Three-dimensional bluff evolution in response to seasonal fluctuations in Great Lakes water levels

2020 ◽  
Vol 46 (6) ◽  
pp. 1533-1543 ◽  
Author(s):  
C.A. Volpano ◽  
L.K. Zoet ◽  
J.E. Rawling ◽  
E.J. Theuerkauf ◽  
R. Krueger
2018 ◽  
Vol 55 (7) ◽  
pp. 709-729 ◽  
Author(s):  
Riley P.M. Mulligan ◽  
Andy F. Bajc

Recent three-dimensional mapping investigations in southern Simcoe County, Ontario, allow refinement of the existing regional stratigraphic framework. Analysis of 25 continuously cored boreholes has revealed a complex but consistent sediment succession that provides a record of the last two glacial cycles (Marine Isotope Stages 1–6). Five stratigraphic units (SU1–SU5) comprise the pre-Late Wisconsin record. The stratigraphy is floored by a presumed Illinoian glacial complex consisting of a lower, coarse-grained till (SU1), locally overlain by stratified glaciolacustrine and glaciofluvial sediments (SU2), but more commonly capped by a stone-poor, fine-grained till (SU3) of the Georgian Bay lobe. A widespread subaerial unconformity developed on the upper surface of SU3 contains organic-bearing, nonglacial deposits (SU4) ranging between 54 800 ± 3000 years BP (considered beyond the limits of radiocarbon dating) and 37 450 ± 590 14C years BP. SU4 is abruptly overlain by a thick succession of rhythmically laminated lacustrine muds graded upwards into glaciolacustrine silts and clays interrupted by regionally continuous sand bodies (SU5). The succession is capped (and locally truncated) by Late Wisconsin Newmarket Till. The sedimentary record of southern Simcoe County is correlated with other well-studied reference sections in southern Ontario and contains information that informs reconstructions of former ice extents in the lower Great Lakes region following the Illinoian glaciation. Several sediment units host aquifers, but limited thickness and spatial extent, as well as issues with naturally occurring dissolved gases and solids, restrict their use for groundwater supply.


2019 ◽  
Vol 5 (9) ◽  
pp. 1877-1892 ◽  
Author(s):  
Majed Rodhan Hussain ◽  
Basim Sh. Abed

The alluvial fan of Mandali located between latitude 30˚45’00” N longitude 45˚30’00” E in east of Diyala Governorate, Iraq. Thirty-five wells were identified in the study area with average depth of 84 m and estimated area of 21550 ha. A three-dimensional conceptual model was prepared by using GMS program. From wells cross sections, four geological layers have been identified. The hydraulic conductivity of these layers was calculated for steady state condition, where the water levels for nine wells distributed over the study area were observed at same time. Afterward, PEST facility in the GMS was used to estimate the aquifer hydraulic characteristics. Other characteristics such as storage coefficient and specific yield have been determined from one year field observations that were collected by General Authority of Groundwater, Diyala Governorate. Also, the observations were used for calibration of unsteady state model. Then wells were hypothetically redistributed and increased to 103 wells, assuming a distance of 1500 m between the wells, a well productivity rate of were 7 l/s, annual rainfall rate was used for recharging. Three different wells operating times were suggested and these 6, 12, and 18 hr/day with total discharge of 150, 300, 450 m3/day and maximum drawdown of 7, 11, and 20 m respectively. For water quality assessment, the collected groundwater samples were analysed at the laboratory.  Results showed that the TDS in all wells was ranged from 1000-3000 mg/l but TDS in well number 18 was exceeded 3000 mg/l which indicate that the groundwater in this well is not recommended to be used for irrigation. According to Iraqi standard for drink (IQS 2009), it can be used for drinking if saline treatment units were provided.


2013 ◽  
Vol 10 (8) ◽  
pp. 10873-10911 ◽  
Author(s):  
M. B. Mabrouk ◽  
A. Jonoski ◽  
D. Solomatine ◽  
S. Uhlenbrook

Abstract. Serious environmental problems are emerging in the River Nile basin and its groundwater resources. Recent years have brought scientific evidence of climate change and development-induced environmental impacts globally as well as over Egypt. Some impacts are subtle, like decline of the Nile River water levels, others are dramatic like the salinization of all coastal land in the Nile Delta – the agricultural engine of Egypt. These consequences have become a striking reality causing a set of interconnected groundwater management problems. Massive population increase that overwhelmed the Nile Delta region has amplified the problem. Many researchers have studied these problems from different perspectives using different methodologies, following different objectives and, consequently, arrived at different findings. However, they all confirmed that significant groundwater salinization has affected the Nile Delta and this is likely to become worse rapidly in the future. This article presents, categorizes and critically analyses and synthesizes the most relevant research regarding climate change and development challenges in relation to groundwater resources in the Nile Delta. It is shown that there is a gap in studies that focus on sustainable groundwater resources development and environmentally sound protection as an integrated regional process in Nile Delta. Moreover, there is also a knowledge gap related to the deterioration of groundwater quality. The article recommends further research that covers the groundwater resources and salinization in the whole Nile Delta based on integrated three-dimensional groundwater modelling of the Nile delta aquifer.


Author(s):  
Won-Tae Kang ◽  
Ki Han Yu ◽  
Seung Yeob Lee ◽  
Byeong Rog Shin

A numerical and an experimental investigation on a suction vortices including cavitation, free vortices and subsurface vortices behavior in the model sump system with multi-intakes is performed at several flow rates and water levels. A test model sump and piping system were designed based on Froude similitude for the prototype of the recommended structure layout by HI-9.8 American National Standard for Pump Intake Design of the Hydraulic Institute. An experiment is performed according to the sump model test procedure of Hyosung Goodsprings, Inc. A numerical analysis of three dimensional multiphase flows through the model sump is performed by using the finite volume method of the CFX code with multi-block structured grid systems. A k-ω Shear Stress Transport turbulence model and the Rayleigh-Plesset cavitation model are used for solving turbulence cavitating flow. Several types of free surface and submerged vortex which occurs with each different water level are identified through the experimental investigation. From the numerical analysis, the vortices are reproduced and their formation, growing, shedding and detailed vortex structures are investigated. To reduce abnormal vortices, an anti-vortex device is considered and its effect is investigated and discussed.


2021 ◽  
Author(s):  
John Crowley ◽  
Jianliang Huang

<p>Correlated errors in the monthly spherical harmonic coefficient (SHC) solutions provided by the GRACE data centers are estimated and removed using the destriping method of Crowley and Huang (2020). Regional estimates for mass change are calculated across Canada using the simple basin average technique of Swenson and Wahr (2002) as well as a simple mascon approach developed by the Canadian Geodetic Survey. A comparison with mascon solutions from the GRACE data centers demonstrates excellent agreement and in some cases reveals larger amplitudes and added temporal structure. This approach does not require additional constraints/dependencies, smoothing, normalizations or scaling factors and can easily be applied to any regional geometry without the need to calculate a global solution. Solutions tend to agree well when data quality is good and diverge when errors are larger. This is expected and demonstrates the underlying uncertainties that remain. The similarity in solutions using such different methodologies provides confidence in the time series solutions. We conclude with a regional validation that uses water level changes in the Great Lakes of North America to demonstrate the effectiveness of the method. The Great Lakes are large enough that GRACE clearly detects changes in their water levels. At the same time, the lakes are close enough to each other that distinguishing signals between adjacent lakes remains a challenge for any method.</p><p>References:</p><p>Crowley, J.W., and J Huang, A least-squares method for estimating the correlated error of GRACE models, Geophysical Journal International, Volume 221, Issue 3, June 2020, Pages 1736–1749, https://doi.org/10.1093/gji/ggaa104.</p><p>Swenson, S., and J. Wahr, Methods for inferring regional surface-mass anomalies from Gravity Recovery and Climate Experiment (GRACE) measurements of time-variable gravity, J. Geophys. Res., 107(B9), 2193, doi:10.1029/2001JB000576, 2002.</p>


2007 ◽  
Vol 59 (2-3) ◽  
pp. 187-210 ◽  
Author(s):  
C.F. Michael Lewis ◽  
Steve M. Blasco ◽  
Pierre L. Gareau

Abstract In the Great Lakes region, the vertical motion of crustal rebound since the last glaciation has decelerated with time, and is described by exponential decay constrained by observed warping of strandlines of former lakes. A composite isostatic response surface relative to an area southwest of Lake Michigan beyond the limit of the last glacial maximum was prepared for the complete Great Lakes watershed at 10.6 ka BP (12.6 cal ka BP). Uplift of sites computed using values from the response surface facilitated the transformation of a digital elevation model of the present Great Lakes basins to represent the paleogeography of the watershed at selected times. Similarly, the original elevations of radiocarbon-dated geomorphic and stratigraphic indicators of former lake levels were reconstructed and plotted against age to define lake level history. A comparison with the independently computed basin outlet paleo-elevations reveals a phase of severely reduced water levels and hydrologically-closed lakes below overflow outlets between 7.9 and 7.0 ka BP (8.7 and 7.8 cal ka BP) in the Huron-Michigan basin. Severe evaporative draw-down is postulated to result from the early Holocene dry climate when inflows of meltwater from the upstream Agassiz basin began to bypass the upper Great Lakes basin.


1976 ◽  
Vol 84 (4) ◽  
pp. 455-465 ◽  
Author(s):  
Barry P. Cohn ◽  
Joseph E. Robinson

1979 ◽  
Vol 5 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Frank H. Quinn ◽  
Jan A. Derecki ◽  
Raymond N. Kelley

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