Introduction to GIS in Water Resources

David R. MaidmentDirector,

Center for Research in Water Resources

University of Texas at Austin

CRWR

National Hydro Data ProgramsNational 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

720

700

680

740

680700720740

720 720

Austin West 30 Meter DEM

32

16

8

64

4

128

1

2

Eight Direction Pour Point Model

Water flows in the direction of steepest descent

Flow Direction Grid

32

16

8

64

4

128

1

2

Cell to Cell Grid NetworkThrough the Landscape

Stream cell

Delineation of Streams and Watersheds on a DEM

GTOPO30 - 1 km Digital Elevation Model of the Earth

Drainage in North America

1500 Major Drainage Basins

National Hydro Data ProgramsNational 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

4

2

6

NED-H

1012

Available In 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 km2 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 networksfor 8-digit HUC watersheds

Lower West Fork, Trinity River BasinHUC = 12030102

NHD River Reaches

412 River ReachesIn Upper West Fork

River Reach Codes

Rch_Code = 12030102000151

Rch_Code = 12030102000005

HUC# Segment#

Colorado River Network1:100,000 scale river network

developed from NHD~ 60,000 edges

40,000 mile2 drainage area

City of Austin Stream Network

Developed from 1”=100’Capco Areal photogrammetry

1:1200 scale63,000 edges

6,300 stream miles

Stream Definition: Waller CreekAustin Watersheds with Streamsderived 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 ReachesLake Travis

From NHD1:100,000

scale

City of AustinStream 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

GIS Environmental Modeling

Environmental description Process representation

Data

Input

Model

Results

(slide from 1st International Conference on GIS and Environmental Modeling, Boulder, 1991)

40

Data-Driven Modeling

Model 1

Model 2

Models

Data base

Data sources

12

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

Sta

te a

nd

Loc

al D

ata

Sta

te a

nd

Loc

al D

ata

DecisionsDecisions

Watershed Management

.

TMDL.

Source Water Protection

.Stormwater

DecisionsDecisions

Watershed Management

.

TMDL.

Source Water Protection

.Stormwater

DataDataCartographicCartographic

MonitoringMonitoring

LoadingsLoadings

DataDataCartographicCartographic

MonitoringMonitoring

LoadingsLoadings

ModelsModels HSPF - NPSMHSPF - NPSM

QUAL2EQUAL2E

TOXIROUTETOXIROUTE

Post-ProcessorsPost-Processors

ModelsModels HSPF - NPSMHSPF - NPSM

QUAL2EQUAL2E

TOXIROUTETOXIROUTE

Post-ProcessorsPost-Processors

ToolsToolsTargetTarget

AssessmentAssessment

Data MiningData Mining

ReportingReporting

ToolsToolsTargetTarget

AssessmentAssessment

Data MiningData Mining

ReportingReporting

BASINSBASINS - Integrating GIS and Water Quality ModelingTarget

Assess

DM

Integrating GIS and HEC Flood Models

ArcViewDigital

ElevationModel

HEC-HMSFlood

discharge

HEC-RASWatersurfaceprofiles

ArcViewFlood

plain maps

HEC-GeoHMS HEC-GeoRAS

Digital Map Database

Austin Watersheds

DEM Watersheds for Austin

Integrating GIS and HEC Flood Models

ArcViewDigital

ElevationModel

HEC-HMSFlood

discharge

HEC-RASWatersurfaceprofiles

ArcViewFlood

plain maps

HEC-GeoHMS HEC-GeoRAS

Digital Map Database

Austin Watersheds

DEM Watersheds for Austin

Selected Watersheds and Streams

Mansfield Dam

ColoradoRiver

HMS Schematic Prepared with CRWR-PrePro

Mansfield Dam

ColoradoRiver

HMS Model of the Austin Region

HMS Results

Watershed 155 Junction 44

Integrating GIS and HEC Flood Models

ArcViewDigital

ElevationModel

HEC-HMSFlood

discharge

HEC-RASWatersurfaceprofiles

ArcViewFlood

plain maps

HEC-GeoHMS HEC-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 View