Notes Coastal Experts Workshop Port Huron, Michigan October 14-16, 2008 The Coastal Zone Technical Working Group (CZTWG) of the International Upper Great Lakes Study (IUGLS) held an Experts Workshop to help develop a strategy to evaluate the impacts of fluctuating water levels due to lake level regulation at Sault Ste. Marie on the coastal riparian interest. Primary issues of concern to the coastal riparian interest include (but are not limited to) flooding, erosion of property, integrity of shore protection, and property value decrease during times of low water conditions. As lake level regulation at Sault Ste. Marie has only a small influence on water levels and the IUGLS covers an extensive geographical area, the CZTWG is challenged with ensuring assessment tools are sensitive to minor differences between regulation plans while being applicable to a large geographic area. The CZTWG is particularly interested in defining features and characteristics that are critical to the evaluation process and providing a general estimate of uncertainty. 1. Welcome and Introductions: The meeting began at 1:20 pm with round table introductions. Those in attendance were: TWG Members: Scott Thieme, US Coastal TWG Lead Mike Shantz, Canadian Coastal TWG Lead Robin Davidson-Arnott, University of Guelph Matt Warner, Michigan Department of Environmental Quality Gene Clark, University of Michigan Ian Cameron, Ontario Ministry of Natural Resources Nick Zager, LRE Associate Coastal Experts: Don Forbes, Natural Resources Canada Phil Keiller, Coastal Expert, University of Wisconsin Dave Hart, Coastal Expert, University of Wisconsin – GIS, WisconsinCoastalGuide.org Ralph Moulton, Canadian, Com. Nav. TWG – Coastal Expert Bill Kamphuis, Coastal Expert, Queens University Brian Greenwood, University of Toronto-Scarborough Heather Stirratt, NOAA-Minnesota Joe Gailani, ERDC-Vicksburg Other International Upper Great Lakes Study Participants: Wendy Leger, Canadian PEG Lead Bill Werick, US PEG Lead David Fay, Canadian Lake Superior Regulation Task Team Lead Tony Eberhardt, US Lake Superior Regulation Task Team Lead 1 Jim Bredin, US Study Board Member Greg Mayne, Acting for Sandie George, Canadian Ecosystem TWG Roger Smithe, US PIAG Member Jim Anderson, Canadian PIAG Member 2. Review of Outline and Objectives for the Workshop in the Context of Upper Lakes Study Objectives: Mike Shantz began with a general overview to set the tone for the workshop as noted in the attached presentation. Key elements to keep in mind throughout the workshop were: Context – sensitivity to water level changes as a result of regulation The need to utilize Impact Analysis Tools to compare regulation plan impacts The TWG budget is limited and will influence some decisions of the TWG Future Projections – consider future hydrologies (climate change, stochastics), but not future economies Welcome and Introduction - Oct 14 2008.pdf 3. Background on Regulation at Sault Ste. Marie: David Fay discussed the history of the regulation of Lake Superior as noted in the attached presentation. Key things noted were: The original orders were issued by the IJC in 1914 with first regulation plan developed and applied in 1916 Supplementary orders were issued in 1979. The important change was the introduction of “systemic” regulation with the intent of trying to balance levels of Lake Superior and Lakes Michigan-Huron (relative to their long term average) Plan 1977-A has been in use since 1990. It incorporates a lower limit for Lake Superior (182.76 m), an upper limit (183.86 m), with chart datum being 183.2 m He noted that you may not be able to differentiate one alternative regulation plan from another, particularly for Lakes Michigan-Huron, since the impacts due to new plans are expected to be small. A question was asked about seasonality of future plans. It was noted that the current regulation plan and the fencepost plans don’t really impact this at all. Fay Presentation 4. Current and Past Water Level Impacts: Scott Thieme provided some background on past water level associated coastal zone impacts and what areas of the upper Great Lakes have been impacted (see attached presentation). Key impacts noted were: 2 Flooding of property and structures, seen mostly heavily in the past around Lakes St. Clair and Erie. Erosion of property and loss of structures. While erosion has been more of a problem on Lakes Michigan, Erie, and parts of Lake Huron, it has been light along large sections of Canadian shoreline of Georgian Bay and Lake Superior. Low water impacts include a variety of things such as aesthetics, environmental quality and ownership issues. There have been complaints related to such issues on Georgian Bay, the eastern shore of Lake Michigan, Saginaw Bay, and Lake St. Clair. Current and Past water level impacts - Oct 14 2008.pdf 5. Performance Indicators: Mike Shantz led a discussion about the use of Performance Indicators (PIs) in the study and things we should be thinking about. Two presentations were used (see attached presentations). For the IJC’s Lake Ontario St. Lawrence River Study, there were three primary PIs used for the coastal impact evaluation including: first floor flooding, erosion to unprotected shoreline property, and damage to existing shore protection. Potential PIs - Oct 14 2008.pdf Following the introductory presentations, the workshop participants brainstormed potential coastal PIs for IUGLS recognizing the need to go offshore to breaking wave depth and the need to consider glacial isostatic adjustment (for example, Georgian Bay is emerging). A variety of suggested PIs were listed, grouped into 4 general categories. Flooding wave set up, structural failure – type of structure, etc. permits and the difficulty acquiring, property claims, insurance premiums. need for monitoring stations. related issues: habitat migration studies, ramps out of service, habitat loss, safe navigation, impact on tribal cultures, 3 Erosion infrastructure concerns - differences between storm and design elevations, number of plants impacted, impacts in creeks, recreational value land value, tourism, deposition of material (low water), the number of boundary disputes, property values (change on municipal tax base) (also relates to flooding), changes in water quality, near-shore erosion, tourism perspectives on public lands, encroachment when levels are low Shore protection assessment of design. Consider updated forecasts of water levels including, possible climate change impacts, adaptation and design decisions and criteria, structural modifications, freeze-thawing cycles (can also effect erosion), movement of sediment resulting in failure (sediment budget), storm surge Low Water Issues exposed sediment development pressure property values inconvenience Georgian Bay wetlands Sediment budget (deposition) Aesthetics – view (vegetation growth, levels too far down to too far away) Tourism (e.g. access to beaches and recreational value) – note that some areas see benefits from low water and other areas see negative impacts Costs to move water level gauges or other infrastructure Safe navigation Change in water velocities/currents as it relates to pathogens and nonpoint source pollution Habitat change (e.g. wild rice beds, changes to hunting areas) Management of contaminated sediment 4 Boat ramps out of service Change in property value – reflected in tax base Drainage in local creeks Following the brainstorming on Day 1, the items were entered into an Excel spreadsheet and an attempt was made to categorize them relative to their importance in relation to water level regulation (low, moderate, or high), whether they could (or needed to be) modelled vs. whether they could be considered in a qualitative sense, and whether they could be used to select new regulation plans or whether they were better used in relation to a potential Adaptive Management program. The excel file is attached for reference. Highlights are included below: Rating Potential PIs Oct 15 2008.xls Flooding Flooding damages to residential/ commercial/ industrial property – high (expert agreement = EA) – related to regulation plan (RP) and adaptive management (AM) Changes in flood hazard management zones (change in return period, 1:100 and linked to climate change) – high (EA), AM Flooding of municipal infrastructure – moderate (expert disagreement = ED – high when considering larger cities like Milwaukee), RP Blowout of barrier beaches – low (EA, need to determine how many exist). Infrastructure flooding – impaired operation – moderate (related to 3 above) Infrastructure flooding – damages to infrastructure – moderate (related to 3 above) Decreased municipal tax base (also erosion) – low (could be done with data and tools now) Loss of beach access due to flooding – moderate (ED – low when compared to residential flooding and infrastructural concerns) Shore Protection Structure failure – high (EA, RP, AM) Deterioration of exposed timbers – moderate (don’t model, more related to climate change) Changes in design standards – high (EA, AM) Permits to protect property – low (EA – describe in contextual narrative, AM) Percent of shoreline protected –high Number of permits requested – low 5 Erosion Distinguished between well engineered and ad hoc – high (EA – link with design standards, AM) Structure modification – low Changes to damage from freeze-thaw – low Loss of land - high Decrease in property values - high Sediment budget - high Nearshore erosion - high Remobilization of contaminated sediments – low Increase in shore protection on unprotected shoreline – moderate (ED – more important, not sure how many sites. Related to climate change) Sediment deposition – high Freeze thaw bluffs – low High vs. low water erosion rates – high Deposition of sediments at creek/ lake interface – moderate Low Water Alga - moderate Exposed sediment - high Development pressure - high Property values – high Inconvenience - low Georgian Bay wetlands - ETWG Sediment budget and deposition - high Aesthetics – view impacts due to vegetation growth - low Aesthetics – view –levels too far down to far away - low Costs to move gauges or other infrastructure impairment – M&I TWG Safe navigation (# of ships groundings or dredging requests) – CNTWG Change in water velocities/ currents - low Habitat change – wild rice beds and people dependent on hunting ETWG Management of contaminated sediments - Moderate Boat ramps out of service - RBTWG Development pressure - high Drainage in local creeks – low Other Tourism – access to beaches – high Tourism – recreational value – high Safe navigation – CNTWG Habitat – ETWG 6 Drowned river mouths – low Water levels as it impacts water quality – low Impact of water levels on tribal lands - ETWG Wild rice – ETWG 6. Uncertainty in Predicting the Future: Robin Davidson-Arnott discussed the concept of uncertainty and the need to consider it in our work (presentation attached). How do we characterize uncertainty and be defensible? There is uncertainty about future climate change and variability, uncertainty about the data we use, uncertainty in the modeling exercises and our ability to distinguish between water level scenarios generated by alternative regulation plans. We need to work with the combinations of lake levels and storms to ensure the range of surge and wave conditions are considered. Likely our primary consideration for uncertainty is how to translate our information from specific sites to broader sections of the study area shoreline. There was general agreement from invited experts on the importance of considering uncertainty in the work of the Coastal Zone TWG. However, recommendations on specific methodologies were not identified in the discussion. Uncertainty Experts Workshop 101508.pdf 7. Flooding of Shoreline Property: Nick Zager presented information to set the context for discussion by identifying locations of past flooding impacts and outlining some key considerations for potential assessment methodologies. The draft guidelines for the FEMA Great Lakes Runup Methodology were presented as an example of a possible option. Potential U.S. sites of interest include: Duluth (Lake Superior) Green Bay (Lake Michigan) Saginaw Bay (Lake Huron) Southeastern Lake Michigan (Lake Michigan) Western Lake Erie (Lake Erie) Buffalo (Lake Erie) Lake St. Clair Potential Canadian sites of interest include: Goulais Bay (Lake Superior) Thunder Bay (Lake Superior) Collingwood (Georgian Bay) Essex (Lake Erie) Lake St. Clair There is a need to define a site on Lake Huron 7 Methodology was discussed: Should be physically-based Should not be too costly Site specific (represent site conditions) A suggestion was to add possible wave surge to the water levels resulting from regulation options at specific sites. Since we have instantaneous gauge data, regression analyses can be run and added to water levels. We can consider the draft guidelines for FEMA Great Lakes Run-up Methodology, using the one percent exceedence: Determine maximum monthly water level Use WIS data to find maximum monthly wave height associated with the maximum water level Use best topography and bathymetry at specific site A distribution can be plotted and a specific return period wave setup elevation can be gathered. Wave data would be required. Circulation modeling may be available from NOAA/GLERL or the NOAA GNOME model. Check with ERDC to see about the timing of WIS updates. LIDAR data may be available but is likely very limited (need to follow up with COE, Mobile and ERDC, Vicksburg) It was strongly recommended that the methodology needs to be verified using field data due to the potential differences between theoretical wave runup and actual conditions along complex shorelines. As well, need to prove that model assumptions are valid through the verification process. However, it was also noted that field verification may be difficult. Given the potential difficulty in differentiating regulation plans that result in fairly similar water levels (especially on Lakes Michigan-Huron and downstream), it was suggested that first efforts should be related to focusing on methods to get the water levels correct and then move to including economic impacts if differences between plans are evident. A suggested process was to start with monthly water levels from available gauge records and determine monthly probability distributions. Next move to add storm surge based on statistical analysis of within month variability at recorded time sequence from water level gauges, then move towards adding local wave and wave transformation impacts and associated runup. These values can then be added to the new water level scenarios generated by alternative regulation plans. Another suggestion is to look at past stage-damage curves generated by other studies, specifically the 1993 IJC Reference Study although there was some concern that these would no longer be useful. It was noted that the State of Wisconsin has good parcel data available and the Office of Coast Survey may have bathymetry data we can use. Coastal TWG Flooding - Oct 15 2008.pdf 8 8. Erosion to Unprotected Land: Robin Davidson-Arnott provided the background for discussion on erosion (see attached presentation). Key points were: Is changing the timing and magnitude of Lake Superior regulation likely to produce significant changes in erosion for either shoreline type (sandy and cohesive shores)? Long term erosion is driven by sediment budget. Problem is if sediment moves out of littoral system. Bay mouth bars could be breached (Wisconsin Point) Low lake levels might cause more bypassing It is difficult to assess catastrophic bluff failure, which is typical on many shorelines in the Great Lakes. Is there a connection between offshore downcutting and deep seated bluff failure? Is it possible to predict such failures? Are there existing models we can use? What are the data requirements? What are the state-of-the-art models that can be used to predict longshore sediment transport gradients within a littorial cell? COSMOS seems to be the most effective for quantitatively evaluating cohesive shorelines, but it would require very site specific data Discussion (based on a report by Baird): the “Superior for Michigan-Huron Plan” increases erosion (cohesive shoreline) at a site on Lake Michigan, about 10 meters more than 77A, Pre-project and “Superior for Superior Plan” over 100 years. Educating Public: the public needs to be educated on various aspects of erosion such as downcutting because it is an issue that can not be visibly seen. The public also needs to be educated on how sandy shorelines erode Some conclusions to move forward with: Dynamic sandy beach Not concerned with dynamic beaches as there was general consensus from the experts that the water levels considered within the fencepost plans were not likely to cause large changes in such systems – only caution would be if sediment were actually being lost from the closed systems – it was noted however, that these types of beaches are inherently dynamic and transient so the question really isn’t whether water levels would impact the processes but would they be to the extent that the normal dynamic nature of the beach would change (e.g. loss of sediment) Erosional sandy beach models can be fairly expensive and also require considerable data information to calibrate properly so they may not be appropriate for trying to compare regulation plans 9 experts thought significant impact were not expected from regulation plan based on the fencepost plan options wave and wave impacts are primary forces influencing longshore transport climate change could be important because of the potential changes in wind and wave conditions. Therefore may want to consider climate change implications Cohesive shoreline Experts thought COSMOS model may be most detailed available given its use on the Lake Michigan Potential Damages Study and other situations. However, the model was also considered fairly data intensive Further sensitivity analysis with COSMOS may be needed using Lake Superior levels as they are likely to be more variable under different regulation plan options (as evidenced by examples presented by David Fay on Day 1 of workshop) There was some concern regarding the challenge of predicting large slump erosion using such a model – it isn’t clear how this could be included erosion cohesive and sandy - Oct 15 2008.pdf 9. Damage to Shore Protection: Gene Clark led this discussion about data, information, and modeling strategies to address damages to shore protection (see attached presentation). One option could be to develop standard failure conditions based on water levels for existing shore protection classes Another option could be a FEPS style analysis Looking at comparison of Baird results on Lake Michigan-Huron (based on a Chicago District project): down-cutting failures vary from $80M (Plan 77A) to $96M (Superior for Michigan-Huron); overtopping failures vary from $17.2M (77A) to $18.7M (Superior for Michigan-Huron); total maintenance relative to 77A, max +14%. What is the shore protection protecting? Some protection is more important than other. We need to address the issue of structure design. Well designed structures should last until old age and not be affected by small changes in water levels. We will need the water level information plus surge for this analysis too, as well as wave run-up. May need more detail on structures currently in place. We could use Google Earth to look for areas with structures. We could use the 1993 10 Levels Reference Study shoreline classification database to inventory structures. We could use the Corps and other agency permit databases to find out information on structure details. Other high resolution imagery may be available in specific locations for use in classifying the shoreline. Some conclusions to move forward with: We could start with hypothetical structures to model with new water level scenarios generated by alternative regulation plans to see what their response is. We should do a sensitivity analysis to take into account the various design parameters. We may need to conduct field surveys of existing structures to evaluate our process. We would need top elevations, notes about the structure, etc. We need to see what modeling packages are available to use. Examples include Baird model (FEPS) or models from ERDC. Still need to consider how sites would be chosen? Also need to consider how many areas would be sampled? IJC Workshop Structures Issues (Clark 10-15-08).pdf 10. Low Water Impacts to Riparians: Mike Shantz led this discussion with a short presentation (attached). Key points of the discussion are summarized below. Lower water levels can be viewed as positive or negative by property owners based on location and perspective. There may be concern with the water intake at Superior Wisconsin. M&I TWG should know about this. There are questions of land ownership as more offshore becomes exposed. Current climate change is increasing bluff recession because bluff faces are not freezing and instead they are failing Should downcutting be examined with Low Water effects? Downcutting during low water is big concern and when water levels rise, catastrophic failures occur. This should be covered directly in erosion and shore protection analysis Do we have to deal with longshore transport and deposition? Is it impacted by low water levels? General expert consensus that fencepost regulation plans weren’t likely to cause major changes in longshore transport and deposition. However, extremely low levels resulting from climate change may be more sensitive. Could deal with as part of erosion assessment Natural inlets are getting blocked with sediment during low water. The inconvenience to fix this is high while the cost to fix it is relatively low. It is 11 relatively easy to fix with equipment available, but can occur several times a year with low water. Not clear as to the geographic extent of such problems and may need to examine further. We need to be able to convey all this information to the public. Need to consider options for clearly explaining processes to the public. A general note was brought up that perhaps if likely regulation plan levels show no change in impacts then it may be advisable to examine extreme levels We may want to look at past studies such as “Design Water Levels” to see how things have changed over the years due to changing water level regimes. We also need to address the benefits of low water levels. One example cited was the restoration of the Cat Island Chain in Green Bay. Low Water Impacts Oct 15 2008.pdf 11. Linking Coastal Processes and Non-Economic Impacts: Robin DavidsonArnott presented information on barriers and dunes (see attached). Modifications of regulated lake levels will effect dynamics and influence biology. If future regulation options are within the natural range, they should not drastically alter processes. If regulation gets beyond historic range, then may be more of a problem to consider. Low terrace or relic beaches have not been mentioned and may want to be considered because there is significant development in these areas. Should work with the ecosystem group to consider impacts for that interest. dunes and barriers Oct 15 2008.pdf 12. Adaptive Management: Scott Thieme lead an open discussion about things the CZTWG should consider recommending to the Study Board as items that would be important to an Adaptive Management Plan. Triggers for when we are outside a defined water level range What about how long we are above or below the range? Need to consider response time – it takes some lead time to implement any changes Need dynamic/ rapid information – better forecasts Need to prepare for extremes – Great Lakes regional climate model Information on the internet 12 It was suggested that the term ‘lake level regulation’ isn’t really accurate on Lake Superior given the relatively limited control regulation has on the water levels. This fact needs to be better conveyed to the public. There was also a sense that adaptive response does not occur until after the situation has reached an extreme. Need to consider adaptive management vs. reactive management. Models are not always accurate especially since evaporation is so difficult to estimate and predicting climate change could bring on more liability Key things to keep track of and consider Wind information Historic ice and coverage Off-shore bathymetry – but one or two sites won’t tell you much. Shore management 13. Final Discussion: Brian Greenwood: Doesn’t see extreme problems with the plans that will be developed. People should be made aware of natural variability. Bill Kamphuis: Nothing more to add. Ralph Moulton: Not much benefit in using old stage-damage/ erosiondamage curves from Levels Reference Study. Consider specific sites. David Hart: Hope to help from a regional urban planner perspective and with GIS. Phil Keillor: Nothing to add. Don Forbes: Consider varying interests around the lake and glacial isostatic rebound. Joe Gailani: Need to consider various coastal models (COSMOS) and their sensitivity to small changes; but many are data intensive. Jim Anderson: Extremely important to have technical commentary regarding what public is experiencing. Understand public concerns and have anticipatory framework. Roger Smithe: No Great Lake water diversions. Opinions regarding changing the GL Charter – don’t push for high lake levels since coastal opinion could change and want to eliminate water. 13