Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007
Winter Erosion Processes and Modeling Meeting
USDA-ARS National Soil Erosion Research Laboratory
West Lafayette, Indiana
May 1 – 3, 2007
Meeting Summary Document
This meeting was held on May 1-3, 2007 at the USDA-ARS National Soil Erosion Research
Laboratory (NSERL) in West Lafayette, Indiana, on the campus of Purdue University. Nineteen
(19) people were in attendance, from a number of ARS, NRCS, FS and university locations. The attached detailed agenda contains the names of all attendees as well as information on the various presentations that were given during the conference.
Winter hydrology and soil erosion processes are important over a large area of the world.
However, current erosion prediction technology models often poorly account for these processes.
Improved estimation of soil freezing/thawing, snow accumulation and melting, and their effects on soil erodibility are needed to help up make better estimates of soil loss by water or by wind.
The new common wind and water soil erosion model being developed by ARS needs to have the best possible predictions of these winter processes.
The objectives of the meeting were:
1.
Learn about the current state of the science related to winter hydrology and soil erosion processes.
2.
Learn about current winter processes modeling techniques and their limitations.
3.
Discuss with other participants areas of needed research and status of model development.
4.
Make plans for cooperative research and modeling efforts among the several locations represented at the meeting.
5.
Update the participants on the status of the common wind and water erosion model development effort, and obtain feedback from the group.
All of the presentations and the 3 formal seminars that were presented can be viewed at the following web site; http://topsoil.nserl.purdue.edu/~flanagan/wintermtg
Other information from discussions at the meeting:
Update from Norm Widman, NRCS National Agronomist – NRCS is on the receiving end from ARS and university research. They need tools for their field office users to apply that are simple, quick, and accurate.
RUSLE2 is currently NRCS’s primary tool for water erosion prediction. The current number one issue with RUSLE2 is that a better way to simulate pasture systems is needed. At present, removal of biomass by livestock is simulated all on one day. Dan Yoder (U-Tennessee) and Seth
Dabney (ARS-Oxford) are working on a new pasture routine for RUSLE2 that alters how
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007 livestock remove biomass, and includes trampling and regrowth aspects. Currently NRCS has had to extremely modify the growth curves for pastures to obtain reasonable results with
RUSLE2.
The second priority issue with RUSLE2 is simulation of ephemeral gully erosion – a prototype was provided last October by Seth Dabney, but the amount of input information and time required to use it is very high.
Snow melt representation in the Pacific Northwest by RUSLE2 is the #3 issue for NRCS in erosion prediction – improved predictions are needed.
The #4 issue for NRCS that is more of a long-term item is the development of the combined wind and water erosion prediction tool within a modular prediction system. Field office personnel would like to bring up their Toolkit with the aerial GIS map view of a farmer’s fields, automatically have all of the topographic, soils, climate, and management information loaded for that location, and then be able to have the erosion prediction tools run and display the outputs for water or wind or combined soil losses – with no need to enter in input information more than a single time.
The main use of erosion prediction tools by NRCS is in conservation planning. However, other issues are also becoming important, in particular water quality concerns in which nutrients, pesticides, manure runoff, leaching, etc. may all be a concern.
Common databases of soils, operations, nutrients, etc. are needed. And as mentioned before, all the field planner would need to do would be to locate and outline the area of interest on the screen, the local databases would be immediately populated, and then all the planner has to do would be to enter the types of land management that he/she wants to evaluate.
Hydrology is needed by NRCS in order to predict nutrient leaching, pesticide runoff, pathogen transport, etc.
Tools for NRCS may be used not only by NRCS staff, but also by technical service providers
(TSPs) that now install many of the recommended conservation practices. As mentioned before, software tools need to be simple and operate quickly.
Some summary points from Dennis Flanagan – ARS-NSERL staff plan to continue cooperative efforts with ARS-Pullman, USDA-FS-Moscow, and WSU on improvement of winter erosion processes modeling for the common wind and water erosion system and WEPP. Based on this meeting, additional cooperators, including Keith Cherkauer at Purdue University, John
Williams at Pendleton, OR. Jan Boll/Erin Brooks at the University of Idaho, and others may also be able to assist.
In particular, a shared database of validation data for winter processes (weather data, soil frost, soil thaw, snow accumulation, snow melt, runoff, erosion, etc.) at a central location would assist all cooperating researchers in evaluating and validating models, model components, or new
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007 prediction equations. Suggest that existing data from Pullman and Morris initially be put at such a site, and other data (Cherkauer – Minnesota, etc.) be added to the site.
Some type of more regular communications, such as monthly (?) teleconferences, bi-annual meetings, etc. would probably be helpful at keeping this effort on track and able to meet its deadlines. The project here at the NSERL is looking to receive input within 1-2 years on improved approaches to simulate soil freezing, thawing, snow melt, and erodibility adjustments, and/or alternative approaches to the current excess flow shear stress equation for rill detachment during melt events.
In terms of the common wind and water erosion model project, NRCS needs to be more than a
“receiver” of technology. Specifically, the development of the common erosion model needs to be a funded project within NRCS and staff at the ITC in Fort Collins, CO (Frank Geter, Ken
Rojas, etc.) need to be able to devote their time to this project. Verbally, NRCS has committed to developing the interfaces and databases needed for this effort, but Frank Geter could not even attend this meeting here because officially there is no project with his time allotted to it. Also, we need to have direct NRCS cooperating scientists at the ARS locations working on the common erosion model development – NSERL in West Lafayette, WERU in Manhattan, and
ASRU in Fort Collins. Direct day-to-day communications with the model, interface and database developers is needed to truly assure NRCS and ARS that the product that is developed will be acceptable and useable by field office staff.
The current common wind and water erosion model project in ARS is very small compared to the WEPP or WEPS projects. Currently at the NSERL there is only 1.0 SY with a total budget of about $300K per year, while in WEPP, for example there were about 20 SY from across the
U.S. involved, which would be a budget of about $5M per year. Much of the current common model project will draw upon existing code, but it is highly dependent upon cooperation with others within ARS and NRCS. This project absolutely needs funding and people resources to be successful. The original letters from NRCS to ARS in 2004 spoke of shared budget planning, and that would certainly be most helpful at this time. If OMS is to be the development platform for the common erosion model project, as well as other ARS software in the future, then it needs to become a true funded project within ARS with a sufficient budget for development, documentation and training.
Regular meetings/teleconferences on the common wind and water erosion model development need to be scheduled, with participants: D. Flanagan, L. Wagner, N. Widman, D. Lightle, F.
Geter, and any NRCS cooperating scientists at the ARS locations. Within the next 3-6 months, input is needed on the user requirements for the initial system, to assist with the design and development of the first prototype for field use.
Finally, in terms of ARS support, more assistance is needed from ARS-Manhattan on development of the wind detachment components and auxiliary components within the OMS system. Also, additional work on the CLIGEN weather generator to complete enhancements to the storm intensity predictions and assess all of the cumulative CLIGEN changes to water and wind erosion predictions is needed.
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007
Some summary comments from Chi-hua Huang
Thank Dennis Flanagan for arranging this focused topical work group meeting to address an identified gap in current erosion prediction technology.
It is apparent from observations that most severe winter erosion events occur when 1) rain is falling on partially melted soil; or 2) during very rapid melting events. In both cases, the oversaturation and lack of a downward hydraulic (or drainage) gradient make the soil highly erodible.
We have experimental data showing that soil erosion was greatly increased (~ 10 times) as the near surface hydraulic gradient was shifted from downward drainage to an upward seepage condition. In other words, soil erodibility derived under the drainage (or summer) condition would tend to underestimate snow-melt erosion when the soil was in fact over-saturated and without downward drainage due to the frozen sub-soil.
The gap in current winter erosion processes is probably on the prediction of the erosive events stated above. A process-based approach has many detailed equations on climate, soil as well as water and energy balances, and therefore requires a very detailed dataset to validate. While this rigorous approach may take a longer time to evolve, it may be feasible to develop a surrogate technique that uses a combination of temperature and snow-/rain- fall to predict the occurrence of the critical melting events.
An emerging challenge or opportunity in erosion prediction technology is the assessment of how bio-energy production will impact the environment and future agricultural production. This will probably be the focus for natural resource and sustainable agriculture community in the next decade. We need to have the proper erosion assessment tool to meet this challenge.
Round-table discussion summary:
Larry Wagner
– ARS and NRCS need to firmly commit to the common wind and water erosion modeling project as well as financial support of the project and the Object Modeling System
(OMS) at Fort Collins, Colorado. ARS and NRCS need to work together very soon on developing user requirements for the common wind and water erosion model, and highest priorities identified, to aid in the design and development of the initial version – it may be necessary to develop multiple versions (web-based, GIS, etc.) to meet different expressed needs of the users.
Bill Elliot – Effects of snow in canopies, and canopy effects are important areas of research and modeling. Current problems with rain going through snow pack in WEPP need to be corrected.
Aspect effects on steep North-facing slopes, and spatial variability in snow distribution on the ground also are important. Energy-based snowmelt routines developed by Utah State for the FS are available ( http://www.engineering.usu.edu/cee/faculty/dtarb/snow/snow.html
). A retired
University of Idaho professor (George Belt) did research work on snow in canopies – his work may be of use here.
John Williams – Is in the process of planning 5-year CRIS project on integrated grazing and animal production. He can build on existing datasets, and wants to use USDA erosion prediction
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007 tools. Cooperating with Dr. Whittaker in Corvallis, OR. Comment by B. Elliot – new capabilities of WEPP to better describe rangeland conditions – need someone to test/parameterize it for application there.
Erin Brooks – Seepage and variable source area contributions are important processes to simulate, and is encouraged with most recent version of WEPP that better simulates these. Can work with Chi-hua Huang on erosion from saturated areas. Has datasets with perched water tables available to share with others. Snow drifting is important! Infiltration through frozen soil also needs more research and better modeling.
John Tatarko – Aggregation and the effects of changes in this due to different over-wintering conditions needs to be represented.
Dave Lightle – Snow in canopies seems to be important. Frozen soil that starts to thaw and has very weak unstable area at the top needs to be represented. Snow drifting and melt, as well as climate and soil related issues are also important. There needs to be dedicated NRCS funding to the common wind and water erosion model project.
Fred Fox – Visualizations of model outputs, such as canopy development and virtual flyovers, would help users better understand models and if they are functioning as desired and parameterized properly. Almost moving to a level of gaming – since it is hard for users to interpret output tables and can more easily understand a picture. The spatial distribution of snow and canopy effects may be very important in modeling efforts, and some info is at
( http://www.treesearch.fs.fed.us/pubs/26319 ).
Don McCool – Saturation should be examined as an alternative to freezing/thawing soil.
Improvements to the erodibility factors need to be made, as current adjustments in WEPP
(maximum adjustment of 2X increase in rill erodibility) not based on much science or measurements, and likely should be higher.
Jim Frankenberger – It appears that much of the recent model development work is in coupling existing models together, as opposed to building new models. Use of OMS as the development platform for a common wind and water erosion system is still questionable. Perhaps another approach would be to design new entry points into existing models. Outside of USDA, OMS is not meaningful at this point. What is important is that code be modular so it can be used in OMS or other models.
Keith Cherkauer – Interests are at a much larger scale than most people at this meeting – in terms of forecasting of river flows related to soil moisture. Bio-energy efforts in the U.S. provide the opportunity to look at what kinds of changes in residue may occur and what will the impacts be through modeling. Models may not provide the best “absolute” values in terms of outputs, but can help one to focus on “hotspots”, for more detailed modeling, monitoring, or program application. Spatial variability is very important. Can help in efforts to pull together validation data, and can also help with putting some of his code into the OMS system, if it would be of value.
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007
Shuhui Dun – Areas of importance that have been identified are interception of snow, energy of snowmelt, seepage from snowmelt, and residue effects.
Joan Wu – Need continued support for WEPP modeling efforts at the NSERL. This tool is the best erosion model for prediction of runoff and soil loss at the field and small watershed scale, particularly with recent updates for lateral subsurface flow, and is used by many people throughout the world.
Thanos Papanicolaou
– Would like to include the Iowa Clear Creek watershed data in the common database web site. Suggest incorporation of the in-stream (ditch) model that he presented at this meeting into WEPP. This coupled model would be a powerful tool and improve predictions of sediment yield at watershed scales. Interested in collaboration with Chi-hua
Huang and use of a laser scanner, and also possibly collaboration with Doug Smith on his channel study. Better prediction of critical erosional strength of soil is needed.
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007
Action Items:
1.
Dennis Flanagan will work with NRCS staff (Widman, Lightle, Geter) and Larry Wagner to arrange a subsequent meeting this year on common wind-water erosion model user requirements, to possibly to be in Ft. Collins sometime in the next 3-6 months.
2.
Norm Widman and Dave Lightle will investigate raising the priority of the common wind and water erosion model development within NRCS, so that it can become a funded project and NRCS-ITC staff at Fort Collins (Geter, Rojas, etc.) can officially devote their time to this project.
3.
A common database web site needs to be created with information from existing winter hydrology/erosion experimental field plots/watersheds. Dennis Flanagan will pursue this more through subsequent discussions with Don McCool, Joan Wu, Keith Cherkauer,
Papanicolaou, and others. Such a web site could be hosted at the NSERL.
4.
There needs to be a comprehensive literature and model review conducted to determine the following related to winter processes:
1) Are new experiments and data collection needed (we don't have the science understood yet)
2) Experiments have been done but behavior has not been captured in a model, data available but not synthesized.
3) Some type of model prediction exists for a winter process but it is in another model or not in a form that can be directly applied to WEPP/WEPS.
4) Code already exists in WEPP/WEPS but has not been tested enough and bugs eliminated.
Shuhui Dun will conduct these reviews/evaluations as part of her thesis work, with assistance from Joan Wu, Don McCool, Dennis Flanagan and others.
5.
Regular meetings/teleconferences need to be scheduled for the scientists working on winter process research/modeling. Since most of that work is currently ongoing at WSU
(Wu, Dun, McCool), they may be best group to arrange meetings/teleconferences.
Dennis Flanagan will follow-up with Don McCool and Joan Wu to see what kind of arrangements can be made.
6.
Joan Wu will work from suggestions made by Thanos Papanicolaou and others to pursue additional sources of possible grant funding. Norm Widman suggested that possibly some funding might be available to universities from NRCS for development of simple, targeted field office tools for NRCS, and asked Joan to contact him about this after the meeting.
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007
Winter Erosion Processes and Modeling Meeting
USDA-ARS National Soil Erosion Research Laboratory
West Lafayette, Indiana
May 1 – 3, 2007
Participant List and Final Agenda
Attendees List:
Dennis Flanagan ARS-NSERL
Jim Frankenberger ARS-NSERL
Doug Smith
Chi-hua Huang
Keith Cherkauer
ARS-NSERL
ARS-NSERL
Purdue ABE
Bill Elliot
Larry Wagner
Fred Fox
John Tatarko
Norm Widman
FS-Moscow
ARS-Manhattan
ARS-Manhattan
ARS-Manhattan
NRCS Washington
Dazhi Mao
Joan Wu
Shuhui Dun
Don McCool
Purdue ABE
WSU BSE – Pullman
WSU BSE – Pullman
ARS-Pullman
Dave Lightle
Thanos Papanicolaou U. of Iowa, Iowa City
Ozan Abaci
John Williams
Erin Brooks
Tuesday, May 1 st
U of Idaho - Moscow
10:30 a.m. – 11:30 a.m. Seminar
“Winter Erosion Processes Research”
NRCS Lincoln
U. of Iowa, Iowa City
ARS-Pendleton, OR
Don McCool
11:30 a.m. – 1:00 p.m.
1:00 p.m. – 1:15 p.m.
Lunch
Welcome, introductions
Meeting objectives
Chi-hua Huang
Dennis Flanagan
1:15 p.m. – 2:00 p.m.
2:00 p.m. – 2:45 p.m.
2:45 p.m. – 3:00 p.m.
3:00 p.m. – 3:30 p.m.
3:30 p.m. – 4:15 p.m.
4:15 p.m. – 5:00 p.m.
Winter Erosion Processes Modeling
Current State of Science
Winter Erosion Processes Research at Washington State University
Snowmelt in Steep Forests
Break
Purdue University Winter Hydrology and Erosion Research
Erodibility Research at the NSERL
Don McCool
Joan Wu
Bill Elliot
Doug Smith
Keith Cherkauer
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11:30 a.m. – 1:00 p.m.
1:00 p.m. - 1:40 p.m.
1:40 p.m. – 2:00 p.m.
2:00 p.m. – 2:15 p.m.
2:15 p.m. – 2:35 p.m.
2:35 p.m. – 2:50 p.m.
2:50 p.m. – 3:10 p.m.
3:10 p.m. – 3:30 p.m.
3:30 p.m. – 4:00 p.m.
4:00 p.m. – 4:45 p.m.
4:45 p.m. – 5:15 p.m.
5:30 p.m.
Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007
All 5:00 p.m. – 5:30 p.m.
5:30 p.m.
Wednesday, May 2 nd
8:00 a.m. – 9:00 a.m.
9:00 a.m. – 10:00 a.m.
10:00 a.m. – 10:30 a.m.
10:30 a.m. – 11:30 a.m.
Discussion
Adjourn
Discussion – “Needed Research Areas”
Current Modeling Approaches
- WEPP
- modified WEPP
- VIC
Break
Seminar
“Development of a Common Wind and
Water Erosion Model”
Lunch
All
Dennis Flanagan
Joan Wu / Don McCool
Dazhi Mao
Dennis Flanagan
Current Modeling Approaches (cont.)
- WEPS Fred Fox
Other Modeling Approaches discussion All
Winter Processes for Wind Erosion
Soil Erodibility and Erosivity
John Tatarko
Modeling Variable Source Area Hydrology Erin Brooks
Erosion/Cropping Systems Research
Erosion Research in Iowa
John Williams
Thanos Papanicolaou
Break
Data Available for Model Validation
Development of Cooperative Research
Plans Discussion
Opportunities for Funding Support?
Adjourn
Don McCool, Joan Wu
All
Joan Wu
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Winter Erosion Processes and Modeling Meeting Summary
USDA-ARS NSERL, West Lafayette, IN, May 1-3, 2007
FINAL – 5/25/2007
Thursday, May 3 rd
8:00 a.m. – 8:30 a.m.
8:30 a.m. – 8:45 a.m.
8:45 a.m. – 9:45 a.m.
9:45 a.m. – 10:00 a.m.
10:00 a.m. – 11:00 a.m.
11:15 a.m. – 11:30 a.m.
11:30 a.m.
12:00 p.m. – 9:00 p.m.
NRCS Erosion Prediction Needs
Summary items from this meeting
Roundtable Discussion
Break
Seminar
“Erosion Research at WSU”
Final Discussions, Wrap-up
Adjourn
Field Tour of SWPI/CEAP Watersheds
(Led by Chi-hua Huang)
Norm Widman
Dennis Flanagan
All
Joan Wu
All
(Optional)
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