CEE 795Water Resources Modeling and GIS

Learning Objectives:• Describe the steps in hydrologic modeling• Evaluate different types of hydrologic models• Summarize the components of AGWA

Handouts: Assignments:

Lecture 8: Hydrologic Modeling and AGWA

April 3, 2006

Design Point

1

5

6

3

2

Hydrologic/Watershed Modeling

Thomas Piechota, Ph.D., P.E.Department of Civil and Environmental Engineering

University of Nevada, Las Vegaspiechota@ce.unlv.edu

Design Point

1

5

6

3

2

Definitions

• Watershed: area that topographically contributes to the drainage to a point of interest

• Streamflow: runoff (rate or volume) at a specified point in a watershed.

• Hydrologic budget: accounting of water in a system.

Conceptual Model of Watershed Modeling

Typical Input

• Topography

• Soil Characteristics

• Land cover

• Land use

• Meteorological data

Typical Output

• Streamflow

• Subsurface Flow

• Depth to water table

Steps to Hydrologic Modeling

1. Delineate watershed

2. Obtain hydrologic and geographic data

3. Select modeling approach

4. Calibrate/Verify model

5. Use model for assessment/prediction/design

What is a Watershed?• Area that topographically contributes to the

drainage to a point of interestNatural Watershed

Points of Interest

• Road crossing

• Stream gage

• Reservoir inlet

• Wastewater treatment plant

• Location of stream restoration

Urban Watershed

100

98

105

100

99

97

100

103

108

110

103

100 98

100

98

98

Design Point

USGS Quad Map

Digital Elevation Model (DEM)• Digital file that stores the elevation of the land

surface a specified grid cell size (e.g., 30 meters)

Steps to Hydrologic Modeling

1. Delineate watershed

2. Obtain hydrologic and geographic data

3. Select modeling approach

4. Calibrate/Verify model

5. Use model for assessment/prediction/design

Geographic Data• Land cover

1992 NALC Hillshade DEM STATSGO

ForestOak WoodlandsMesquite WoodlandsGrasslandsDesertscrubRiparianAgricultureUrbanWaterBarren / Clouds

Land CoverForestOak WoodlandsMesquite WoodlandsGrasslandsDesertscrubRiparianAgricultureUrbanWaterBarren / Clouds

Land Cover

0 5 10 km0 5 10 km

NN

• Land use

Geographic Data• Soil type/classification

1992 NALC Hillshade DEM STATSGO

ForestOak WoodlandsMesquite WoodlandsGrasslandsDesertscrubRiparianAgricultureUrbanWaterBarren / Clouds

Land CoverForestOak WoodlandsMesquite WoodlandsGrasslandsDesertscrubRiparianAgricultureUrbanWaterBarren / Clouds

Land Cover

0 5 10 km0 5 10 km

NN

Hydrologic Data• Meteorological Data

– Temperature– Precipitation– Wind speed– Humidity

• Extrapolation of point measurements– Theissen Polygons– Inverse distance weighting

Hydrologic Data• Hydrologic Data

– Streamflow• Peak discharge• Daily flow volume• Annual flow volume

– Soil moisture– Groundwater level

Design Point

1

5

6

3

2

Streamflow

Steps to Hydrologic Modeling

1. Delineate watershed

2. Obtain hydrologic and geographic data

3. Select modeling approach

4. Calibrate/Verify model

5. Use model for assessment/prediction/design

Modeling Approaches (examples)TIME SCALE

Event-based

(minute to day)

Continuous Simulation

(days – years)

Empirical

Regression equ’s

Transfer Functions

Simple models

Rational Method

SCS Unit Hydrograph Simple Model

Physically-based

Based on physical processes

Complicated

Many parameters

KINEROS

Stanford Watershed Model

TOPMODEL

SWAT

VIC-3L

TOPMODEL

Basis for Many Hydrologic Models

• Hydrologic Budget (In – Out = ΔStorage)

Watershed

Precipitation (P)Groundwater in (GWin)

Evaporation (E)

Transpiration (T) Streamflow (Q)

Groundwater out (GWout)

Reservoir

Infiltration (I)

(P + GWin) – (E + T + I + GWout + Q) = ΔStoragereservoir

Which Model Should be Used?

• It Depends on:

– What time scale are you working at?

– What hydrologic quantity are you trying to

obtain?

– What data do you have for your watershed?

– How fast of a computer do you have?

Spatial Scaling of Models

LumpedParameters assigned to each subbasin

A1A2

A3

Fully-DistributedParameters assigned to each grid cell

Semi-DistributedParameters assigned to each grid cell, but cells with same parameters are grouped

Stanford Watershed Model(HSPF)• Physically-based and continuous simulation

STANFORD WATERSHED MODEL

To Stream

Actual ET

Potential ETPrecipitationTemperature

RadiationWind,Dewpoint

Snowmelt

InterceptionStorage

Lower ZoneStorage

GroundwaterStorage

InterflowUpper Zone Storage

Overland Flow

Deep or InactiveGroundwater

CEPSC*

BASETP*

AGWETP*

DEEPFR*

LZSN*

INFILT*

INTFW*UZSN*

AGWRC*

NSUR*SLSUR*LSUR*

IRC*

Delayed Infiltration

DirectInfiltration

PERC

1 ET

2 ET

3 ET

4 ET

5 ET

LZETP*

* Parameters

Output

Process

Input

Storage

ET - Evapotranspiration

n Order taken tomeet ET demand

Decision

Kinematic Runoff and Erosion Model (KINEROS)

• Developed by USDA• http://www.tucson.ars.ag.gov/kineros/

• Event oriented & physically based• Describes the processes of

interception, infiltration, surface runoff and erosion

TOPMODEL• Semi-distributed &

physically-based• Relates hydrologic

processes (e.g., overland flow, subsurface flow) to topographic characteristics of watershed

• Efficiency of lumped model and physical theory of a distributed model

Infiltration

Drainage

MacroporeFlow

Subsurface Flow

TotalFlow

OverlandFlow

Source Area

Precipitation

Evapotranspiration

TOPMODEL Example

Pacific OceanPacific Ocean

Variable Infiltration Capacity (VIC-3L)

• Continuous simulation and physically-based• Macroscale hydrologic model that solves full water

and energy balances

VIC-3L Example

Anamoly Three Layers Soil Moisture( Upper Mississippi Basin)

-200

-100

0

100

200

Jan-50 Sep-63 May-77 Feb-91 Oct-04

Time (Month)

Anom

aly

Soil

Moi

stur

e (in

ch)

layer1 layer2 layer3

Steps to Hydrologic Modeling

1. Delineate watershed

2. Obtain hydrologic and geographic data

3. Select modeling approach

4. Calibrate/Verify model

5. Use model for assessment/prediction/design

Calibrating a Model• Typically the model is calibrated against

observed streamflow data• Depending on the model complexity,

parameters are adjusted until observed streamflow equals model streamflow

• Which observed value to use:– Qpeak

– Qvolume

– tpeak

Qpeak

Q

t

ttpeakpeak QQvolumevolume

Sensitive Parameters

• Precipitation

• Soil parameters– Hydraulic conductivity– Soil water holding capacity

• Evaporation (for continuous simulation)

• Flow routing parameters (for event-based)

Uncertainties• Precipitation

– Extrapolation of point to other areas– Temporal resolution of data

• Soils information– Surveys are based on site visits and then

extrapolated

• Routing parameters– Usually assigned based on empirical studies

Steps to Hydrologic Modeling

1. Delineate watershed

2. Obtain hydrologic and geographic data

3. Select modeling approach

4. Calibrate/Verify model

5. Use model for assessment/prediction/design

Use of Models

• Assessment– What happens if land use/land cover is

changed?

• Prediction– Flood forecasting

• Design– How much flow will occur in a 100 year

storm?

AUTOMATED GEOSPATIAL WATERSHED ASSESSMENT AUTOMATED GEOSPATIAL WATERSHED ASSESSMENT A GIS-BASED WATERSHED MODELING TOOLA GIS-BASED WATERSHED MODELING TOOL

William Kepner and Darius SemmensWilliam Kepner and Darius SemmensUS – EPA Landscape Ecology Branch Las Vegas, NVUS – EPA Landscape Ecology Branch Las Vegas, NV

David Goodrich, Mariano Hernandez, Shea Burns, David Goodrich, Mariano Hernandez, Shea Burns, Averill Cate, Soren Scott, and Lainie LevickAverill Cate, Soren Scott, and Lainie Levick

USDA-ARS Southwest Watershed Research Center, Tucson, AZUSDA-ARS Southwest Watershed Research Center, Tucson, AZ

Phillip GuertinPhillip GuertinUniversity of Arizona, Tucson, AZUniversity of Arizona, Tucson, AZ

Scott MillerScott MillerUniversity of Wyoming, Laramie, WYUniversity of Wyoming, Laramie, WY

Project Background & Acknowledgements

• Long-Term Research Project – Landscape Ecology Branch – 5 years

• Interdisciplinary– Watershed management– Landscape ecology– Atmospheric modeling– Remote sensing– GIS

• Multi-Agency– USDA – ARS– US – EPA– University of Arizona– University of Wyoming– USGS

• Student Support– 2 Post-Doc– 2 PhD– 2 Masters

USDA-ARS David Goodrich Mariano Hernandez Averill Cate Ian Burns Casey Tifft Soren ScottUS-EPA Bill Kepner Darius Semmens Dan Heggem Bruce Jones Don EbertUniversity of Arizona Phil GuertinUniversity of Wyoming Scott Miller

• PC-based GIS tool for watershed modeling

– KINEROS & SWAT (modular)

• Investigate the impacts of land-use/cover change on runoff, erosion, and water quality at multiple scales

• Compare and visualize results

• Targeted for use by research scientists and management specialists

• Useful in conducting TMDL analyses

• Widely applicable

Introduction

(SWAT)• Daily time step• Distributed: empirical and physically-based model• Hydrology, sediment, nutrient, and pesticide yields• Larger watersheds (> 1,000 km2)• Similar effort used by BASINS

71

7373

Soil and Water Assessment Tool

71

73

pseudo-channel 71

channel 73

Abstract Routing Representation

to next channel

(KINEROS2)• Event-based (< minute time steps)

• Distributed: physically-based model with dynamic routing

• Hydrology, erosion, sediment transport

• Smaller watersheds (< 100 km2)

74

72

Kinematic Runoff and Erosion Model

73

71 71

73

72

74Abstract Routing Representation

AGWA ArcView Interface

Watershed Discretization (model elements) ++

LandCover

Soils

Rain (Observed or

Design Storm)

Results

Run model and import results

Intersect model elements with

Watershed Delineation using Digital Elevation

Model (DEM)

Sediment yield (t/ha)Sediment discharge (kg/s)

Water yield (mm)Channel Scour (mm)

Transmission loss (mm)Peak flow (m3/s or mm/hr)

Channel Disch. (m3/day)Sediment yield (kg)

Percolation (mm)Runoff (mm or m3)

ET (mm)Plane Infiltration (mm)

Precipitation (mm)Channel Infiltration (m3/km)

SWAT OutputsKINEROS Outputs

AGWA Conceptual Design: Inputs and Outputs

Output results that can be displayed in AGWA

Navigating Through AGWA

Subdivide Watershed Into Model Elements

SWAT KINEROS

Generate rainfall input files

Daily Rainfall from…Gauge locationsThiessen mapPre-defined continuous record

Storm Event from…NOAA Atlas-IIPre-defined return-period / magnitude“Create-your-own”

Intersect Soils & Land Cover

Generate Watershed Outline grid

polygon

Choose the model to run

look-up tables

Navigating Through AGWA, Cont’d…

Subwatersheds & ChannelsContinuous Rainfall Records

Prepare input data

Run The Hydrologic Model & Import Results

Display/Compare Results

SWAT outputs:•Runoff, water yield (mm)•Channel Discharge (m3/day)•Evapotranspiration (mm)•Percolation (mm)•Transmission Losses (mm)•Sediment Yields (mm)

Channel & Plane ElementsEvent (Return Period) Rainfall

KINEROS outputs:•Runoff (mm,m3)•Sediment Yield (kg/ha)•Infiltration (mm)•Transmission losses (m3/km)•Peak runoff rate (m3/s) •Peak sediment discharge (kg/s)

external to AGWA

Visualization for each model

element

NLCD

Land cover A B C D Cover (%)

High intensity residential (22) 81 88 91 93 15

Bare rock/sand/clay (31) 96 96 96 96 2

Forest (41) 55 75 80 50

Shrubland (51) 63 77 85 88 25

Grasslands/herbaceous (71) 80 87 93 70

Small grains (83) 65 76 84 88 80

CURVE NUMBERHydrologic Soil Group

SWAT Parameter Estimation

- Example: Curve Number from NLCD land cover

Higher numbers result in higher runoff

Texture Ksat Suction Porosity Smax CV Sand Silt Clay Dist Kff Clay 0.6 407.0 0.475 0.81 0.50 27 23 50 0.16 0.34

Fractured Bedrock 0.6 407.0 0.475 0.81 0.50 27 23 50 0.16 0.05

Clay Loam 2.3 259.0 0.464 0.84 0.94 32 34 34 0.24 0.39

Sandy Clay Loam 4.3 263.0 0.398 0.83 0.60 59 11 30 0.40 0.36

Silt 6.8 203.0 0.501 0.97 0.50 23 61 16 0.23 0.49

Loam 13.0 108.0 0.463 0.94 0.40 42 39 19 0.25 0.42

Sandy Loam 26.0 127.0 0.453 0.91 1.90 65 23 12 0.38 0.32

Gravel 210.0 46.0 0.437 0.95 0.69 27 23 50 0.16 0.15

KINEROS Parameter Estimation Parameters based on soil texture (STATSGO, SSURGO, FAO)

Parameters based on land-cover classification (e.g. NLCD)

Land Cover Type Interception (mm/hr) Canopy (%) Manning's n Forest 1.15 30 0.070 Oak Woodland 1.15 20 0.040 Mesquite Woodland 1.15 20 0.040 Grassland 2.0 25 0.050 Desertscrub 3.0 10 0.055 Riparian 1.15 70 0.060 Agriculture 0.75 50 0.040 Urba n 0.0 0.0 0.010

AZ061

Component 1

20%

Component 2

45% Component 3

35%

9 inches

Layer 1

Layer 2

Layer 3

2

2

5

Layers for component 3

Components for MUID AZ061

Intersection of model element with soils map

AGWA Soil Weighting (KINEROS)

• Area and depth weighting of soil parameters

• Area weighting of averaged MUID values for each watershed element

AZ076

AZ067

Parameter Manipulation (optional)

Ksat

Can manually change parameters for each channel and plane element

Stream channel attributes

Upland plane attributes Ksat

Automated tracking of simulation inputs

Calculate and view differences between

model runs

Multiple simulation runs for a given watershed

Color-ramping of results for each element to show spatial variability

Visualization of Results

Spatial and Temporal Scaling of Results

High urban growth1973-1997

Upper San PedroRiver Basin

#

#

ARIZONA

SONORA

Phoenix

Tucson

<<WY >>WY

Water yield change between 1973 and 1997

SWAT Results

Sierra Vista Subwatershed

KINEROS Results

N

ForestOak WoodlandMesquite DesertscrubGrasslandUrban1997 Land Cover

Concentrated urbanization

Using SWAT and KINEROS for integrated watershed assessment Land cover change analysis and impact on hydrologic response

Urbanization Effects (KINEROS2)

Pre-urbanization

1973 Land cover

Post-urbanization

1997 Land cover

• Results from pre- and post-urbanization simulations using the 10-year, 1-hour design storm event

Limitations of GIS - Model Linkage

• Model Parameters are based on look-up tables- need for local calibration for accuracy- FIELD WORK!

• Subdivision of the watershed is based on topography- prefer it be based on intersection of soil, lc, topography

• No sub-pixel variability in source (GIS) data- condition, temporal (seasonal, annual) variability- MRLC created over multi-year data capture

• No model element variability in model input- averaging due to upscaling

Most useful for relative assessment unless calibrated

Land-Cover Modification Tool Allows users to build management scenarios Location of land-cover alterations specified by either drawing a polygon on the display, or specifying a polygon map

Types of Land-Cover Changes:• Change entire user-defined area to new land cover • Change one land-cover type to another in user-defined area • Change land-cover type within user-supplied polygon map • Create a random land-cover pattern

• e.g. to simulate burn pattern, change to 64% barren, 31% desert scrub, and 5% mesquite woodland

Alternative Futures: Base Change Scenarios1. CONSTRAINED – Assumes population increase less than 2020 forecast

(78,500). Development in existing areas, e.g. 90% urban.

2. PLANS – Assumes population increase as forecast for 2020 (95,000). Development in mostly existing areas, e.g. 80% urban and 15% suburban.

3. OPEN – Assumes population increase more than 2020 forecast (111,500). Most constraints on land development removed. Development occurs mostly into rural areas (60%) and less in existing urban areas (15%).

Percent Change in Runoff under Future Scenarios

• There is considerable variation – particularly between extremes produced by constrained and open scenarios (Kepner et al., 2004)

• Surface runoff will increase in all three scenarios

• Sediment yield will increase especially as new surfaces are disturbed and surface runoff increases

(Derived from using future land covers

and AGWA)

Plans

Applications of National & International Significance

NationalNational• NYCDEP – NYCDEP – Catskill/Delaware watershed Catskill/Delaware watershed

assessmentassessment• Upper San Pedro Partnership – Upper San Pedro Partnership – watershed watershed

planning, cost-benefit analysisplanning, cost-benefit analysis• EMAP – EMAP – Oregon (AGWA-ATtILA) integrated Oregon (AGWA-ATtILA) integrated

alternative futures assessmentalternative futures assessment• ReVA – ReVA – SEQL alternative futuresSEQL alternative futures• EPA Region 9 – EPA Region 9 – CWA 404 and NEPACWA 404 and NEPA• EPA Region 10 – EPA Region 10 – 404/NEPA, transportation planning404/NEPA, transportation planning• NWS – NWS – Real-time flood warningReal-time flood warning• USFS – USFS – Post-fire assessment & rehabilitation planningPost-fire assessment & rehabilitation planning• AZ – AZ – State is using AGWA for TMDL planning and education of municipal officialsState is using AGWA for TMDL planning and education of municipal officials

InternationalInternational• NATO Committee on the Challenges to Modern Society (CCMS) – NATO Committee on the Challenges to Modern Society (CCMS) – Integrated Integrated

hydrologic/ecological landscape change assessmenthydrologic/ecological landscape change assessment• Southwest Consortium for Environmental Research and Policy (SCERP) – Southwest Consortium for Environmental Research and Policy (SCERP) –

U.S./Mexico trans-border watershed managementU.S./Mexico trans-border watershed management• UNESCO Global Network for Water and Development Information (G-WADI) – UNESCO Global Network for Water and Development Information (G-WADI) –

International arid-region hydrologic modelingInternational arid-region hydrologic modeling

• AGWA 1.1 released at the Fed. Interagency AGWA 1.1 released at the Fed. Interagency Hydrologic Modeling Conference, July 2002Hydrologic Modeling Conference, July 2002

• Externally peer-evaluated through two separate federal review Externally peer-evaluated through two separate federal review processes (EPA/600/R-02/046 & ARS/137460)processes (EPA/600/R-02/046 & ARS/137460)

• AGWA added to AGWA added to • EPA Council for Regulatory Environmental Modeling (CREM) databaseEPA Council for Regulatory Environmental Modeling (CREM) database• NASA Applied Sciences Directorate model and analysis systemsNASA Applied Sciences Directorate model and analysis systems• USGS Surface-water Modeling Interest Group archivesUSGS Surface-water Modeling Interest Group archives

• AGWA 1.4 released in July, 2004AGWA 1.4 released in July, 2004

• AGWA integrated into BASINS 3.1 release, August 2004AGWA integrated into BASINS 3.1 release, August 2004

• Training – national and internationalTraining – national and international

• Free public download and full documentation via parallel EPA Free public download and full documentation via parallel EPA and ARS web sitesand ARS web sites

• 1200+ registered users (excluding BASINS users)1200+ registered users (excluding BASINS users)

AGWA Milestones

AGWA Support & Distribution• Fact Sheets, Product Announcement, Brochures

• Documentation and User Manual

• Quality Assurance Report Research Plan Code Structure (Avenue

Scripts, Dialogs, System Calls)

EPA and USDA/ARS companion Websites

Journal Publications (Hernandez et al. 2000, Miller et al. 2002a, Miller et al. 2002b, Kepner et al., 2004)

Training: Las Vegas (2001); Reston (2002); Tucson (2003); San Diego (2004)

• AGWA Web Sites

http://www.epa.gov/nerlesd1/land-sci/agwa/index.htm

http://www.tucson.ars.ag.gov/agwa

Future Directions

• Final ArcView version (AGWA 1.5) release at FIHMC (April 2006)Final ArcView version (AGWA 1.5) release at FIHMC (April 2006)

• Detailed, peer reviewed design plan for AGWA migration to ArcGIS Detailed, peer reviewed design plan for AGWA migration to ArcGIS and Internet completed April, 2005and Internet completed April, 2005

• Beta-release of ArcGIS and Internet versions, 2006Beta-release of ArcGIS and Internet versions, 2006

• Final ArcGIS and Internet release with full documentation, 2007 Final ArcGIS and Internet release with full documentation, 2007

Migrating to ArcGIS (AGWA 2.0) and the Internet (DotAGWA)

Integration of additional models

• Opus – USDA-ARS integrated simulation model for transport of non-Opus – USDA-ARS integrated simulation model for transport of non-point source pollutants (2007)point source pollutants (2007)

• MODFLOW – USGS ground-water model will be coupled with AGWA-MODFLOW – USGS ground-water model will be coupled with AGWA-KINEROS surface-water model (planning meeting 2006)KINEROS surface-water model (planning meeting 2006)

• GAP habitat models – integrated hydrologic and ecological GAP habitat models – integrated hydrologic and ecological assessments (proposal pending)assessments (proposal pending)