scholarly journals Depositional age constraint on channel sediments in an incised meandering river using feldspar OSL dating : A case study in the Totsukawa River, Kii Mountains

2021 ◽  
Author(s):  
Manabu Ogata ◽  
Tetsuya Komatsu ◽  
Toshimichi Nakanishi
Keyword(s):  
Osl Dating ◽  
Meandering River ◽  
Depositional Age

Kissimmee River restoration: a case study

2002 ◽  
Vol 45 (11) ◽  
pp. 55-62 ◽  
Author(s):  
P.J. Whalen ◽  
L.A. Toth ◽  
J.W. Koebel ◽  
P.K. Strayer
Keyword(s):  
Ecological Integrity ◽  
Flow Characteristics ◽  
River Channel ◽  
Floodplain Wetlands ◽  
Water Control ◽  
Control Structures ◽  
Meandering River ◽  
Hydrologic Processes ◽  
Kissimmee River

Channelization of the Kissimmee River transformed a 167 km meandering river into a 9 metre deep, 75 metre wide, 90 km drainage canal (C-38) that is compartmentalized with levees and water control structures into a series of five stagnant pools. Channelization dramatically changed water level and flow characteristics, drained 21,000 hectares of floodplain wetlands and severely impacted fish and wildlife populations. A $500 million dollar restoration project will restore the ecological integrity of the river-floodplain system by reconstructing the natural river channel and reestablishing hydrologic processes. Sixty expectations have been established to quantify the ecosystem's recovery. The first phase of reconstruction was completed in February 2001 and included movement of 9.2 million cubic metres of earth to backfill 12 km of C-38, the explosive demolition of one water control structure, construction of two sections (2.4 km) of new river channel, and reestablishment of 24 contiguous km of river. Numerous social, political, and technical challenges have been encountered during the project's evolution. Recommendations are provided for future restoration projects.

scholarly journals Optical dating of alluvial deposits at the orogenic front of the andean precordillera (Mendoza, Argentina)

2012 ◽  
Vol 39 (1) ◽  
pp. 62-75 ◽  
Author(s):  
Silke Schmidt ◽  
Sumiko Tsukamoto ◽  
Eric Salomon ◽  
Manfred Frechen ◽  
Ralf Hetzel
Keyword(s):  
Debris Flow ◽  
Alluvial Fan ◽  
Osl Dating ◽  
Tectonic Activity ◽  
Humid Climate ◽  
Alluvial Deposits ◽  
Three Samples ◽  
Minimum Age ◽  
Floodplain Deposits ◽  
Depositional Age

AbstractWell constrained numerical ages of alluvial fan sediments are key to understanding the chronology of alluvial episodes and tectonic activity at the front of the Andean Precordillera. We tested the application of radiocarbon and optically stimulated luminescence (OSL) dating in the distal part of an alluvial fan five kilometers north of Mendoza. For OSL dating a large number of aliquots (n > 70) — each composed of ∼50 quartz grains — were measured in order to obtain reliable burial ages despite scattered dose distributions. Owing to a feldspar contamination in all samples, an infrared stimulation was inserted before each OSL measurement, which reduced the feldspar OSL signal successfully. By using the minimum age model we obtained stratigraphically consistent burial ages of alluvial deposits in a depth profile. The uppermost ∼1 m of sediment is composed of debris flow deposits buried 770±76 years ago. Three plant remnants used for radiocarbon dating from the same layer, however, yielded ages younger than 350 years, which are interpreted to underestimate the depositional age. Underneath the debris flow, a major unconformity cuts a series of distal alluvial fan sediments with interstratified floodplain deposits, which are composed of sandy and calciterich silt layers, respectively. Three samples from this unit which were distributed over one meter of sediment thickness yielded statistically concordant OSL ages of 12.3±1.2 ka, 12.3±1.2 ka, and 11.7±1.1 ka. The deposition of these sediments during the latest Pleistocene coincides with a phase of cool and humid climate, which occurred before the alluvial fan propagated farther into the foreland. The overlying debris flow sediments are associated with alluvial fan incision during the arid Late Holocene.

Ecological degradation of a meandering river by local channelization effects: a case study in an Austrian lowland river

Hydrobiologia ◽  
2016 ◽  
Vol 772 (1) ◽  
pp. 145-160 ◽  
Author(s):  
W. Graf ◽  
P. Leitner ◽  
I. Hanetseder ◽  
L. D. Ittner ◽  
F. Dossi ◽  
...  
Keyword(s):  
Lowland River ◽  
Meandering River ◽  
Ecological Degradation

scholarly journals Polyphase low-grade metamorphism of the Ingleton Group, northern England, UK: a case study of metamorphic inversion in a mudrock succession

2008 ◽  
Vol 146 (2) ◽  
pp. 237-251 ◽  
Author(s):  
S. J. KEMP ◽  
R. J. MERRIMAN
Keyword(s):  
Heat Flow ◽  
White Mica ◽  
Low Grade ◽  
Lower Grade ◽  
Lake District ◽  
Windermere Supergroup ◽  
Cell Dimensions ◽  
Lower Palaeozoic ◽  
Depositional Age

AbstractA series of boreholes in Horton Quarry, northwest Yorkshire (Horton-in-Ribblesdale Inlier) penetrated mudstones and slates belonging to the Austwick Formation (Windermere Supergroup) overlying laminated mudstones of the Ingleton Group. Illite (IC) and chlorite (ChC) crystallinity measurements indicate a metamorphic inversion between the two groups of mudrocks. The Windermere Supergroup mudrocks are mostly in the high anchizone or epizone, whereas the Ingletonian samples are lower grade in terms of IC, and are mostly deep diagenetic zone or low anchizone. Hence younger strata at higher grades rest on older strata at lower grades, creating a metamorphic inversion. Ingletonian slates exposed at Pecca Falls on the River Twiss show epizonal and anchizonal IC values, and greywacke samples from Ingleton Quarry contain pumpellyite. This suggests that grade in the Ingletonian may increase to the NW from the Horton to Ingleton inliers. K-white mica b cell dimensions show further differences between the Ingleton Group and the Windermere Supergroup. The Ingletonian samples are characterized by low b cell values (8.989–9.035, mean 9.007 Å), whereas the Windermere Supergroup has higher values in the range 9.022–9.034, mean 9.027 Å. The Windermere Supergroup values are similar to those recorded from the Windermere Supergroup of the southern Lake District, and Lower Palaeozoic rocks from the Scottish Southern Uplands, and are consistent with metamorphism in a low heat flow, convergent geotectonic setting. The Ingletonian b cell values suggest metamorphism in a higher heat flow setting, most likely an extensional basin. The metamorphic inversion at Horton and differences in K-white mica b cell dimensions suggest that the Ingleton Group and Windermere Supergroup strata evolved in different geotectonic settings and record two separate metamorphic events. The discovery of the metamorphic inversion at Horton provides further evidence in favour of an Ordovician rather than Neoproterozoic depositional age for the controversial Ingleton Group.

Sources of uncertainties in OSL dating of archaeological mortars: The case study of the Roman amphitheatre “Palais-Gallien” in Bordeaux

2015 ◽  
Vol 72 ◽  
pp. 100-110 ◽  
Author(s):  
P. Urbanova ◽  
D. Hourcade ◽  
C. Ney ◽  
P. Guibert
Keyword(s):  
Osl Dating

scholarly journals Computing urban flooding of meandering river using 2D numerical model (case study : Kebon Jati-Kalibata segment, Ciliwung river basin)

2019 ◽  
Vol 270 ◽  
pp. 04021
Author(s):  
Dian Indrawati ◽  
Bagus Yakti ◽  
Agustin Purwanti ◽  
Rono Hadinagoro
Keyword(s):  
Numerical Model ◽  
River Basin ◽  
Urban Flooding ◽  
Model Case ◽  
Meandering River ◽  
Stilling Basin ◽  
Diversion Channel ◽  
1D Model ◽  
2D Numerical Model

This research is an extension from a previous study titled modelling the diversion channel at Kalibata-Kebonjati meandering segment in Ciliwung watershed. Based on http://pusatkrisis.kemkes.go.id data, there are five sub districts that were flooded because of the rainfall in 5 February 2018 i.e : Pasar Minggu, Pancoran, Cilandak, Jagakarsa and Tebet. Their flood levels were achieved 300 cm, and the worst disaster happened in Pancoran, at Kebonjati to Kalibata segment in particular. Thus, this segment needs to manage accurately with appropriate structures. Formerly, the last study using 1D HEC-RAS, but the model has several lackness related to the rates of meandering velocities and discharges at the river edges, whereas, these numbers have significant effects for river scouring. Since several studies which applied 2D and 1D/2D coupling hydraulics modelling have been providing satisfactory results on complex river, this research was redeveloped and compared the meandering segment by using 2D HEC-RAS and Coupling 1D/2D HEC-RAS. Using rainfall data from three stations (Bendung Gadog, FT UI and Gunung Mas), the models indicated better results comparing with 1D model beside relations between velocity and discharge, respectively. Further, a diversion channel and stilling basin will be held in order to manage the flooding and scouring issues.

Sign in / Sign up

Export Citation Format

Share Document