Lake Clark National Park and Preserve: Geologic resources inventory report

Geologic Resources Inventory reports provide information and resources to help park managers make decisions for visitor safety, planning and protection of infrastructure, and preservation of natural and cultural resources. Information in GRI reports may also be useful for interpretation. This report synthesizes discussions from a scoping meeting held in 2005 and a follow-up conference call in 2018. Chapters of this report discuss the geologic setting and significance, geologic features and processes, and geologic resource management issues within Lake Clark National Park and Preserve. Information about the previously completed GRI map data is also provided. GRI map posters (separate product) illustrate these data. Geologic features, processes, and resource management issues identified include volcanoes and volcanic hazards, bedrock, faults and folds, landslides and rockfall, earthquakes, tsunamis, mineral development and abandoned mineral lands, paleontological resources, glaciers and glacier monitoring, lakes, permafrost, and coastal features.

The Impact of Sea Level Rise on Maritime Limits: A Grotian Moment in the Law of the Sea?

The legal order of the oceans centres on coastal geography which is undergoing unprecedented changes. Claims to national jurisdiction are based on distance from the coast and are only enforceable as long as they are consistent with international law. Consequently, sea level rise and submergence of coastal features can affect the location and enforceability of unilateral maritime limits and bilateral boundaries. Some States wish to maintain previously established entitlements around submerged territory but the only way to prevent fluctuations of unilateral limits is through artificial conservation of coastlines. Therefore, a change, in either the location of maritime entitlements or rules governing such entitlements, is inevitable. It has been proposed that maritime limits should be frozen to ensure opposability as coastlines change. That would enable States to exercise sovereignty and sovereign rights over areas that have no anchor in coastal territory, arguably causing a departure from the land dominates the sea principle and a Grotian Moment in the law of the sea. However, this article concludes that it is unlikely that proposals to freeze maritime limits will change the law of the sea and that the proposals may in fact serve to deter another paradigm shift, one that involves a departure from the principle of stable boundaries.

Pacific Islands Countries Declare Permanent Maritime Baselines, Limits and Boundaries

The Pacific Island countries are in the front line of adverse impacts from sea level rise. For the last decade the South Pacific Forum Members have been seeking ways to preserve their entitlements to their maritime zones and resources in the event of inundation of coasts and coastal features as a result of sea level rise. The issue was explored by the International Law Association in its 2018 Report and is being considered by a Study Group of the International Law Commission. This 2021 Declaration by the 18 Members of the South Pacific Forum purporting to fix permanently their maritime entitlements represents a major development in State practice for the region.

POSTGLACIAL SEA-LEVEL LOWSTAND ON CUMBERLAND PENINSULA, BAFFIN ISLAND, EASTERN ARCTIC CANADA

This study investigates the postglacial sea-level history of eastern Cumberland Peninsula, a region of Baffin Island, Nunavut where submerged terraces were documented in the 1970s. The gradient in elevation of emerged postglacial marine-limit deltas and fiord-head moraines led Dyke (1979) to propose a conceptual model for continuous postglacial submergence of the eastern peninsula. Multibeam mapping over the past decade has revealed eight unequivocal submerged deltas at 19-45 m below [present] sea level (bsl) and other relict shore-zone landforms (boulder barricade, spits, and sill platform) at 16-51 m bsl. Over a distance of 115 km from Qikiqtarjuaq to Cape Dyer, the submerged coastal features increase in depth toward the east, with a slope (0.36 m/km), somewhat less than that of the marine-limit shoreline previously documented (0.58-0.62 m/km). The submerged ice-proximal deltas, deglacial ice limits, and radiocarbon ages constrain the postglacial lowstand between 9.9 and 1.4 ka cal BP. The glacial-isostatic model ICE-7G_NA (VM7) (Peltier 2020) computes a lowstand relative sea level at 8.0 ka, the depth of which increases eastward at 0.28 m/km. The difference between observed and model-derived lowstand depths ranges from 1 m in the west to 10 m in the east and the predicted tilt is significantly less than observed (p=0.0008). The model results, emerging data on Holocene glacial re-advances on eastern Baffin Island, and evidence for proglacial delta formation point to a Cockburn (9.5-8.2 ka) age for the lowstand, most likely later in this range. This study confirms the 1970s conceptual model of postglacial submergence in outer Cumberland Peninsula and provides field evidence for further refinement of glacial-isostatic adjustment models.

Coastline Modeling Using Stacked Curve Spline Tension Interpolation

The coastal area is a dynamic environment influenced by atmosphere, land, and ocean interactions. Similarly, the position of coastlines is also changing due to natural and human-induced components, for instance, erosion, wave, daily tide, storm, and coastal development. In literature, coastline position can be identified based on proxies such as coastal features identified from an aerial photo or very high-resolution image and tidal datum-based indicators extracting from a ground survey. This research proposed a method in deriving datum-based coastline by integrating various bathymetric data, including single beam and multibeam echo sounding data, the National Digital Elevation Model, the national bathymetry data, as well as satellite-derived bathymetry data. The stacked curve spline tension method was applied to assimilate those various bathymetric data, and finally, the coastline was generated. Based on the accuracy assessment conducted, coastline similarity accuracy varies; namely, the LAT coastline had an accuracy of 29.28%, the MSL coastline was 65.45%, and the HAT coastline was 47.48%. These variations are due to several reasons, including the lack of input data, the density of depth data that varies greatly, the difference in data acquisition time between the data used for the LPI map and the data used in this study. Although the accuracy values obtained were not sufficiently high, the proposed method was quite promising to adopt. The method can be used as an alternative for the coastline model and overcome data, time, and cost limitations in providing national coastlines

Semi-Supervised Segmentation for Coastal Monitoring Seagrass Using RPA Imagery

Intertidal seagrass plays a vital role in estimating the overall health and dynamics of coastal environments due to its interaction with tidal changes. However, most seagrass habitats around the globe have been in steady decline due to human impacts, disturbing the already delicate balance in the environmental conditions that sustain seagrass. Miniaturization of multi-spectral sensors has facilitated very high resolution mapping of seagrass meadows, which significantly improves the potential for ecologists to monitor changes. In this study, two analytical approaches used for classifying intertidal seagrass habitats are compared—Object-based Image Analysis (OBIA) and Fully Convolutional Neural Networks (FCNNs). Both methods produce pixel-wise classifications in order to create segmented maps. FCNNs are an emerging set of algorithms within Deep Learning. Conversely, OBIA has been a prominent solution within this field, with many studies leveraging in-situ data and multiresolution segmentation to create habitat maps. This work demonstrates the utility of FCNNs in a semi-supervised setting to map seagrass and other coastal features from an optical drone survey conducted at Budle Bay, Northumberland, England. Semi-supervision is also an emerging field within Deep Learning that has practical benefits of achieving state of the art results using only subsets of labelled data. This is especially beneficial for remote sensing applications where in-situ data is an expensive commodity. For our results, we show that FCNNs have comparable performance with the standard OBIA method used by ecologists.

A Spatiotemporal Change Detection Analysis of Coastline Data in Qingdao, East China

This study focuses on the coastal features, environments, and dynamics to accurately describe and regularly monitor the Qingdao shoreline in eastern China. It collects categorical ETM+ and OLI data from 2000, 2010, and 2019 on the mainland coastline and explores the characteristics and spatiotemporal differences across the past 19 years by using remote sensing and geographic information system (GIS) technologies. The results show that the length of the Qingdao coastline has increased continuously over the last two decades, for a total increase of 18.14 km. There are different natural and artificial coastlines that have undergone major changes. The human-induced deterioration of coastlines has gradually and substantially risen from 53.63% in 2000 to 68.40% in 2019, while the length of the natural coastlines has decreased dramatically. Jiaozhou Bay focuses on areas with significantly changing coastlines, and major changes have occurred in the west and east of the Qingdao coast. The coastline has largely expanded seaward because of the comprehensive impact of natural and anthropogenic factors. The leading factor in coastal evolution is coastal engineering constructions. In addition, the top three other construction activities are the restoration of the aquaculture pond, salt field, and harbor edifices. The driving force that triggered the shift in the coastline reveals significant temporal heterogeneity.

Stochastic dynamics of barrier island elevation

Barrier islands are ubiquitous coastal features that create low-energy environments where salt marshes, oyster reefs, and mangroves can develop and survive external stresses. Barrier systems also protect interior coastal communities from storm surges and wave-driven erosion. These functions depend on the existence of a slowly migrating, vertically stable barrier, a condition tied to the frequency of storm-driven overwashes and thus barrier elevation during the storm impact. The balance between erosional and accretional processes behind barrier dynamics is stochastic in nature and cannot be properly understood with traditional continuous models. Here we develop a master equation describing the stochastic dynamics of the probability density function (PDF) of barrier elevation at a point. The dynamics are controlled by two dimensionless numbers relating the average intensity and frequency of high-water events (HWEs) to the maximum dune height and dune formation time, which are in turn a function of the rate of sea level rise, sand availability, and stress of the plant ecosystem anchoring dune formation. Depending on the control parameters, the transient solution converges toward a high-elevation barrier, a low-elevation barrier, or a mixed, bimodal, state. We find the average after-storm recovery time—a relaxation time characterizing barrier’s resiliency to storm impacts—changes rapidly with the control parameters, suggesting a tipping point in barrier response to external drivers. We finally derive explicit expressions for the overwash probability and average overwash frequency and transport rate characterizing the landward migration of barriers.

Bringing Bathymetry LiDAR to Coastal Zone Assessment: A Case Study in the Southern Baltic

One of the major tasks in environmental protection is monitoring the coast for negative impacts due to climate change and anthropopressure. Remote sensing techniques are often used in studies of impact assessment. Topographic and bathymetric procedures are treated as separate measurement methods, while methods that combine coastal zone analysis with underwater impacts are rarely used in geotechnical analyses. This study presents an assessment of the bathymetry airborne system used for coastal monitoring, taking into account environmental conditions and providing a comparison with other monitoring methods. The tests were carried out on a section of the Baltic Sea where, despite successful monitoring, coastal degradation continues. This technology is able to determine the threat of coastal cliff erosion (based on the geotechnical analyses). Shallow depths have been reported to be a challenge for bathymetric Light Detection and Ranging (LiDAR), due to the difficulty in separating surface, water column and bottom reflections from each other. This challenge was overcome by describing the classification method used which was the CANUPO classification method as the most suitable for the point cloud processing. This study presents an innovative approach to identifying natural hazards, by combining analyses of coastal features with underwater factors. The main goal of this manuscript is to assess the suitability of using bathymetry scanning in the Baltic Sea to determine the factors causing coastal erosion. Furthermore, a geotechnical analysis was conducted, taking into account geometrical ground change underwater. This is the first study which uses a coastal monitoring approach, combining geotechnical computations with remote sensing data. This interdisciplinary scientific research can increase the awareness of the environmental processes.

GEOTECHNOLOGY APPLIED TO THE MORPHOLOGICAL ANALYSIS OF ARACATIMIRIM RIVER ESTUARY (TORRÕES - CE)

Estuaries are unstable coastal environments of transitional character between the continent and the ocean that plays an important role in fauna reproduction. In general, these types of coastal features have suffered several environmental impacts due to inadequate forms of use and occupation, which result in significant modifications in the morphology of river mouths. This work aims to apply geotechnologies to study the morphological changes at the mouth of Aracatimirim River, Ceará, Brazil, contributing with useful information on the monitoring and environmental management of tropical coastal estuaries. The methodology was divided into three stages: recognition of the study area; field activity and data processing and integration. The Aracatimirim River estuary underwent major changes between 1985 and 2013, where it was possible to identify five evolutionary phases into this period. Previously, built by bar, it evolved to an estuary of coastal plain, accompanied by the progression of Torrões beach and agglutination of "barriers spits" to the continent. It is the main navigable river of the area of Itarema municipality. After the development of this work, it was possible to conclude that the forms of use and occupation in the surroundings of the Aracaratimirim River estuary had a wide growth in the last years, which reflects clearly in the estuary morphology, currently classified as an estuary of coastal plain. The morphological changes within the estuary interfere on not only the environmental conditions, but also in the economy and social conditions of the local community.