Arc Hydro groundwater data model: a data model for groundwater systems within ArcGIS ESRI user conference May 2004 Gil Strassberg and David Maidment, University of Texas at Austin Norman Jones, Brigham Young University

Hydrologic Information Systems Modeling Geodatabase A hydrologic information system is a combination of geospatial and temporal hydrologic data with hydrologic models that supports hydrologic practice, science and education

Arc Hydro: GIS for Water Resources 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

Arc Hydro — Hydrography

Arc Hydro — Hydrology

Arc Hydro surface water A data model for representing surface water systems

Describing the hydrologic cycle

1.Support representation of regional groundwater systems. 2.Support representation of site scale groundwater studies. 3.Enable the integration of surface water and groundwater data. 4.Connect to groundwater modeling software. Data model goals Objective Extend the Arc Hydro data model to include a representation of groundwater systems.

Regional groundwater systems Usually the horizontal scale >> vertical scale In many cases modeled as 2 dimensional

Site scale groundwater studies Characterization of Savannah River Site in South Carolina Usually model 3D flow to study mass transport Important to establish a 3D model of the system

Integration of surface water and groundwater information Geographic relationship between the surface and groundwater elements Need to represent movement of water between the surface and subsurface Complex subject!!

Connection to groundwater models Data model = Database Model input Model outputs

Data model framework Raster catalog to represent geologic formations and parameter distribution Features describing the hydrogeology of the system Raster catalog to represent water related parameters Features used in relation with modeling Table that describes hydrogeologic units and their properties Describes surfaces

Hydrogeology feature dataset GeoSection (3D polygon)GeoVolume (Multipatch) Objects describing hydrogeology GeoArea (2D Polygon) GeoLine (2D line) GeoPoint (3D Point) BoreLine (3D line)

Hydrogeology feature dataset Aquifer (2D Polygon)Wells (points) Water Area (2D Polygon) Water Line (2D line)

GeoRasters TransmisivityHydraulic conductivity GeoRasters: Distribution of properties Define boundaries of hydrogeologic units Top of formationFormation base Raster ID DescriptionUnits 1Transmisivitym 2 /day 2Hydraulic conductivity m/day 3Formation topm 4Formation basem Raster catalog GeoRasters are usually constant over time Woodbine aquifer, Texas

Raster Series describe water related properties over time Potentiometric surface Saturated thickness Contaminant concentration Raster ID DescriptionUnitsTime 1Potentiometric surface mMay Potentiometric surface mJune Potentiometric surface mJuly 2003

Modeling feature dataset 3 dimensional models Connection to modeling tools: enable the preparation of model inputs and communication of model outputs 2 dimensional models

Hydrogeologic unit HGU IDHGU CodeFormationReference 11Sand 28Red Clay 323Bouldery till Hydrogeologic unit table Describes the hydrogeologic unit and links together the spatial representations

Example 1: Representing hydrogeology of an aquifer system North Carolina coastal aquifer system

Introduction to the Arc Hydro Groundwater toolbar Create Volume objects from feature or import from external sources Create Volume objects from base polygons by extrusion Generate BoreLines from wells Definition Query tool Available on the CD Available on CRWR website:

North Carolina coastal aquifer system * From USGS, Water Resources Data Report of North Carolina for WY 2002 Section line

Defining the control volume This control volume is the boundary of the Neuse River basin down to a specified depth Next step - Describe the subsurface within this control volume

Boundaries of aquifers Map view of the aquifers

Beaufort aquifer A display of the water quality zones in the aquifer Outline of the Neuse River Basin

Hydrostratigraphy information North Carolina Division of Water Resources website Hydrostratigraphy from boreholes in the Beaufort boundary

Hydrostratigraphy attributes Attributes of the borehole describe the hydrostratigraphy at varying depths Beaufort aquifer top Elevations above mean sea level Land surface elevation Castle Hayne confining layer top Castle Hayne aquifer top Beaufort confining layer top

3D view of the information Start from a 2D point (X, Y) with attributes describing the Z dimension Conceptual description of the subsurface Beaufort aquifer Elevations are feet above mean sea level Land surface elevation Castle Hayne confining layer Castle Hayne aquifer Beaufort confining layer

Transform into 3D lines The HydroID relates the vertical description of hydrogeologic units back to the borehole point Hydro ID = 66

Transform into 3D lines Given the X and Y coordinates and the Z coordinate for the hydrogeologic units, 3 dimensional lines can be generated to represent the hydrostratigraphy within the borehole

Interpolate to create a model of the subsurface Cross sections, fence diagrams Interpolating to create cross section views

Interpolate to create a model of the subsurface Creating solid models Beaufort confining layer Beaufort aquifer Using external models we can compute the volume of the solids

Analysis Once we have a model of the subsurface we can look at interaction between control volumes and how water will move between them Recharge zones Streams

Introduction to Multipatches Multipatches in ArcGIS A multipatch is a series of three-dimensional surfaces that are represented as groups of geometries We can use closed multipatches to represent the geometry of volume objects Limitations: Not a true volume object, doesn’t know its volume, surface area etc. No ability to do intersections, proximity and other operations available on points, lines, and polygons in 2D space

Importing Solids from XML Stratigraphy information in a spatial database Interpolation in external software (for example GMS) Store solids in XMLBack to spatial database

Demo 1: Creating BoreLines and GeoVolumes Create a control volume from the Neuse River Bain polygon by extruding between two values. Use the Definition Query tool to display only hydrostratigraphy wells. Then make a well selection and create borelines using the wells to borelines tool. Select a set of borelines for a specific aquifer (Black Creek), then create a GeoVolume of the aquifer using the BoreLines to GeoVolume tool. Display time series for the wells (water elevations) in ArcMap.

Example 2: Representing groundwater models Savannah River Site, South Carolina

Connection to groundwater models Data model = Database Model input Model outputs

Savannah River Site South Carolina Savannah River Site Radioactive waste burial ground

Conceptual model horizontal dimension General head boundaries Package Streams Radioactive burial ground

Conceptual model vertical dimension 5 layers in the conceptual model Zone IIB2 “Water Table” “Tan Clay” 180 Zone IIB1 “Barnwell / McBean” 130 “Green Clay” 125 Zone IIA Gordon aquifer 50 (feet)

GIS representation of the horizontal dimension Represent the horizontal properties of the surface within ArcMap Each cell is 100 meters by 100 meters 1600 m 3000 m

Create a 3 dimensional representation of the model Can generate a 3D model in ArcScene Vertical dimension ~ 75 meters Each cell in the 2D representation is transformed into a 3D object (Multipatch) Control volume for the model domain

Views of the subsurface Once a solid model is constructed we can generate views of the subsurface Cross section along streams intersecting the model domain

Can relate the 3D Cells to modeling information Cell2D Cell3D Cell IDTransmissivityConductivity Model inputs and outputs

To Review the Groundwater Data Model Please see “Groundwater” at To Get Latest Groundwater Tools Please see “Groundwater” at