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Planning for Extremes Workshop

Planning for Extremes Workshop

Milwaukee, Wisconsin

November 1-3, 2006

Briefing Paper

Session 1: Reviewing the Case for Action

Objectives:

· Review and evaluate the evidence that incorporating variability in precipitation—particularly the frequency and intensity of server storms—explicitly into conservation planning is needed to adapt to a climate regime in which extreme precipitation events are more frequent and more severe.

· Characterize the severity of the threat to the Great Lakes ecosystem posed by more frequent and more severe precipitation events.

· Articulate a sense of the urgency with which this problem should be addressed.

· Set the stage for Sessions 1 and 2—identify the most important issues that should be discussed and resolved in order to recommend a course of action.

Adapting to Impacts on Soil and Water Quality from Higher Intensity Rains with Climate Change in the Great Lakes Basin

Dr. James Bruce, SWCS Canada
Dr. W. Trevor Dickinson, University of Guelph
Dr. David Lean, University of Ottawa
Paper / Presentation
Abstract: The study of the effects of a changing rainfall regime, as climate change, on erosion, sediment transport and water quality in the Canadian part of the Great Lakes basin was coordinated by SWCS-Ontario and funded by the Walter and Duncan Gordon Foundation. This study was considered in part a follow-up to the SWCS Report of 2003 which concentrated on the USA. Analyses of the rainfall data indicate that in many parts of the basin, short duration intensities and one day amounts have been on the rise since 1970 by about 3% to 5% per decade. This starting date was selected since up until the mid-1960s natural forcing factors were important in driving the changes in climate but since 1970, greenhouse gases were overwhelmingly responsible, and this is expected to continue. Of greatest concern for erosion, the most consistent heavy rainfall increases have been in Spring. Implications for water quality in the Great Lakes and its tributaries are being explored. For example, there is evidence that after several decades of decline, phosphorus loadings to Lake Erie are on the rise again. Is this related to increased frequency of heavy rains?

Apparent Changes in Rainfall Intensities, Possible Impacts on Soil Erosion and Sediment Yield, and Remediation Needs in Ontario
Dr. W. Trevor Dickinson

Presentation
Abstract: This paper clarifies apparent changes (and the lack of changes) in extreme rainfall intensities in Ontario, explores estimates of the possible impacts of such changes on soil erosion and sediment yield from fields and small watersheds, and stresses the continuing vital need for targeting of remedial measures. Extreme rainfall amounts have been quite variable in recent decades, with most consistent increases being evident in spring intensities. The possible impacts of hypothetical increases in short-duration rainfall intensities for spring and summer storm situations have been evaluated for soil erosion and sediment yield, including the possible net impacts on seasonal and annual erosion and sediment amounts. In light of evidence that relatively small percentages of rolling rural upland landscapes in Ontario contribute a majority of downstream suspended sediment loads during a brief period of each year, the need to select and target remedial measures in time and space is stressed.

Overview of findings from Great Lakes/Clean Water workshops
Mr. Craig Cox
Presentation
Abstract: SWCS held four workshops in the Great Lakes basin in May 2006. The workshops, funded by The Joyce Foundation, brought together people with hands-on experience working with USDA conservation programs to share their ideas of how those programs could be used more effectively to restore the health of the Great Lakes Ecosystem. SWCS is currently developing specific recommendations for administrative and legislative reform of USDA conservation programs that would advance the ideas generated by workshop participants. Participants’ ideas for change were very diverse, but there was clear consensus that the most important change needed is to “get real.” Getting real means driving Great Lakes goals upstream into critical watersheds; getting ourselves organized around those critical watersheds; getting the right practices on the ground in the right places in those watersheds to make real change happen; build local capacity and leadership to sustain watershed restoration work; get more trained technical people on the ground; cut through red tape that impedes creative use of conservation programs; and put more emphasis on regulatory programs that set standards and motivate participation in voluntary programs.

Simulated effect of change in precipitation regime on sediment, nutrient, and pesticide loss from farm fields in the Great Lakes region
Dr. Robert Kellogg, Natural Resources Conservation Service
Mr. Steve Potter, Texas A & M University Blackland Research and Extension Center
Presentation

Abstract: Studies indicate that increasing the precipitation intensity or volume of storm events may increase soil erosion losses and sediment yields (SWCS, 2003). Since water movement into the soil and across the landscape is the primary mechanism driving the offsite movement of soils, nutrients, and pesticides, it follows that an increase in the occurrence frequency of extreme precipitation events would increase nutrient and pesticide losses. However, there is a paucity of literature identifying the specific nutrient and pesticide impacts that may be affected by changes in the precipitation regime. Furthermore, conservation practices that were designed and implemented based on the current precipitation regime may not provide the same conservation benefits under a precipitation regime having an increased occurrence frequency of extreme precipitation events. The efficacy of conservation practices with respect to possible precipitation regime changes is not well studied. We address the two issues through a simulation study of cropland in the Great Lakes region. Using a microsimulation modeling technique, we simulated two scenarios: a baseline with an “as is” distribution of precipitation events, and a projected scenario having an increased occurrence frequency of extreme precipitation events. All other simulation variables remained consistent between the two scenarios. Scenario differences in total nitrogen, total phosphorus, and pesticide losses indicate the relative effects that might be expected given the projected change in the precipitation regime. A second part of the study examines whether loss differences for the subset of model runs having conservation practices differed from loss differences for the entire suite of model runs.

Session 2: Planning at Field/Farm Scale

Objectives:

· Develop an action agenda for improving our ability to plan for and manage the effect of variable precipitation and severe storms at the field and farm scale.

o Enhance planning tools (RUSLE 2 etc.).

o Strengthen practice standards and performance data.

o Identify research agenda.

o Other actions needed.

· Prioritize action agenda.

Planning options in the short and long term
Dr. Daniel Yoder, University of Tennessee
Presentation

Abstract: Planning has traditionally been done on either very short or very long time scales, depending on the purpose. The use of a single design storm for sizing a culvert or channel is a short-term example, while a long-term example would be use of average annual soil erosion for conservation planning. This presentation will use planning based on soil erosion by water to first argue that planners should make use of the entire range of time scales, depending on the available information and on the planning goals. For example, determining whether a construction site silt fence will fail might best be done on a design-storm basis, while sizing of a sediment basin should probably be done on the basis of accounting period ranging over some months, and determining the deterioration of the soil resource should be done on at least an annual basis. The presentation will then discuss the use of average values as opposed to a value based on some specific return period, and will end with a discussion of the need for long-term modeling of the situation regardless of the time interval on which the planning is done.

Single Storm Analysis for Conservation Planning
Dr. William Elliot, USDA Forest Service Rocky Mountain Research Station
Presentation
Abstract: Most current erosion prediction tools used for soil conservation planning are based on average annual erosion rates, or on erosion associated with a predetermined single “design storm.” The average annual method does not suit erosion prediction when a disturbance is for a single season, such as a wildfire in a forest, or a construction site, where it is more important to know the risk of a given erosion amount occurring during a single year, and what are the benefits gained by mitigation for that year. The design storm approach also has its limitations in that the return period associated with the design storm may not be the same as the return period associated with a given erosion event. A large storm occurring when the soil is dry may cause less runoff and erosion than a smaller event when the soil is saturated. An additional problem in the context of trying to incorporate climate change into the prediction is determining how to model the erosivity of an altered climate. Two tools that solve these problems have been developed for predicting erosion following wildfire by the USDA Forest Service Rocky Mountain Research Station. Both interfaces are online, and are accessible by any web browser from anywhere in the world. The climate interface allows a user to easily alter average monthly temperatures, precipitation amounts, and number of wet days. Additional fields could be added to allow users to alter the peak storm intensity values. A second interface incorporates variability of climate, soil properties, and spatial distribution of disturbances following wildfire. This interface carries out a soil erosion event return period analysis using the Water Erosion Prediction Project (WEPP) model. The climate is built by the online climate interface, the topography can be acquired by GIS tools, and the soils database is online. The output screens provide a summary of when the erosion events occurred, the sediment delivery associated with a given probability of occurrence, and the effectiveness of three types of mitigation (seeding, mulching, and installation of logs on the contour on hillsides). These interfaces demonstrate that erosion can easily be predicted for single storms, and that scenarios for different changing climatic conditions can readily be incorporated into soil erosion prediction and conservation practice analysis.

Implications for the Field: Planning in the United States
Mr. Steve Davis, Natural Resources Conservation Service in Ohio
Presentation

Implications for the Field: Planning in Canada
Mr. Kevin J.G. McKague, Ontario Ministry of Agriculture, Food and Rural Affairs

Presentation

Session 3: Planning at Watershed/Regional Scales

Objectives:

· Develop an action agenda for improving our ability to plan for and manage the effect of variable precipitation and severe storms at the watershed and regional scale.

o Enhance planning tools (SWAT etc.).

o Enhance targeting.

o Landscape restoration and management.

o Research agenda.

o Other actions needed.

· Prioritize action agenda.

Process-based Decision-Support for Impact Assessment of Extreme Events at the Watershed Scale
Dr. Chris Renschler, Dept. of Geography, SUNY
Presentation
Abstract: Geospatial modeling tools using environmental models and Geographic Information Science (GIScience) techniques are increasingly used for decision-making and policy-making in natural resources or natural hazards management. Extreme events as well as environmental or policy change, however, may change the scale of interest in assessing environmental processes to that extent that models are not applied at the scales for which they were created. The design and successful implementation of the Geospatial Interface for the Water Erosion Prediction Project (GeoWEPP) at the watershed scale illustrates the challenges and solutions to build valid and useful assessment tools for cumulative watershed effects analysis. GeoWEPP enables natural resources managers of agricultural, grassland, rangeland, and forests to assess the spatial and temporal scheduling of management activities. The design, development, implementation and validation of GeoWEPP is based on a formulation of an integrated data transformation and scaling theory allowing scientists of various disciplines to effectively collaborate, to design flexible process-based modeling approaches and to implement them as useful decision support tools. This research contributes to our fundamental understanding and ability to communicate how we (a) represent the spatiotemporal variability, extremes, and uncertainty of environmental properties and processes in the digital domain, how we (b) transform their spatiotemporal representation across scales during data processing and modeling in the digital domain, and how we design and develop tools for (c) geo-spatial data management and (d) geo-spatial process modeling and implement them to effectively (e) support decision- and policy-making in natural resources and hazard management at various spatial and temporal scales of interest. The great interest of the forest and rangeland management community in using GeoWEPP resulted in two successful consecutive grant proposals to the interagency Joint Fires Science Program to use GeoWEPP for post-fire rehabilitation of watersheds and as a fuel reduction tool to spatially and temporally schedule management activities in watersheds (cumulative watershed effects analysis). GeoWEPP has been used for an erosion potential analysis tool for various burned areas including the 200 km2 School Fire near Pomeroy, WA, the largest fire in the US in 2005.

Targeting within a Watershed: Focusing Policies, Information, and Practices
Dr. Jon Bartholic, Michigan Institute of Water Research
Mr. Anthony Friona, USACE Great Lakes Tributary Modeling Program
Dr. William Northcott, Michigan State University
Presentation
Abstract: Several simultaneous global trends are occurring and if this continues, they could interact to create the “imperfect storm.” These factors include predicted global climate changes with impacts on rainfall timing and intensity, temperature increases, and general intensification of weather events. Global population is expected to increase from six billion in 2000 to nine billion over the next 75 years (The Environmental Literacy Council). These combined effects will stress our agricultural systems resulting in the need to increase food production requiring intensively managed row crops to obtain maximum yields, and will necessitate expansion into more fragile and erosion prone areas. This expanding intensive approach could increase the number of agricultural areas that experience a greater vulnerability to extremes in weather (particularly rainfall) events. The combined impact of climate change and human food production demand’s, could yield this “imperfect storm” of erosion and subsequent sediment impacts on ecosystems, aquatic resources, and soil productivity. With spatial decision support systems (SDSS) to aid in developing better land use policy related to food production and biomass prediction at various scales from national to regional, state to local and field scale levels, there is the possibility of sustaining food production and ecological services provided by the landscape. Specifically, use of the High Impact Targeting (HIT) GIS web-accessible system for detecting potential high sediment delivery areas, will be discussed as an important component of the SDSS.