Development of a Common Wind and Water Erosion Model Dennis C. Flanagan Agricultural Engineer USDA-Agricultural Research Service National Soil Erosion.

Development of a Common Development of a Common Wind and Water Erosion ModelWind and Water Erosion Model

Dennis C. FlanaganDennis C. FlanaganAgricultural EngineerAgricultural Engineer

USDA-Agricultural Research ServiceUSDA-Agricultural Research Service

National Soil Erosion Research LaboratoryNational Soil Erosion Research Laboratory

West Lafayette, Indiana, USAWest Lafayette, Indiana, USA

OutlineOutline

Brief history of erosion prediction Brief history of erosion prediction technology development in the U.S. technology development in the U.S.

User needs for a common water and User needs for a common water and wind erosion model.wind erosion model.

Plans for model development.Plans for model development. Progress to date.Progress to date.

History of Erosion Prediction History of Erosion Prediction Technology Development in U.S.Technology Development in U.S.

Universal Soil Loss Equation (USLE) Universal Soil Loss Equation (USLE) developed from ~1954 to 1978.developed from ~1954 to 1978.

Revised Universal Soil Loss Equation Revised Universal Soil Loss Equation (RUSLE/RUSLE2) from ~1987 to 2002.(RUSLE/RUSLE2) from ~1987 to 2002.

Wind Erosion Equation (WEQ) from ~1953 to Wind Erosion Equation (WEQ) from ~1953 to 1965 and Revised WEQ from ~1990 to 19981965 and Revised WEQ from ~1990 to 1998

Wind Erosion Prediction System (WEPS) model Wind Erosion Prediction System (WEPS) model from 1985 to 2007from 1985 to 2007

Water Erosion Prediction Project (WEPP) Water Erosion Prediction Project (WEPP) model from 1985 to 2007model from 1985 to 2007

USLEUSLE Developed from ~1954-1978 to predict long-Developed from ~1954-1978 to predict long-

term average annual soil loss on hillslopes.term average annual soil loss on hillslopes. Soil conservation experiment station data Soil conservation experiment station data

from the 1930’s to 1950’s was utilized in its from the 1930’s to 1950’s was utilized in its development (over 10,000 plot-years).development (over 10,000 plot-years).

First publication on USLE was in 1961.First publication on USLE was in 1961. Implemented in SCS field offices during the Implemented in SCS field offices during the

1960’s.1960’s. USLE is an empirical model:USLE is an empirical model:

A = R K L S C PA = R K L S C P

RUSLE / RUSLE2RUSLE / RUSLE2 Developed from ~1987 to ~2002.Developed from ~1987 to ~2002. RUSLE was implemented in SCS field offices RUSLE was implemented in SCS field offices

in paper form only in ~1993.in paper form only in ~1993. RUSLE2 was implemented in NRCS field RUSLE2 was implemented in NRCS field

offices in ~2002.offices in ~2002. RUSLE/RUSLE2 are empirical models with RUSLE/RUSLE2 are empirical models with

some process-based enhancements.some process-based enhancements. Improvements to USLE R, K, C factors.Improvements to USLE R, K, C factors. Extremely large management rotation Extremely large management rotation

databases for every state in the U.S.databases for every state in the U.S. Maintained by ARS-Oxford, MS.Maintained by ARS-Oxford, MS.

WEQ / RWEQWEQ / RWEQ WEQ was developed from ~1953 to 1965 to WEQ was developed from ~1953 to 1965 to

predict soil loss from wind erosion on an predict soil loss from wind erosion on an average annual basis.average annual basis.

WEQ was adopted by the SCS for predictions WEQ was adopted by the SCS for predictions of soil erosion by wind, and is used mainly in of soil erosion by wind, and is used mainly in the western U.S.the western U.S.

The difficulty of use of WEQ prompted The difficulty of use of WEQ prompted development of several computerized versions development of several computerized versions by both ARS and SCS/NRCS.by both ARS and SCS/NRCS.

A revised wind erosion equation (RWEQ) was A revised wind erosion equation (RWEQ) was developed by ARS from ~1990 to 1998, but no developed by ARS from ~1990 to 1998, but no widespread adoption by NRCS is planned.widespread adoption by NRCS is planned.

RWEQ is maintained by ARS-Lubbock.RWEQ is maintained by ARS-Lubbock.

WEPSWEPS Process-based, continuous simulation, Process-based, continuous simulation,

wind erosion model.wind erosion model. Developed from 1985-2007 by ARS-Developed from 1985-2007 by ARS-

Wind Erosion Research Unit (WERU) in Wind Erosion Research Unit (WERU) in Manhattan, Kansas.Manhattan, Kansas.

Field testing and implementation by Field testing and implementation by NRCS has begun in last 2 years.NRCS has begun in last 2 years.

Recently WEPS has incorporated Recently WEPS has incorporated WEPP model hydrology to decrease WEPP model hydrology to decrease run time.run time.

WEPS Windows SoftwareWEPS Windows Software

WEPPWEPP Process-based, continuous simulation Process-based, continuous simulation

water erosion model.water erosion model. Developed from 1985-2007 by ARS, Developed from 1985-2007 by ARS,

SCS/NRCS, FS, BLM, WSU and others.SCS/NRCS, FS, BLM, WSU and others. WEPP model is maintained by ARS-WEPP model is maintained by ARS-

National Soil Erosion Research National Soil Erosion Research Laboratory in West Lafayette, Indiana.Laboratory in West Lafayette, Indiana.

Large number of users, both within and Large number of users, both within and outside U.S., including Forest Service, outside U.S., including Forest Service, BLM, universities, consultants.BLM, universities, consultants.

WEPP statusWEPP status Current public model version is Current public model version is

v2006.5v2006.5 V2006.5 contains recent updates to V2006.5 contains recent updates to

water balance, subsurface lateral flow, water balance, subsurface lateral flow, perennial plant growth – to better perennial plant growth – to better simulate forests on shallow soils simulate forests on shallow soils above bedrock.above bedrock.

Variety of user interfaces – Windows-Variety of user interfaces – Windows-based, Web-based, and GIS-linked.based, Web-based, and GIS-linked.

WEPP Windows InterfaceWEPP Windows Interface

WEPP Web-based InterfacesWEPP Web-based Interfaces

Separation of Wind / Water ResearchSeparation of Wind / Water Research

Initial research studies were focused in areas Initial research studies were focused in areas with specific erosion concerns – water erosion with specific erosion concerns – water erosion in the eastern and central U.S., and wind in the eastern and central U.S., and wind erosion in the Great Plains.erosion in the Great Plains.

ARS programs, experiment stations, research ARS programs, experiment stations, research units, and funding were separated between units, and funding were separated between water and wind erosion locations since the water and wind erosion locations since the inception of the agency in 1953.inception of the agency in 1953.

Process-based modeling efforts that began in Process-based modeling efforts that began in 1985 (WEPP and WEPS) were for the most part 1985 (WEPP and WEPS) were for the most part separate, due to the existing institutional separate, due to the existing institutional framework.framework.

This Separation resulted in:This Separation resulted in:

Two separate teams of ARS scientists building Two separate teams of ARS scientists building continuous process-based simulation models.continuous process-based simulation models.

Two models that were required to simulate Two models that were required to simulate many of the same physical processes (soil many of the same physical processes (soil water balance, hydrology, plant growth, residue water balance, hydrology, plant growth, residue decomposition, soil disturbance by tillage, etc.).decomposition, soil disturbance by tillage, etc.).

Separate model interfaces and databases.Separate model interfaces and databases. Large potential for different model results (for Large potential for different model results (for

crop growth, runoff, etc.) for same site of crop growth, runoff, etc.) for same site of application, since different science application, since different science implemented in the two different models.implemented in the two different models.

In 2004In 2004 The Natural Resources Conservation The Natural Resources Conservation

Service re-evaluated its need for Service re-evaluated its need for erosion prediction technology from erosion prediction technology from ARS.ARS.

High priority long-term need of NRCS High priority long-term need of NRCS was development of a common wind was development of a common wind and water erosion process model, to and water erosion process model, to work with a single interface and work with a single interface and database and give consistent results database and give consistent results for plant growth, water balance, crop for plant growth, water balance, crop yield, etc.yield, etc.

From March 1, 2004 Letter from NRCS:From March 1, 2004 Letter from NRCS:““For the long term, NRCS proposes to collaborate For the long term, NRCS proposes to collaborate with ARS to build a single process based model to with ARS to build a single process based model to make erosion prediction calculations. NRCS make erosion prediction calculations. NRCS proposes that this model be capable of making proposes that this model be capable of making rainfall induced rill and interrill erosion rainfall induced rill and interrill erosion computations, as well as computations for wind computations, as well as computations for wind erosion together or independently of one another. erosion together or independently of one another. This model would naturally incorporate the This model would naturally incorporate the technologies currently in WEPS, the Water technologies currently in WEPS, the Water Erosion Prediction Project (WEPP), and those Erosion Prediction Project (WEPP), and those found in the Water Erosion Prediction Project - found in the Water Erosion Prediction Project - Simulation of Production and Utilization of Simulation of Production and Utilization of Rangelands (WEPP-SPUR). Unlike the current Rangelands (WEPP-SPUR). Unlike the current models, the model proposed by NRCS would models, the model proposed by NRCS would operate as a single decision support tool, and use operate as a single decision support tool, and use common databases.”common databases.”

- - Larry Clark, NRCS Deputy Chief Science & TechnologyLarry Clark, NRCS Deputy Chief Science & Technology

2004 ARS NSERL Erosion Prediction 2004 ARS NSERL Erosion Prediction Program RedirectionProgram Redirection

Modification of NSERL erosion prediction CRIS Modification of NSERL erosion prediction CRIS research projectresearch project– Stop new development work on existing WEPP Stop new development work on existing WEPP

model science and interface codemodel science and interface code– Minimize resources towards current WEPP Minimize resources towards current WEPP

model code and user supportmodel code and user support– Focus majority of resources towards Focus majority of resources towards

development of new wind and water erosion development of new wind and water erosion model.model.

Top short-term priorityTop short-term priority - Incorporation of WEPP - Incorporation of WEPP hillslope erosion science within the Object hillslope erosion science within the Object Modeling System (OMS) being developed by ARS-Modeling System (OMS) being developed by ARS-GPSRU in Fort Collins, CO.GPSRU in Fort Collins, CO.

2004 Project Objectives2004 Project Objectives Short-termShort-term

– Incorporate the WEPP hillslope erosion Incorporate the WEPP hillslope erosion code within OMS.code within OMS.

– Evaluate the feasibility of using OMS as Evaluate the feasibility of using OMS as the platform for the full combined wind the platform for the full combined wind and water erosion model.and water erosion model.

– Develop a complete project plan for Develop a complete project plan for development of the new model.development of the new model.

Long-termLong-term– Develop a fully functional continuous Develop a fully functional continuous

simulation wind and water erosion simulation wind and water erosion process model for field application by process model for field application by 2011.2011.

New CRIS projectNew CRIS project Entitled “Common Modular Wind and Water Entitled “Common Modular Wind and Water

Erosion Modeling for Conservation Erosion Modeling for Conservation Planning”Planning”

Recently approved (12/2006) through OSQRRecently approved (12/2006) through OSQR 2006-2011 Develop a common wind and 2006-2011 Develop a common wind and

water soil erosion model for use by NRCS water soil erosion model for use by NRCS field offices.field offices.

Utilize water erosion components from Utilize water erosion components from WEPP model, and wind erosion WEPP model, and wind erosion components from WEPS model.components from WEPS model.

Develop necessary interfaces and Develop necessary interfaces and databases for the new modeling system.databases for the new modeling system.

New CRIS Project ObjectivesNew CRIS Project Objectives Integrate the WEPP and WEPS model erosion Integrate the WEPP and WEPS model erosion

technologiestechnologies through the use of the Object through the use of the Object Modeling System (OMS) into a Modeling System (OMS) into a single wind/water single wind/water erosion prediction systemerosion prediction system using common using common databases and interfaces at the plot and field scale.databases and interfaces at the plot and field scale.

Incorporate, test and verify new erosion science or Incorporate, test and verify new erosion science or related componentsrelated components, such as winter processes, , such as winter processes, tillage erosion, ephemeral gully erosion, irrigation tillage erosion, ephemeral gully erosion, irrigation erosion and rangeland erosion, into the integrated erosion and rangeland erosion, into the integrated erosion prediction system.erosion prediction system.

Cooperate withCooperate with all ARS scientists and NRCS staff all ARS scientists and NRCS staff involved with involved with the CEAP effortthe CEAP effort to extract relevant to extract relevant modules from existing models and integrate them modules from existing models and integrate them into the OMS for into the OMS for development of regional water and development of regional water and air quality modelsair quality models at the plot, field, and watershed at the plot, field, and watershed scales.scales.

New CRIS Project MilestonesNew CRIS Project Milestones 12 months 12 months

- Development of wind detachment component in OMSDevelopment of wind detachment component in OMS- Testing/validation of hydrologic & water erosion Testing/validation of hydrologic & water erosion

prototypeprototype- Develop user requirements for system with major user Develop user requirements for system with major user

agenciesagencies- Addition of dynamic water erosion calculationsAddition of dynamic water erosion calculations

24 months24 months

– Development of detailed software design document.Development of detailed software design document.

– Unified Plant Growth Model incorporated into OMS.Unified Plant Growth Model incorporated into OMS.

– Prototype OMS wind-water model with most needed Prototype OMS wind-water model with most needed components.components.

– Validation of single event wind erosion predictions.Validation of single event wind erosion predictions.

– Addition of tillage erosion modules into OMS.Addition of tillage erosion modules into OMS.

New CRIS Project MilestonesNew CRIS Project Milestones 36 months36 months

– Development of ARS interface for testing/validationDevelopment of ARS interface for testing/validation

– Development of core combined model databasesDevelopment of core combined model databases

– New winter components added into OMSNew winter components added into OMS

– Addition of tillage erosion simulation into wind-water model Addition of tillage erosion simulation into wind-water model

48 months48 months– Development of NRCS interfaces for model testing and training.Development of NRCS interfaces for model testing and training.

– Validation studies on wind, water and tillage erosion predictions. Validation studies on wind, water and tillage erosion predictions.

– Addition of rangeland componentsAddition of rangeland components

60 months60 months– Integrated field-scale erosion prediction system initially for cropland Integrated field-scale erosion prediction system initially for cropland

applications and prediction of wind, water or tillage erosion delivered to applications and prediction of wind, water or tillage erosion delivered to NRCS.NRCS.

– Model technical and user documentation written.Model technical and user documentation written.

– Creation of irrigation erosion modules.Creation of irrigation erosion modules.

– Testing of rangeland and irrigation erosion modulesTesting of rangeland and irrigation erosion modules

– Prototype regional field-to-watershed model for CEAP, integrating Prototype regional field-to-watershed model for CEAP, integrating appropriate modules from wind-water system.appropriate modules from wind-water system.

Two Development PathsTwo Development Paths First PathFirst Path – Extract individual – Extract individual

components from WEPP and WEPS components from WEPP and WEPS and other relevant models. Develop and other relevant models. Develop modules within OMS from these modules within OMS from these components, then build new model components, then build new model within OMS. (as written in Plan)within OMS. (as written in Plan)

Second PathSecond Path – Utilize WEPS model – Utilize WEPS model code as the basic framework and code as the basic framework and add WEPP model water balance, add WEPP model water balance, runoff, water erosion components.runoff, water erosion components.

Object Modeling System (OMS)Object Modeling System (OMS)

What is the Object Modeling What is the Object Modeling System?System?

An object-oriented toolset to build, An object-oriented toolset to build, run, and deploy simulation models run, and deploy simulation models

An object-oriented framework for An object-oriented framework for the management of reusable the management of reusable simulation component librariessimulation component libraries

A collaboration infrastructure for A collaboration infrastructure for common model developmentcommon model development

Object Modeling SystemObject Modeling System Modeling framework to support the Modeling framework to support the

model development/application model development/application lifecyclelifecycle

OMS Facilitates: OMS Facilitates: – Code reuse and sharingCode reuse and sharing– Capture of legacy knowledgeCapture of legacy knowledge– Collaborative developmentCollaborative development– Database accessDatabase access– Verification/validation Verification/validation – QA/QCQA/QC– Maintenance and change Maintenance and change

managementmanagement

ComponentIntegration,

Model Development

ModelApplication,

Analysis

Component Development,

Testing

Components in OMSComponents in OMS

““Components are software Components are software units that are context-units that are context-independent both in the independent both in the conceptual and technical conceptual and technical domain”domain”

Well adopted methodology for Well adopted methodology for software reusesoftware reuse

Scientific componentScientific component Infrastructure Infrastructure

componentcomponent Utility componentUtility component ……

Input OutputComponent

Component

Internal hiddenbehavior

Well known interfaces

Scientific ComponentScientific Component

Represents a basic processing unitRepresents a basic processing unit Conceptual purposeConceptual purpose

– Runoff computationRunoff computation– Soil erosion computationSoil erosion computation– ……

Input OutputComponent

Component

Components are “tagged” by implementing Components are “tagged” by implementing interfaces:interfaces:

– Native, Runable, Stateful, VisualizableNative, Runable, Stateful, Visualizable Customization by implementing these Customization by implementing these

interfaces:interfaces:

– Minimum: Runable Minimum: Runable

InputData

Step 1: Create Components

Create Components

Step 2: Create Model

New Model - Training

Component Library

Step 3: Build Model From Components

Model BuildingStructures

Attributes

ComponentConnectivity(Hookups)

Step 4: Run Assembled Model

Modeling Projects

Component Library

Assembled Model

Parameter Editor

ComponentEditor

OutputAnalysis

OMS also hasoutput graphicand parameterediting capabilities

OMS Workflow SummaryOMS Workflow Summary

Component Builder

Component Library

ModelBuilder

ModelRuntime

OutputAnalysis

Publish IntegrateExecute Analyze

Component DevelopmentComponent Library Management

Component IntegrationModel Application

Data Analysis

First Development PathFirst Development Path Extract individual components from Extract individual components from

WEPP and WEPS and other relevant WEPP and WEPS and other relevant models. Develop modules within OMS models. Develop modules within OMS from these components, then build new from these components, then build new model within OMS.model within OMS.

AdvantagesAdvantages – modular approach best for long-term – modular approach best for long-term agency code maintainability, can access and use agency code maintainability, can access and use existing components in OMS library, NRCS desires new existing components in OMS library, NRCS desires new model development in OMS, multiple spatial model development in OMS, multiple spatial representations for wind and water may be easier.representations for wind and water may be easier.

DisadvantagesDisadvantages - OMS system not fully developed and - OMS system not fully developed and easy to use, incorporation of legacy models in OMS easy to use, incorporation of legacy models in OMS can be difficult and time-consuming, agencies’ can be difficult and time-consuming, agencies’ continued support of OMS is uncertain.continued support of OMS is uncertain.

Path 1 - Progress to DatePath 1 - Progress to Date WEPP hillslope water erosion code WEPP hillslope water erosion code

extracted and stand-alone program extracted and stand-alone program created (2004).created (2004).

WEPP hillslope surface hydrology WEPP hillslope surface hydrology (infiltration, runoff) extracted and stand-(infiltration, runoff) extracted and stand-alone program created (2005).alone program created (2005).

Stand-alone hydrology and erosion code Stand-alone hydrology and erosion code converted to components in OMS (2005).converted to components in OMS (2005).

Single storm and continuous Single storm and continuous hydrology/erosion model created in OMS hydrology/erosion model created in OMS (2005).(2005).

ApproachApproach

Initially in 2004-2005Initially in 2004-2005

– Convert hillslope erosion Convert hillslope erosion component from WEPP into a component from WEPP into a standalone Fortran program.standalone Fortran program.

– Test and verify standalone program Test and verify standalone program against original WEPP v2004.7 against original WEPP v2004.7 modelmodel

– Incorporate standalone program into Incorporate standalone program into OMS, test and verify.OMS, test and verify.

September-October 2004September-October 2004– Extracted relevant hillslope erosion code Extracted relevant hillslope erosion code

from WEPP v2004.7 for single storm.from WEPP v2004.7 for single storm.– Removed all common blocks and moved Removed all common blocks and moved

only necessary variables into argument lists.only necessary variables into argument lists.– Created input files to just conduct single Created input files to just conduct single

storm water erosion calculations.storm water erosion calculations.– Tested standalone for range of inputs – Tested standalone for range of inputs –

slope lengths, gradients, and shapes and slope lengths, gradients, and shapes and compared to WEPP v2004.7 output.compared to WEPP v2004.7 output.

– This resulted in corrections to the This resulted in corrections to the standalone code and ultimately a verified standalone code and ultimately a verified single storm program that operated for a single storm program that operated for a single spatial plane.single spatial plane.

Results of Final 10/2004 Results of Final 10/2004 Standalone Verification TestsStandalone Verification Tests

Standalone vs WEPP (Soil Loss)

y = 0.9996x

R2 = 1

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WEP P S oil Loss (kg/ m^2)

Standalone vs WEPP (Sedim ent Yie ld)

y = 0.9996xR2 = 1

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400

500

600

700

800

0 200 400 600 800

WEPP Se dim e nt Yie ld (tonnes /ha)St

anda

lone

Sed

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(ton

nes/

ha)

January-February 2005January-February 2005– Made code active to handle multiple Made code active to handle multiple

spatial planes.spatial planes.– Modified input files to provide Modified input files to provide

information necessary for multiple information necessary for multiple planes.planes.

– Tested standalone for range of inputs – Tested standalone for range of inputs – 1, 2, 4, 10 overland flow elements and 1, 2, 4, 10 overland flow elements and compared to WEPP v2004.7 output.compared to WEPP v2004.7 output.

– This resulted in corrections to the This resulted in corrections to the standalone code and ultimately a standalone code and ultimately a verified single storm program that verified single storm program that operated for a multiple spatial planes. operated for a multiple spatial planes. This contained spatial looping similar to This contained spatial looping similar to WEPP in the standalone MAIN program.WEPP in the standalone MAIN program.

Standalone Fortran erosion code: Standalone Fortran erosion code: 2/20052/2005

MAIN program and 30 subroutinesMAIN program and 30 subroutines under it. MAIN contained under it. MAIN contained spatial plane (iplane) looping similar to WEPP.spatial plane (iplane) looping similar to WEPP.

Reads from a single input file and creates 2 output files, almost Reads from a single input file and creates 2 output files, almost identical to current WEPP outputs.identical to current WEPP outputs.

Will compile and run with standard F-77 to F-95 compilers.Will compile and run with standard F-77 to F-95 compilers.

March-April 2005March-April 2005– Spatial looping in MAIN program and all subroutines Spatial looping in MAIN program and all subroutines

removed, so that code could be better utilized within removed, so that code could be better utilized within OMS with other models, as well as with potential OMS with other models, as well as with potential spatial representation needed for wind erosion.spatial representation needed for wind erosion.

– Existing standalone Hydrology component (based Existing standalone Hydrology component (based largely on WEPP) from Ascough was converted into largely on WEPP) from Ascough was converted into a format ready for OMS inclusion.a format ready for OMS inclusion.

– Pass file creation with information generated by Pass file creation with information generated by Hydrology standalone and needed for Erosion Hydrology standalone and needed for Erosion standalone calculations was added to Hydrology standalone calculations was added to Hydrology code.code.

– This work resulted in standalone Hydrology and This work resulted in standalone Hydrology and Erosion code that would function in tandem to do Erosion code that would function in tandem to do infiltration/runoff calculations (Green-Ampt), runoff infiltration/runoff calculations (Green-Ampt), runoff hydrograph and peak rate calculation (kinematic hydrograph and peak rate calculation (kinematic wave), and hillslope interrill/rill erosion calculations wave), and hillslope interrill/rill erosion calculations for a single storm/single plane.for a single storm/single plane.

Standalone Fortran hydrology code: Standalone Fortran hydrology code: 4/20054/2005

MAIN program and 19 subroutinesMAIN program and 19 subroutines under it. under it. Reads from a single input file and creates 2 Reads from a single input file and creates 2

output files: hydrology output identical to WEPP, output files: hydrology output identical to WEPP, and a hydrology-to-erosion pass file (runoff and a hydrology-to-erosion pass file (runoff depth, peak rate, intensities, durations).depth, peak rate, intensities, durations).

June 2005June 2005– Individual Hydrology and Erosion Individual Hydrology and Erosion

Models were created within OMS, Models were created within OMS, tested and verified against the tested and verified against the standalone programs.standalone programs.

– A linked hydrology and erosion model A linked hydrology and erosion model for a single storm and spatial plane for a single storm and spatial plane was created in OMS.was created in OMS.

– The linked OMS model was expanded The linked OMS model was expanded to successfully perform spatial to successfully perform spatial (multiple planes) and temporal (multiple planes) and temporal (multiple storm days) looping.(multiple storm days) looping.

OMS individual Hydrology and OMS individual Hydrology and Erosion Models: 6/2005Erosion Models: 6/2005

To build models in OMS, the functionality in the To build models in OMS, the functionality in the standalone Fortran MAIN programs had to be duplicated.standalone Fortran MAIN programs had to be duplicated.

All processing logic in existing MAIN had to be either All processing logic in existing MAIN had to be either moved to one of the existing subroutines, or a new moved to one of the existing subroutines, or a new component created.component created.

OMS with 6/2005 Temporal/Spatial Erosion ModelOMS with 6/2005 Temporal/Spatial Erosion Model

Erosion Model

Output window showingmodel screen outputs

Erosion Model – named “erroder” here

Conditional – to do Erosion Calculations only if there is outflow from or inflow to plane.

Conditional – to do infiltration, runoff and erosion calculations, only if there is rainfall on the day

Conditional – Daily Time step – goes through loop for number of days read in from climate file.

Path 1 - Progress to Date (cont.)Path 1 - Progress to Date (cont.)

Continuous water balance model (based Continuous water balance model (based on RZWQM) constructed in OMS, and on RZWQM) constructed in OMS, and hydrology and water erosion modules hydrology and water erosion modules linked into this (2006).linked into this (2006).

Wind detachment stand-alone code from Wind detachment stand-alone code from WEPS converted into an OMS module WEPS converted into an OMS module (2006).(2006).

Prototype wind and water combined Prototype wind and water combined model constructed in OMS, linking wind model constructed in OMS, linking wind detachment module with water balance detachment module with water balance model (2006).model (2006).

10/2006 Wind & Water Model Prototype in OMS10/2006 Wind & Water Model Prototype in OMS

Wind & Water Model Wind & Water Model Prototype in OMSPrototype in OMS

Water Balance Initializations

Potential Evapotranspiration Calculations

Daily loop

24 Hour loop

Infiltration Calculations

Soil Water Redistribution

Erosion by Water Components

Erosion by Wind Component

OMS Model water erosion outputsOMS Model water erosion outputs

OMS Model wind erosion outputsOMS Model wind erosion outputs

Future OMS WorkFuture OMS Work Add more components (plant growth, Add more components (plant growth,

parameter estimation, etc.) to library and parameter estimation, etc.) to library and link these with existing prototype.link these with existing prototype.

Properly set up spatial looping to Properly set up spatial looping to represent both a gridded wind represent both a gridded wind detachment region and a water erosion detachment region and a water erosion hillslope profile.hillslope profile.

Test OMS models against original Test OMS models against original WEPP/WEPS models, and compare to WEPP/WEPS models, and compare to field experiment data.field experiment data.

Second Development PathSecond Development Path Utilize the WEPS model code as the basic Utilize the WEPS model code as the basic

framework and add WEPP model water framework and add WEPP model water balance, runoff, water erosion balance, runoff, water erosion components.components.

AdvantagesAdvantages – WEPS is already being implemented and tested by – WEPS is already being implemented and tested by NRCS, WEPS databases and interface already available, WEPS has NRCS, WEPS databases and interface already available, WEPS has recently incorporated WEPP water balance/hydrology code. recently incorporated WEPP water balance/hydrology code.

DisadvantagesDisadvantages - WEPS code can only simulate single accounting - WEPS code can only simulate single accounting region – does not provide spatial representation currently in region – does not provide spatial representation currently in WEPP or in water erosion model in OMS, does not provide WEPP or in water erosion model in OMS, does not provide modules for OMS code repository, does not help with agency modules for OMS code repository, does not help with agency goals of more maintainable and reusable model components.goals of more maintainable and reusable model components.

Path 2 - Progress to DatePath 2 - Progress to Date WEPP Water Balance incorporated into WEPS WEPP Water Balance incorporated into WEPS

model code (2005-2006).model code (2005-2006). WEPP kinematic wave computations for WEPP kinematic wave computations for

prediction of peak runoff rate, and also prediction of peak runoff rate, and also prediction of effective rainfall intensity and prediction of effective rainfall intensity and associated durations added to WEPS code associated durations added to WEPS code (2006)(2006)

WEPP hillslope (interrill/rill) erosion code WEPP hillslope (interrill/rill) erosion code added to modified WEPS model (2007), and is added to modified WEPS model (2007), and is currently being tested and parameters linked currently being tested and parameters linked to WEPS values where possible.to WEPS values where possible.

Path 2 – Future WorkPath 2 – Future Work Complete linkage of WEPP parameters to Complete linkage of WEPP parameters to

WEPS values.WEPS values. Where not possible or feasible to utilize Where not possible or feasible to utilize

existing WEPS information, need to add WEPP existing WEPS information, need to add WEPP components to generate necessary components to generate necessary information (e.g. water sediment particle size, information (e.g. water sediment particle size, water erodibility parameterization/updating)water erodibility parameterization/updating)

Test and verify combined WEPS/WEPP code Test and verify combined WEPS/WEPP code against individual models.against individual models.

Modify WEPS interface/database to provide Modify WEPS interface/database to provide additional data necessary for WEPP. additional data necessary for WEPP.

Possibly develop a new combined interface.Possibly develop a new combined interface.

SummarySummary

Current development efforts are towards Current development efforts are towards creation of a combined wind and water creation of a combined wind and water model based upon WEPP and WEPS model based upon WEPP and WEPS science, for ultimate use in NRCS field science, for ultimate use in NRCS field offices.offices.

Two development paths for a common Two development paths for a common model are being pursued at present – model are being pursued at present – one building a modular combined model one building a modular combined model within OMS, the other utilizing WEPS as within OMS, the other utilizing WEPS as the basic framework.the basic framework.

Questions??Questions??