Bibliografie tematiche / Aggradation

Letteratura scientifica selezionata sul tema "Aggradation"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 10 marzo 2023

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Articoli di riviste sul tema "Aggradation"

Nikic, Zoran, Ratko Ristic, Nenad Maric, Vukasin Milcanovic, Sinisa Polovina e Ivan Malusevic. "Function of check dam aggradation in local water supply of mountainous areas". Bulletin of the Faculty of Forestry, n. 120 (2019): 117–30. http://dx.doi.org/10.2298/gsf1920117n.

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Check dams are built to control erosion processes and torrential floods. In Serbia, legally binding documents, VOS (2002) and PPRS (2010), provide the concept for the water supply of the population and industry by regional systems for which water is provided by building high dams and formation of reservoirs. With this concept, it is often not possible to meet the needs of local communities in mountainous areas. In order to contribute to solving the water supply problems of these mostly poor villages, research was conducted on the possibility of using check dam aggradation groundwater for this purpose. Field investigations and analysis of project documentation for numerous check dams and aggradations in Serbia were carried out. Potential quantities and quality of groundwater in the aggradations were analyzed as a resource for the water supply of the population. The results of the research indicate very favorable possibilities of the aggradations for the accumulation of groundwater in the form of unconfined or phreatic aquifer with a free water table, in quantities that can be used for water supply. It was stated that: 1) under favorable conditions, with check dams on watercourses with constant flow and large-scale aggradations, there is a possibility of accumulating sufficient quantities of groundwater as a resource for water supply, 2) improving the quality of infiltrated waters by the process of filtration through intergranular porous media of the aggradation, and reaching the level of water supply quality, and 3) favorable economic parameters for opening the source at the aggradation, compared to other types of water sources. The possibility that check dams, in addition to their traditional role, could be used for local water supply facilities was also highlighted.

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Johnson, Peggy A., Richard D. Hey, Michael W. Horst e Amanda J. Hess. "Aggradation at Bridges". Journal of Hydraulic Engineering 127, n. 2 (febbraio 2001): 154–57. http://dx.doi.org/10.1061/(asce)0733-9429(2001)127:2(154).

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Alappat, Linto, Palaniandy Seralathan, Anil Shukla, Kyth Thrivikramji e Ashok Singhvi. "Chronology of red dune aggradations of South India and its Palaeo-environmental significance". Geochronometria 40, n. 4 (1 dicembre 2013): 274–82. http://dx.doi.org/10.2478/s13386-013-0118-5.

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Abstract Red sand dunes occur in the coastal plains of south east and west of Tamil Nadu, India between the coordinates of 8°00′ to 9°30′ N; 77°18′ to 79° 00′ E. OSL dating of these sands indicated aggradations between ∼16-9 ka and ∼9-3 ka in the west and east coasts respectively. Dating results from inland red dunes at the foothills of Western Ghats show a break in deposition at ∼6 ka and aggradation since ∼2 ka. The sand aggradations in the west coast occurred during the transition period when SW monsoon in the area was reestablishing. The dunes attained their stability by 9 ka. In the coastal region, the aggradations were controlled by sea level changes and a local recycling of earlier dunes (in the east coast). In the inland areas, the dune building was controlled by sand supply from fluvial sources.

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Treat, Claire C., e Miriam C. Jones. "Near-surface permafrost aggradation in Northern Hemisphere peatlands shows regional and global trends during the past 6000 years". Holocene 28, n. 6 (19 gennaio 2018): 998–1010. http://dx.doi.org/10.1177/0959683617752858.

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The history of permafrost aggradation and thaw in northern peatlands can serve as an indicator of regional climatic history in regions where records are sparse. We infer regional trends in the timing of permafrost aggradation and thaw in North American and Eurasian peatland ecosystems based on plant macrofossils and peat properties using existing peat core records from more than 250 cores. Results indicate that permafrost was continuously present in peatlands during the last 6000 years in some present-day continuous permafrost zones and formed after 6000 BP in peatlands in the isolated to discontinuous permafrost regions. Rates of permafrost aggradation in peatlands generally increased after 3000 BP and were greatest between 750 and 0 BP, corresponding with neoglacial cooling and the Little Ice Age (LIA), respectively. Peak periods of permafrost thaw occurred after 250 BP, when permafrost aggradation in peatlands reached its maximum extent and as temperatures began warming after the LIA, suggesting that permafrost thaw is likely to continue in the future. The broader correlation of permafrost aggradation in peatlands with known climatic trends and other proxies such as pollen records suggests that this record can be a valuable addition to regional climate reconstructions.

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Humlum, Ole. "Holocene permafrost aggradation in Svalbard". Geological Society, London, Special Publications 242, n. 1 (2005): 119–29. http://dx.doi.org/10.1144/gsl.sp.2005.242.01.11.

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Vandermaelen, Nathan, Koen Beerten, François Clapuyt, Marcus Christl e Veerle Vanacker. "Constraining the aggradation mode of Pleistocene river deposits based on cosmogenic radionuclide depth profiling and numerical modelling". Geochronology 4, n. 2 (15 dicembre 2022): 713–30. http://dx.doi.org/10.5194/gchron-4-713-2022.

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Abstract. Pleistocene braided-river deposits commonly represent long periods of non-deposition or erosion that are interrupted by rapid and short aggradation phases. When dating these sedimentary sequences with in situ-produced cosmic radionuclides (CRNs), simple concentration depth profiling approaches often fall short, as they assume that the alluvial sedimentary sequence has been deposited with a constant and rapid aggradation rate and been exposed to cosmic radiations afterwards. Numerical modelling of the evolution of CRNs in alluvial sequences permits one to account for aggradation, non-deposition and erosion phases and can simulate which scenarios of aggradation and preservation most likely represent the river dynamics. In this study, such a model was developed and applied to a Middle Pleistocene gravel sheet (Zutendaal gravels) exposed in NE Belgium. The model parameters were optimised to the observed 10Be and 26Al concentrations of 17 sediment samples taken over a depth interval of 7 m that constitutes the top of a gravel sheet up to 20 m thick. In the studied sedimentary sequence, (at least) three individual aggradation phases that were interrupted by non-deposition or erosion can be distinguished, each interruption lasting ∼ 40 kyr. The age for the onset of aggradation of the upper 7 m of the gravel sheet was further constrained to 654-62+218 ka. This age, within error limits, does not invalidate previous correlations of the gravel sheet with the Cromerian Glacial B and Marine Isotope Stage (MIS) 16. The deposition of the entire gravel sheet likely represents more than one climatic cycle and demonstrates the importance of accounting for the depositional modes of braided rivers when applying in situ cosmogenic radionuclide techniques.

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Pelletier, J. D. "The linkage between hillslope vegetation changes and late-Quaternary fluvial-system aggradation in the Mojave Desert revisited". Earth Surface Dynamics Discussions 2, n. 1 (24 marzo 2014): 181–213. http://dx.doi.org/10.5194/esurfd-2-181-2014.

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Abstract. Valley-floor-channel and alluvial-fan deposits and terraces in the southwestern US record multiple episodes of late Quaternary fluvial aggradation and incision. Perhaps the most well constrained of these episodes took place from the latest Pleistocene to the present in the Mojave Desert. One hypothesis for this episode, i.e. the paleo-vegetation change hypothesis (PVCH), posits that a reduction in hillslope vegetation cover associated with the transition from Pleistocene woodlands to Holocene desert scrub generated a pulse of sediment that triggered a primary phase of aggradation downstream, followed by channel incision, terrace abandonment, and initiation of a secondary phase of aggradation further downstream. A second hypothesis, i.e. the extreme-storm hypothesis, attributes episodes of aggradation and incision to changes in the frequency and/or intensity of extreme storms. In the past decade a growing number of studies has advocated the extreme-storm hypothesis and challenged the PVCH on the basis of inconsistencies in both timing and process. Here I show that in eight out of nine sites where the timing of fluvial-system aggradation in the Mojave Desert is reasonably well constrained, measured ages of primary aggradation and/or incision are consistent with the predictions of the PVCH if the time-transgressive nature of paleo-vegetation changes with elevation is fully taken into account. I also present an alternative process model for PVCH that is more consistent with available data and produces sediment pulses primarily via an increase in drainage density (i.e. a transformation of hillslopes into low-order channels) rather than solely via an increase in sediment yield from hillslopes. This paper further documents the likely important role of changes in upland vegetation cover and drainage density in driving fluvial-system response during semiarid-to-arid climatic changes.

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Pelletier, J. D. "The linkages among hillslope-vegetation changes, elevation, and the timing of late-Quaternary fluvial-system aggradation in the Mojave Desert revisited". Earth Surface Dynamics 2, n. 2 (21 agosto 2014): 455–68. http://dx.doi.org/10.5194/esurf-2-455-2014.

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Abstract. Valley-floor-channel and alluvial-fan deposits and terraces in the southwestern US record multiple episodes of late-Quaternary fluvial-system aggradation and incision. Perhaps the most well-constrained of these episodes took place from the latest Pleistocene to the present in the Mojave Desert. One hypothesis for this episode – i.e., the paleovegetation-change hypothesis (PVCH) – posits that a reduction in hillslope vegetation cover associated with the transition from Pleistocene woodlands to Holocene desert scrub generated a pulse of sediment that triggered a primary phase of aggradation downstream, followed by channel incision, terrace abandonment, and initiation of a secondary phase of aggradation further downstream. A second hypothesis – i.e., the extreme-storm hypothesis – attributes episodes of aggradation and incision to changes in the frequency and/or intensity of extreme storms. In the past decade a growing number of studies has advocated the extreme-storm hypothesis and challenged the PVCH on the basis of inconsistencies in both timing and process. Here I show that in eight out of nine sites where the timing of fluvial-system aggradation in the Mojave Desert is reasonably well constrained, measured ages of primary aggradation are consistent with the predictions of the PVCH if the time-transgressive nature of paleovegetation changes with elevation is fully taken into account. I also present an alternative process model for PVCH that is more consistent with available data and produces sediment pulses primarily via an increase in drainage density (i.e., a transformation of hillslopes into low-order channels) rather than solely via an increase in sediment yield from hillslopes. This paper further documents the likely important role of changes in upland vegetation cover and drainage density in driving fluvial-system response during semiarid-to-arid climatic changes.

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Tamang, Sagar Kumar, Wenjun Song, Xing Fang, Jose Vasconcelos e J. Brian Anderson. "Framework for quantifying flow and sediment yield to diagnose and solve the aggradation problem of an ungauged catchment". Proceedings of the International Association of Hydrological Sciences 379 (5 giugno 2018): 131–38. http://dx.doi.org/10.5194/piahs-379-131-2018.

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Abstract. Estimating sediment deposition in a stream, a standard procedure for dealing with aggradation problem is complicated in an ungauged catchment due to the absence of necessary flow data. A serious aggradation problem within an ungauged catchment in Alabama, USA, blocked the conveyance of a bridge, reducing the clearance under the bridge from several feet to a couple of inches. A study of historical aerial imageries showed deforestation in the catchment by a significant amount over a period consistent with the first identification of the problem. To further diagnose the aggradation problem, due to the lack of any gauging stations, local rainfall, flow, and sediment measurements were attempted. However, due to the difficulty of installing an area-velocity sensor in an actively aggrading stream, the parameter transfer process for a hydrologic model was adopted to understand/estimate streamflow. Simulated discharge combined with erosion parameters of MUSLE (modified universal soil loss equation) helped in the estimation of sediment yield of the catchment. Sediment yield for the catchment showed a significant increase in recent years. A two-dimensional hydraulic model was developed at the bridge site to examine potential engineering strategies to wash sediments off and mitigate further aggradation. This study is to quantify the increase of sediment yield in an ungauged catchment due to land cover changes and other contributing factors and develop strategies and recommendations for preventing future aggradation in the vicinity of the bridge.

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Hereford, Richard. "Modern Alluvial History of the Paria Rver Drainage Basin, Southern Utah". Quaternary Research 25, n. 3 (maggio 1986): 293–311. http://dx.doi.org/10.1016/0033-5894(86)90003-7.

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Stream channels in the Paria River basin were eroded and partially refilled between 1883 and 1980. Basin-wide erosion began in 1883; channels were fully entrenched and widened by 1890. This erosion occurred during the well-documented period of arroyo cutting in the Southwest. Photographs of the Paria River channel taken between 1918 and 1940 show that the channel did not have a floodplain and remained wide and deep until the early 1940s. A thin bar (<50 cm), now reworked and locally preserved, was deposited at that time. Basin-wide aggradation, which began in the early 1940s, developed floodplains by vertical accretion. The floodplain alluvium, 1.3–3 m thick. consists of two units recognizable throughout the studied area. An older unit was deposited during a time of low flow and sediment yield whereas the younger unit was deposited during times of high flow, sediment yield, and precipitation. Tree-ring dating suggests that the older unit was deposited between the early 1940s and 1956, and the younger between 1956 and 1980. The units are not time transgressive, suggesting that deposition by knickpoint recession was not an important process. High peak-flood discharges were associated with crosion and low flood discharges with aggradation. The erosional or aggradational mode of the streams was determined principally by peak-flood discharge, which in turn was controlled by precipitation.

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Più fonti

Tesi sul tema "Aggradation"

Townsend, Kirk F. "A Chronostratigraphic Record of Arroyo Entrenchment and Aggradation in Kanab Creek, Southern Utah". DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4492.

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Arroyos are entrenched channels characterized by near-vertical walls of alluvium and flat channel bottoms. Historic channel entrenchment in the southwest United States during the late AD 1800s and early 1900s has stimulated extensive research on these dynamic fluvial systems. The near-synchronous episodes of arroyo entrenchment and aggradation in Kanab Creek and other drainages in southern Utah during the last ~1 Ka has led many researches to argue that hydroclimatic forcings drive arroyo processes. These hypotheses remain largely untested, and there remains considerable uncertainty regarding the timing of these events and the specific mechanisms responsible for arroyo formations. Previous work established an alluvial chronology for the kanab canyon reach of Kanab creek, but it remained unclear if arroyo events in this reach were continuous with those downstream or synchronous with events in the disconnected arroyo in the upper basin. Using deailed sedimentologic and stratigraphic descriptions coupled with AMS radiocarbon and optically stimulated luminescence (OSL) dating, a new chronostratigraphic record of arroyo entrenchment and aggradation for kanab creek is produced in this study. Results suggest at least five periods of fluvial aggradation and episodic arroyo entrenchment during the middle-to late-Holocene, with aggradation occuring from ~6.2 to 3.67 ka (Qfl), ~3.2 to 2.5 ka (Qf2), ~2.2 to `.45 ka (Qf3), 1.4 to 0.8 ka (Qf4), and 0.75 to 0.14 ka (Qf5). This record is compared to regional alluvial and paleoclimate records to explore potential allogenic and autogenic forcing mechanisms. Rapid transitions from exceptional drought to pluvial periods are quasi-synchronous with regional arroyo entrenchment over the last ~1.5 Ka, but the lack of clear correlations amongst the regional alluvial records and between paleoclimate records beyond 1.5 Ka suggests that internal geomorphic thresholds are important controls on the timing of entrenchment in individual catchments. Previous research on arroyo dynamics has largely focused on the timing of entrenchment. The few studies that have investigated the processes related to aggradation have used historic observations, and not the stratigraphic record of arroyo deposits. In this study, the alluvial records from three reaches of Kanab Creek are combined to test models of the processes and geometric patterns of paleoarroyo aggradation. Results indicate that aggradation initially propagates upstream and then transitions to synchronous vertical aggradation along the entire channel profile as arroyos approach complete filling.

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Shaffner, Adam Levis. "SPECIFIC GAGE ANALYSIS ON THE LOWER WHITE RIVER, ARKANSAS". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/1009.

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This study documents the stage adjustments in the Lower White River between 1931 and 2012 at four rated gaging stations along the trunk stem of the river. The study reach extends from Calico Rock, Arkansas, to the confluence of the White River with the Mississippi River north of Arkansas City, a distance of about 509 km. The specific gage approach was used to track hydrological response in the study reach. In order to approach spatial homogeneity across the four gaging locations along the study reach, input discharges were normalized to multiples of mean daily flow (MDF). Specific gage analysis tracks water surface elevation changes for fixed discharge conditions over time. Three discharges were analyzed at each station: low flow, mean flow, and high flow. The low flow specific gage trends are emphasized to highlight degradation and aggradation due to the sensitivity of specific stages at low flows to channel bed elevation changes. An `enhanced interpolation' technique was used to fill gaps in the specific stage time series in order to avoid errors derived from extrapolation of annual rating curves. The analysis shows decreasing trends in specific stage at Clarendon and DeValls Bluff at low flows, indicating net degradation. The gages at Newport and Calico Rock show increasing trends in specific stage over time at low flows, indicating aggradation downstream of Norfork and Bull Shoals reservoirs.

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Vecsei, Adam Vecsei Adam Vecsei Adam. "Aggradation und Progradation eines Karbonaplattform-Randes : Kreide bis Mittleres Tertiär der Montagna della Maiella, Abruzzen /". Zürich : [s.n.], 1991. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=9550.

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Clauson, Karen D. "Measuring Trends In Riverbed Gradation: A Lower Mississippi River Case Study". OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/75.

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The trends of degradation and aggradation are measured in this study for the Lower Mississippi River. Historical riverbed elevation and stage data from the past hundred years were used from six gages in order to measure changes in riverbed gradation. It was found that using stage data to measure gradation changes is a superior method to using riverbed elevations, due to stage data’s reliability, length of record and daily measurements. Degradation in the Lower Mississippi River was seen during the

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Summa, Michelle Carlene. "Geologic Mapping, Alluvial Stratigraphy, and Optically Stimulated Luminescence Dating of the Kanab Creek Area, Southern Utah". DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/506.

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At the turn of the century, Kanab Creek incised 30-meters into its alluvium, leaving behind fluvial terraces and thick basin fill sediments exposed along arroyo walls. Research objectives were to determine the timing and causes of past valley-filling and arroyo-cutting episodes along a 20 km-long reach of Kanab Creek in southern Utah. Fluvial deposits were mapped at the 1:12,000 scale and sediments were described and dated using Optically Stimulated Luminescence (OSL) and radiocarbon dating. The Kanab Creek valley can be divided into a narrow, upper terraced reach and a broad lower basin fill reach near Kanab, Utah. The most prominent terrace in the upper reach is Quaternary alluvial terrace 4 (Qat4), followed by Qat3, Qat2/3, and Qat2 map units. These are composed of tabular-bedded, fine-grained sand, silt, and clay layers. The Qat2/3 map unit is a both a fill and fill-cut terrace underlain by Qa4, Qa3, and Qa2 alluvium and is used when the Qat3 fill-cut (fill-strath) terrace can not be differentiated from the Qat2 fill terrace due to their similar geomorphic position. The Qat3 fill-cut terrace upstream correlates to ~8 meters of aggradation downstream. The youngest terrace, Qat1, is a minor terrace, composed of coarse-grained channel facies. More recent channel and floodplain deposits were deposited over the last century following arroyo cutting. OSL and radiocarbon results suggest at least four cycles of fluvial cutting and filling: >6-3.5ka (Qa4), ~3->1ka (Qa3), 0.7-0.12ka (Qa2), and post-1880 AD (Qa1). Correlation to regional climate records suggests major periods of aggradation correlate to regionally cooler and wetter climatic intervals. Periods of arroyo cutting occurred at >6ka, ~3ka, 1-0.7ka, and during historic arroyo cutting (1882-1914 AD), and correlate to regionally warmer, drier intervals. These periods of aggradation and incision are roughly contemporaneous with regional drainages, except for the large aggradation seen in Kanab Creek 6-3.5ka (Qa4). Analysis of terrace longitudinal profiles indicates Qat4 has the lowest concavity suggesting that Qat4 aggraded during a period of greater sediment supply and/or reduced flood regime. Although OSL samples exhibited some degree of incomplete zeroing, calculated ages using a minimum age model are consistent with radiocarbon results.

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Hodge, Joshua B. "Hurricane Storm Surge Sedimentation on the McFaddin National Wildlife Refuge, Texas: Implications for Coastal Marsh Aggradation". Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849751/.

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This study uses the storm surge sediment beds deposited by Hurricanes Audrey (1957), Carla (1961), Rita (2005) and Ike (2008) to investigate spatial and temporal changes in sedimentation rates on the McFaddin National Wildlife Refuge in Southeast Texas. Fourteen sediment cores were collected along a transect extending from 90 to 1230 meters inland from the Gulf Coast. Storm-surge-deposited sediment beds were identified by texture, organic content, carbonate content, the presence of marine microfossils, and Cesium-137 dating. The hurricane-derived sediment beds are marker horizons that facilitate assessment of marsh sedimentation rates from nearshore to inland locations as well as over decadal to annual timescales. Near the shore, on a Hurricane Ike washover fan, where hurricane-derived sedimentation has increased elevation by up to 0.68 m since 2005, there was no measurable marsh sedimentation in the period 2008-2014. Farther inland, at lower elevations, sedimentation for the period 2008-2014 averaged 0.36 cm per year. The reduction in sedimentation in the period 2008-2014 on the nearshore part of the marsh is likely due to reduced flooding in response to increased elevation from hurricane storm surge sediment deposition. These results provide valuable knowledge about the sedimentary response of coastal marshes subject to storm surge deposition and useful guidance to public policy aimed at combating the effects of sea level rise on coastal marshes along the Gulf of Mexico.

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Zuniga, David. "Flood dynamics, hazard and risks in an active alluvial fan system threatening Ciudad Juàrez Chihuahua Mexico". Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/13049.

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The aim of this research is to assess hazards and risks associated with flooding in the city of Juárez, northern México, where there is a flood threat from active alluvial fans from mountains to the southwest and from the Rio Grande (Bravo River) to the northwest forming the northeast border of the city. Aims of this Ph.D. were addressed processing a digital elevation model (DEM) of the study area in a GIS platform to define the several alluvial fans, and thus to examine their history and palaeohydrology. Three OSL dates in the youngest parts of the fans show ages ranging from 74 - 31 ka. However, the fans were subsequently incised, broadly correlating with later Pleistocene to Holocene processes upstream, published in literature, in New México. These changes are not obviously linked to glacial-interglacial cycles, and there is indication of local controls of interplay of climate and topography, for which this work is a preliminary study. The flood threat to Juárez was addressed by using a classification of the uneven topography of the eroded alluvial fans, plus the Bravo River flood plain, into basins and subbasins. Field and laboratory work was used to define litho-facies of soils and rocks, location of structures such as, topographic and hydrologic apex and drainage system in the fans. The data were then used in association with published information on the parameters of the basins and sub-basins provided in published documents from the Mexican authorities to make flood models of the area, using standard models of HEC-HMS and HEC-RAS methods widely applied in semi-arid regions. The result was estimation of the ability of existing flood defences to resist high-flow floods that may be expected in upcoming decades. The modelling predicts that only a small number of the existing defences will hold in a catastrophic 1:100-year flood, and that substantial parts of the city are in considerable danger. Such results are important in relation to the expanded and dense population in Juárez, which is concentrated mostly on the most active part of the flooding system, the Colorado Fan, which is the subject of a focussed secondary study of vulnerability mapping. The map reveals that areas of the city of low socioeconomic development are under the greatest threat. Therefore there is a need for reconsideration of the city's flood planning, and remediation, plus the application of enforcements of areas which should not be built on, because of the threats.

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Sheridan, Mattilda. "The effects of an Alpine Fault earthquake on the Taramakau River, South Island New Zealand". Thesis, University of Canterbury. Geology, 2014. http://hdl.handle.net/10092/10253.

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An Alpine Fault Earthquake has the potential to cause significant disruption across the Southern Alps of the South Island New Zealand. In particular, South Island river systems may be chronically disturbed by the addition of large volumes of sediment sourced from coseismic landsliding. The Taramakau River is no exception to this; located north of Otira, in the South Island of New Zealand, it is exposed to natural hazards resulting from an earthquake on the Alpine Fault, the trace of which crosses the river within the study reach. The effects of an Alpine Fault Earthquake (AFE) have been extensively studied, however, little attention has been paid to the effects of such an event on the Taramakau River as addressed herein. Three research methods were utilised to better understand the implications of an Alpine Fault Earthquake on the Taramakau River: (1) hydraulic and landslide data analyses, (2) aerial photograph interpretation and (3) micro-scale modelling. Data provided by the National Institute of Water and Atmospheric Research were reworked, establishing relationships between hydraulic parameters for the Taramakau River. Estimates of landslide volume were compared with data from the Poerua landslide dam, a historic New Zealand natural event, to indicate how landslide sediment may be reworked through the Taramakau valley. Aerial photographs were compared with current satellite images of the area, highlighting trends of avulsion and areas at risk of flooding. Micro-scale model experiments indicated how a braided fluvial system may respond to dextral strike-slip and thrust displacement and an increase in sediment load from coseismic landslides. An Alpine Fault Earthquake will generate a maximum credible volume of approximately 3.0 x 108 m3 of landslide material in the Taramakau catchment. Approximately 15% of this volume will be deposited on the Taramakau study area floodplain within nine years of the next Alpine Fault Earthquake. This amounts to 4.4 x 107 m3 of sediment input, causing an average of 0.5 m of aggradation across the river floodplains within the study area. An average aggradation of 0.5 m will likely increase the stream height of a one-in-100 year flood with a flow rate of 3200 m3/s from seven metres to 7.5 m overtopping the road and rail bridges that cross the Taramakau River within the study area – if they have survived the earthquake. Since 1943 the Taramakau River has shifted 500 m away from State Highway 73 near Inchbonnie, moving 430 m closer to the road and rail. Paleo channels recognised across the land surrounding Inchbonnie between the Taramakau River and Lake Brunner may be reoccupied after an earthquake on the Alpine Fault. Micro-scale modelling showed that the dominant response to dextral strike-slip and increased ‘landslide’ sediment addition was up- and downstream aggradation separated by a localised zone of degradation over the fault trace. Following an Alpine Fault Earthquake the Taramakau River will be disturbed by the initial surface rupture along the fault trace, closely followed by coseismic landsliding. Landslide material will migrate down the Taramakau valley and onto the floodplain. Aggradation will raise the elevation of the river bed promoting channel avulsion with consequent flooding and sediment deposition particularly on low lying farmland near Inchbonnie. To manage the damage of these hazards, systematically raising the low lying sections of road and rail may be implemented, strengthening (or pre-planning the replacement of) the bridges is recommended and actively involving the community in critical decision making should minimise the risks of AFE induced fluvial hazards. The response of the Taramakau River relative to an Alpine Fault Earthquake might be worse, or less severe or significantly different in some way, to that assumed herein.

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Fitzgibbon, Holly Ann. "Interpretation of Whether Incision Rates in Appalachian Karst Reflect Long-term Downcutting toward a Surface Versus Subsurface Base Level". Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1289851338.

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Denlinger, Emily E. "Contribution of Hurricane Ike Storm Surge Sedimentation to Long-term Aggradation of Coastal Marshes in Southeastern Texas and Southwestern Louisiana". Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc500114/.

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Coastal marshes and wetlands are vital natural resources that offer habitats for plants and animals, serve as ecological filtration for soil and water pollutants, and act as protection for coastlines. Fishing, both commercial and sport, has a large economic impact in the study area – the Gulf Coast between Galveston Bay, TX and Oak Grove, LA. The objective of this research was to determine the contribution of Hurricane Ike storm surge sedimentation to long-term marsh aggradation in Texas and Louisiana coastal marshes. The research hypothesized that Hurricane Ike’s storm surge deposit would be equal to decades and possibly even a century’s worth of the average annual non-storm sedimentation. A quantitative field study was performed. The storm surge deposit was examined in a series of 15 transects covering approximately 180 km east of Hurricane Ike’s landfall. Nine of the 15 transects were re-surveyed a year after the initial measurement to assess preservation of the deposit. The results demonstrate that Hurricane Ike contributed between 10 to 135 years’ worth of sediment to coastal marshes along the coasts of Texas and Louisiana, and the sediment deposits have been preserved for over two years.

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Libri sul tema "Aggradation"

Jackson, M. P. A. Centrifuge modeling of the effects of aggradation and progradation on syndepositional salt structures. Austin, Tex: Bureau of Economic Geology, University of Texas at Austin, 1988.

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Jackson, M. P. A. Centrifuge modeling of the effects of aggradation and progradation on syndepositional salt structures. Austin, TX: University of Texas at Austin, 1988.

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Conference on Missouri River Streambed Degradation, Aggradation, and Bank Erosion (1986 Omaha, Neb.). Summary proceedings, Conference on Missouri River Streambed Degradation, Aggradation, and Bank Erosion, April 2-3, 1986. Omaha, Neb. (10834 Old Mill Rd., Suite 1, Omaha 68154): MBSA, 1986.

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Eash, David A. Flood-plain and channel aggradation at selected bridge sites in the Iowa and Skunk River Basins, Iowa. Iowa City, Iowa: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Eash, David A. Flood-plain and channel aggradation at selected bridge sites in the Iowa and Skunk River Basins, Iowa. Iowa City, Iowa: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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C, Schmidt John. Aggradation and degradation of alluvial sand deposits, 1965 to 1986, Colorado River, Grand Canyon National Park, Arizona. Denver, Colo: Dept. of the Interior, U.S. Geological Survey, 1988.

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Eash, David A. Flood-plain and channel aggradation at selected bridge sites in the Iowa and Skunk River Basins, Iowa. Iowa City, Iowa: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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C, Schmidt John. Aggradation and degradation of alluvial sand deposits, 1965 to 1986, Colorado River, Grand Canyon National Park, Arizona. Washington: U.S. G.P.O., 1990.

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Eash, David A. Flood-plain and channel aggradation at selected bridge sites in the Iowa and Skunk River Basins, Iowa. Iowa City, Iowa: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Eash, David A. Flood-plain and channel aggradation at selected bridge sites in the Iowa and Skunk River Basins, Iowa. Iowa City, Iowa: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Capitoli di libri sul tema "Aggradation"

Bowman, Dan. "Aggradation". In Principles of Alluvial Fan Morphology, 57–60. Dordrecht: Springer Netherlands, 2018. http://dx.doi.org/10.1007/978-94-024-1558-2_7.

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Bull, William B. "Correlation of Fluvial Aggradation Events to Times of Global Climate Change". In AGU Reference Shelf, 456–64. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/rf004p0456.

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Elston, Donald P. "Pre-Pleistocene(?) deposits of aggradation, Lees Ferry to Western Grand Canyon, Arizona". In Geology of Grand Canyon, Northern Arizona (with Colorado River Guides): Lee Ferry to Pierce Ferry, Arizona, 175–85. Washington, D. C.: American Geophysical Union, 1989. http://dx.doi.org/10.1029/ft115p0175.

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Robinson, Ruth A. J., Rudy L. Slingerland e Jeremy M. Walsh. "Predicting Fluvial-Deltaic Aggradation in Lake Roxburgh, New Zealand: Test of a Water and Sediment Routing Model". In Geologic Modeling and Simulation, 119–32. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1359-9_7.

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Jianheng, Xie. "Tentative Ideas for Controlling the Aggradation of the Lower Yellow River in the Near and Remote Future". In The GeoJournal Library, 339–54. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2450-5_23.

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Grötsch, J. "Guilds, Cycles and Episodic Vertical Aggradation of a Reef (Late Barremian to Early Aptian, Dinaric Carbonate Platform, Slovenia)". In Orbital Forcing and Cyclic Sequences, 227–42. Oxford, UK: Blackwell Publishing Ltd., 2009. http://dx.doi.org/10.1002/9781444304039.ch17.

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Krautblatter, Michael. "Patterns of Multiannual Aggradation of Permafrost in Rock Walls with and Without Hydraulic Interconnectivity (Steintälli, Valley of Zermatt, Swiss Alps)". In Landform - Structure, Evolution, Process Control, 199–219. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-75761-0_13.

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Wadhawan, Sudesh Kumar. "Palaeogene–Neogene Tectonics and Continental Aggradational Basins in North-Western India: Implications for Geological Evolution of Thar Desert". In Society of Earth Scientists Series, 151–66. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-77443-5_5.

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"aggradation". In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 28. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_10972.

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"aggradation…". In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 28. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_10973.

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Atti di convegni sul tema "Aggradation"

Dulovicova, Renata. "CURRENT STATE OF AGGRADATION AT KOMARNANSKY CHANNEL." In 15th International Multidisciplinary Scientific GeoConference SGEM2015. Stef92 Technology, 2011. http://dx.doi.org/10.5593/sgem2015/b31/s12.026.

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Radice, Alessio, Barbara Zanchi e Ehsan Heydari. "Laboratory experiments for channel aggradation in supercritical flow". In Proceedings of the 39th IAHR World Congress From Snow to Sea. Spain: International Association for Hydro-Environment Engineering and Research (IAHR), 2022. http://dx.doi.org/10.3850/iahr-39wc252171192022467.

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Jakob, Matthias, Michael Porter, K. Wayne Savigny e Eugene Yaremko. "A Geomorphic Approach to the Design of Pipeline Crossings of Mountain Streams". In 2004 International Pipeline Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ipc2004-0239.

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Several hydrological methods are available to determine flood discharge and scour of streams at pipeline crossings. These methods are appropriate for streams dominated by purely hydrological processes, but fail where other, more hazardous processes occur within the design recurrence interval. Several investigations have shown that scour, impact and aggradation associated with debris flows, outburst floods or related phenomena may fundamentally change the parameters needed for proper pipeline crossing design. Depending on the process type, the peak discharge of the hazardous process can exceed that of the design flood (typically 50 to 200 year return period) by a factor of 2 to 50. Similarly, scour or aggradation by a non-fluvial process can exceed the hydrologically-derived estimates by several factors. It is therefore recommended that a geomorphic approach be taken in recognizing and quantifying the potential for non-fluvial processes and that the findings be integrated in the design of pipeline crossings.

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Ghaly, Ashraf. "Variation of flow pattern in waterways due to degradation and aggradation". In the 3rd International Conference. New York, New York, USA: ACM Press, 2012. http://dx.doi.org/10.1145/2345316.2345356.

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Neagu, Nathalie, Ari Matmon, Yehouda Enzel e Naomi Porat. "CONTROLS ON QUATERNARY AGGRADATION-INCISION CYCLES IN A HYPERARID WATERSHED, NORTHEASTERN NEGEV, ISRAEL". In GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-295906.

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Ahmed, Joshua, Jeff Peakall, Dan Parsons e Matt Balme. "EXCEPTIONAL CHANNEL AGGRADATION ON MARS AND WHAT IT MEANS FOR WATER LEVEL RISE". In GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-358815.

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Wong, Annie, Darrell S. Kaufman, R. Scott Anderson, Nicholas P. McKay, Erik Schiefer e Al Werner. "TIMING AND RATE OF GLACIALLY DRIVEN OUTWASH PLAIN AGGRADATION: POTHOLE LAKE, SOUTH-CENTRAL ALASKA". In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-318986.

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Carson, Eric C., Stefanie E. Dodge, John W. Attig e J. Elmo Rawling. "LATE MIS 3 ONSET TO LARGE-SCALE AGGRADATION ON THE UPPER MISSISSIPPI RIVER VALLEY, USA". In GSA Annual Meeting in Phoenix, Arizona, USA - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019am-334287.

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Sutfin, Nicholas, Ellen Wohl, Tim Fegel e Laurel Lynch. "HOW MIGHT LOGJAMS REDUCE FLOODPLAIN FINE SEDIMENT AGGRADATION AND ORGANIC CARBON STORAGE IN MOUNTAIN STREAMS?" In GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-359381.

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Massey, Matthew A. "PLEISTOCENE FLUVIAL INCISION, AGGRADATION, AND SLACKWATER DEPOSITION ASSOCIATED WITH THE LICKING RIVER IN NORTHERN KENTUCKY". In GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-301603.

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Rapporti di organizzazioni sul tema "Aggradation"

Pollard, W. H. Ground-ice aggradation on Fosheim Peninsula, Ellesmere Island, Nunavut. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2000. http://dx.doi.org/10.4095/211971.

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Weissinger, Rebecca, e Dana Witwicki. Riparian monitoring of wadeable streams at Courthouse Wash, Arches National Park: Summary report, 2010–2019. A cura di Alice Wondrak Biel. National Park Service, novembre 2021. http://dx.doi.org/10.36967/nrr-2287907.

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The goal of Northern Colorado Plateau Network (NCPN) riparian monitoring is to determine long-term trends in hydrologic, geomorphic, and vegetative properties of wadeable streams in the context of changes in other ecological drivers, stressors, and processes. This information is intended to provide early warning of resource degradation and determine natural variability of wadeable streams. This report summarizes NCPN monitoring of Courthouse Wash in Arches National Park (NP) from 2010 to 2019. The focus of this report is to (1) present geomorphology and vegetation data from five reaches monitored in Courthouse Wash from 2010 to 2015, and (2) examine patterns in water availability at one monitoring reach from November 2010 to December 2019. Vegetation sampling and geomorphology surveys were suspended in 2016 due to budget cuts; this report presents baseline data for future comparisons. The NCPN has five monitoring reaches located between the inflow of Sevenmile Canyon, a major tributary, and the terminus of Courthouse Wash, at the Colorado River. Two reaches (2, 5) are located in Upper Courthouse Wash, and three (1, 4, 7) in Lower Courthouse Wash. Hydrologic monitoring wells are installed only at Reach 1. During our monitoring period, which included drought years in 2012 and 2018 and a wetter-than-average period from fall 2013 to 2014, groundwater levels showed steep declines corresponding to the start of the growing season each year. Hot, dry summers and falls in 2012, 2018, and 2019 showed the deepest troughs in groundwater levels. Active monsoon years helped elevate summer and fall groundwater levels in 2013 and 2014. Continued monitoring will help us better understand the relationship of climate and water availability at this reach. A geomorphic survey was completed once for reaches 2, 4, and 7, and twice for reaches 5 and 1. Powerful floods during our monitoring period resulted in aggradation of the channel in reaches 5 and 1, which were first surveyed in March 2013. Flooding in September 2013 resulted in an average of 0.24 meters of deposition found in the channel thalweg at Reach 1 in March 2014. Storm events in May 2014 caused additional aggradation. In March 2015, an average of 0.41 meters of deposition was recorded in the channel thalweg at Reach 5, with 0.32 meters of deposition between the vegetation transect headpins compared to the 2013 data. The riparian vegetation recorded at our monitoring reaches is consistent with an open-canopy Fremont cottonwood woodland with a diverse understory. Canopy closure ranged from 29% to 52%. Measurements were sensitive enough to detect a 10% reduction in canopy closure at Reach 5 during a pest infestation in June 2013. Canopy closure subsequently rebounded at the reach by 2015. Total obligate and facultative wetland cover ranged from 7% to 26%. Fremont cottonwood seedlings, saplings, and overstory trees were present at all reaches, indicating good potential for future regeneration of the canopy structure. These data can serve as a baseline for comparison with future monitoring efforts. One area of management concern is that exotic-plant frequency and cover were relatively high in all monitoring reaches. Exotic cover ranged from 2% to 30%. High exotic cover was related to years with high cover of annual brome grasses. High cover of exotic grasses is associated with increased wildfire risk in southwestern riparian systems, which are not well-adapted to fire. Managers should be prepared for this increased risk following wet winters that promote annual brome grass cover. Beaver activity was noted throughout bedrock-constrained reaches in Courthouse Wash. Beaver activity can reduce adjacent woody riparian vegetation cover, but it also contributes to maintaining a higher water table and persistent surface water. Climate change is likely to be an increasingly significant stressor in Courthouse Wash, as hotter, drier conditions decrease water levels and increase drought stress...

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Dechert, T. V., P. A. McDaniel e A. L. Falen. Aggradational and erosional history of the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory. Office of Scientific and Technical Information (OSTI), settembre 1994. http://dx.doi.org/10.2172/10191420.

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Flood-plain and channel aggradation of selected bridge sites in the Iowa and Skunk River basins, Iowa. US Geological Survey, 1996. http://dx.doi.org/10.3133/wri954290.

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