
• For surface water resources we need
– Close connection between raster terrain and vector stream
data
– Linkage to time varying water data observations stored at
gages
– Access to precipitation and evaporation data “fields”
• For groundwater resources we need
– 3D representation of boreholes and hydrogeologic units
– Integration with groundwater models, especially
MODFLOW, which has become the ArcInfo of groundwater
Arc Hydro Groundwater – Time Line
• Arc Hydro book and tools published - 2002
• Initial groundwater data model discussions, initial designs at the Center
for Research in Water Resources, UT Austin - 2003
• First complete design of Arc Hydro Groundwater data model - 2006
• Arc Hydro Groundwater presented at ESRI User Conference - 2007
• ESRI and Aquaveo team to develop Arc Hydro Groundwater Tools - 2007
• Arc Hydro Groundwater Tools released - 2009
• Arc Hydro Groundwater book - 2009-2010
What is a hydrologic data model
Booch et al. defined a model: “a simplification of reality created to
better understand the system being created”
Objects
Aquifer
Stream
Well
Volume
R.M. Hirsch, USGS
Developing a groundwater data model
Take a variety of spatial information and integrate into one
geospatial database with a common terminology
• Better communication
• Integration of data
• Base for applications
Geologic maps
Time series observations
Borehole data
Groundwater data model
(geospatial database)
Hydrostratigraphy
Geospatial vector layers
Numerical models
Gridded data
Framework and Components
Components can be added to the framework to represent
specific themes in more detail
Surface water components
Network
Drainage
Groundwater components
Geology
Framework
Hydrography
Borehole data
Hydrostratigraphy
Channel
Temporal (enhanced)
Simulation
Arc Hydro Framework
• Basic representation of surface water and groundwater
• Components can be added to the framework to represent
specific themes in more detail
Well
• Wells are the most basic features in groundwater databases
• Attributes of wells describe the location, depth, water use,
owner, etc.
Well
• Wells are defined as 2D point features
• Only some basic attributes are predefined to describe the
well use, and geometry and relationship with aquifers
Wells in the Edwards Aquifer
Point dataset
Well
HydroID
HydroCode
LandElev
WellDepth
AquiferID
AqCode
HGUID
FType
Aquifer features
• Polygon features for representing aquifer boundaries and
zones within them
• Representation of Aquifer maps
Aquifer features
• An aquifer is defined by one or a set of polygon features
• Aquifer features can be grouped by HGUID
Hydro Features
• Key attributes for feature identification
• HydroID – Unique ID within the geodatabase (internal relationships)
• HydroCode – Public identifier (external relationships)
HydroID
• A new ID assigned to features in a Arc Hydro geodatabase
• Uniquely identifies features within a geodatabase
• Is used to manage relationships between features and to relate
features with tabular data (e.g. time series)
• Custom tool for managing HydroIDs
HydroCode links to external applications
• Web interface for groundwater data in Texas
• Texas Water Information Integration & Dissemination (WIID)
Aquifer and well
• Well features are related to Aquifers: The AquiferID of a well feature is
equal to the HydroID of an aquifer feature
• An aquifer can be associated with one or more wells (1:M relationship)
• Can take a different approach to support M:N relationship
Aquifer
HydroID
HydroCode
Name
HGUID
FType
Well
1
*
HydroID
HydroCode
LandElev
WellDepth
AquiferID
AqCode
HGUID
FType
Aquifer and well
Well HydroID = 53
Wells and TimeSeries
Well features are related with time series (water
levels, water quality)
Monitoring Well
(295443097554201)
Sink Creek
San Marcos springs
San Marcos
Springs
MonitoringPoint has time series
Monitoring points are related with time series (streamflow,
water quality, precipitation)
Integration of surface water and groundwater data
The common framework supports analysis of surface water
and groundwater data together
Well in the Edwards
Aquifer)
Streamflow Gage at
Comal Springs, New
Braunfels Texas
Surface water - groundwater linkage
Relationships between surface water and aquifer enable analysis
based on spatial and hydrologic relationships
Streams over the outcrop
= recharge features
Implementing the Arc Hydro framework
1. Create the classes of the Arc Hydro Framework (manually
using ArcCatalog or by importing from an xml schema)
2. Add project specific classes, attributes, relationships, and
domains as necessary
3. Document datasets and changes made to the data model
4. Import data into the framework classes (e.g. streams, wells,
aquifers, time series)
5. Assign key attributes to uniquely identify the features and
establish relationships
6. Apply tools to create new features and calculate attributes
7. Visualize data and create products (maps, scenes, reports)
Components
• Geology - Representation of data from geologic maps
• Wells and Boreholes – Description of well attributes and
borehole data
• Hydrostratigraphy – 2D and 3D description of
hydrostratigraphy
• Temporal – Representation of time varying data
• Simulation – Representation of groundwater simulation
models (focus on MODFLOW)
Geologic maps
A geologic map is a cartographic product that portrays information
about the geologic character of a specific geographic area
• Groundwater features are closely tied to geology
• Geologic maps vary in scale (continental, regional, local)
• Provide a simple data structure to support mapping
Geology
Aquifers
Maps from the United States National Atlas (http://nationalatlas.gov/).
Geologic map databases
Geodatabase design for storing data from
the Geologic Atlas of Texas
(http://www.tnris.org/news.aspx?id=244)
Arc Geology: generic geologic map
data model implemented within
ArcGIS
(figure from Raines et al. 2007)
Geology component
GeologyPoint: Point feature (e.g. springs, caves, sinks, and observation points)
GeologyLine: Line features (e.g. faults, contacts)
GeologyArea: Areal features (e.g. rock units and alteration zones)
GeologyPoint
GeologyLine
GeologyArea
HydroID
HydroCode
GeoAbbrev
Description
HGUID
HGUCode
FType
GeologyLine
HydroID
HydroCode
GeoAbbrev
Description
HGUID
HGUCode
FTyp
GeologyArea
HydroID
HydroCode
GeoAbbrev
Description
HGUID
HGUCode
FTyp
GeologyPoint
Map modified from: Geologic map of
the Edwards Aquifer recharge zone,
south-central Texas. U.S. Geological
Survey SIM 2873
Components
• Geology - Representation of data from geologic maps
• Wells and Boreholes – Description of well attributes and borehole
data
• Hydrostratigraphy – 2D and 3D description of hydrostratigraphy
• Temporal – Representation of time varying data
• Simulation – Representation of groundwater simulation models
(focus on MODFLOW)
Well databases
• Wells are basic features in groundwater databases
• Attributes of wells describe its location, depth, water use, owner, etc.
• Data are collected from drilling/construction reports and permits
Well databases
•
Well databases store information on wells and related data
•
Data are related to wells such as construction, water levels, water quality, and stratigraphy
•
Usually a central table is used to describe well features and other data are linked to it
through key attributes (e.g. state well number)
Relationships in the
TWDB groundwater
database
Well
• The Well location is defined as a 2D point in the
Well feature class
• In the Arc Hydro model we only predefine a set of
basic attributes
Point dataset
Well
Wells in the Edwards Aquifer
HydroID
HydroCode
LandElev
WellDepth
AquiferID
AqCode
HGUID
FType
Borehole data
• 3D data (screens, completion intervals, stratigraphy) are referenced
along the well
• From depth (top) – To depth (bottom)
BoreholeLog table
• Used to store 3D borehole data related with well features
• Each row in the table represents a point/interval along a borehole
• Data are related with a Well feature through the WellID attribute
• 3D geometry is defined by the TopElev and BottomElev attributes
3D features (BorePoints and BoreLines)
• Can create 3D features representing data in the BoreholeLog table
• BorePoint is a 3D point feature class for representing point locations
along a borehole (e.g. geologic contacts, samples)
• BoreLine is a 3D line feature class for representing intervals along a
borehole
BorePoint
BoreLine
Components
• Geology - Representation of data from geologic maps
• Wells and Boreholes – Description of well attributes and borehole
data
• Hydrostratigraphy – 2D and 3D description of hydrostratigraphy
• Temporal – Representation of time varying data
• Simulation – Representation of groundwater simulation models
(focus on MODFLOW)
Hydrogeologic units
“Hydrogeologic unit is any soil or rock unit or zone which by virtue of its
hydraulic properties has a distinct influence on the storage or
movement of ground water” (USGS glossary of hydrologic terms)
Hydrogeology can be derived by classifying stratigraphic units
Stratigraphic units
Hydrogeologic units
Upper confining unit
Georgetown Fm. (GTOWN)
Cyclic + Marine member (CYMRN)
Leached + collapsed member (LCCLP)
Georgetown
Fm.
Pearson Fm.
Edwards
Aquifer
Regional dense member (RGDNS)
Grainstone member (GRNSTN)
Kirschberg evaporite member (KSCH)
Kainer Fm.
Dolomitic member (DOLO)
Basal Nodular member (BSNOD)
Upper Glen Rose (UGLRS)
Hydrogeologic unit table
• HydroGeologicUnit table provides a conceptual
description of hydrogeologic units
• Hydrogeologic units can be attributed with an AquiferID
such that they can be grouped to represent an aquifer
• Spatial features are indexed with a HGUID to relate to
the conceptual representation of the units
Representations of hydrogeologic units
• Different spatial representations of hydrogeologic units with 2D and 3D
objects
• Workflow for creating 3D hydrogeologic models
Cross sections/Fence diagrams
Define hydrogeologic
units along boreholes
Interpolate and edit
cross sections
Borehole Stratigraphy
Create surfaces from
borehole data and
cross sections
Surfaces defining the extent
of hydrogeologic units
Build volumes
between surfaces
Create cross sections
based on the surfaces
“Cut” cross sections
from the solid model
Volume objects representing
hydrogeologic units
Cross sections derived
from the solid model
Hydrogeologic unit table
• Hydrogeologic units are described with different spatial instances
(outcrops, borehole intervals, surfaces, cross sections, and volumes)
• HGUID is the key attribute
GeoArea
Polygon feature class
1 SectionLine
GeoSection
HydrogeologicUnit
Multipatch feature class
Table
HGUID
Conceptual description
HGUID
Spatial description
GeoRasters
Raster dataset
GeoVolume
Multipatch feature class
*
PointZ feature class
GeoArea
• 2D polygons defining boundaries of hydrogeologic units
• GeoArea (conceptual/interpolated boundary) ≠ GeologyArea (mapped
outcrop)
GeologyArea features
represent data from geologic
maps
GeologyArea
GeoArea feature representing the
Kainer hydrogeologic unit
Data points representing top
elevations of the Kainer formation
Representation of Cross Sections
• SectionLine defines the 2D cross section
• GeoSection represent 3D sections as 3D features
• SectionID of the polygon relates back to the section line
B
A
B’
A’
GeoRasters
• Raster catalog for storing and indexing raster datasets
• Can store top and bottom of formations
• Each raster is related with a HGU in the hydrogeologic unit table
Georgetown
Person
Kainer
Glen Rose
GeoRasters
• GeoRasters also store hydraulic properties such
as transmissivity, conductivity, and specific yield
K (feet/day)
Raster of hydraulic conductivity in the Edwards Aquifer
GeoVolume
• Objects for representing 3D volume objects
• Geometry is multipatch - Can create the volumes as a set of 3D
triangles
• Not real volume – can’t do any 3D operations
Components
• Geology - Representation of data from geologic maps
• Wells and Boreholes – Description of well attributes and borehole
data
• Hydrostratigraphy – 2D and 3D description of hydrostratigraphy
• Temporal – Representation of time varying data
• Simulation – Representation of groundwater simulation models
(focus on MODFLOW)
Types of time varying datasets
• Single variable time series (time series) – A single
variable recorded at a location, such as stream
discharge or groundwater levels
• Multi-variable time series (attribute series) – Multiple
variables recorded simultaneously at the same
location, such as chemical analysis of a water sample
• Time varying surfaces (raster series) – Raster datasets
indexed by time. Each rater is a “snapshot” of the
environment at a certain time.
• Time varying features (feature series) – A collection of
features indexed by time. Each feature in a feature
series represents a variable at a single time period.
Time series
• The most basic case is a monitoring device recording
values over time (e.g. monitoring well, streamflow
gage)
Monitoring Well
(295443097554201 )
Sink Creek
San Marcos springs
San Marcos
Springs
Time series
• TimeSeries table is the basic table for storing time series data
• Need to support: what, where, and when
• VariableDefinition table describes variables
Time (TsTime)
Space (FeatureID)
Variables (VarID)
Time series
• By querying the table we can create different data views
(a)
TsTime
2791
(b)
FeatureID
(c)
FeatureID
2
VarID
TsTime
VarID
TsTime
2791
2
VarID
FeatureID
Time series views – create time series graph
• FeatureID of the time series = HydroID
of the spatial feature (e.g. Well)
Well HydroID = 2791
Time series views – map a variable at a given time
Map a certain variable (e.g. water levels) at a given time (e.g.
February 2004)
TsTime
Feet above mean sea level
2/2004
FeatureID
2
VarID
Multi-variable time series
• Data are indexed by space (FeatureID) and by time (TsTime) but
instead of one variable we store multiple variables.
• The column heading is the variable key (VarKey)
Variables (VarKey)
RasterSeries
• Raster datasets indexed by time
• Each raster represents a continuous surface describing a
variable for a given time over an area of interest
January 1991
January 1992
January 1993
Feature Series
• A collection of features indexed by time (e.g. particle tracks)
• Features are indexed by VarID, TsTime.
• Features can also be indexed with a GroupID. Each group of
features creates a track over time
Components
• Geology - Representation of data from geologic maps
• Wells and Boreholes – Description of well attributes and borehole
data
• Hydrostratigraphy – 2D and 3D description of hydrostratigraphy
• Temporal – Representation of time varying data
• Simulation – Representation of groundwater simulation models
(focus on MODFLOW)
Representing simulation models
• Georeference model inputs and outputs (in space and time)
• Focus on MODFLOW, block centered finite difference grid (nodes are in
the center of the cells)
• Represent 2D and 3D models
Block-centered finite difference grid
Simulation component
Features for representing data from simulation models
Boundary
Polygon feature class for representing the extent and
orientation of a simulation model
Cell2D and Node
Cell2D: polygon feature class that represents cells or elements
associated with a two-dimensional simulation model or a single layer
of a three-dimensional model
Node: point feature class used in combination with Cell2D to
represent the model’s mesh/grid.
a) Finite element mesh
Node Features
b) Mesh centered finite
difference grid
Cell2D Features
c) Cell centered finite
difference grid
(a)
(b)
(c)
Cell2D and Node
Used to create maps of model data
Node3D and Cell3D
•
•
•
•
Node3D – a Z enabled point feature class
Cell3D - Multipatch feature class
Represent three-dimensional cells and Nodes
Used mostly for visualization of 3D models
Summary Concepts
• Arc Hydro Groundwater…
– extends Arc Hydro to represent groundwater
datasets in GIS
– includes components for aquifers, wells,
hydrogeologic features, time series, and simulation
model output
– links features to hydrogeologic layers via HGUID,
and to aquifers via AquiferID
Websites
• ESRI Data Model Website: www.esri.com/datamodels
• Arc Hydro Groundwater Websites: www.archydrogw.com
www.aquaveo.com/archydro
Contact:
•Norm Jones (njones@aquaveo.com)
•Gil Strassberg (gstrassberg@aquaveo.com)
•Steve Grisé (sgrise@esri.com)