Arc Hydro and Modeling Intrinsic Modeling – within a particular application eg Excel, ArcGIS Dynamic Linked Library – tightly coupled package of functions (e.g. LibHydro from HEC) Independent Modeling – separate hydrologic model with data exchange

Thematic Layers supporting the Arc Hydro data model (from Michael Zeiler “Modeling Our World” Volume 2) Streams Drainage Areas Hydrography Channels Terrain Surfaces Rainfall Response Digital Orthophotos

Data Model Based on Behavior Follow a drop of water from where it falls on the land, to the stream, and all the way to the ocean.

Integrating Data Inventory using a Behavioral Model Relationships between objects linked by tracing path of water movement

Intrinsic Hydrologic Modeling Dr Tarboton –DEM-based hydrologic modeling USGS –Stream Stats Mean annual flows and pollutant loads Streamstats

Dynamic Linked Library Can have Fortran subroutines in a DLL Muskingum flow routing

Independent Hydrologic Model VB progam reads and writes text files

Analysis, Modeling, Decision Making Arc Hydro Geodatabase Visual Basic ArcGIS Relational Database (Access) Excel Interfaces to Arc Hydro Data and Models

ArcGIS Development at DHI Extend the ArcGIS Hydro Data ModelExtend the ArcGIS Hydro Data Model

DHI TimeSeries Package TimeSeries Package ArchitectureTimeSeries Package Architecture

Three basic water problems Too little water (Drought and water supply) Too much water (Flooding) Its dirty (Water Quality) Also have significant GIS effort on environmental issues related to water such as habitat assessment

1996 Texas Drought George W. Bush, (then Governor of Texas) asked: “Tell me how much water we have, how much water we’re using and how much water we need” State water officials did not have adequate answers

Texas Water Planning 1997 Texas Legislature passed Senate Bill 1 which provided for –State-wide geospatial data development (topography, hydrography, land use, soils and orthophotos) –Water planning in 14 regions rather than state- wide –Assessment of water availability for all water permits

Hydrologic Cataloging Units (HUCS) Guadalupe Basin (4 HUC’s) H ydrologic U nit C ode = HUC’s cover continental US average area ~ 1 county

Water Availability in the Guadalupe Basin Stream Gauge (14) Water Diversion (440) Estimate water availability at each legally permitted water diversion point based on “naturalized” flow at stream gages and the effects of other permitted diversions

Digital Elevation Model National Elevation Dataset 30m x 30m cells 11,000,000 cells to cover San Marcos basin 70,000,000 cells to cover Guadalupe basin San Marcos basin

Drainage Area Delineated from the Digital Elevation Model Arc Hydro attribute DrainArea

Estimating Naturalized Flow at Diversion Points QdQd QfQf AdAd AfAf Q d = Q f AdAfAdAf Naturalized flow record at stream gage (50 years of monthly flows) Estimated flow record at diversion point

Length Downstream D F Flow distance (D to F) = Length Downstream (D) – Length Downstream (F) Length Downstream (D) Length Downstream (F) F D Arc Hydro attribute LengthDown Seepage losses

Water Availability Modeling Hydrologic Modeling Water Rights Analysis Package (WRAP) 50 year series of naturalized monthly flows at stream gages GIS data for each diversion point Letter to each water permit owner specifying % of permitted flow available during a drought Completed for ~ 10,000 water permit holders,

Letter to each water permit owner specifying % of permitted flow available during a drought Geospatial data development by Center for Research in Water Resources, Univ. of Texas Texas Natural Resources Conservation Commission Hydrologic modeling by engineering consultants Water Availability Assessment (completed for ~ 10,000 permit holders, )

Flood Hydrology and Hydraulics ArcView Input Data DEM HEC-HMS Flood discharge HEC-RAS Water surface profiles ArcView Flood plain maps HEC-GeoHMSHec-GeoRAS

Status of the Software HEC-GeoHMS ver 1.0 available from HEC for ArcView version 3 hms4arcview/geohmsprogram.html hms4arcview/geohmsprogram.html Arc Hydro terrain and watershed functions replace some but not all of HEC-GeoHMS HEC-GeoRAS ver ras4arcview/georasprogram.html ras4arcview/georasprogram.html ESRI has developed a beta-version of GeoRAS for ArcGIS

Austin Digital Elevation Model Waller Creek

Austin Watersheds

CRWR-PrePro (a precursor of HEC-GeoHMS) ArcView-based preprocessor for HEC-Hydrologic Modeling System (HEC-HMS) Digital Elevation Model Stream Map HMS Basin File Control point locations Soil and Land Use Maps

DEM Watersheds for Austin

Selected Watersheds and Streams Mansfield Dam Colorado River

HMS Schematic Prepared with CRWR-PrePro Mansfield Dam Colorado River

HMS Model of the Austin Region

HMS Results Watershed 155Junction 44

Flood Hydrology and Hydraulics ArcView Input Data DEM HEC-HMS Flood discharge HEC-RAS Water surface profiles ArcView Flood plain maps HEC-GeoHMSHec-GeoRAS

Colorado River Network 1:100,000 scale Developed from National Hydrography Dataset

City of Austin Stream Network Developed from 1”=100’ Capco Areal photogrammetry 1:1200 scale

Stream Definition: Waller Creek Austin Watersheds with Streams derived from Aerial Photographs Streamlines generated by the aerial photographs are not always continuous.

Information for Correcting Stream Network DEM Contours Storm sewers Orthophotos

Resulting Corrected Stream Subsequent steps: Verification of corrected streams by flood hydrologists. Running “tracer” program to connect arcs. Burning of streams into DEM.

Waller Creek HMS Model

Flood Plain Mapping

Connecting HMS and RAS

Flood Hydrology and Hydraulics ArcView Input Data DEM HEC-HMS Flood discharge HEC-RAS Water surface profiles ArcView Flood plain maps HEC-GeoHMSHec-GeoRAS

HEC-RAS: Background River Analysis System model of the U.S. Army Corps of Engineers Input = cross-section geometry and flow rates Output = flood water elevations Cross-Section Schematic

Waller Creek Watersheds Channel Network

Points describe channel and floodway geometry Bank station locations Water surface elevations and floodplain boundaries HEC-RAS: Cross-Section Description

Discharge at a Particular Cross-Section

HEC-RAS: Output Text File Graphical

Floodplain Mapping: Plan View

3D Terrain Modeling: Ultimate Goal