Hydrogeomorphic Classification for Great Lakes Coastal Wetlands

A hydrogeomorphic classification scheme for Great Lakes coastal wetlands is presented. The classification is hierarchical and first divides the wetlands into three broad hydrogeomorphic systems, lacustrine, riverine, and barrier-protected, each with unique hydrologic flow characteristics and residence time. These systems are further subdivided into finer geomorphic types based on physical features and shoreline processes. Each hydrogeomorphic wetland type has associated plant and animal communities and specific physical attributes related to sediment type, wave energy, water quality, and hydrology.     

Exotic and Invasive Aquatic Plants in Great Lakes Coastal Wetlands: Distribution and Relation to Watershed Land Use and Plant Richness and Cover

We use data from inundated-area surveys of 58 coastal wetlands spanning a gradient of anthropogenic impacts across all five Laurentian Great Lakes to describe the distribution of nine exotic and invasive taxa of aquatic plants. We found plants that were exotic or have invasive strains to be substantially more prevalent in wetlands in Lakes Erie and Ontario than in Lakes Superior and Huron, with Lake Michigan wetlands intermediate. Najas minor (slender naiad), Butomus umbellatus (flowering rush), and Hydrocharis morsus-ranae (European frogbit) were restricted to the lower lakes and rarely dominant. Myriophyllum spicatum (Eurasian milfoil), Potamogeton crispus (curly pondweed), Lythrum salicaria (purple loosestrife), Phalaris arundinacea (reed canary grass), Phragmites australis (common reed), and Typha sp. (cattail) were more widespread and except for P. crispus, often among the dominant taxa. None of the submerged or floating-leaf exotic taxa were associated with altered total plant cover or richness, although M. spicatum, P. crispus, and native Stuckenia pectinatus (sago pondweed) were positively associated with agricultural intensity in the watershed (a surrogate for nutrient loading). Emergent P. australis, L. salicaria, and Typha were more likely to be present and dominant as agricultural intensity increased, and were associated with elevated emergent cover and decreased emergent genera richness. Effects of dominant taxa on plant cover and richness were readily detected using ordinal data from 100 m inundated segments but were harder to discern with data aggregated to the wetland scale. The sum of shoreline-wide abundance scores for four easily identified taxa (S. pectinata, P. australis, Typha, and L. salicaria) is proposed as a rapidly-measured indicator of anthropogenic disturbance across the Great Lakes.     

Characterizing Seiche and Tide-driven Daily Water Level Fluctuations Affecting Coastal Ecosystems of the Great Lakes

Seiches in the Great Lakes probably play a role similar to that of tides in estuaries in organizing the structure and function of coastal wetlands and embayments, but information needed to test this idea is lacking. Past Great Lakes work has focused on enumerating frequencies of oscillation but without addressing their combined influence. Information on seiche magnitude is sparse and focused on extremes rather than typical levels, and tools that integrate magnitude and frequency components to derive net day-scale effects are lacking. This study uses water level time series to characterize daily fluctuation regimes for 51 stations around the Great Lakes. Distributions of fluctuation magnitude typically had long upper tails, with some level of activity always present. Logarithmic mean daily water level range varied from ∼4 cm in Lake Ontario to > 20 cm in Lake Erie, with largest values at the ends of lakes and in large bays. Oscillation frequency patterns were spatially variable and had both seiche and tide components. One-half the daily sum of water level increments is a computationally tractable metric of fluctuation intensity that integrates magnitude and frequency. This metric is directly interpretable as the column of water moved by all seiche and tide modes combined, which when multiplied by an area of interest yields the volume of water involved. Logarithmic mean values for this metric ranged from ∼10 cm in Lake Ontario to > 50 cm in Lake Erie. Data and tools provided will support future efforts to establish seiche and tide influences on Great Lakes wetlands and embayments.     

Vegetation Change in Great Lakes Coastal Wetlands: Deviation from the Historical Cycle

Water-level change is integral to the structure and function of Great Lakes coastal wetlands, and many studies document predictable relationships between vegetation and water level. However, anthropogenic stressors, such as invasive species, land-use change, and water-level stabilization, interact to shift the historical cycle (of native vegetation migration up- and down-slope) toward dominance by invasive Typha species. Knowing from earlier studies that water-level stabilization alters the historical vegetation cycle, we asked if similar shifts can occur where water levels are not stabilized. Using historical aerial photographs of three coastal wetlands (in Lake Michigan's Green Bay, Wisconsin), we determined that habitat dominated by Typha species has expanded to eliminate wet meadow habitat. Between 1974 and 1992, linear regressions showed strong, significant relationships of both meadow area (R² ≥ 0.894; p < 0.02) and marsh area (R² ≥ 0.784; p < 0.05) to water level in all three wetlands. In 2000, meadow area was below that predicted by the historical pattern due to the landward advance of marsh habitat during a year of decreasing water levels. In the same period, land use in the wetland watersheds converted from agriculture to urban. Urbanization and the replacement of native Typha latifolia by the invasive hybrid Typha xglauca may have overwhelmed the beneficial impact of water-level fluctuation. The documentation of vegetation shifts, as herein, is an essential step in the process of preserving and restoring ecological integrity.     

Assessment of Sediment Yields for a Mixed-landuse Great Lakes Watershed: Lessons from Field Measurements and Modeling

The Soil Water Assessment Tool (SWAT) was implemented to determine annual sediment yields and critical source areas of erosion for the Buffalo River Watershed. Model calibrations were performed by comparing simulated streamflow discharge and sediment concentrations against measured values. Monte-Carlo simulations were performed to identify the most sensitive parameters and the “best-fit” parameter ranges. This study especially highlighted the importance of snow parameters, which, previously had not been identified as sensitive for model simulations. The cover (C) and practice (P) values for croplands had to be reduced considerably from default model values to constrain simulated sediment yields within the observed data range. The model did not simulate an ice-scour event which generated a substantial amount of sediment. The average annual sediment yield simulated by SWAT for the Buffalo River watershed (108,593 ha) amounted to 0.8 tons/ha/yr. The Cazenovia Creek subwatershed contributed the largest portion (45%) of the total sediment yield from the Buffalo River watershed. We attribute the higher sediment yields from Cazenovia Creek to the greater proportion of steep slopes in this subwatershed. The accuracy and reliability of SWAT sediment predictions at the small watershed (second order or less) and storm-event scales will depend on the accuracy of input information, especially the resolution of the landuse-landcover (LULC) layer, the number of rainfall stations used in simulations, and the number of internal sites against which the model has been calibrated.     

Nearshore Community Characteristics Related to Shoreline Properties in the Great Lakes

Successful protection and restoration of Great Lakes nearshore ecosystems will likely rely on management of terrestrial resources along Great Lakes shorelines. However, relationships between biological communities and changing shoreline environmental properties are poorly understood. We sought to begin understanding the potential roles of shoreline geomorphological and land cover properties in structuring nearshore biological communities in the Laurentian Great Lakes. Despite high variability in densities (benthic macroinvertebrates and zooplankton) and catch per unit effort (CPUE, shallow water and nearshore fish) within and among lake areas, several biological community patterns emerged to suggest that nearshore aquatic communities respond to shoreline features via the influences of these features on nearshore substrate composition and stability. Benthic macroinvertebrate densities were not different between shoreline types, although they were generally lower at nearshore sites with less stable substrates. Shallow water fish CPUE and zooplankton densities were generally lower for nearshore areas adjacent to developed mid-bluff shorelines and sites characterized by less stable substrates. Larger fish CPUE appeared to be unresponsive to local shoreline and substrate properties of nearshore zones. The emergence of these patterns despite significant ecological differences among lake areas (e.g., productivity, community composition, etc.) suggests that shoreline development may have comparable influences on nearshore ecosystems throughout the Great Lakes, providing a terrestrialbased indicator of relative nearshore biological and ecological integrity.     

The Impact of Changes in Water Level and Human Development on Forage Fish Assemblages in Great Lakes Coastal Marshes

Changes in water levels and development of shorelines are expected to negatively affect coastal marshes. The small-bodied fish assemblage was sampled in the inner marsh vegetation zone in five Les Cheneaux bays with differing levels of development. Observations were made from 1996 to 2004 during which time summer water levels varied from 177.2 m to 176.0 m (chart datum = 176.0 m). Each marsh was sampled for 10 consecutive days in July and August using gangs of five baited commercial minnow traps. Assemblage composition was assayed by species richness, the number of native minnow species, the percentage of selected tolerant fishes (bowfin, Amia calva, mudminnow, Umbra limi, common carp, Cyprinus carpio, and brown bullhead, Ameiurus nebulosus), and catch-per-unit-effort (CPUE). There were no consistent relationships between fish assemblage measures and year, water level, annual change in water level, exposure, and water temperature. Fish assemblage measures except CPUE were impacted by the density of building along the shoreline, a measure of development. Impervious surface area was < 4.5% and was not consistently related to fish assemblage measures.     

Water Diversion from the Great Lakes: Is a Cooperative Approach Possible?

The concern about other states diverting water from the Great Lakes has prompted the Great Lakes States and provinces to adopt institutional arrangements that have effectively blocked any new diversions.Since the current arrangements do not allow diversions, important opportunities may be lost in the future. This article considers the possibility of 'economically desirable diversions' and how the gains should be allocated among the states and provinces to foster cooperation. The study shows that in most cases, new institutional arrangements will be needed before agreements can be reached. Game theory is used to determine how coalitions may be formed to reach cooperative agreements for diversions. Five different lake diversion games are tried involving Lake Ontario, Lake Superior, Lake Erie, Lake Michigan-Huron, and finally, all the lakes together. Diversions from Lake Ontario may offer the best opportunity for cooperation since there are no interlake effects.     

Revisiting the Great Lakes Water Quality Agreement phosphorus targets and predicting the trophic status of Lake Michigan

LM3-Eutro is a high-resolution eutrophication model with several improved features lacking in historical Great Lakes models. We calibrated LM3-Eutro using a 2-year (1994-1995) dataset and performed a hindcast simulation from 1976 to 1995 to evaluate the model's ability to make predictions over an extended period of time. Results show a reasonable agreement between model output and field data over this time period. The model predicted that an annual loading of 5600 metric tons (MT) would result in a lake-wide annual total phosphorus (TP) concentration of 7.5 μg L^− 1. Using best estimates of future TP loadings, LM3-Eutro forecasts suggest that Lake Michigan will remain oligotrophic and will continue to meet the 7 μg L^− 1 spring TP concentration Great Lakes Water Quality Agreement objective.     

The Lake Ontario Great Lakes Science Practicum: A Model for Training Limnology Students on How to Conduct Shipboard Research in the Great Lakes

The authors designed and led an 8-day limnology practicum conducted on the R/V Lake Guardian that focused on classical and emerging technologies in a series of four inter-dependent teaching modules. The practicum was tied together by a general research question (Are spatial patterns of Lake Ontario productivity a function of distance from the shoreline?), and a guided inquiry approach was used to help students frame testable hypotheses to address this question. Students collected a research-quality data set while participating in the practicum's teaching models, and subsequent to the cruise presented their results as oral papers at research conferences and as research papers. The design of this practicum may provide a useful model for other educators who wish to train the next generation of Great Lakes limnologists by conducting courses on a research vessel.     

Applying Water Quality Modeling to Regulating Land Development in a Watershed

Achieving a balance between land development and environmental protection has always been a challenge for many policy makers around world. The purpose of our project is to build a management system for protected drinking water source watersheds where land development is restricted for reasons of water health and drinking safety. Ideally under this proposed management system, land development is not considered taboo, but can proceed with preconditions. We first divided a protected area into two protection zones for different types of regulations. In the first zone, any type of land development is strictly prohibited, as the currently dominant philosophy for watershed protection. In the second zone, development is allowed but only when a permit with more environmental protection requirements is granted by a responsible governmental agency. In response to land development regulations, we proposed three compensation programs to the landowners of the protected watersheds to reduce their resistance on the inclusion of their properties into the designated protected areas. How to delineate and divide a protected area for different levels of regulation is thus a concern of all parties involved in management and compensation programs. In this paper, we demonstrate a case study on the Kao-Ping River Watershed, a subtropical watershed with highly heterogeneous land uses and a wide range of elevations in southern Taiwan. Through this study, we empirically examined the feasibility of the proposed management and compensation schemes. The targeted water pollution abatement goals were regarded as the basis of determining the area requirements for these two types of protection zones. Under this principle, the Arc/View GIS software and two water quality prediction models, QUAL2E and GWLF, were repeatedly applied to simulate the effects of water pollution reduction with different acreage of development-restricted areas. The optimal areas of the protected zones from the modeling results were further used to estimate the amounts of compensation fees based on the three following mechanisms: land banking, conservation easement, and transferable development rights.     

Great Lakes Vegetation Dynamics: The Role of Fluctuating Water Levels and Buried Seeds

The objective of this study was to review the relationship between fluctuating water levels and shoreline vegetation dynamics in the Great Lakes. Low water periods allow many plant species and vegetation types to regenerate from buried seeds. A review of published seed bank densities shows that some lakeshores have densities of buried seeds greater than l0⁴ seeds m⁻², an order of magnitude greater than densities reported from prairie marshes. High water periods kill dominant species (e.g., Typha sp.), thereby creating gaps which other species can colonize during low water periods. High water also kills woody plants, thereby extending marshes landward. Fluctuating water levels therefore increase the area of shoreline vegetation, and the diversity of vegetation types and plant species. Any stabilization of water levels would likely reduce marsh area, vegetation diversity, and plant species diversity. Four basic shoreline vegetation types (forest and shrub thickets, wet meadow, marsh, and aquatic) can be recognized; both wet meadow and marsh largely result from fluctuating water levels.     

Updated census in the Laurentian Great Lakes Watershed: A framework for determining the relationship between the population and this aquatic resource

The Laurentian Great Lakes Watershed (LGLW) is a complex socio-ecological system that spans the United States and Canada and includes Anishinaabe Nations, the Haudenosaunee Confederacy, and Métis Nations. However, this system contains overlapping political and ecological boundaries that do not conform, obscuring a true geographic definition of the LGLW and complicating the inclusion of population data in policy and social-ecological systems research. In this Short Communication, we provide a spatial framework for assessing the LGLW population using the watershed footprint under the Great Lakes Commission’s jurisdiction with international consistency to support regional science and policy, and discuss challenges in accurately assessing Indigenous areas. Using the best available sources, we estimate a population of 38,327,681 people (2015–2019) within the watershed and 133,737 residents within government-delineated Indigenous, First Nation, and Métis census areas of 2021.     

Updated invasion risk assessment for Ponto-Caspian fishes to the Great Lakes

Majority of invasive species discovered in the Great Lakes since 1985 are native to the Ponto-Caspian region, including species that have had strong negative impacts in the Great Lakes (for example, dreissenid mussels and the round goby). The rich biota of the Ponto-Caspian region coupled with a high volume of commercial shipping traffic strongly suggests that this region will continue to be a major source of invasive species to the Great Lakes. To assess invasion risk by Ponto-Caspian fishes that have not been included in previous studies, we reviewed English-language publications and untranslated European literature (published primarily in Russian), focusing on physiological and ecological traits that have proven useful in previous risk assessments. We then used discriminant analysis to identify fishes that had a high probability of becoming established, spreading, and having significant negative impacts in the Great Lakes. Our updated listing of high-risk Ponto-Caspian fishes includes five species identified previously (the Black and Caspian Sea sprat, Eurasian minnow, big-scale sand smelt, European perch, and monkey goby) and five additional species (the Black sea shad, Caspian tyulka, Volga dwarf goby, Caspian bighead goby, and black-striped pipefish). Of these ten species, four (the monkey goby, big-scale sand smelt, Caspian tyulka, and black-striped pipefish) are likely to survive ballast water exchange as eggs, larvae, or adults based on salinity tolerances. Our results can be used to focus ongoing surveillance and rapid response efforts by highlighting Ponto-Caspian fishes that pose the greatest risk of becoming established and having significant negative impacts in the Great Lakes.     

Coastal geomorphic response to seasonal water-level rise in the Laurentian Great Lakes: An example from Illinois Beach State Park,USA

Hydrodynamic processes, such as fluctuating water levels, waves, and currents, shape coastlines across timescales ranging from minutes to millennia. In large lacustrine systems, such as the Laurentian Great Lakes, the role of water level in driving long-term (centuries to millennia) coastal evolution is well understood. However, additional research is needed to explore short-term (weeks to months) beach geomorphic response to fluctuating water level. Developing a process-focused understanding of how water level fluctuations shape coastal response across these shorter time scales is imperative for coastal management. Here, we present measurements of geomorphic response along a lacustrine beach ridge plain to seasonal water level fluctuations during a decadal high-stand in Lake Michigan water level. Frequent topographic change measurements revealed high spatial and temporal variability in geomorphic response to rising lake level. Sites immediately downdrift of shore protection began to erode immediately as lake level increased. The co-occurrence of peak seasonal lake levels and a modest increase in wave energy resulted in erosion and overwash at sites that resisted erosion during the initial seasonal rise in lake level. None of the sites in this study returned to their initial morphology following seasonal lake level rise. Given that peak water levels were nearly identical in 2017 and 2018, yet the majority of erosion at our sites occurred in 2017, we postulate that erosion associated with seasonal lake level rise is primarily a function of the change in annual maximum water level from year to year, rather than solely the elevation of the water level.     

Flood Management and Sustainable Development of Water Resources: The Case of Great Lakes Basin

Abstract

One challenging issue in flood planning and management is to design and apply integrated approaches to estimate likely future economic, social, and other human vulnerabilities to (and impacts of flood), and to identify desirable options that could be used to reduce these vulnerabilities. Given the uncertainties in flood management, it is difficult to decide which options are effective and desirable. Research on developing well-designed flood management strategies can provide the information and understanding necessary for identifying more effective options and better plans for ensuring regional sustainability. This paper focuses on methodology development for the multi-criteria evaluation of flood management options using the Great Lakes Basin as an example. It starts wivh an introduction of some major concerns about flood management in a context of watershed sustainability. This is followed by an indication of the importance of flood management option evaluation to sustainable water resource development. Then, it presents an integrated assessment (IA) approach to evaluate the performance of alternative flood management options, and to identify more effective and desirable policies. Application of the IA in the case study shows how the approach can be used for identifying the more desirable and effective options     

Can-GLWS: Canadian Great Lakes Weather Service for the Soil and Water Assessment Tool (SWAT) modelling

The rapid rise in availability of large geospatial datasets for the development of hydrological models such as Soil and Water Assessment Tool (SWAT) has led to a dramatic increase in both the demand and availability of web services and tools that assist watershed modellers in incorporating data and knowledge into their modelling frameworks. Within the Canadian Great Lakes region, there is a huge potential for the application of SWAT in integrated water resources management. However, a potential barrier is the preparation of SWAT weather inputs that require time-intensive preprocessing of large data sets. Because such preprocessing is reproducible, the redundancy associated with it can be removed by introducing a web service that enables easy and open dissemination of climate data (including climate change and historical data) in SWAT-ready format. This short communication introduces such a web service called the Canadian Great Lakes Weather Data Service for SWAT (Can-GLWS). It hosts observed (historical) and projected (future) daily precipitation, daily maximum/minimum temperature, as well as weather generator database at regular grids (300 arc seconds or ~10 km) for use in SWAT simulations of the region. The novel Can-GLWS web service offers flexibility in selecting the region of interest by allowing them to be uploaded as a shapefile or to draw a rectangle or a polygon. We believe that such data as a service platform will help many practitioners to explore several issues pertaining to the sustainability of the freshwater resources of Canadian Great Lakes using the SWAT model.     

如意湖污染负荷估算及水质保障措施

对郑州如意湖潜在的污染源进行了分析并计算了主要污染物的负荷量,结果表明:主要污染途径为河道补水、地表径流、湖面降水、湖面旅游等,主要污染物NH3-N、CODMn、BOD5、TP、TN的污染负荷分别为3 211、23 924、2 456、827、427 kg/a.基于实用性、景观性、生态性和统筹规划的原则,提出了污染防治措施.     

Water Resources Sustainability Indicator: Application of the Watershed Characteristics Approach

The quantification of the renewable flux (i.e. sustainable limit) of the hydrologic system is the prerequisite for transitioning from unsustainable to sustainable water resources management. The application of the Watershed Characteristics Approach to estimate the renewable flux of the hydrologic system was demonstrated using Minnesota’s (USA) Twin Cities Metropolitan Area (TCMA). The methodology quantified the relationships between landscape properties and water balance characteristics, resulting in the development of functioning hierarchical hydrogeological units with corresponding recharge rates. This renewable flux is a key quantitative characteristic for the assessment of a sustainability indicator. The key indicator of sustainable water use is the ratio of the renewable capacity of the hydrologic system to the water use by humans and the environment. By incorporating water use estimates for the TCMA relative to the calculated recharge rates, sustainability indicators for groundwater and total flux were calculated for the metropolitan area. As far back as the 1890s, declines in TCMA groundwater levels have been observed, which correspond to the unsustainable groundwater extraction estimates identified in the results of this study. The non-stationary characteristics of urban watersheds influenced by ongoing land use/land cover changes as illustrated in this paper, emphasizes the need for conservative hydrologic planning to achieve sustainable water management. This approach can also be applied to other metropolitan areas as a hydrologic tool for decision-makers to design sustainable water policy and prevent the over-extraction of the water flowing through the hydrologic system.