Literatura académica sobre el tema "Ridge and swale topography"
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Artículos de revistas sobre el tema "Ridge and swale topography"
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Oliver, Thomas S. N. y Toru Tamura. "Sub-centennially resolved behavior of an accreting sandy shoreline over the past ∼ 1000 years". Journal of Sedimentary Research 91, n.º 2 (28 de febrero de 2021): 211–18. http://dx.doi.org/10.2110/jsr.2020.074.
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ABSTRACT Coastal ridge plains represent a valuable record of past shoreline deposition. However, there remain questions regarding shoreline behavior on intermediate timescales (sub-centennial), the impact of storms, and process of ridge genesis. We address these questions through high-resolution reconstruction of the sandy-beach progradation at Boydtown Beach in Twofold Bay, southeastern Australia, over the past 1000 years using ground-penetrating radar (GPR) and optically stimulated luminescence (OSL) dating. GPR profiles are dominated by seaward-dipping reflections that result from beach and dune progradation. Prominent reflections with heavy-mineral concentrations are also preserved resulting from storm erosion. OSL ages reveal alternative phases of steady and episodic accretion, rather than a constant progradation. We hypothesize that steady phases may result from moderate storm events where each successive storm only partially erodes the recovery of the previous event. This results in incremental seaward accretion of the active beach. Phases of episodic accretion could be the result of larger storm events or storm clusters when large post-storm recovery rapidly shifts the active shoreline seaward. The two modes of shoreline progradation (steady and episodic) appear broadly associated with a change in ridge-and-swale morphology whereby subdued ridge swale topography is associated with steady or incremental progradation and higher, better-defined ridges with episodic accretion. These results suggest that a single coastal ridge plain experiences variable intermediate-scale shoreline behavior in response to storm events which then lead to multiple modes of ridge genesis.
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Holley, George R., Rinita A. Dalan y Philip A. Smith. "Investigations in the Cahokia Site Grand Plaza". American Antiquity 58, n.º 2 (abril de 1993): 306–19. http://dx.doi.org/10.2307/281972.
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Research designed to explore the Grand Plaza at the Cahokia Mounds site, the largest Mississippian-period mound center in the eastern United States, documents that plazas may yield significant information regarding Mississippian manipulation of the landscape and the initial growth of mound centers. Probing and excavation within the Grand Plaza revealed that buried ridge-swale topography, identified through an electromagnetic-conductivity survey, was stripped and then filled by the Cahokians. Excavation also corroborated the presence of deep-pit borrows identified by remote sensing. Based on the ceramics recovered from our excavations, we argue that these earth-moving events were initiated prior to the onset of the Mississippian period (ca. A.D. 1000). Reclamation of the borrowed areas resulted in the formation of the mound-plaza configuration early during the Mississippian period.
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Dalan, Rinita A. "Defining archaeological features with electromagnetic surveys at the Cahokia Mounds State Historic Site". GEOPHYSICS 56, n.º 8 (agosto de 1991): 1280–87. http://dx.doi.org/10.1190/1.1443150.
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Electromagnetic (EM) surveys have been used at the Cahokia Mounds State Historic Site in southwestern Illinois to locate and define a number of buried archaeological features. Two instruments, Geonics EM31-D and EM38 conductivity meters, were employed to locate portions of a wooden stockade known as the Central Palisade; delineate a number of leveled earthen mounds; and explore a broad, flat area in the central portion of the site known as the Grand Plaza. EM surveys, together with limited excavation, provide a cost effective and nondestructive means of exploring a site as large and complex as Cahokia. Archaeological excavations confirmed that EM surveys were able to locate the Central Palisade, and more importantly, that they provided information on anthropogenically modified terrain within the Grand Plaza. The EM survey documented buried ridge and swale topography and borrow pits within this area. This evidence of landscape modification challenges previous conceptions about the extent of earthmoving at this important Mississippian center and suggests a promising area of application for EM surveys in archaeology.
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Thonon, I., H. Middelkoop y M. van der Perk. "The influence of floodplain morphology and river works on spatial patterns of overbank deposition". Netherlands Journal of Geosciences - Geologie en Mijnbouw 86, n.º 1 (abril de 2007): 63–75. http://dx.doi.org/10.1017/s0016774600021326.
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AbstractFloodplain topography and related hydraulic patterns of overbank flow constitute a major control on the amounts and patterns of sediment deposition on floodplains. We studied the differences in sediment deposition at two scales along two river branches of the lower River Rhine in the Netherlands: the Waal and IJssel River. Human alterations like levelling and embankment construction have severely impacted the floodplains along the Waal River branch (average discharge: 1500 m3·s‒1), whereas the relatively wide floodplains along the IJssel River (average discharge: 250 m3·s‒1) still exhibit their characteristic ridge-and-swale topography and natural levees. We found that, in general, the amounts of sediment deposited sediment decreases with increasing distance to the sediment source. Clay and organic matter content generally increase with decreasing floodplain elevation. These trends are, however, far less pronounced in the Waal River floodplains than in the IJssel River floodplains. Sediment deposited on the IJssel River floodplains also contains significantly more sand than the sediment deposited on the Waal River floodplains, probably because of the absence of minor embankments along the IJssel River and its higher sinuosity. Furthermore, during inundation the individual Waal River floodplains receive more sediment per unit area than the IJssel River floodplains. At the scale of the river branch, however, the conveyance losses in the Waal River are less than in the IJssel River, because of the larger surface area of the floodplains along the IJssel River relative to its water and sediment discharge during flood events. This discrepancy stresses that both the individual floodplain sections and the total river branch should be taken into account when studying the role of overbank deposition as part of a river’s sediment budget.
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Hargrave, Michael L., Tad Britt y Matthew D. Reynolds. "Magnetic Evidence of Ridge Construction and Use at Poverty Point". American Antiquity 72, n.º 4 (octubre de 2007): 757–70. http://dx.doi.org/10.2307/25470444.
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A magnetic field gradient survey was conducted at Poverty Point to determine if that technique could detect discrete subsurface features and differentiate the ridges and swales in an area that today exhibits very little topographic relief. The survey area (280 m long by 20 to 60 m wide) crossed Ridges 1 through 5 in the southwest portion of the site. The ridges were revealed as variegated bands of positive and negative magnetic anomalies whereas the swales appeared to be relatively homogeneous. Ridge 1, nearest the plaza, is wider and higher but has less of a flank midden than the other ridges. Two roughly circular arrangements of anomalies on Ridge I are potentially important but cannot be reliably interpreted without ground truthing excavations. Future large-area, high-resolution magnetic gradient surveys could dramatically enhance our understanding of this enigmatic site.
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Clark, David B., Deborah A. Clark, Paul M. Rich, Stuart Weiss y Steven F. Oberbauer. "Landscape-scale evaluation of understory light and canopy structures: methods and application in a neotropical lowland rain forest". Canadian Journal of Forest Research 26, n.º 5 (1 de mayo de 1996): 747–57. http://dx.doi.org/10.1139/x26-084.
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Light is a key resource controlling tree regeneration in the understory of closed-canopy old-growth forests. To evaluate the distribution of understory light environments at a landscape scale, we used stratified random sampling in a 500-ha stand of Costa Rican tropical rain forest. Fifteen 100 m long transects were placed using random coordinates within two soil–geomorphology units (flat alluvial terraces and dissected ridge-slope-swale terrain). At 2.5-m intervals we measured canopy height and slope angle, classified topographic position, and took canopy photographs with a fish-eye lens at 1 and 3 m above the ground (and at 0.6 and 5 m height at five stations per transect). Photographs were analyzed for global site factor (GSF), which is analogous to the percentage of full sun radiation reaching a point. Canopy height and GSF at 1 and 3 m above the ground were significantly autocorrelated (Moran's I) at 2.5-m intervals. The autocorrelation rapidly declined at greater intervals, reaching nonsignificance at ca. 20 m. Both canopy height and GSF at 3 m height had a weak tendency for negative autocorrelations at intervals of 25–50 m. Median canopy height (615 stations) was 23 m (range 0–37). Gaps (canopy height ≤2 m, Brokaw 1982) were only 1.5% of sample points. Gaps were more frequent on steep slopes than on terraces, ridgetops, swales, and gentle slopes. Canopy height varied significantly across this topographic gradient. At all four heights (0.6, 1, 3, and 5 m) median GSF was ≤2.4%. GSF values >8% accounted for only 3% of the total sample (N = 1380). GSF was only weakly negatively correlated with canopy height and the relation was not monotonie. Under canopies 13-19 m tall, nearly all GSF values were ≤5%. Higher GSFs were more frequent under both shorter and taller canopies. Given the observed variance in GSF and canopy height, 100–200 points separated by intervals of ≥20 m are necessary to measure the forest-wide means of these variables to ±10%. We discuss implications of these results for current approaches to modeling understory light based on canopy characteristics. We compared the random background of light environments from 1–3 m above the ground at La Selva with those occupied by saplings of pioneer and nonpioneer tree species. The two pioneers (Cecropia spp.) occurred in microsites significantly brighter than random sites, while sapling microsites of all five nonpioneer species were significantly darker than random. Comparing the landscape-scale distribution of key resources with species' actual distributions at similar scales offers a quantitative method for assessing plant life histories within and among forests.
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AlYousif, Ahmad, Arnoldo Valle-Levinson, Peter N. Adams y Jorge A. Laurel-Castillo. "Tidal and subtidal hydrodynamics over ridge-swale bathymetry". Continental Shelf Research 219 (abril de 2021): 104392. http://dx.doi.org/10.1016/j.csr.2021.104392.
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Houser, Chris. "Feedback between ridge and swale bathymetry and barrier island storm response and transgression". Geomorphology 173-174 (noviembre de 2012): 1–16. http://dx.doi.org/10.1016/j.geomorph.2012.05.021.
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Nadeau, Louis-Philippe, David N. Straub y David M. Holland. "Comparing Idealized and Complex Topographies in Quasigeostrophic Simulations of an Antarctic Circumpolar Current". Journal of Physical Oceanography 43, n.º 8 (1 de agosto de 2013): 1821–37. http://dx.doi.org/10.1175/jpo-d-12-0142.1.
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Abstract The circumpolar transport of a wind-driven quasigeostrophic Antarctic Circumpolar Current is considered. Simple theory suggests transport in a strongly forced regime—the focus of this study—is largely determined by a partitioning of the southward Sverdrup flux into Drake Passage latitudes: some streamlines feed a “basin contribution” to the circumpolar transport and others feed a large-scale recirculation gyre. Simulations assuming an idealized Scotia Ridge topography are considered to test for sensitivity to resolution. Considerable sensitivity to both vertical and horizontal resolution is found, and associated with this is a tight stationary eddy trapped on the western flank of the ridge. That is, this eddy is sensitive to resolution and exerts an influence that acts to reduce the circumpolar transport. Simulations using the Scotia Ridge–like topography are also compared to others using more realistic topography. In the idealized (ridge) topography experiments, there is only a single ridge against which topographic form drag can act to remove eastward momentum from the system; in the complex topography experiments, there are many. It is found that the experiments assuming realistic topography do not develop an analog to the single topographically trapped eddy prevalent in the Scotia Ridge topography simulations. Additionally, circumpolar transport in these simulations agrees better with the theory. Whether this agreement is simply fortuitous, however, is unclear. To address this, a series of simulations assumes topography that varies smoothly between the idealized ridge and realistic configurations.
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Xu, Guo Dong, Zheng Hua Zhou, Jing Shan Bo y Wei Hua Fang. "Effect of Ridge Topography on Earthquake Ground Motion". Advanced Materials Research 594-597 (noviembre de 2012): 1696–701. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1696.
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The ridge topography can substantially influence seismic ground motion and, in general, causes the amplification of seismic ground motion amplitude at ridges. Fortunately, sets of three-component accelerogram, obtained by the observation arrays for topographic effect at Zigong Xishan, Jiangyou Doutuan and Qingchuan Sanguo from the great Wenchuan earthquake and its aftershocks, provided basic data for analyzing the effect of ridge topography on seismic ground motion. On the base of these acceleration records, peak ground acceleration and response spectrum ratios are calculated, and examined and compared in order to grasp the effect of ridge topography on ground motion. The findings showed that ridge topography has the remarkable effect on seismic ground motion, in which the amplification characteristics varies depending on the shape of ridge topography, and the amplification effect of the horizontal directions are not similar to the vertical direction, and in some periods are even less than 1.0.
Tesis sobre el tema "Ridge and swale topography"
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Jorczak, Eric. "Influence of hydrology on Everglades ridge and slough soil topography". [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0014414.
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BRIKOWSKI, TOM HARRY. "A QUANTITATIVE ANALYSIS OF HYDROTHERMAL CIRCULATION AROUND MID-OCEAN RIDGE MAGMA CHAMBERS". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184128.
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Hydrothermal activity is one of the dominant processes affecting the chemical and thermal evolution of oceanic crust at the mid-ocean ridge (MOR), but little is known about the sub-surface portions of ridge hydrothermal systems. These systems can be investigated using numerical modeling techniques, and models of two-dimensional cross-sections are utilized in this study to investigate the behavior of MOR hydrothermal systems. The influence of magma chamber geometry is explored by modeling two extremes of proposed geometry. Seismological evidence supports a dike-like 2 km half-width chamber, and models of this chamber indicate that: (1) complete crystallization of the magma requires 30,000 years, (2) hydrothermal upflow and hot springs are concentrated in a narrow band within 1.5 km of the ridge axis for the lifetime of the system, (3) a large hydrothermal cell forms and remains centered above the distal tip of the intrusion for the lifetime of the system, (4) effective hydrothermal activity ends by 70,000 yrs. Petrological evidence supports a wide sill-like chamber 15 km in half-width, and models of this chamber indicate that: (1) complete crystallization of the magma requires 100,000 yrs, (2) hydrothermal vents are present at the ridge axis, but most of the vents are located 5-10 km away from the axis, (3) a large hydrothermal cell develops at the distal tip of the magma chamber, while a series of small but vigorous cells develops directly above the intrusion, both features migrate toward the ridge axis as the magma solidifies, (4) effective hydrothermal activity ends by 170,000 yrs. Substantially different hydrothermal systems develop around these two chamber geometries and comparison of the models shows this is because different patterns of near-critical P-T conditions developed around them. The fundamental influence on the nature and pattern of hydrothermal circulation at MOR is the distribution of near-critical conditions.
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Lassner, Lisa A. "Examining the effects of mid ocean ridge topography on 3D marine magnetometric resistivity model responses". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/58867.
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Thesis (S.M.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2004.Includes bibliographical references (leaves 68-69).
Methods which measure seafloor resistivity are uniquely suited to studying hydrothermal circulation in the crust. The magnetometric resistivity (MMR) technique is a galvanic method which uses a bipole current source with a magnetometer receiver. The resistivity of the subsurface can be estimated from the magnetic field read in MMR. In order to analyze and invert MMR data taken near Mid Ocean Ridges, it is important to understand the effects of ridge topography on MMR models. To analyze these effects a 3D MMR forward modeling program MMR3Df̲wd is used to model Mid Ocean Ridges with varying slopes, resistivities, and source/receiver geometries. The modeled magnetic fields are compared with models with a flat seafloor to determine the impact of the ridge topography. Results show that for some of the ridges modeled, the effects of the topography were significant, suggesting that in some instances it is important to include ridge topography in forward models to obtain accurate results from data inversion.
by Lisa A. Lassner.
S.M.
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Bowman, Emilie Elisabeth. "North-south variations in structure, topography, and melting regime along the ultra-slow spreading Red Sea Ridge". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122237.
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Thesis: S.M. in Geology, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 88-98).
The Red Sea rift is a nascent ultra-slow spreading ridge superimposed on the Afar plume. Based on high-resolution seismic data, the southernmost (south of the Danakil rift at 17.05°N), southern (17.05-19.75°N), and central (19.75-23.8°N) segments display seafloor spreading that is anomalously magma-rich compared to other ultra-slow spreading centers. In contrast, the northern segment (23.8-28°N) exhibits magma-poor extension along large-offset east- and west-dipping detachments. Sediment-corrected basement depths along the northern Red Sea reveal an axial valley as deep as the Gakkel Ridge (4200-5100 m). South of 19.75°N, plume-supported axial shoaling matches that of adjacent parts of Arabia, Africa, and the Gulf of Aden. Geochemically, the southernmost Red Sea is the locus of plume-ridge interaction. Here, E-MORBs are enriched in alkali, incompatible, and light rare-earth elements.
High mantle potential temperatures (T[subscript p]; 1326±5°C), melting pressures (12±0 kbars) and temperatures (1306±6°C), and fractionation pressures (5.3±1.6 kbars) calculated using the reverse fractional crystallization model of Brown (2019) suggest thickened oceanic crust created by high-degree partial melting of a plume-like source. North of the Danakil rift, T[subscript p] (1307± 11°C) spans a narrow range and is within the range of ambient mantle. The southern Red Sea contains N- to E-MORB depleted in alkali, incompatible, and light rare-earth elements indicating limited mixing with Afar plume material, while the central segment is host to the most depleted magmas along the ridge (La/Sm[subscript N] < 0.8). Within the southern and central regions, fractionation pressures (2.0±1.2 and 4.8±2.1 kbars, respectively) indicate lithosphere (5-15 km) thinner than that of normal ultra-slow spreading ridges (15-35 km).
In the northern Red Sea, high Na₈ and deep pressures of melting (10.4±1.4 kbars) suggest thickened lithosphere, undulations in which induce melt focusing into volcanic deeps. Based on these results, we propose that the Red Sea south of at least 26.5°N is an oceanic spreading center. We find that anomalously magma-rich spreading in the central and southern segments cannot be related to the Afar plume. Instead, the Danakil rift diverts plume-related mantle flow northeast beneath Arabia. Thus, the southern and central Red Sea must be characterized by vigorous mantle upwelling that causes heightened melt production and lithospheric thinning.
by Emilie Elisabeth Bowman.
S.M. in Geology
S.M.inGeology Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences
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Craig, Jessica. "Distribution of deep-sea bioluminescence across the Mid-Atlantic Ridge and Mediterranean Sea : relationships with surface productivity, topography and hydrography". Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=186379.
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Bioluminescence is widespread in the deep sea. In this study, the density of bioluminescent zooplankton (BL) in the deep Mediterranean Sea (MS) and at the Mid- Atlantic Ridge (MAR) was measured using low light video cameras, including a novel Image intensified Charge coupled device for Deep-sea research (ICDeep). Sampling across the MS was undertaken to assess the potential optical interference from bioluminescent zooplankton at sites under consideration for the construction of a large volume deep-sea neutrino telescope. This revealed a general decrease in deep pelagic BL densities from the western to the eastern MS. Deep mesopelagic (500- 1000 m depth) BL density was significantly correlated (p
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Prince, Philip S. "Evolution of transient topography on passive margins: A study of landscape disequilibrium in the southern Appalachian Mountains". Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/77065.
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The mechanism through which the Appalachian Mountains have maintained moderate relief some ~300 Myr after the cessation of mountain building has long puzzled geomorphologists. As recent studies have shown that Appalachian exhumation has occurred at slow rates consistent with isostatic rebound of thickened crust, the driving forces behind localized episodes of accelerated incision and the associated rugged topography have been difficult to explain given the absence of tectonic uplift. This study uses previously undocumented relict fluvial gravels and knickpoint location to confirm the role of drainage rearrangement in producing local base level drop and subsequent basin-scale transient incision in the southern Appalachians. This process is fundamentally driven by the high potential energy of streams flowing across the elevated, slowly eroding Blue Ridge Plateau relative to the present Atlantic and landward interior base levels. Gravel deposits confirm that repeated capture of landward-draining Plateau streams by Atlantic basin streams, whose immediate base level is 250-300 m lower, forces episodic rapid incision and overall erosional retreat of the Blue Ridge Escarpment along the Plateau margin. The distribution of knickpoints, bedrock gorges, and relict surfaces in the interior of the Plateau indicate that the New River, which drains to the continental interior, is actively incising the low-relief Plateau surface due to episodic drops in landward base level. The origin of landward base level perturbation is unclear, but it may be the result of glacially-driven shortening and steepening of the lower New River during the Pleistocene. Collectively, these data indicate that rapid base level drop through drainage reorganization can energize streams in otherwise stable landscapes and accelerate fluvial incision and relief production without uplift of the land surface. This process is likely quite significant in post-orogenic settings, where inherited drainage patterns may not reflect the most direct, and thus energetically appropriate, path to present base level. Passive margins may therefore never achieve a topographic steady-state, despite uniformly slow and constant uplift due to isostatic rebound.Ph. D.
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Isherwood, Ewan. "The Effect of Contemporary Hydrologic Modification on Vegetation Community Composition Distinctness in the Florida Everglades". FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/1027.
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The historic Everglades Ridge and Slough landscape maintained regularly spaced and elevated sawgrass ridges interspersed among exposed deeper-water sloughs; however, widespread but irregular hydrologic modification has degraded much of this landscape patterning. My study assessed the effects of hydrologic modification on vegetation community distinctness within the Ridge and Slough landscape through sampling species composition at fine-scales along a hydrologic gradient to measure the magnitude of segregation of species among patch types. The results show that vegetation community and topographic variation degradation is widespread, with distinctness differences proceeding and possibly being driven by topographic variation loss. Vegetation responses to past hydrologic regime modifications are likely affected by temporal lags; however, vegetation distinctness regeneration may also be hindered by a vegetatively homogeneous alternative stable state. Hydrologic regime restoration is critical for Ridge and Slough patterned landscape reestablishment, but management targets are complicated by vegetation response lags and possibly alternative stable states.
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Labude, Daniel. "Rip Channel Morphodynamics at Pensacola Beach, Florida". Thesis, 2012. http://hdl.handle.net/1969.1/148074.
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80% of all lifeguard related rescues along the beaches of northwest Florida are believed to be related to rip currents. A rip current is the strong flow of water, seaward extending from the beach to the breaker line. It has previously been shown that there are rip current hot spots at Pensacola Beach, forced by a ridge and swale topography offshore, but the annual evolution/behavior of these hotspots (i.e. location, size, frequency, and orientation) have not been examined in detail. Remote imagery from Casino Beach was rectified to a planar view in order to examine the rip channel characteristics. These characteristics were analyzed to determine variations and patterns on a daily, monthly, and seasonal basis and in relation to reset storms, wind and wave characteristics, and the beach states of Casino Beach in order to characterize the rip development and variation throughout a year.
Beach states and rip configurations were impacted by many frontal storms and one tropical storm, which were classified as a reset storm when reconfigurations of the beach state and rips occurred. Given sufficient time between reset storms, the bar migrated onshore in a manner consistent with the Wright and Short (1984) model, transitioning from LBT, to RBB, and finally to TBR state. The lack of reset storms after March 2010 resulted in a large frequency of observed rip channels (64) between April and May. It is shown that these rip channels are clustered into 7 statistically significant groups based on their location alongshore at the 95 % confidence interval. It is argued that the rip channel clusters are a direct result of the wave forcing caused by the ridge and swale topography. This situation causes the bar to move onshore that without interruption of a reset storm will attach at certain locations creating a transverse bar and rip morphology. The bar appears to attach to the beach at consistent locations throughout the year creating similar rip locations and subsequently the rip clusters. The risk posed to beach users by these rip currents is concentrated in certain locations which are persistent throughout the year.
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Bedard, Jeannette. "Tidal interactions with local topography above a sponge reef". Thesis, 2011. http://hdl.handle.net/1828/3320.
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The interaction of tidal currents with Fraser Ridge in the Strait of Georgia, B.C., generates an internal lee-wave on each strong flood but, due to the ridge's asymmetry, not during ebbs. Just prior to lee-wave formation, a strong accelerated bottom jet forms with magnitudes up to 0.7 m s^-1 forms during barotropic tidal flows reaching 0.2 m s^-1. On the steepest slope, this jet forms directly above a rare glass sponge reef, and may prevent the sponges from being smothered in sediment by periodically resuspending and carrying it away. Both the accelerated jet and lee-wave remove tidal energy. At peak flood tide, the lee-wave has energy dissipation rates reaching 10^-5 W kg^-1 that removes energy at a rate of ~611 W m^-1, while the bottom boundary layer at the time of the accelerated jet has energy dissipation rates reaching 10^-4 W kg^-1 that removes energy at a rate of ~525 W m^-1.Graduate
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Heil, Darla J. "Response of an accretionary prism to transform ridge collision south of Panama". 1988. http://catalog.hathitrust.org/api/volumes/oclc/18236979.html.
Texto completoLibros sobre el tema "Ridge and swale topography"
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Miller, Kay L. Bathymetric comparison of three mid-ocean ridge areas with slow- spreading characteristics. [Rockville, Md.]: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Oceanic and Atmospheric Administration, Office of Undersea Research, 1989.
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A, Zierenberg Robert y Geological Survey (U.S.), eds. Preliminary report of the 1988 A2-88-NC Gorda Ridge cruise. Menlo Park, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1995.
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Preliminary report of the 1988 A2-88-NC Gorda Ridge cruise. Menlo Park, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1995.
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A, Zierenberg Robert y Geological Survey (U.S.), eds. Preliminary report of the 1988 A2-88-NC Gorda Ridge cruise. Menlo Park, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1995.
Buscar texto completoCapítulos de libros sobre el tema "Ridge and swale topography"
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Monecke, Katrin. "Erosional signatures and reorganization in ridge-and-swale sequences". En Geological Records of Tsunamis and Other Extreme Waves, 471–89. Elsevier, 2020. http://dx.doi.org/10.1016/b978-0-12-815686-5.00022-5.
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OERTEL, GEORGE F. "SEDIMENTARY PATTERNS AT RIDGE AND SWALE BATHYMETRY, INNER CONTINENTAL SHELF, VIRGINIA, U.S.A." En Shelf Sedimentation, Shelf Sequences and Related Hydrocarbon Accumulation. SEPM Society for Sedimentary Geology, 1989. http://dx.doi.org/10.5724/gcs.89.07.0077.
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"The effect of ridge topography on earthquake ground motion". En Resources, Environment and Engineering, 197–202. CRC Press, 2014. http://dx.doi.org/10.1201/b17389-31.
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Maun, M. Anwar. "The Ammophila problem". En The Biology of Coastal Sand Dunes. Oxford University Press, 2009. http://dx.doi.org/10.1093/oso/9780198570356.003.0012.
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Even a cursory look on foredune plant communities shows vigorous dense stands of dune species in areas with moderate recurrent sand accretion levels specific for each plant species (Disraeli 1984; Maun and Baye 1989; Maun 1998). The phenomenon has been well documented in species of Ammophila arenaria (Carey and Oliver 1918; Tansley 1953), Corynephorus canescens (Marshall 1965), A. breviligulata (Eldred and Maun 1982) and Calamovilfa longifolia (Maun 1985). Burial has a positive influence on growth and flowering of plants and debilitated populations of foredune plant species can be rejuvenated by sand deposition (Maun 1998). Clear evidence of this phenomenon was presented by Maze and Whalley (1992a), who examined population dynamics of Spinifex sericeus in five zones receiving different amounts of sand deposition on a coastal dune system of Australia: the sea side of the first dune ridge, crest of first dune ridge, swale, Acacia thickets and stable hind dunes. In the very dynamic area on the sea side or toe of the first dune ridge (high beach) with regular burial or erosion of up to 1 m or more the plants produced very vigorous stolons with long internodes. On the crest of the dune ridge with sand deposition of about 17.5 cm per year even though plants had fewer stolons, they responded to burial by growing upwards with long internodes. In Acacia thickets in spite of very little sand deposition, plants were vigorous with little or no dead material, produced stolons and grew upwards with some long and some short internodes, probably because of greater nitrogen content in the soil. However, in the swale (slack) with little or no sand deposition, plants showed strong clumping tendency with very short internodes, a large amount of dead material on the surface and very low vigour. Unburied nodes usually died. Similarly, in the stable sand dunes with little or no sand deposition debilitated low-vigour clumps with very few stolons were abundant. Another example of this decline was presented by Martin (1959) on a shoreline along the Atlantic coast of North Carolina. He measured deposition and deflation of sand on two transects and showed that as one moved inland from the shoreline the total deposition of sand decreased.
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Chen, Yongshun John. "Dependence of crustal accretion and ridge-axis topography on spreading rate, mantle temperature, and hydrothermal cooling". En Ophiolites and oceanic crust: new insights from field studies and the Ocean Drilling Program. Geological Society of America, 2000. http://dx.doi.org/10.1130/0-8137-2349-3.161.
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Greenland, David y Mark Losleben. "Climate". En Structure and Function of an Alpine Ecosystem. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195117288.003.0007.
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Climate is one of the most important determinants of biotic structure and function in the alpine. High winds and low temperatures are defining elements of this ecosystem, requiring adaptations of the alpine biota. Interaction between topography and snowcover strongly influences spatial heterogeneity of microclimate, which in turn influences and is influenced by the distribution of vegetation. For nearly 50 years investigators have used Niwot Ridge to examine and document the climate and its interaction with the biota of the alpine tundra. This chapter reviews some of the many findings of these ongoing bioclimatic investigations. Climate studies started on Niwot Ridge in October 1952 when Professor John W. Marr and his students set up a transect of climate stations across the Front Range between Boulder and the Continental Divide (Marr 1961). There were originally 16 stations in groups of four representing different slope exposures in what he defined as the Lower and Upper Montane Forest, the Subalpine Forest, and the Alpine Tundra ecosystems of the Front Range. After 1 year, the network was reduced to four stations, called Al, Bl, Cl, and Dl, which all had ridge-top locations and ranged from lower montane (Al) to high alpine (Dl). From time to time, these stations were supplemented by other stations that supported particular studies. This was especially true during the International Biological Programme years in the early 1970s when focus on work on the Saddle research site of the Ridge began. Following the establishment of Niwot Ridge and Green Lakes Valley as a Long-Term Ecological Research (LTER) site in 1980, even more intensive climatological work has been conducted. The construction of the Tundra Laboratory in August 1990 facilitated intensive winter climatological studies. Geographical locations and elevational data on most of the stations has been provided by Greenland (1989) and is also found in the LTER electronic database (http://culter.colorado.edu/). The climate of Niwot Ridge is characterized by large seasonal and annual variability with very windy and cold winters, wet springs, mild summers, and cool, dry autumns.
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Walker, Marilyn D. y Donald A. Walker. "The Vegetation: Hierarchical Species-Environment Relationships". En Structure and Function of an Alpine Ecosystem. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195117288.003.0012.
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The vegetation of Niwot Ridge has a rich history of study, beginning with phytosociological studies directly on the Ridge and in the surrounding mountains and incorporating more experimental and dynamic approaches in later years. This chapter provides an overview of the spatial patterns of Niwot Ridge plants and plant communities relative to the primary controlling environmental gradients at scales from the individual to the landscape. The spatial patterns of vegetation at all scales are dominated by physical forces, particularly the interaction of wind, snow, and topography. The controls of biotic factors on the distribution and abundance of plant species on Niwot Ridge have received considerably less attention than have physical factors, but recent studies have revealed the importance of competition and certain mutualisms in structuring community composition. Community research on Niwot Ridge has been organized around a hierarchy of spatial scales, from the plot to the region. Plot-based studies have focused on physiological and ecological dynamics of specific species and communities, and more spatially extensive studies have provided a hierarchical framework for the plot studies. In this chapter, we first present an overview of the broader patterns in the vegetation, followed by descriptions of the communities, and then the specifics of physical and biotic controls on species and plant growth that drive the community patterns. The landscape-scale patterns in the Niwot vegetation are driven by a complex elevation gradient, which is a combination of temperature and snow regime, with wind modifying and interacting with temperature and snow at all points along the gradient (chapter 2). Certainly the most critical boundary in the system is the upper tree limit, which defines the alpine system and which lies roughly between 3400 and 3600 m elevation on Niwot Ridge. Billings (1988) provided a climatic-floristic-physiographic review of major North American alpine systems that helps to place Niwot Ridge into a larger perspective. Climatically, Niwot is intermediate between the dry Sierras, which have greater precipitation but almost none of it falling during the summer, and the wetter northern Appalachians (Mt. Washington), which have fairly even annual precipitation and no drought.
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Dealing, Denise. "Plant-Herbivore Interactions". En Structure and Function of an Alpine Ecosystem. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195117288.003.0021.
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The alpine provides a tremendous opportunity for studying plant-herbivore interactions at the population, community, and ecosystem levels. For herbivores, variations in topography and microclimate result in a relatively large amount of spatial variation in plant communities within short distances (chapter 6). A large community of herbivores, from nematodes to grasshoppers to elk, occurs on Niwot Ridge. Furthermore, given the low rates of nutrient availability in alpine soils (Fisk and Schmidt 1995; chapter 12) combined with the slow-growing perennial habit of the vegetation, alpine plants should, in theory, invest heavily in defense against herbivores (Coley et al. 1985). The goal of this chapter is to provide: (1) a summary of the feeding behaviors of the herbivores on Niwot Ridge, (2) information on the nutritional and secondary chemistry of plants on Niwot Ridge as it relates to herbivory, and (3) a review of hypotheses on community dynamics of herbivores and plants relevant to the alpine. The ultimate objective is to provide a synthesis of information that will stimulate interest in alpine tundra as a system for studying the dynamics of plant-herbivore interactions at all levels of ecological organization. The flora of Niwot Ridge has been divided into six communities (May and Webber 1982; chapter 6). Regardless of community association, nearly all of the plant species occurring on the ridge are perennials and several are very long lived (May and Webber 1982). Communities can change across small spatial scales (meters), and community origin and maintenance are believed to be largely determined by abiotic factors (Walker et al. 1994; chapter 6). However, several studies suggest that biotic factors such as herbivory may have a significant impact on plant community dynamics (Huntly et al. 1986; Davies 1994). There is significant variation in the nutritional composition of plants on Niwot Ridge. Generally, and in the absence of plant secondary compounds, species that are high in nitrogen and low in fiber are presumed to be the most desirable as forage. Based solely on these nutritional variables, the clover Trifolium parryi is hypothesized to be one of the more-preferred forages, whereas alpine sandwort, Minuartia obtusiloba, should be one of the less-preferred food items.
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Seastedt, Timothy R. "Soils". En Structure and Function of an Alpine Ecosystem. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195117288.003.0014.
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This chapter examines alpine soils from a traditional soil science and ecological perspective, with a bias toward the latter. Soil physical and chemical properties are presented, but the soils as a resource for the biota as well as the feedbacks between abiotic and biotic processes are emphasized. Over half a century ago, Hans Jenny (1941) developed a conceptual model of the factors responsible for soil development. Jenny recognized that parent material, climate, topography, and geological and ecological disturbance factors could be viewed as independent phenomena that interact to produce soils. Jenny (1980) subsequently expanded this model to one that was also useful to describe entire ecosystems. To date, I've found no better framework with which to explain soils as true ecosystem characteristics—an entity generated by the interaction of biota with the abiotic environment. Accordingly, the roles that parent materials, topography, climate, biota, and disturbance frequencies have in controlling the structural and functional aspects of alpine soils are discussed. Because each of these five factors of soil formation has the potential to interact with various combinations of the other four factors, the number of possible combinations—and soil types—is surprisingly large, especially when one or more of the five factors exhibits tremendous within-site variability. Certainly the alpine must rank “most heterogeneous” among terrestrial ecosystem types in terms of topography, making this variable particularly important in any discussion of soil characteristics. As will be demonstrated, however, the other four factors also exhibit significant variation that contributes to the complexity of the alpine soil landscape. Soil characteristics emphasized here include those variables that affect and are affected by biotic processes over time scales ranging from a single growing season to decades to centuries. Hence, cation exchange capacity (CEC), soil acidity (pH), soil water content, nutrient content and flux, and carbon storage and flux, are of primary concern. Detailed information about the soils of this region comes primarily from two sources, Scott Burns’s 1980 dissertation on soil distribution and development in the Niwot Ridge-Green Lakes region, and an extensive series of publications by M. I. Litaor. Burns provided classical soil descriptions based on the analysis of 97 extensive soil pit excavations.
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White, Robert E. "Site Selection and Soil Preparation". En Soils for Fine Wines. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195141023.003.0010.
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At the Pine Ridge winery in Napa Valley, California, a sign lists six essential steps in wine production. The first step reads . . . Determine the site—prepare the land, terrace the slopes for erosion control, provide drainage and manage soil biodiversity. . . . Determining the site means gathering comprehensive data on the local climate, topography, and geology, as well as the main soil types and their distribution. Traditionally, site determination was done using the knowledge and experience of individuals. Now it is possible to combine an expert’s knowledge with digital data on climate, parent material, topography, and soils in a GIS format to assess the biophysical suitability of land for wine grapes. Viticultural and soil experts together identify the key properties and assign weightings to these properties. An example of an Analytical Hierarchy Process is shown in figure 8.1. In this approach, both objective and subjective data were pooled and evaluated to decide the suitability of land for viticulture in West Gippsland, Victoria. In this region with a relatively uniform, mild climate, soil was given a 70% weighting, and the important soil properties were identified as depth, drainage, sodicity, texture, and pH. But in other areas, with another group of experts, a different set of key properties and weightings may well be identified. For example, a similar approach used in Virginia, in the United States, gave only a 25% weighting to soil and 30% to elevation (which affected temperature, a critical factor governing growth rate and ripening) (Boyer and Wolf 2000). This kind of approach can be refined to indicate site suitability for a particular variety within a region of given macroclimate. For example, Barbeau et al. (1998) assessed the suitability of sites in the Loire Valley, France, for the cultivar Cabernet Franc, using an index of “precocity.” Such an index is related to the ability of the fruit to accumulate sugar and anthocyanins and to attain a favorable acidity.
Actas de conferencias sobre el tema "Ridge and swale topography"
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Rocha, Renata de M. F., Armann Hoskuldsson, Ingibjorg Jonsdottir, Fernando Martinez y Richard Hey. "Bathymetry and changes on seafloor topography of the southern Reykjanes Ridge (2013 multibeam survey — SOEST/HÍ)". En 2017 IEEE/OES Acoustics in Underwater Geosciences Symposium (RIO Acoustics). IEEE, 2017. http://dx.doi.org/10.1109/rioacoustics.2017.8349751.
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Jian Chen, Thanh G. Phan y David C. Reutens. "Ridge penalized logistic partial least squares for predicting stroke deficit from infarct topography: A proof of concept study". En 2008 International Conference on Technology and Applications in Biomedicine (ITAB). IEEE, 2008. http://dx.doi.org/10.1109/itab.2008.4570535.
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"New Data for the Development of the Model of Formation of Ridge Topography in the South of Western Siberia". En Interexpo GEO-Siberia. Siberian State University of Geosystems and Technologies, 2018. http://dx.doi.org/10.18303/2618-981x-2018-2-92-96.
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Austermann, Jacqueline, Jessica R. Creveling y Andrea Dutton. "THE CONTRIBUTIONS OF KARST ISOSTASY, GLACIAL ISOSTATIC UPLIFT, AND DYNAMIC TOPOGRAPHY TO THE ELEVATION OF THE TRAIL RIDGE, FL". En GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-320849.
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Zhu, Xiangdong, Gang Fan, Dezheng Ning, Huaikong Zhang y Shouyuan Fan. "Influence of the Angle between Ridge and Wind Direction on Wind Speed Distribution in the Wind Farm under Complex Topography". En 2015 2nd International Workshop on Materials Engineering and Computer Sciences. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/iwmecs-15.2015.122.
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Мануйлов, В. y V. Manuylov. "RELIEF AND LANDSCAPES UNDERWATER COASTEL SLOPE ISLANDS OF THE SMALL KURIL RIDGE". En Sea Coasts – Evolution ecology, economy. Academus Publishing, 2018. http://dx.doi.org/10.31519/conferencearticle_5b5ce3d19ab875.91478839.
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The Small Kuril ridge – part of the island arc system of the Kuril Islands, located in the continental-ocean transition zone. The report notes the correlation between elements of the bottom topography of landscapes complexes and discusses their basic types. The most common elements of underwater slopes are bench – aligned, buried, ridge, with dense thickets of kelp and the community of echinoderms. Underwater ridge slopes with alternating asymmetrical ridges and troughs that separate them, inhabited by red algae, holothurians. In the bays of the main natural complexes – the central valley, the slopes on the sides of blocky, in the tops of the sedimentary dehydration. Straits between the islands have a width from hundreds of meters to tens of kilometers. The central part of the strait is plain with gravel-pebble material. Species of animals adapted for life
in a hydrodynamically active zone – some mollusks, echinoderms. Common elements of islands shallow water – reefs. Their dismembered surface occupied by biocenosis of brown algae, holothurians, sea anemones. Accumulative plain, composed of sand and gravel material, which is located at depths of 20‒30 meters – the border of the coastal zone.
Informes sobre el tema "Ridge and swale topography"
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Downard, Alicia, Stephen Semmens y Bryant Robbins. Automated characterization of ridge-swale patterns along the Mississippi River. Engineer Research and Development Center (U.S.), abril de 2021. http://dx.doi.org/10.21079/11681/40439.
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The orientation of constructed levee embankments relative to alluvial swales is a useful measure for identifying regions susceptible to backward erosion piping (BEP). This research was conducted to create an automated, efficient process to classify patterns and orientations of swales within the Lower Mississippi Valley (LMV) to support levee risk assessments. Two machine learning algorithms are used to train the classification models: a convolutional neural network and a U-net. The resulting workflow can identify linear topographic features but is unable to reliably differentiate swales from other features, such as the levee structure and riverbanks. Further tuning of training data or manual identification of regions of interest could yield significantly better results. The workflow also provides an orientation to each linear feature to support subsequent analyses of position relative to levee alignments. While the individual models fall short of immediate applicability, the procedure provides a feasible, automated scheme to assist in swale classification and characterization within mature alluvial valley systems similar to LMV.