Lake Erie Shoreline Research Articles

Effect of Various Aspects of Joints on Permeability of Jointed Glacial Till, Northeastern Ohio

ABSTRACT Glacial till bluffs along Lake Erie's shoreline, northeastern Ohio, contain three sets of joints that influence the hydraulic behavior of till mass like joints in rock influence the hydraulic behavior of rock mass. According to the Unified Soil Classification System, the till classifies as low plasticity silt to low plasticity clay, with a clay content of 36–41 percent. Mineralogically, it consists of quartz, illite, and kaolinite. The joints in till are either open or filled with sand, silt, or both from the overlying lacustrine material or with disintegrated till from the joint walls. We used double-ring infiltration and dye tests to estimate field permeability. Laboratory permeability tests were performed on dry and saturated samples of till material, with manually created joints that were either kept open or filled with sand or disintegrated till material to simulate field conditions. Field and laboratory test results showed that permeability of jointed till depended upon whether the joints were open or filled, the nature of the joint-filling material, and the water content of the till (dry versus saturated) and that permeability generally decreased with increasing test time. Dry samples exhibited a substantially larger decrease in permeability than saturated samples, with the largest decrease occurring during the first 24 hours. Open joints in dry samples collapsed during the test procedure, and the permeability of these samples was generally similar to the permeability of the collapsed till material. Permeability tests on saturated samples with open joints were inconclusive. We present a comparison of field and laboratory test results.

Artificial Displacement Alters Movement Behavior of a Terrestrial Amphibian

Homing abilities have been widely documented in amphibians, but it remains unclear whether individuals have homing tendencies in the absence of motivational cues related to breeding and site fidelity. We tested whether artificial displacement would affect the movement behavior of a nonphilopatric terrestrial amphibian, the Fowler's Toad (Anaxyrus fowleri), within its home range and after its breeding season had ended. We translocated 65 male and female Fowler's Toads from their initial points of capture a total of 104 times over one of three different distances (100 m, 250 m, and 500 m) and compared these toads' subsequent 24-h movements with those of a control group of 43 untranslocated toads. To shield the translocated toads from auditory, visual, and olfactory cues en route, we translocated them in opaque enclosed boxes and performed the experiment in the uniformly unobstructed landscape of the Lake Erie shoreline of Long Point, ON, Canada. We mainly investigated directionality bias as the orientation between control and translocated groups, homing tendency as the correlation between movements after translocation and translocation distance, and homing accuracy as the variation in distance between final and initial capture points. Our results provide clear evidence that translocation changes the movement behavior of these toads and that they possess homing tendencies outside of their breeding season. Toads had a strong directional bias to move in the opposite direction to the one in which they were artificially displaced, in contrast with the control group, which showed no directional bias among 61 recorded 24-h movements. This tendency for amphibians to home after artificial displacement might be a significant confounding factor in any procedure involving their relocation.

Social-Ecological Risk and Vulnerability to Flooding and Erosion along the Ohio Lake Erie Shoreline

The Laurentian Great Lakes system holds approximately 20% of the world’s available surface freshwater and represents an immense economic engine for the region. Lake Erie, one of the five North American Great Lakes is classified as highly stressed and deteriorating with significant flooding and erosion issues stemming from record-high water levels. This study adapts a well-established oceanic coastal vulnerability index to estimate impacts and risks of lake-level rise on the Ohio portion of Lake Erie coastal social-ecological system. The authors worked closely with coastal engineers, planners, and other practitioners associated with the Ohio Department of Natural Resources (ODNR) and the Office of Coastal Management (OCM) to help adapt a scientifically-grounded framework for natural resource and policy decision making. Overall, place-based risk and vulnerability to flooding and erosion necessitates an integrated approach that combines socio-economic, built-environment, political boundaries, and bio-physical characteristics. While most of the integrated methodologies are focused on the oceanic coasts at the county scale, this research presents a model for Lake Erie-relevant variables at the higher-resolution census-tract unit of analysis and a coastal vulnerability index at 100-foot intervals along the coastline for four decades and each season. The result is both a foundation for Ohio’s Department of Natural Resources, Office of Coastal Management to identify scientifically-informed, place-based priority management areas for flooding and erosion, as well as a methodological roadmap to adapt the Coastal and Place Vulnerability Indices to the other Great Lakes’ states and provincial shorelines.

Population Trends of Monarch Butterflies (Lepidoptera: Nymphalidae) Migrating From the Core of Canada’s Eastern Breeding Population

Abstract The Monarch butterfly (Danaus plexippus) (Linnaeus 1758) is being considered for up-listing to Endangered under the Canadian federal Species-at-Risk Act due to population declines recorded throughout the annual life cycle. Understanding local population dynamics is therefore necessary to assess the effect of environmental and human induced stressors, and to establish a benchmark from which management success can be measured through time. Using fall count data collected along the Lake Erie shoreline, which captures migrants moving south from the core eastern breeding population in Canada, monarch abundance trends are quantified. Count data from three migration count sites and one roost site were analyzed following similar methods as Crewe and McCracken (2015) to make findings comparable. Two of these datasets are newly compiled and are analyzed here for the first time. Results suggest that during the past 10 yr, the number of migrating monarchs along the north shore of Lake Erie has been stable [mean: −3.05% per year, credibility interval (CI): −13.15, 9.97], which is consistent with changes being observed on the wintering grounds. Only migration counts collected between 1995 and 2018 at the Long Point sites demonstrated significant abundance declines (5.25% per year, CI: −8.60, −1.39), which is a similar results to previous analysis of this dataset. Opportunities for future research are discussed within the context of using monarch count data for future conservation efforts.

Spatiotemporal controls on septic system derived nutrients in a nearshore aquifer and their discharge to a large lake

This study evaluates spatiotemporal variability in the behavior of septic system derived nutrients in a sandy nearshore aquifer and their discharge to a large lake. A groundwater nutrient-rich plume was monitored over a two-year period with the septic system origin of the plume confirmed using artificial sweeteners. High temporal variability in NO3-N attenuation in the nearshore aquifer prior to discharge to the lake (42–96%) reveals the complex behavior of NO3-N and potential importance of changing hydrological and geochemical conditions in controlling NO3-N discharge to the lake. While PO4-P was retarded in the nearshore aquifer, the PO4-P plume extended over 90 m downgradient of the septic system. It was estimated that the PO4-P plume may reach the lake within 10 years and represents a legacy issue whereby PO4-P loads to the lake may increase over time. To provide broader assessment of the contribution of septic systems to P and N loads to a large lake, a regional scale geospatial model was developed that considers the locations of individual septic systems along the Canadian Lake Erie shoreline. The estimated P and N loads indicate that septic systems along the shoreline are only a minor contributor to the annual P and N loads to Lake Erie. However, it is possible that nutrients from septic systems may contribute to localized algal blooms in shoreline areas with high septic system density. In addition, disproportionate P and N loads in discharging groundwater may change the N:P ratio in nearshore waters and promote growth of harmful cyanobacteria. The study provides new insights into factors controlling the function of the reaction zone near the groundwater-lake interface including its impact on groundwater-derived nutrient inputs to large lakes. Further, the study findings are needed to inform septic system and nutrient management programs aimed at reducing lake eutrophication.

Numerical Study of Longshore Variation in Beach Morphodynamics along Eastern Lake Erie Shoreline due to Seiche

Sogut, E. and Farhadzadeh, A., 2021. Numerical study of longshore variation in beach morphodynamics along Eastern Lake Erie shoreline due to seiche. Journal of Coastal Research, 37(1), 92–103. Coconut Creek (Florida), ISSN 0749-0208.Extreme coastal events and abrupt changes in atmospheric pressure in an enclosed or semi-enclosed basin can trigger low-frequency water surface oscillations known as seiches. This exploratory study numerically quantifies the effects of seiche on morphological changes along the eastern Lake Erie shoreline. The quantification is made by simulating the hydrodynamics of the lake using a coupled circulation and spectral wave model (ADCIRC+SWAN), providing the flow boundary conditions to the two-dimensional nearshore morphodynamic model, XBeach. The process-based XBeach model is used to simulate the nearshore morphological variations under two water-level conditions: the lake's actual water level and the synthetically generated seiche-free water level. The XBeach model is cross-calibrated using the process-based nearshore morphodynamic model, CSHORE, which was extensively validated using lab and field data. It is found that the seiching motions have a contribution of ∼1.5% to the erosion of beaches along the 2-km stretch of the shoreline in eastern Lake Erie shoreline.

Onshore and offshore wind energy potential assessment near Lake Erie shoreline: A spatial and temporal analysis

Choosing a proper location is a pivotal initial step in building a wind farm. As appropriate locations for onshore wind farms become more and more scarce, offshore wind farms have drawn significant attention. The coastal line of the Great Lakes is an area that has great wind energy potential. This research conducted detailed statistical analysis of the onshore, nearshore, and offshore wind energy potential of Lake Erie near Cleveland, Ohio. It analyzed the wind data collected in 10-min time intervals from three locations near the Lake Erie shoreline to assess wind characteristics. Statistical analyses of wind data include the Weibull shape and scale factors, turbulence intensity, and wind power density. In addition, the capacity factor and the potential energy output are estimated by using two commercial wind turbines, which are appropriate for the sites at 50 m and 80 m hub heights. The results show that offshore sites will produce at least 1.7 times more energy than the onshore and nearshore sites when using the same commercial wind turbine. Furthermore, offshore wind turbines could produce more power during peak hours in the spring and winter. This indicates that offshore wind turbines offer advantages over onshore wind turbines in Lake Erie.

The vascular plant flora and plant communities of Erie Bluffs State Park, Erie County, Pennsylvania

Abstract Erie Bluffs State Park in Erie County, Pennsylvania, established in 2004, occupies 219 ha along 2.25 km of Lake Erie shoreline. The park is notable for its highly erodible lakeshore bluffs, black oak sand barrens, and lakeplain swamp forests. A vascular plant inventory was undertaken and supplemented with historical collections to provide a vouchered checklist from the site now occupied by Erie Bluffs State Park. A second checklist with a list of unconfirmed records is based on unvouchered sightings from the park and specimen records from the vicinity of the park that cannot confidently be mapped within the park boundaries. The checklist includes 555 vascular taxa in 309 genera and 98 families with taxa representing the following groups: Equisetophyta (5), Lycopodiophyta (4), Pteridophyta (22), Coniferophyta (3), Liliopsida (136), and Magnoliopsida (385). Poaceae (56 species), Asteraceae (56 species), Cyperaceae (41 species), Rosaceae (36 species), and Brassicaceae (22 species) are the five large...

Contribution of Emergent Aquatic Insects to Refueling in Spring Migrant Songbirds

Refueling by spring migrant landbirds is an important determinant of arrival timing and, thus, should also affect acquisition of high-quality territories and mates. Spring migrants can encounter adverse weather and low prey availability, but emergent aquatic insects (e.g., chironomid midges) may provide an important food resource in wetland areas. We used stable-carbon-isotope (δ13C) analysis of exhaled CO2 as an indication of recent dietary intake (contributions from aquatic or terrestrial food webs), plasma lipid metabolite profiling to assess refueling performance, and arthropod sampling to investigate whether diet and refueling differed between Lake Erie shoreline and inland forest sites and how diet, condition, and midge availability (biomass) were associated with refueling along the lakeshore in northwestern Ohio in spring 2007 and 2008. Midge availability was not associated with refueling performance for Yellow-rumped Warblers (Dendroica coronata), Magnolia Warblers (D. magnolia), or White-throated Sparrows (Zonotrichia albicollis), but Magnolia Warblers had greater refueling performance as the day progressed. We detected no relationship between diet and refueling for any species; however, Yellow-rumped Warblers had a stronger aquatic δ13C value at two shoreline sites than at other sites. In shoreline and inland sites, migrants used a combination of aquatic and terrestrial arthropods and received energetic benefits from their use, even within small shoreline sites (1.18–2.86 ha), which often had high densities of stopover migrants. We suggest that conservation and restoration of shoreline and inland forest patches within landscapes that contain wetlands can promote refueling by migrant landbirds.

An Evaluation of Effects of Groundwater Exchange on Nearshore Habitats and Water Quality of Western Lake Erie

Historically, the high potentiometric surface of groundwater in the Silurian/Devonian carbonate aquifer in Monroe County, MI resulted in discharge of highly mineralized, SO 4-rich groundwater to the Lake Erie shoreline near both Erie State Game Area (ESGA) and Pointe Mouillee State Game Area (PMSGA). Recently, regional groundwater levels near PMSGA have been drawn down as much as 45 m below lake level in apparent response to quarry dewatering. From August to November of 2003, we conducted preliminary studies of groundwater flow dynamics and chemistry, shallow lake water chemistry, and fish and invertebrate communities at both sites. Consistent with regional observations, groundwater flow direction in the nearshore at ESGA was upward, or toward Lake Erie, and shallow nearshore groundwater chemistry was influenced by regional groundwater chemistry. In contrast, at PMSGA, the groundwater flow potential was downward and lake water, influenced by quarry discharge seeping downward into nearshore sediments, produced a different lake and shallow groundwater chemistry than at ESGA. Although the invertebrate and young fish community was similar at the two sites, taxonomic groups tolerant of degraded water quality were more prevalent at PMSGA. Sensitive taxa were more prevalent at ESGA. We propose a conceptual model, based on well-described models of groundwater/seawater interaction along coastal margins, to describe the interconnection among geologic, hydrologic, chemical, and biological processes in the different nearshore habitats of Lake Erie, and we identify processes that warrant further detailed study in the Great Lakes.

Phylogeography ofBufo fowleriat its northern range limit

Many of the species that recolonized previously glaciated areas in the Great Lakes basin of North America over the past 10-12,000 years exhibit genetic evidence of multiple invasion routes and present-day secondary contact between deeply divergent lineages. With this in mind, we investigated the phylogeographical structure of genetic variability in Fowler's toads (Bufo fowleri) at the northern edge of its distribution where its range encircles the Lake Erie basin. Because B. fowleri is so closely tied to habitats along the Lake Erie shoreline, we would expect to find clear evidence of the number of invasions leading to the species' colonization of the northern shore. A 540 bp sequence from the mitochondrial control region was amplified and analysed for 158 individuals from 21 populations. Interpopulation sequence variation ranged from 0% to 6%. Phylogenetic analysis of p-distance using the neighbor-joining method revealed two deeply divergent (6% sequence divergence) mtDNA lineages (Phylogroup 1 and 2), possibly arising as a result of secondary contact of populations that entered the region from two separate glacial refugia. However, the phylogeographical pattern was not simple. The populations at Long Point, on the north shore of Lake Erie, clustered with the population from Indiana Dunes on Lake Michigan to form Phylogroup 2 whereas all other B. fowleri populations examined from both sides of Lake Erie constituted Phylogroup 1. Furthermore, mtDNA sequences from the related species Bufo americanus, obtained from populations outside the range of B. fowleri, clustered with mtDNA haplotypes of B. fowleri Phylogroup 1, indicating the possibility of partial introgression of mitochondria from one species to the other.

Innovative erosion control involving the beneficial use of dredge material, indigenous vegetation and landscaping along the Lake Erie Shoreline

Current conventional erosion protection techniques are both costly and can detract from the natural environment. The purpose of this paper is to describe how Presque Isle State Park, located along the shoreline of Lake Erie in Pennsylvania, implemented a low-cost and innovative erosion protection project. Erosion within the back bay area of the park threatened the park's heavily used multi-purpose trail. With a matching grant from the Great Lakes Commission, the park developed a plan that placed riprap off the shoreline of the trail, anchored downed trees from the park in the riprap to function as timber groins, and then filled in the area between the trail and the riprap with sand dredged from a local sandbar. Geotextile and wattles were then positioned in the fill to aid in vegetative rooting. After placement of the geotextile and the wattles, indigenous vegetation was transplanted in the newly created area. Completion of the project resulted in several additional hectares of stabilized vegetation while providing an economical, natural, and aesthetic alternative to conventional shoreline erosion protection. The project affords a valuable example to other parks and recreational facilities along the Great Lakes faced with the challenge of minimizing erosion and maintaining a natural appearance.

Valuing water quality advisories and beach amenities in the Great Lakes

This paper presents estimates of the value of reducing beach advisories in Great Lakes beaches located along Lake Erie's shoreline in Ohio. Given the potential health consequences associated with swimming in contaminated water, health officials have made more effort in recent years to ensure that information about beach advisories is available through the media and other sources. A recent survey of over 800 single‐day beach visitors during the summer of 1998 found that nearly two thirds of visitors take advantage of this information when making decisions about their beach trips. When accounting for this information in a travel cost model, we find that the average (across all visitors) seasonal benefits of reducing one advisory is approximately $28 per visitor. Individuals who use the media in advance of trips gain less, approximately $24 per year, while those who use only signs posted at the beach would gain more, $38 per year.

Geological Causes of Local Variation in Coastal Bluff Recession Rates, Northeast Ohio Shoreline of Lake Erie

The Lake Erie shoreline at Painesville-on-the-Lake has receded 180 m since 1876, yet during the past decade rates have varied locally by 0–5 m/yr. The study area is a portion (0.5 km in length) of a continuous section of coastal bluffs 17 m tall. The section was selected to minimize variation in physical parameters, including shoreline orientation and exposure, offshore bathymetry and sediment, beach width, minimal shoreline protection structures, and generally homogeneous bluff materials. In spite of these similarities, some portions of the bluff recede episodically by block-fall and other portions continuously by slumping.

Sources of bias in the use of shell fragments to estimate the size of zebra and quagga mussels (Dreissena polymorpha and Dreissena bugensis)

Several researchers have examined size-selective predation on dreissenid mussels by first measuring septa from crushed mussel shells found in predators' gastrointestinal tracts and then using a regression of septum length on shell length to infer the size of consumed mussels. We examine three assumptions made when using this approach: (1) that the shell length : septum length relationship is site-independent within the study area, (2) where both zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena bugensis) are present, that the shell length : septum length relationship is the same for both mussel species, and (3) that the predator foraged exclusively at the site of collection. We collected mussels at 6 sites along an 8-km stretch of Lake Erie shoreline and found that the shell length : septum length relationship varied significantly both among sites and between zebra mussels and quagga mussels. We then compared the regression for quagga mussels at one of these sites with that for intact valves of mussels taken from scaup (Aythya marila, Aythya affinis) collected at the site. Although ice cover at the time of collection restricted scaup to the site while foraging within the study area, regressions were again significantly different, i.e., scaup had been foraging elsewhere. Our results indicate that for at least some study sites, the use of septa to estimate dreissenid mussel size is not appropriate. However, when intact valves are found in a predator, variation in shell morphology can help to confirm or exclude possible foraging locales.

Role of Soil Joints in Causing Bluff Erosion Along the Lake Erie Shoreline, Northeast Ohio

Bluff erosion along the Lake Erie shoreline in Ohio is a major environmental problem causing extensive damage to homes, agricultural land, and lakeshore roads. The most extensive erosion takes place in areas where the bluffs are made of well-jointed, overeonsolidated, glacial till material (CL; ML-CL) that is overlain by lacustrine silts (ML) or silty clays (CL). In order to investigate the effect of soil joints on bluff erosion, four sites, all characterized by the presence of well-developed joints, were selected between Painesville, Ohio, and the Ohio-Pennsylvania border. The detailed line survey technique was used to measure orientations and other aspects (continuity, spacing, surface features, aperture, nature of infilling material, presence or absence of water) of the joints at the four sites. Erosion rates were monitored on a bi-weekly basis for a period of one year, using equally spaced pegs on the bluff face. Photographs were taken frequently to aid in monitoring of bluff erosion. Results indicate that bluff erosion in the study area is greatly influenced by the presence of joints in the glacial till. The joints enhance erosion by providing pathways for water movement in both horizontal and vertical directions which, in turn, leads to widening of the joint openings and piping of the overlying silty material. The buildup of pore pressure along the joints, after a prolonged rainfall or a sudden snowmelt, also contributes to bluff instability. In the toe area, wave attack results in the formation of notches, cavities, and concave zones. Erosion at the bluff toe, accelerated by soil joints, initiates block falls and planar slides along the pre-existing joint surfaces above the toe area. The slump and flow type failures that occur in the overlying lacustrine material are a consequence of the joint-promoted failures in the underlying till. Thus, any remedial measures that are undertaken to minimize bluff erosion along Lake Erie must take into account the effect of soil joints.

Integration of Photomosaics and Stratigraphy in the Western Appalachian Basin as an Aid to Identify Potential Hydrocarbon Reservoirs: ABSTRACT

Paleozoic stratigraphy of the southern Lake Erie region is commonly interpreted as being dominated by flat-lying sedimentary rocks. Recent surface stratigraphic studies in New York, Pennsylvania, and Ohio have revealed the widespread presence of NW- and NE-trending folds and faults exposed along stream beds, and in bluffs along the southern Lake Erie shoreline. A black shale unit, previously unknown in northwestern Pennsylvania, was also discovered and its lateral continuity mapped. The shale forms a disconformable contact with the overlying Northeast Shale. Ship-based photomosaics were made of bluffs along Lake Erie, and integrated with land-based stratigraphic sections to map the continuity of units, identify displacement zones, and identify low amplitude folds. The black shale unit aided identification of offset and folding. Faults observed at the surface off-set Devonian and Mississippian rocks, and unconsolidated Quaternary sediments. Subsurface wrench faults, apparently extending into Precambrian rocks, have been identified by others. These wrench faults are generally perpendicular to the strike of the Appalachian Mountains, and are known as cross-strike discontinuities (CSDs). Principle zones of displacement associated with the CSDs can be recognized at the surface by numerous fractures having little offset, aligned drainage systems, and zones of increased hydrocarbon productivity and fluid migration. Increasedmore » hydrocarbons production occurs where reservoirs are cross-cut by the faults. The faults offset various reservoirs in Pennsylvania and Ohio in the subsurface. Identifying the location of these faults at the surface may provide information that leads top the discovery of new potential reservoirs.« less

Hydrogeology Of An Unconfined Sand Aquifer And Its Effect On The Behavior Of Nitrogen From A Large-Flux Septic System

Detailed monitoring of groundwater in a shallow sand aquifer impacted by a large-flux septic system showed that water quality in the shallow water table zone below the tile bed was similar to that of smaller-flux septic systems in similar hydrologic settings where effluent residency in the unsaturated zone was of similar duration. During residency of about one week in the 4-m thick unsaturated zone, effluent NH+ 4 was largely oxidized to NO− 3, about 75% of DOC was biodegraded, and acidity produced by the above reactions was neutralized by dissolution of calcite. Beneath the tile bed and extending laterally downgradient a distance of 80 m to the Lake Erie shoreline, a distinct plume of impacted groundwater was easily distinguished by elevated levels of electrical conductance, Cl−, NO− 3, HCO− 3, NA+, Ca2+, and K+ and by depressed levels of pH and dissolved oxygen. High NO− 3 levels that occur below the tile bed disappear, however, in the anaerobic plume core zone 10 to 70 m downgradient, apparently as a result of denitrification. The rich reserve of solid-phase organic carbon in the aquifer sediment (2.5%) probably provides much of the organic carbon for heterotrophic denitrification. This condition is in contrast to other septic system plumes in sand aquifers where high NO− 3 levels persist and where aquifer organic carbon values are much lower. Although NO− 3 is attenuated in the plume core, persistence of NO− 3 along the aerobic upper fringe of the plume demonstrates the ability of septic systems to cause significant water-quality degradation of sand aquifers when the conditions favorable for denitrification do not exist. The sharp boundary between the plume water and non-impacted water adjacent to and overlying the plume in the area 50 to 100 m downgradient from the tile bed, and the undiluted nature of non-reactive solutes such as Cl− throughout the core of the plume, demonstrates that dispersion has only a weak influence on the plume. This is consistent with dispersion studies in many other sand aquifers.

TILE RATIONALE FOR OHIO'S DETERGENT PHOSPHORUS BAN1

ABSTRACT: Ohio signed into law a detergent phosphorus ban on March 26, 1988. This law limits the elemental phosphorus content of household laundry detergents to 0.5 percent in all 35 Lake Erie counties in Ohio by 1990. Ohio's detergent phosphorus ban will help non‐compliant municipal wastewater treatment plants achieve compliance with the 1 mg/L effluent phosphorus standard. By limiting the phosphorus content of household laundry detergents, Ohio will also benefit from less phosphorus entering surface waters from combined sewer overflows, communities with treatment plant bypasses, and riparian homes with septic tanks. This is important because most of the phosphorus in laundry detergents is in the bioavailable form and Ohio's Lake Erie shoreline is particularly sensitive to Cladophora problems. When viewed in conjunction with reduced chemical costs for phosphorus removal and savings in sludge disposal costs, Ohio's detergent phosphorus ban is a pragmatic component of an international phosphorus management strategy to protect the Great Lakes.

Design and construction of a 3 km (2 mi) long shoreline protection system for the City of Luna Pier

In 1982, N.K. Becker & Associates Ltd. designed a precast concrete flood protection and beach restoration system for the 3 km (2 mi) long Lake Erie shoreline of the City of Luna Pier, Michigan. The construction of these works, which included beach sills, shorewalls, and a marina basin, was completed in 1984.The shorewall system is unique in that it was designed of interconnected, open-ended, earth-filled, thin-walled precast concrete cylinders, placed on-end and in-line to form a continuous wall. This seawall design was selected by the City of Luna Pier over alternative systems because it was estimated to cost 50% less than conventional steel sheet piling or cast-in-place concrete systems.During the final design, hydraulic model tests were carried out at both the University of Michigan and the University of Windsor to study the uprush, scour, longshore transport, and wave pressure characteristics of the proposed system. The methods used to design this economical and functional flood protection system are presented along with an analysis of its performance to date. Key words: beach, beach sill, flushing, hydraulic model testing, ice, longshore drift, overtopping, precast cellular concrete wall system, scour, shorewall, uprush, water levels, waves, wave deflector.