The discovery of the nonindigenous,mottled fingernail clam, Eupera cubensis (Prime, 1865) (Bivalvia: Sphaeriidae) in the Chicago Sanitary and Ship Canal (Illinois River Drainage), Cook County,Illinois

The nonindigenous mottled fingernail clam, Eupera cubensis is reported from the Upper Mississippi River Basin for the first time. This record represents a significant northern range expansion for the species in the United States. It appears to be presently confined to a 35-km stretch of the Chicago Sanitary and Ship Canal (CSSC), an artificial waterway that connects the Mississippi River drainage to the Great Lakes. Although the introduction of this species to the Great Lakes basin poses uncertain risks to the general aquatic community, the immediate effects of Eupera cubensis on the fauna of the CSSC are expected to be minimal.     

Status of the major aquaculture carps of China in the Laurentian Great Lakes Basin

There is concern of economic and environmental damage occuring if any of the four major aquacultured carp species of China, black carp Mylopharyngodon piceus, bighead carp Hypophthalmichthys nobilis, silver carp H. molitrix, or grass carp Ctenopharyngodon idella, were to establish in the Laurentian Great Lakes. All four are reproducing in the Mississippi River Basin. We review the status of these fishes in relation to the Great Lakes and their proximity to pathways into the Great Lakes, based on captures and collections of eggs and larvae. No black carp have been captured in the Great Lakes Basin. One silver carp and one bighead carp were captured within the Chicago Area Waterway System, on the Great Lakes side of electric barriers designed to keep carp from entering the Great Lakes from the greater Mississippi River Basin. Three bighead carp were captured in Lake Erie, none later than the year 2000. By December 2019, at least 650 grass carps had been captured in the Great Lakes Basin, most in western Lake Erie, but none in Lake Superior. Grass carp reproduction has been documented in the Sandusky and Maumee rivers in Ohio, tributaries of Lake Erie. We also discuss environmental DNA (eDNA) results as an early detection and monitoring tool for bighead and silver carps. Detection of eDNA does not necessarily indicate presence of live fish, but bigheaded carp eDNA has been detected on the Great Lakes side of the barriers and in a small proportion of samples from the western basin of Lake Erie.     

Dividing the waters: The case for hydrologic separation of the North American Great Lakes and Mississippi River Basins

Legislation has been introduced this year in the U.S. Congress, but not yet enacted, that would direct the U.S. Army Corps of Engineers to complete a study of the options that would prevent the spread of aquatic nuisance species between the Great Lakes and Mississippi River Basins. Hydrologic separation is the only option which closes the aquatic connection between the two basins and does not require continuous operation and maintenance of various technologies that have some risk of failure. The one-time, capital cost to separate the two basins is widely acknowledged to be high, and the outstanding question is whether the costs are justified given the significant risk of future ecological damages and long-term economic losses. Interests opposing separation have mounted a public campaign that the news media have picked up to deny that hydrologic separation should be considered or that a problem even exists. The campaign rests on four assertions: (1) existing electric barriers in the Chicago canals are effective; (2) it is too late--the carps are already in the Great Lakes or soon will be; (3) Asian carps will not thrive in the Great Lakes due to inadequate food and spawning habitat; and (4) Asian carps are unlikely to cause serious harm. Our review of these assertions and the ecological and socio-economic threats to both basins supports our recommendation that the pending legislation be passed and that it include analysis of hydrologic separation of the two basins.     

Laurentian Great Lakes Hydrology and Lake Levels under the Transposed 1993 Mississippi River Flood Climate

The Laurentian Great Lakes are North America's largest water resource, and include six large water bodies (Lakes Superior, Michigan, Huron, Erie, Ontario, and Georgian Bay), Lake St. Clair, and their connecting channels. Because of the relatively small historical variability in system lake levels, there is a need for realistic climate scenarios to develop and test sensitivity and resilience of the system to extreme high lake levels. This is particularly important during the present high lake level regime that has been in place since the late 1960s. In this analysis, we use the unique climate conditions which resulted in the 1993 Mississippi River flooding as an analog to test the sensitivity of Great Lakes hydrology and water levels to a rare but actual climate event. The climate over the Upper Mississippi River basin was computationally shifted, corresponding to a conceptual shift of the Great Lakes basin 10̊ west and 2̊ south. We applied a system of hydrological models to the daily meteorological time series and determined daily runoff, lake evaporation, and net basin water supplies. The accumulated net basin supplies from May through October 1993 for the 1993 Mississippi River flooding scenario ranged from a 1% decrease for Lake Superior to a large increase for Lake Erie. Water levels for each lake were determined from a hydro-logic routing model of the system. Lakes Michigan, Huron, and Erie were most affected. The simulated rise in Lakes Michigan and Huron water levels far exceeded the historically recorded rise with both lakes either approaching or setting record high levels. This scenario demonstrates that an independent anomalous event, beginning with normal lake levels, could result in record high water levels within a 6- to 9-month period. This has not been demonstrated in the historical record or by other simulation studies.     

Contemporary genetic structure of walleye (Sander vitreus) reflects a historical inter-basin river diversion

River diversions can have unexpected biological consequences. In the mid-20th century, the upper Ogoki River in northern Ontario was diverted from its original Hudson Bay drainage to flow into the Great Lakes. Although walleye were present in both systems prior to the diversion, the Hudson Bay and Great Lakes watersheds had previously been separated since the early Holocene (7500–8500 years ago). We assessed the effects that this inter-basin diversion has had on the genetic structure of two formerly allopatric populations. We assessed the genetic structure and diversity of walleye in the Ogoki and Little Jackfish river systems and Lake Nipigon (number, distribution, and divergence of identified genetic groups) and quantified the contribution of fish from the historical population (Hudson Bay drainage Ogoki River) and Lake Nipigon to walleye in the Ogoki and Little Jackfish Rivers. Walleye from Ogoki Lake, the Ogoki River diversion through the Little Jackfish River, Lake Nipigon and Nipigon Bay were genotyped at 10 microsatellite loci. Significant genetic differences were detected among sampling locations: walleye from Ogoki Lake, presumably representing fish originally from the historical Ogoki River gene pool, were genetically similar to but statistically distinct from walleye within the diversion. Walleye from sample sites within the diversion and Ombabika Bay appear to form a single genetic group that is largely derived from the Ogoki watershed and differs significantly from walleye in Lake Nipigon and Nipigon Bay. Our findings confirm that the historical river diversion has had long-term effects on the genetic composition of contemporary walleye populations.     

Population genetic diversity and phylogeographic divergence patterns of the yellow perch (Perca flavescens)

Great Lakes populations of yellow perch have fluctuated throughout past decades to the present due to unstable recruitment patterns and exploitation. Our study analyzes genetic diversity and structure across the native range in order to interpret phylogeographic history and contemporary patterns. We compare complete mitochondrial DNA control region sequences (912 bp) from 568 spawning individuals at 32 sites, encompassing all 5 Great Lakes and outlying watersheds from the upper Mississippi River, Lake Winnipeg, Lake Champlain, and Atlantic and Gulf coastal relict populations. These broad-scale divergences additionally are compared with fine-scale patterns from 334 individuals at 16 spawning sites across Lake Erie's 4 fishery management units. We identify 21 mtDNA haplotypes, including a widespread type that totals 87% of individuals across the Great Lakes. Overall genetic diversity is relatively low in comparison with other Great Lakes fishes, congruent with prior allozyme and microsatellite studies. The largest genetic demarcation separates 2 primary population groups: one in the Great Lakes, Lake Winnipeg, and upper Mississippi River watersheds and the other along the Atlantic and Gulf coasts, together with Lake Champlain; which diverged ∼ 365,000 years ago. In addition, the watersheds house genetically separable groups, whose patterns reflect broad-scale isolation by geographic distance. A few spawning groups show some fine-scale differentiation within Lake Erie, which do not reflect fishery management units and need further study with higher-resolution markers.     

Nutrient Contributions from Alluvial Soils Associated with the Restoration of Shallow Water Habitat in the Lower Missouri River

The Missouri River has been extensively altered as the result of channelization, bank stabilization, and the construction of six main stem reservoirs. In response to the resultant habitat loss, the US Army Corps of Engineers was tasked with restoring approximately 8100 ha of shallow water habitat (SWH), in part, for the benefit of the endangered pallid sturgeon (Scaphirhynchus albus). Construction of off‐channel habitats involves the removal and disposal of excavated alluvium either by direct discharge into the river or by secondary erosion, which raised concerns regarding the introduction of sediment and associated nutrients into the Missouri River. Soils from nine side‐channel chutes were sampled to represent nutrient concentrations from habitat restoration activities. Soils from 12 historically undisturbed sites were also sampled to represent reference conditions in the Missouri River flood plain. The results of this study indicate that nutrient characteristics of soils from selected SWH locations generally are similar to those of historically undisturbed soils. The estimated mass of total phosphorus from chutes accounted for 1.9% of Missouri River and 0.5% of Mississippi River total phosphorus loads during the 1993–2012 analysis period. The mass of nitrate, the constituent most closely related to gulf hypoxia, was 0.01% or less of the Missouri and Mississippi River nitrate loads. Sediment volumes from the chutes accounted for 3.1 and 1.5% of total suspended loads from the Missouri and Mississippi Rivers. Overall, the introduced sediment from side‐channel chute construction associated with SWH restoration accounts for a small portion of total nutrient and sediment transport in the Missouri and Mississippi Rivers. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. River Research and Applications published by John Wiley & Sons, Ltd.     

Responses of consumers and food resources to a high magnitude,unpredicted flood in the upper Mississippi River basin

The Mississippi and Missouri Rivers experienced flooding in 1993 that fell outside the annual predictable flood period of spring and early summer. Flooding began in late June, peaked in late July (25 232 m³/s on the upper Mississippi and 21 240 m³/s on the Missouri) and remained at or near flood stage into October 1993. This study was performed to determine if disturbance by an unpredicted flood event would alter trophic dynamics of river–floodplain systems by creating shifts in the composition of organic matter available to consumers. The Ohio River, which did not flood during the same period, was examined for comparison. Stable isotopic ratios of carbon and nitrogen from samples collected in 1993 and 1994 were used to characterize potential food sources and determine linkages between food sources and invertebrate and fish consumers. Pairwise contrasts, performed separately for each river, indicated there were few interannual differences in δ¹³C and δ¹⁵N of organic matter sources and consumers. Between sample period (flood year versus normal water year) trends in both flooded rivers were similar to between‐year trends observed for the Ohio River. Trophic structure of the Mississippi and Ohio Rivers was similar in both years, with fine and ultra‐fine transported organic matter and dissolved organic matter representing the major sources of organic matter. Overlapping isotopic signatures in the Missouri River made tracking of sources through the consumers difficult, but similarities in δ¹³C and δ¹⁵N between years indicated trophic structure did not change in response to the flood. The results suggest that consumers continued to rely on sources of organic matter that would be used in the absence of the unpredicted 1993 flood. It is proposed that trophic structure did not change in response to flooding in the Mississippi and Missouri Rivers because both rivers exhibited the same trends observed in the Ohio River. Copyright © 2001 John Wiley & Sons, Ltd.     

Recruitment Sources of Channel and Blue Catfishes Inhabiting the Middle Mississippi River

Insight into environments that contribute recruits to adult fish stocks in riverine systems is vital for effective population management and conservation. Catfishes are an important recreational species in the Mississippi River and are commercially harvested. However, contributions of main channel and tributary habitats to catfish recruitment in large rivers are unknown. Stable isotope and trace elemental signatures in otoliths are useful for determining environmental history of fishes in a variety of aquatic systems, including the Mississippi River. The objectives of this study were to identify the principal natal environments of channel catfish Ictalurus punctatus and blue catfish Ictalurus furcatus in the Middle Mississippi River (MMR) using otolith stable oxygen isotopic composition (δ¹⁸O) and strontium : calcium ratios (Sr : Ca). Catfishes were sampled during July–October 2013–2014, and lapilli otoliths were analysed for δ¹⁸O and Sr : Ca. Water samples from the MMR and tributaries were collected seasonally from 2006 to 2014 to characterize site‐specific signatures. Persistent differences in water δ¹⁸O and Sr : Ca among the MMR and tributaries (including the upper Mississippi, Illinois, and Missouri rivers as well as smaller tributaries) were evident, enabling identification of natal environment for individual fish. Blue and channel catfish stocks in the MMR were primarily recruited from the large rivers (Missouri and Mississippi) in our study area, with minimal contributions from smaller tributaries. Recruitment and year class strength investigations and efforts to enhance spawning and nursery habitats should be focused on in large rivers with less emphasis on smaller tributaries. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis of changes in the Great Lakes hydro-climatic variables

A study of changes in hydro-climatology of the Great Lakes was performed incorporating the nonparametric Mann–Kendall trend detection test and a recently developed Bayesian multiple change point detection model. The Component Net Basin Supply (C-NBS) and its components (runoff, precipitation, evaporation) as well as water levels of Great Lakes were analyzed for gradual (i.e. trend type) and abrupt (i.e. shift type) nonstationary behaviors at seasonal and annual scales. It was found that the C-NBS experienced significant upward trends only in the lower Great Lakes (Erie, Ontario) during the summer portion of the year. At an annual scale upward trends were observed only in Lake Ontario. Change point analysis suggested an upward shift in Great Lakes C-NBS in the late 1960s and early 1970s. A combination of gradual and abrupt change analysis of Great Lakes water levels indicated a common upward shift along with a change in trend direction around the early 1970s. It was also found that precipitation and runoff are on a plateau and in some cases on a decreasing course following an increasing trend in the early twentieth century. Results obtained from this study show that the hydro-climatology of Great Lakes is characterized by nonstationary behavior. Changes in this behavior have caused the Great Lakes water levels to decrease during the last few decades. This study provides valuable insights into the nature of the nonstationary behavior of hydro-climatic variables of Great Lakes and contributes useful information to the future water management planning.     

Towards improving an Area of Concern: Main-channel habitat rehabilitation priorities for the Maumee River

The Maumee River watershed in the Laurentian Great Lakes Basin has been impacted by decades of pollution and habitat modification due to human settlement and development. As such, the lower 35 km of the Maumee River and several smaller adjacent watersheds comprising over 2000 km² were designated the Maumee Area of Concern (AOC) under the revised Great Lakes Water Quality Agreement in 1987. As part of pre-rehabilitation assessments in the Maumee AOC, we assessed fish and invertebrate communities in river km 24–11 of the Maumee River to identify: 1) areas that exhibit the highest biodiversity, 2) habitat characteristics associated with high biodiversity areas, 3) areas in need of protection from further degradation, and 4) areas that could feasibly be rehabilitated to increase biodiversity. Based on benthic trawl data, shallow water habitats surrounding large island complexes had the highest fish diversity and catch per unit effort (CPUE). Electrofishing displayed similar fish diversity and CPUE patterns across habitat types early in the study but yielded no discernable fish diversity or CPUE patterns towards the end of our study. Although highly variable among study sites, macroinvertebrate density was greatest in shallow water habitats <2.5 m and around large island complexes. Our results provide valuable baseline data that could act as a foundation for developing rehabilitation strategies in the lower Maumee River and for assessing the effectiveness of future aquatic habitat rehabilitation projects. In addition to increasing in-channel habitat, watershed-scale improvements of water quality might be necessary to ensure rehabilitation strategies are successful.     

A pound of prevention,plus a pound of cure: Early detection and eradication of invasive species in the Laurentian Great Lakes

Ballast water regulations implemented in the early 1990s appear not to have slowed the rate of new aquatic invasive species (AIS) establishment in the Great Lakes. With more invasive species on the horizon, we examine the question of whether eradication of AIS is a viable management strategy for the Laurentian Great Lakes, and what a coordinated AIS early detection and eradication program would entail. In-lake monitoring would be conducted to assess the effectiveness of regulations aimed at stopping new AIS, and to maximize the likelihood of early detection of new invaders. Monitoring would be focused on detecting the most probable invaders, the most invasion-prone habitats, and the species most conducive to eradication. When a new non-native species is discovered, an eradication assessment would be conducted and used to guide the management response. In light of high uncertainty, management decisions must be robust to a range of impact and control scenarios. Though prevention should continue to be the cornerstone of management efforts, we believe that a coordinated early detection and eradication program is warranted if the Great Lakes management community and stakeholders are serious about reducing undesired impacts stemming from new AIS in the Great Lakes. Development of such a program is an opportunity for the Laurentian Great Lakes resource management community to demonstrate global leadership in invasive species management.     

Stable isotopes in zebra mussels as bioindicators of river–watershed linkages

Concerns about biodiversity and sustainability extend to many ecological systems, including large river systems that are highly modified by human activities. The Mississippi River is one such system that is currently regulated for navigational and flood control purposes, bears a large agricultural nutrient load, and has experienced rapid spread of the exotic zebra mussel, Dreissena polymorpha, since 1991. Human development of the extensive watershed system of the Mississippi River is ongoing and is expected to lead to further changes in river ecology. This study tested whether stable isotope compositions of the zebra mussel could help identify watershed and tributary loading of carbon (C), nitrogen (N), and sulphur (S) to the mainstem river. Zebra mussels were collected seasonally in the lower Mississippi River at Baton Rouge in 1997, and along most of the length of the river in a north–south transect from Minnesota to Louisiana during August 1998. Results showed substantial seasonal variations in C, N and S isotopic compositions of 2‰ or greater, but also that seasonal changes appeared regular and linked to changing watershed inputs and chemistry of the river water. Nitrate was the dominant N nutrient in the Mississippi River, but isotope analyses showed that food webs based on ammonium rather than nitrate were likely important for the zebra mussel. Results from the north–south transect followed expectations based on mixing of mainstem river water with tributaries that had different chemistries, so that local zones of influence were detectable in the combined CNS zebra mussel isotopes downstream of major tributary confluences for the Illinois, Missouri and Ohio Rivers. Overall, the study supports use of stable isotopes to help monitor watershed development and downstream effects on aquatic food webs. Copyright © 2003 John Wiley & Sons, Ltd.     

Monitoring metal and persistent organic contaminant trends through time using quagga mussels (Dreissena bugensis) collected from the Niagara River

Historically, the Niagara River received the discharge of persistent bioaccumulative and toxic chemicals from municipal and industrial outfalls and hazardous waste landfills. American and Canadian governments have coordinated investigations of chemicals entering the river and initiated remedial measures and monitoring programs with a goal to reduce loadings of toxic chemicals to the river. This study, a component of the Ontario Ministry of Environment Mussel Biomonitoring Program, compares contaminant concentrations in quagga mussels (Dreissena bugensis) collected from nine locations in the Niagara River in 1995 and 2003 to assess anticipated changes in tissue concentrations of contaminants in response to ongoing remedial efforts by government agencies and local industries. The concentrations of persistent organic compounds (e.g., PCBs, hexachlorobenzene, hexachlorobutadiene, octachlorostyrene) in quagga mussels in 2003 were lower than concentrations measured in 1995, consistent with a decrease in reported mean annual concentrations of these compounds in water. Significant differences in total PCB concentrations in mussels between stations (F = 4.6; P < 0.001) suggested sources of PCBs on the American side of the upper Niagara River. In general, highest concentrations of persistent organic compounds were found downstream of the Occidental Chemical Corporation Buffalo Avenue facility suggesting local sources of these contaminants notwithstanding remedial efforts. In contrast, metal concentrations in quagga mussels in 2003 were similar to concentrations found in 1995 and to values reported in the literature for mussels collected from industrialized areas in the Great Lakes. Overall, our results suggest that remedial efforts to improve water quality in the Niagara River have been successful.     

The Ven Te Chow Memorial Lecture: On Future Professional Activities Of The International Water Resources Association

ABSTRACT

The Upper Mississippi River Basin has experienced considerable hydrologic change in the last two centuries as a result of removal of wetland areas, deforestation and subsequent reforestation, changes in agricultural practices, urbanization, navigation projects, and the construction of levees. It is popularly accepted that the human-induced modifications to the river and its watersheds have increased the amount of flow in the Mississippi River, particularly during flooding events. Long-term streamgage records in the Upper Mississippi River Basin were analyzed to determine trends in streamflows and flooding. Over the 130 years of gaging there have been various periods in which the frequency and magnitude of floods have fluctuated. Trends in average flow and flooding are strongly correlated to coincident increases in average annual precipitation. For many portions of the watershed, precipitation and streamflows over the last three decades have been higher than any earlie period on record. Outside of the dominant influence of climate variation, only one major change on Mississippi River flood discharges is observed. Flood control reservoirs in the Missouri River watershed appear to produce a 10 per cent reduction in the average flood peak and average flood volume for the Mississippi River at St. Louis, Missouri.     

Effectiveness of Piscicides for Controlling Round Gobies (Neogobius melanostomus)

Round gobies (Neogobius melanostomus) were introduced to the Great Lakes presumably as a result of ballast water releases from seagoing freighters returning from European water bodies. These unwelcome fish have become established in the Great Lakes region and are expanding their range to suitable portions of other interior drainage basins including the Mississippi River traversing the central United States and the Trent-Severn waterway spanning south-central Ontario. If the invasion continues, use of chemical toxicants as a control measure may be necessary. Toxicity tests of the currently registered piscicides antimycin, rotenone, 3-trifluoromethyl-4-nitrophenol (TFM), and Bayluscide^® were conducted with three fish species native to the Great Lakes and round gobies collected from the Illinois Waterway. Tests indicated that round gobies are sensitive to all of the piscicides, however, the level of sensitivity is similar to that of the native fish species tested. Therefore, currently registered piscicides have limited potential to selectively remove round gobies. Bottom-release formulations of Bayluscide^® and antimycin were also evaluated as control agents for the normally bottom-dwelling round goby. Avoidance behavior tests demonstrated that the round goby did not react to the presence of either chemical. Therefore, the bottom-release formulations may have some application for the selective removal of round gobies, and may be one of the few tools presently available to fishery managers to help limit the range expansion of this invasive fish.     

未来黄河下游治理的主要对策

针对黄河下游治理难度大、河情十分特殊的实际,提出了黄河下游治理的主要对策：①必须把握黄河未来水沙变化的规律;②要解决好黄河下游水资源不足的实际问题,在加大减沙入黄措施的同时寻求调水济黄途径;③应加大宽河道整治力度,重点研究“二级悬河”治理的对策;④对黄河下游宽河道边界应有新的布局;⑤黄河口治理应采取“输、挖、分”并举的方案,即束水冲沙、输沙入海,挖沙疏浚和科学分洪。     

Natal environments of age‐0 paddlefish in the middle Mississippi River inferred from dentary microchemistry

Effective management and conservation of riverine fish species relies on identification of habitats that contribute recruits to fish populations. Paddlefish are an important commercial and recreational species inhabiting North American large rivers. However, despite the knowledge of adult paddlefish movement patterns in large rivers, their principal natal environments and early life dispersal patterns remain unknown. Paddlefish dentary microchemistry can be used to identify natal environment of fish in large river networks such as the middle Mississippi River (MMR) and tributaries. The goals of this study were to (a) use dentary microchemistry (strontium:calcium ratios; Sr:Ca) to determine natal environment and potential drift for age‐0 paddlefish collected from the MMR and (b) assess whether MMR reach or year of collection influenced the percentage of recruits originating from different rivers. Age‐0 paddlefish were collected during 2010–2011 from two reaches of the MMR (upstream and downstream of the Kaskaskia River confluence). Water samples from the MMR and tributaries (upper Mississippi, Missouri, Illinois, Osage, and Kaskaskia Rivers) were collected during 2006–2016. Water Sr:Ca differed among rivers, enabling identification of natal environment for individual fish using dentary core Sr:Ca. The MMR (44–69% of fish sampled) and Missouri River (25–45% of fish sampled) were the primary natal environments for age‐0 paddlefish across both river reaches and collection years. The upper Mississippi River and smaller tributaries contributed few recruits (<13% of fish sampled). Conservation of paddlefish populations should include maintenance or improvement of connectivity between river reaches used for spawning and juvenile rearing and stock assessments of riverine paddlefish may need to be conducted at a riverscape scale because multiple rivers can contribute to paddlefish recruitment in a particular river reach.     

The deceptively complicated “elevation ordinary high water mark” and the problem with using it on a Laurentian Great Lakes shore

In 2013 the Laurentian Great Lakes are at historically low levels; but they will undoubtedly rise again as they always have in an ongoing pattern of seasonal, annual and decadal fluctuations. Those fluctuations, coupled with other physical dynamics unique to the Great Lakes system, will continue to shift shorelines lake-ward and land-ward dramatically over time, perhaps more so because of increased storminess from climate change. These shifting shores implicate legal doctrines that attempt to balance public interests and private property rights at the shore, and they complicate the Great Lakes states' efforts to effectively and fairly manage their Great Lakes shorelands. One challenge comes from using an elevation-based standard to mark ordinary high water, a method that is difficult conceptually to administer and that yields multiple marks over time. We describe briefly Great Lakes shoreline dynamics and the application of state Public Trust Doctrines to those shorelines, and we discuss in detail recent litigation in Michigan regarding use of an elevation-based standard to mark ordinary high water, illustrating the inherent problems with that standard. We conclude that the elevation-based standard should be abandoned, or if not abandoned applied in a manner to adequately safeguard public trust shorelands.     

Exploring market-based environmental policy for groundwater management and ecosystem protection for the Great Lakes region: Lessons learned

The Great Lakes–St. Lawrence River Basin Water Resources Compact (the Compact) was created to protect future water supplies and aquatic ecosystems in the Great Lakes. The Compact requires the eight Great Lakes state to regulate, among other things, large withdrawals of groundwater and surface water so that they do not negatively affect stream flows and ecosystems within the Great Lakes Basin. Thus, the Compact raises the possibility of increased restrictions on groundwater withdrawals in many locations throughout the Great Lakes region. However, restricting withdrawals is likely to encounter opposition from water users when such restrictions are viewed as an infringement on existing water use rights and/or as negatively impacting local economic development. Such conflicts could hinder effective implementation of state and regional water policy. This paper explores the application of a market-based environmental management tool called “Conservation Credit Offsets Trading (CCOT)” that could facilitate allocation of groundwater withdrawals, and develops a framework for guiding the implementation of CCOT within the context of a groundwater permitting system. Using a watershed in southwestern Michigan, this study demonstrates how bio-physical information and input from various local stakeholders were combined to aid groundwater policy designed to achieve the objective of no net (adverse) impact on stream ecosystems. By allowing flexibility through trading of conservation credit offsets, this groundwater policy tool appears to be more politically acceptable than traditional, less flexible, regulations. The results and discussion provide useful lessons learned with relevance to other areas in the Great Lakes Basin.