ArcHydro Groundwater Data Model Build off from the ArcHydro surface water data model to create a logical connection between surface water and groundwater systems. Create a 3-dimensional representation of the subsurface. Provide a data interface between ArcGIS and commonly used groundwater modeling programs.

Layer 1 Layer 3 Layer 2 Layer 4 Layer 5 Surface elevation

Aquifer top Aquifer base Outcrop Wells

Two conceptual models Surface – groundwater interaction: Interaction between river networks and aquifers. Groundwater model: 3-dimensional representation of the subsurface. Describes the aquifer architecture (geological formations), hydrogeologic parameters, boreholes and temporal data. Aquifers River network

Surface water – groundwater relationship Build a connection between river networks (stored in the Arc Hydro framework) and aquifers. Outcrop Down dip Geometric network Polygon features

Surface water – Groundwater features Data model features: River network (Line features in a geometric network) Aquifers (polygon features) Wells (Point features) Relationships: Aquifer – Edge relationship Aquifer – Well relationship

ArcHydro data model with groundwater

Surface – Groundwater relationship Need to create a relationship between the edges of the river network and the outcrop sections of the aquifers. Requires splitting a number of the network edges where they intersect the outcrops of the aquifer features. Aquifer outcrop River Edge Intersection point

Guadalupe basin river network Edwards south Wilcox Outcrop Downdip Intersection points Surface – Groundwater application

3-dimensional model Layer 1 Layer 2 Layer 3 Layer 4 Hydro Element Hydrogeologic unit The Hydro Element is the basic modeling unit. Each Hydro Element can be related to a number of layers Layers are grouped into Hydrogeologic units (i.e. aquifers) Attributes ( conductivity, porosity etc.) are stored in the layer.

3-dimensional data model features Connect with modeling software

Savannah river site Savannah River Site Radioactive waste burial ground

Savannah river site conceptual model General head boundaries Package River Package

Savannah river site conceptual model 5 layers in the conceptual model

Savannah river site GIS representation Use Fishnet (an assembly of polygon features) to create the modeling grid Radioactive waste burial site

Savannah river site 3 dimensional representation Layers 1- 5 in the Savannah River Site model: The layer table stores the attributes needed to represent the subsurface layers and these can be used to connect to modeling software. Savannah River Site model outline

Hydro geologic Units Formations Extent and physical properties of the aquifer Layer 1 HydroGeologic Unit Top Layer 2 Layer 3 Layer 4 HydroGeologic Unit Base Hydraulic conductivity Porosity Transmisivity Storativity

Aquifer Information Aquifer Top (Formation top) Aquifer Base (Formation base) Formation Thickness Aquifer Thickness Confining Thickness Potentiometric surface Saturated Thickness Land Surface Aquifer properties: Hydraulic conductivity Porosity Transmisivity Storativity

Borehole Information Land Elevation Benchmark Interval Bottom Distance down the borehole can be measured from the benchmark or the land elevation Temporal information: Hydraulic head Water quality data Geologic data: Lithology Screen