Introduction to GIS in Water Resources David R. Maidment Director, Center for Research in Water Resources University of Texas at Austin CRWR

National Hydro Data Programs National Elevation Dataset (NED) National Hydrography Dataset (NHD) Watershed Boundary DatasetNED-Hydrology

National Elevation Dataset Digital Elevation Model with 1 arc- second (30m) cells Seamless in 1° blocks for the United States 10 billion data Derived from USGS 1:24,000 quadrangle sheets

Digital Elevation Model (DEM) Contours

Austin West 30 Meter DEM

Eight Direction Pour Point Model Water flows in the direction of steepest descent

Flow Direction Grid

Cell to Cell Grid Network Through the Landscape Stream cell

Delineation of Streams and Watersheds on a DEM

GTOPO km Digital Elevation Model of the Earth

Drainage in North America

1500 Major Drainage Basins

National Hydro Data Programs National Elevation Dataset (NED) National Hydrography Dataset (NHD) Watershed Boundary DatasetNED-Hydrology

Watersheds of the US 2-digit water resource regions 8-digit HUC watersheds

Hydrologic Unit Code Watersheds ~ 2000 for US, about the size of counties

Watershed Hierarchy 8 HUC NED-H AvailableIn Progress Digit #

Watershed Boundary Dataset National Program by USGS and USDA (NRCS) Boundaries for 10- and 12- digit watersheds First cut is by automated delineation from NED Hand checked and edited 10-digit watersheds

National program by USGS and NWS 5000 cell threshold on a 30m DEM (~ 8 km 2 average drainage area) ~ 1 million catchments for US when completed Includes grid derived products e.g. topmodel index

EPA River Reach File 1 (RF1)

River networks for 8-digit HUC watersheds

Lower West Fork, Trinity River Basin HUC =

NHD River Reaches 412 River Reaches In Upper West Fork

River Reach Codes Rch_Code = Rch_Code = HUC# Segment#

Colorado River Network 1:100,000 scale river network developed from NHD ~ 60,000 edges 40,000 mile 2 drainage area

City of Austin Stream Network Developed from 1”=100’ Capco Areal photogrammetry 1:1200 scale 63,000 edges 6,300 stream miles

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.

Colorado River at Mansfield Dam River Reaches Lake Travis From NHD 1:100,000 scale City of Austin Stream network 1:1200 scale

Detailed Comparison between NHD and Austin streams Good agreement between data sets developed independently at very different spatial scales

County Level Digital Soil Maps

National Land Cover Dataset

PRISM Mean Annual Precipitation

National Water Information System Web access to USGS water resources data in real time

39 Synthesis of GIS and Modeling GISEnvironmental Modeling Environmental descriptionProcess representation Data Input Model Results (slide from 1 st International Conference on GIS and Environmental Modeling, Boulder, 1991)

40 Data-Driven Modeling Model 1 Model 2 Models Data base Data sources 1 2 Form the model within the frame of the available data (slide from 3rd International Conference on GIS and Environmental Modeling, Santa Fe, 1996)

Successes in GIS-Model Integration EPA Office of Science and Technology –BASINS Hydrologic Engineering Center –HEC GeoRAS and HEC-GeoHMS Waterways Experiment Station and Brigham Young University –WMS, GMS, SMS,… Danish Hydraulic Institute –Mike11 GIS, Mike Basin, Mike21 GIS

State and Local Data Decisions Watershed Management. TMDL. Source Water Protection. StormwaterDecisions Watershed Management. TMDL. Source Water Protection. Stormwater DataCartographic Monitoring MonitoringLoadingsDataCartographic LoadingsModels HSPF - NPSM HSPF - NPSM QUAL2E QUAL2E TOXIROUTE TOXIROUTEPost-ProcessorsModels HSPF - NPSM HSPF - NPSM QUAL2E QUAL2E TOXIROUTE TOXIROUTEPost-ProcessorsToolsTargetAssessment Data Mining ReportingToolsTargetAssessment Reporting BASINS BASINS - Integrating GIS and Water Quality Modeling Target Assess DM

Integrating GIS and HEC Flood Models ArcView Digital Elevation Model HEC-HMS Flood discharge HEC-RAS Water surface profiles ArcView Flood plain maps HEC-GeoHMSHEC-GeoRAS Digital Map Database

Austin Watersheds

DEM Watersheds for Austin

Integrating GIS and HEC Flood Models ArcView Digital Elevation Model HEC-HMS Flood discharge HEC-RAS Water surface profiles ArcView Flood plain maps HEC-GeoHMSHEC-GeoRAS Digital Map Database

Austin Watersheds

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

Integrating GIS and HEC Flood Models ArcView Digital Elevation Model HEC-HMS Flood discharge HEC-RAS Water surface profiles ArcView Flood plain maps HEC-GeoHMSHEC-GeoRAS Digital Map Database

Waller Creek DEM

Waller Creek HMS Model

Connecting HMS and RAS HMS RAS

Discharge at a Particular Cross-Section (HMS) (RAS)

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

Flood Plain Mapping

Floodplain Mapping: 3-D ViewView