Anthony O. Gabriel

Impacts of Riprap on Wetland Shorelines, Upper Winnebago Pool Lakes, Wisconsin

Isolation of causative factors has proved challenging in characterizing the physical, chemical, and biological effects of shoreline hardening on the nearshore environment because of logistical challenges in identifying comparable sites. Extensive shoreline hardening and interspersion with unaltered shores in the large, shallow lakes in central Wisconsin provide an opportunity to surmount this. We compared the effects of shoreline protection on wave climate, bottom topography and substrate, water quality, and plant and animal assemblages at five adjacent pairs of natural and armored (riprapped) shorelines. Armored shorelines were characterized by coarser, more compacted substrates with lower organic content; cooler temperatures with higher dissolved oxygen; and greater water clarity. Differences in physical and chemical properties likely influenced plant growth forms and fish feeding guild differences between riprapped and natural sites. For example, floating-leaved plants were more abundant and fish were nearly twice as abundant and were represented by larger individuals at natural versus armored shorelines. Substrate characteristics may account for the differences in water quality and plant and animal associations observed in this study. As shoreline property owners continue to install riprap as protection against erosion, we expect the nearshore environment and associated biological communities to increasingly reflect this practice.

Ontario's Great Lakes Flood History

Abstract This note summarizes a reconstruction of Ontarios Great Lakes flood history undertaken for the Canada-Ontario Flood Reduction Program. Stressed is the temporal and spatial distribution of flood events and damages along the shores of the Great Lakes and their connecting channels. A content analysis of selected newspapers from 1847 to 1989 revealed 131 flood events, defined on a lake and channel basis, affecting at least 85 of Ontarios 212 shore municipalities. Reported damages exceeded

Historical Changes in Mid-Water Stands of Common Reed in the Winnebago Pool Lakes, Wisconsin

188 million (1989 dollars) between 1859 and 1987, including

Inventory and characterization of wetland habitat on the Winnebago Upper Pool Lakes, Wisconsin, USA: An integrated multimedia-GIS approach

113 million on Lake Erie. Analysis of flood events and damages in relation to lake levels revealed the critical role of storm-induced flooding.

Cumulative Patterns and Controls of Seawall Construction, Thurston County, Washington

ABSTRACT Despite the tolerance of common reed grass to environmental extremes, mid-water stands in the Winnebago pool lakes of central Wisconsin appear to be diminishing. Formerly occupying shoreline locations, water level manipulations subsequent to dam construction beginning in the 1850s have isolated reed stands off shore. These stands have persisted but casual observations indicate that stand size has been declining. To address this perception we obtained an approximately decadal series of aerial photographs dating back to 1937 for four stands in Lake Poygan. Annual records were available for 1986–94. Using image analysis software, we determined shape and size metrics. Changes in stands varied widely, with areal losses ranging from 2% to 94%. The perimeter showed corresponding losses. Perimeter to area ratio and number of patches indicate that stand loss is characterized by increased fragmentation and shrinking patch size. The pattern of loss appears to proceed through an increase in irregularities along the perimeter, especially along edges facing the summer prevailing winds. This process exposes more of a patch to wind and wave action and eventually results in a division of the patch, culminating in periodic losses of the smallest patches. Despite an overall decrease in stand size, changes in size varied among the years of record with limited recovery occurring during some years.

Management Issues, Characteristics and Effectiveness of Lake Associations and Lake Districts in Wisconsin

An integrated, multimedia-geographic information system (GIS) approach to inventorying and characterizing thirty-nine wetland sites identified on the Winnebago Upper Pool Lakes in Wisconsin, USA was developed. Available black-and-white aerial photogrpahs recorded in 1937, 1957, and 1981 and color digital orthophotos of 2000 were employed as primary data sources to develop a spatio-temporal GIS database using a combination of digital image processing, GIS, Global Positioning System (GPS), and field survey techniques. Ten representative sites were selected to investigate the physical, chemical, and biological characteristics of the wetland habitat in the study area further. Multimedia information as text, graphics, ground photogrpahs, and digital video was then developed to highlight the ecosystem function and structure of those representative wetlands. A computer-based interactive multimedia system, consisting of a graphical user interface and a GIS application module, was constructed to allow easy access to both the spatial data sets and the multimedia information. Given the increased concern over environmental preservation, expansion of urban development, and agricultural land use, it is anticipated that the database will prove valuable for a series of management tasks. The integrated approach provides an innovative way for integrating, analyzing, and presenting wetland information, thus enabling truly interactive collaborations among resource managers, policy makers, reserachers, and stakeholders.

Ecosystem functions of mid-lake stands of common reed in Lake Poygan, Wisconsin

Abstract This paper develops and applies techniques to describe and analyze spatial patterns and controls of seawall construction on Puget Sound Lowland shores, Washington State. The main objectives are: (1) to further develop a methodology that statistically differentiates between sequential, clustered, or random patterns of seawall installation; (2) to apply the cumulative pattern assessment methodology to three drift cells in Thurston County that are representative of those typically found along the Puget Sound; and (3) to identify physical and human controls of seawall construction and patterns by analyzing differences for 109 properties in a variety of relevant drift-cell factors, including direction of sediment transport, slope stability, vegetative cover, land use, and property owner experiences and motives. Property-level information was gathered using a combination of on-site field surveys, property assessment records, aerial photograph/map analysis, and property owner questionnaires. The aerial photo analysis showed that shore protection has greatly increased in each drift cell over the last 33–45 years, increasing from 4–15% to 71–83%. Dates of bulkhead installation, as well as the direction and distance of protected sites relative to the first protected sites within each drift cell, were analyzed using a Spearman rank correlation coefficient. Additional statistical analyses did not identify many significant differences in shoreline characteristics or hazard experiences between shoreline reaches that might help explain patterns in seawall installation, with some exceptions, such as differences in shore protection, erosion experiences, and beach types. Similarly, statistical analyses comparing protected and unprotected properties identified few significant differences or associations, primarily related to improved acreage, backshore uses, historic slumping and recent slope failure, and upland/slope vegetation types.

Impacts, Perceptions, and Management of Shoreline Hazards and Water Levels on a Fluctuating Reservoir: A Case Study of the Winnebago System, Wisconsin

ABSTRACT Through a state-wide survey, this paper compares the characteristics of lake associations and lake districts, including their management objectives, issues, activities, and use of funds and contacts. It also examines the relationships between reported management activities and effectiveness and the nature of the issues, lake characteristics, and organizational characteristics. Lake associations and districts have distinct goals and significant differences in the lake issues each finds important, their activities, and effectiveness. Overall, lake districts tend to initiate higher numbers of actions on important issues, while lake associations tend to report a significantly higher proportion of management actions effectively addressing those issues. Lake associations and districts also differ greatly in their sources of revenue and expenditures, with lake districts having significantly higher amounts in both. We found a positive correlation between the total number of lake management activities undertaken by lake management organizations and the number of cottages, percentage of permanent residents, and property values found on their lake, as well as their membership sizes and annual membership fees. The number of cottages and membership sizes were also significantly correlated with the number of management activities initiated, while the number of cottages was the only factor significantly correlated with the number of issues effectively addressed. We found that organizations affiliated with Wisconsin Association of Lakes are engaged insignificantly higher number of activities and effective solutions. In addition, significantly higher numbers of activities are undertaken by lake districts, as well as organizations that are incorporated and have written by-laws.

Great Lakes Flood Thresholds and Impacts

Mid-lake stands of common reed grass (Phragmites australis) have persisted in the shallow Winnebago Pool Lakes of east-central Wisconsin for more than 65 years. Previous research documented that the stands are declining in area with losses up to 94%. Our goal was to characterize the ecological functions of these stands, in part to assess the implications of their loss. To do so, we studied the common reed stands of Lake Poygan during summer, 1999. Common reed stands stabilized the silty/sandy substrate. Wind velocity and wave action were reduced on the downwind sides, and fine, organic sediment accumulated leeward relative to summer prevailing winds. Water clarity was greater on the leeward side. Within stands, dissolved oxygen was less variable, and temperature tended to be cooler. The 18 species of associated aquatic plants covered three or more times the area in the leeward side than windward side. Twenty-nine species of fish were found using the perimeter of the common reed stands. We expect that stand loss will be accompanied by loss of associated wetland vegetation, and the unique combination of habitat attributes afforded by these stands. The current conditions leeward of the stands suggest that stand loss will have a broader spatial effect on ecological characteristics, including fish populations, and thus the implications may be lakewide.

Response of mid-water common reed stands to water level variations and winter conditions in Lake Poygan, Wisconsin, USA

ABSTRACT This paper provides the results of a mail survey of 872 residential property owners along the shorelines of the Winnebago System, Wisconsin that determined their hazard experiences, adjustments, and management preferences in regards to fluctuating water levels. While half of the respondents were aware of hazard potentials prior to purchase, properties have been impacted by a range of shoreline hazards from flooding (27%) to high water levels (54%). Principally caused by a combination of storm-driven waves and high water levels, hazard damages are hazard-specific, and tend to relate to either the shoreline directly (e.g. loss of beach, lawn and garden damage) or to structures directly on the shoreline (e.g. shore protection or docks). Similar to other systems, many residents have resorted to structural hazard adjustments, generally as a response to erosion or high water levels. The majority of property owners indicated a preference for water level regulation to reduce shoreline hazards. However, the majority of respondents also would prefer the water levels to remain the same, while the remaining respondents were extremely divided between the various options for target summer and winter water levels, actually preferring levels that would increase hazard potentials. There is a need for a public education program on the Winne bago System that focuses on publicizing the technical limitations of lake level regulation to reduce hazard losses, the range of alternative hazard adjustment strategies, and the financial and technical assistance for hazard management available from various government agencies.