scholarly journals Water Balance of Paleolake Qinghai and Its Precipitation Estimation at Three High Lake-Level Stages since 40 kaBP

2000 ◽  
Vol 12 (3) ◽  
pp. 211-218 ◽  
Author(s):  
JIA Yulian ◽  
◽  
SHI Yafeng ◽  
FAN Yunqi
Keyword(s):  
Water Balance ◽  
Lake Level ◽  
Precipitation Estimation ◽  
High Lake Level

Lake Michigan Beach-Ridge and Dune Development, Lake Level, and Variability in Regional Water Balance

1995 ◽  
Vol 44 (2) ◽  
pp. 181-189 ◽  
Author(s):  
John Lichter
Keyword(s):  
Water Balance ◽  
Lake Level ◽  
Lake Michigan ◽  
Plant Macrofossils ◽  
Time Intervals ◽  
Beach Ridges ◽  
Average Return ◽  
High Lake Level ◽  
High Level ◽  
Regional Water

AbstractA sequence of northern Lake Michigan beach ridges records lake-level fluctuations that are probably related to changes in late Holocene climate. Historically, episodes of falling and low lake level associated with regional drought led to the formation of dune-capped beach ridges. The timing of prehistoric ridge formation, estimated by radiocarbon dating of plant macrofossils from early-successional dune species, shows that return periods of inferred drought, averaged for time intervals of 100 to 480 yr, ranged between 17 and 135 yr per drought during the last 2400 yr. In five of ten of these time intervals, the average return period ranged between 17 and 22 yr per drought. These intervals of frequent ridge formation and drought were associated with the development of parabolic dunes, which is indicative of high lake level and moist climate. This seeming paradox suggests that unusually moist decades alternated with unusually dry decades during these time intervals. Regional water balance probably varied less during the time intervals when ridges formed less often and the lake produced no evidence of high level.

Mid-Holocene palaeohydrochemistry and palaeohydrology of Yamdrok Yumtso, southern Tibetan Plateau, reconstructed from δ18O and δ13C of fossil shells of the gastropod Radix auricularia

The Holocene ◽  
2020 ◽  
Vol 30 (12) ◽  
pp. 1741-1751 ◽  
Author(s):  
Feng Chen ◽  
Jin-Liang Feng ◽  
Hai-Ping Hu ◽  
Ping Wang
Keyword(s):  
Tibetan Plateau ◽  
Lake Level ◽  
Sedimentary Environment ◽  
Lacustrine Sediments ◽  
High Lake Level ◽  
Isotope Study ◽  
Southern Tibetan Plateau ◽  
Stable Isotope Study ◽  
Radix Auricularia ◽  
Closed Lake

Palaeohydrochemical and palaeohydrological changes of lakes have seldom been reconstructed from the fossil shells of the gasropod Radix auricularia, which is a new, and potentially high-resolution environnmental archive. We conducted a geochemical and stable isotope study of the shells of Radix from the exposed fluvio-lacustrine sediments near Lake Yamdrok Yumtso in the southern Tibetan Plateau. Our aims were to determine the sedimentary environment, palaeo-lake hydrochemistry and hydrological status. AMS 14C and OSL dating indicates that a lake-level stage of Yamdrok Yumtso higher than that of today occurred during ~4.7–1.2 cal. kyr BP. Results of Sr/Ca, δ13C and δ18O analysis of the fossil shells of Radix auricularia indicate that the lake-level fluctuations were mainly controlled by changes of the Indian Summer Monsoon; decreasing evaporation during the mid- to late-Holocene was also responsible. In addition, based on the geochemical relationship between Radix sp. shells and the ambient water in lakes, the values of δ18OPalaeo-water and Sr/CaPalaeo-water reconstructed using the fossil shells of Radix auricularia are −8.2‰ to −5.1‰ and 0.0012 to 0.0057, respectively. Further, based on the values of δ18Oshell, together with geomorphological evidence, we infer that Yamdrok Yumtso was a closed lake system, and we estimate its possible extent during the interval of high lake-level. In addition, we speculate that the water level of Yamdrok Yumtso at this time exceeded 4448.9 m a.s.l., but was less than 4451 m a.s.l., and that the major separation of various components of the Yamdrok Yumtso system occurred after 1.2 kyr BP.

The characteristics of tight oil sand reservoir-source assemblage in lacustrine basins: A case study of the Cretaceous Qingshankou Formation, Songliao Basin, northeast China

2018 ◽  
Vol 6 (2) ◽  
pp. T299-T311 ◽  
Author(s):  
Yaohua Li ◽  
Yan Song ◽  
Zhenxue Jiang ◽  
Lishi Yin ◽  
Mo Chen ◽  
...  
Keyword(s):  
Lake Level ◽  
Songliao Basin ◽  
Qualitative Description ◽  
Hydrocarbon Potential ◽  
Tight Oil ◽  
Sweet Spot ◽  
Oil Sand ◽  
Tight Reservoir ◽  
High Lake Level ◽  
Lacustrine Basins

The complicated source-reservoir-assemblage characteristics of lacustrine tight oil sand in China are the main controlling factors of tight reservoir oiliness (i.e., oil richness). Several studies have focused on qualitative description of source-reservoir-assemblage characteristics without quantitative assessment. In this study, reservoir-source-assemblage (RSA) has been evaluated quantitatively by fitting the RSA log in the evaluation of Qijia Depression in the Songliao Basin. Total organic carbon (TOC) and sand volume (Vs) logs are used to fit the RSA log in three steps: (1) TOC and Vs log fitting and normalization, (2) RSA log fitting, and (3) extraction of root-mean-square (rms) amplitude and frequency (Frq(0)) information from the RSA log. The rms represents the reservoir capability and hydrocarbon potential, and Frq(0) represents the interbedding frequency that changes with the lake level. Positive values (0–1] of the RSA log correspond to a high lake level, whereas negative values [[Formula: see text], 0) correspond to a low lake level. Based on RSA log values, we defined the parameter RSAsuf, a product of rms and Frq(0), to quantitatively evaluate the tight oil sweet spot. RSAsurf serves as tight oil sweet spot indicator and correlates positively to oil richness. As a result, four types of effective reservoirs (RI, RII, RIII, and RIV), two types of effective sources (SI and SII), and three types of RSAs (R-S-R, S-R-S, and S-S-R) are identified based on cores and RSA logs. High RSAsuf values on the isoline map indicate the sweet spot zones around the G933 and J392 well areas, which correlates very well with the oilfield test data. The approach is appropriate for lacustrine basins with complicated RSA, in which RSA logs serve as indicator for the sedimentary rhythm, reservoir capability, and hydrocarbon potential.

scholarly journals Modelling the water balance of Lake Victoria (East Africa) – Part 1: Observational analysis

2018 ◽  
Vol 22 (10) ◽  
pp. 5509-5525 ◽  
Author(s):  
Inne Vanderkelen ◽  
Nicole P. M. van Lipzig ◽  
Wim Thiery
Keyword(s):  
Water Balance ◽  
Lake Level ◽  
Lake Victoria ◽  
Balance Model ◽  
Lake Victoria Basin ◽  
Lake Level Fluctuations ◽  
Lake Evaporation ◽  
In Situ Observations ◽  
The Individual

Abstract. Lake Victoria is the largest lake in Africa and one of the two major sources of the Nile river. The water level of Lake Victoria is determined by its water balance, consisting of precipitation on the lake, evaporation from the lake, inflow from tributary rivers and lake outflow, controlled by two hydropower dams. Due to a scarcity of in situ observations, previous estimates of individual water balance terms are characterized by substantial uncertainties, which means that the water balance is often not closed independently. In this first part of a two-paper series, we present a water balance model for Lake Victoria, using state-of-the-art remote sensing observations, high-resolution reanalysis downscaling and outflow values recorded at the dam. The uncalibrated computation of the individual water balance terms yields lake level fluctuations that closely match the levels retrieved from satellite altimetry. Precipitation is the main cause of seasonal and interannual lake level fluctuations, and on average causes the lake level to rise from May to July and to fall from August to December. Finally, our results indicate that the 2004–2005 drop in lake level can be about half attributed to a drought in the Lake Victoria Basin and about half to an enhanced outflow, highlighting the sensitivity of the lake level to human operations at the outflow dam.

scholarly journals Modelling the water balance of Lake Victoria (East Africa) – Part 2: Future projections

2018 ◽  
Vol 22 (10) ◽  
pp. 5527-5549 ◽  
Author(s):  
Inne Vanderkelen ◽  
Nicole P. M. van Lipzig ◽  
Wim Thiery
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Lake Level ◽  
Climate Models ◽  
Emission Scenario ◽  
Lake Victoria ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Management Scenario ◽  
Dam Management

Abstract. Lake Victoria, the second largest freshwater lake in the world, is one of the major sources of the Nile river. The outlet to the Nile is controlled by two hydropower dams of which the allowed discharge is dictated by the Agreed Curve, an equation relating outflow to lake level. Some regional climate models project a decrease in precipitation and an increase in evaporation over Lake Victoria, with potential important implications for its water balance and resulting level. Yet, little is known about the potential consequences of climate change for the water balance of Lake Victoria. In this second part of a two-paper series, we feed a new water balance model for Lake Victoria presented in the first part with climate simulations available through the COordinated Regional Climate Downscaling Experiment (CORDEX) Africa framework. Our results reveal that most regional climate models are not capable of giving a realistic representation of the water balance of Lake Victoria and therefore require bias correction. For two emission scenarios (RCPs 4.5 and 8.5), the decrease in precipitation over the lake and an increase in evaporation are compensated by an increase in basin precipitation leading to more inflow. The future lake level projections show that the dam management scenario and not the emission scenario is the main controlling factor of the future water level evolution. Moreover, inter-model uncertainties are larger than emission scenario uncertainties. The comparison of four idealized future management scenarios pursuing certain policy objectives (electricity generation, navigation reliability and environmental conservation) uncovers that the only sustainable management scenario is mimicking natural lake level fluctuations by regulating outflow according to the Agreed Curve. The associated outflow encompasses, however, ranges from 14 m3 day−1 (−85 %) to 200 m3 day−1 (+100 %) within this ensemble, highlighting that future hydropower generation and downstream water availability may strongly change in the next decades even if dam management adheres to he Agreed Curve. Our results overall underline that managing the dam according to the Agreed Curve is a key prerequisite for sustainable future lake levels, but that under this management scenario, climate change might potentially induce profound changes in lake level and outflow volume.

A hydrogeological model for palygorskite formation in the Danian continental facies of the Provence Basin (France)

Clay Minerals ◽  
1998 ◽  
Vol 33 (2) ◽  
pp. 333-347 ◽  
Author(s):  
J. Colson ◽  
I. Cojan ◽  
M. Thiry
Keyword(s):  
Lake Level ◽  
Simultaneous Occurrence ◽  
Hydrogeological Model ◽  
Fine Grained ◽  
Ephemeral Ponds ◽  
Wide Range ◽  
High Lake Level ◽  
Alteration Processes ◽  
Confined Environment ◽  
The Vertical Distribution

AbstractThe Danian of the Provence basin (SE France) is characterized by a strong subatmospheric alteration processes throughout the basin. A wide range of facies, depositional and weathering, were recognized in an interval of 5 Myr and include floodplain fine-grained alluvium, palustrine limestones, playa dolostones, mottled palaeosols, vadose and phreatic calcretes, and phreatic dolocretes. Palygorskite was invariably found in laminar, massive and honeycomb vadose calcretes and phreatic dolocretes, as well as in playa dolostones, and only exceptionally in floodplain siltstones, nodular calcretes and palustrine limestones. Regardless of the facies, palygorskite is associated with smectites. An authigenic origin, based on the morphology of the fibres and the vertical distribution of clay minerals, is proposed for palygorskites in all of the facies. The simultaneous occurrence of palygorskite in these environments is interpreted as a sign of a stable seasonal semi-arid climate and low detrital input during a period of low lake level (-0.5 Myr). The occurrence of authigenic palygorskite in siltstones around the lake was attributed to the rising of the water table, retention of the already saturated water in the pore spaces of the sediment, and its subsequent evaporation in a confined environment. A hydrogeological model is proposed for the distribution of palygorskite. The elongated shape of the Provence basin enhanced the influence of lateral inflow of freshwater during the low lake period which explains the distribution of palygorskite in different environments of the Provence basin as well as spatial distribution of phreatic calcretes and dolocretes. During the high lake level, palygorskite formed in the few remaining ephemeral ponds and on the floodplain along the lake margin.

scholarly journals Late Quaternary lake-level changes of Lake El'gygytgyn, NE Siberia

2011 ◽  
Vol 76 (3) ◽  
pp. 441-451 ◽  
Author(s):  
Olaf Juschus ◽  
Maksim Pavlov ◽  
Georg Schwamborn ◽  
Frank Preusser ◽  
Grigory Fedorov ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Level ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Lake Ice ◽  
Oxygen Isotope Stage ◽  
Northeastern Siberia ◽  
Lake El’Gygytgyn ◽  
High Lake Level ◽  
High Lake Levels

AbstractLake El'gygytgyn is situated in a 3.6 Ma old impact crater in northeastern Siberia. Presented here is a reconstruction of the Quaternary lake-level history as derived from sediment cores from the southern lake shelf. There, a cliff-like bench 10 m below the modern water level has been investigated. Deep-water sediments on the shelf indicate high lake levels during a warm Mid-Pleistocene period. One period with low lake level prior to Marine Oxygen Isotope Stage (MIS) 3 has been identified, followed by a period of high lake level (10 m above present). In the course of MIS 2 the lake level dropped to − 10 m. At the end of MIS 2 the bench was formed and coarse beach sedimentation occurred. Subsequently, the lake level rose rapidly to the Holocene level. Changes in water level are likely linked to climate variability. During relatively temperate periods the lake becomes free of ice in summer. Strong wave actions transport sediment parallel to the coast and towards the outlet, where the material tends to accumulate, resulting in lake level rise. During cold periods the perennial lake ice cover hampers any wave activity and pebble-transport, keeping the outlet open and causing the lake level to drop.

scholarly journals Extent of Sedge/Grass Meadow in a Lake Michigan Drowned-River-Mouth Wetland Dictated by Topography/Bathymetry and Lake Level

2021 ◽  
Author(s):  
Douglas A. Wilcox ◽  
John Bateman ◽  
Kurt Kowalski ◽  
James Meeker ◽  
Nicole Dunn
Keyword(s):  
Great Lakes ◽  
Plant Communities ◽  
Lake Level ◽  
Lake Michigan ◽  
River Mouth ◽  
Water Level Fluctuations ◽  
Lake Levels ◽  
High Lake Level ◽  
Grass Meadow ◽  
High Lake Levels

Abstract Water-level fluctuations are critical in maintaining the diversity of plant communities in Great Lakes wetlands. Sedge/grass meadows are especially sensitive to such fluctuations. We conducted vegetation sampling in a sedge/grass-dominated Lake Michigan drowned-river-mouth wetland in 1995, 2002, and 2010 that followed high lake levels in 1986 and 1997. We also conducted photointerpretation studies in 16 years dating back to 1965 to include responses to high lake level in 1952 and 1974. Topographic/bathymetric data were collected to assess their influence on areal extent of sedge/grass meadow. Dominant species in short emergent and submersed/floating plant communities changed with water availability from 1995 to extreme low lake levels in 2002 and 2010. Sedge/grass meadow was dominated by Calamagrostis canadensis and Carex stricta in all years sampled, but Importance Values differed among years partly due to sampling in newly exposed areas. Photointerpretation studies showed a significant relation between percent of wetland in sedge/grass meadow and summer lake level, as well as the number of years since an extreme high lake level. From the topographic/bathymetric map created, we calculated the cumulative area above each 0.2-m contour to determine the percent of wetland dewatered in select years following extreme high lake levels. When compared with percent sedge/grass meadow in those years, relative changes in both predicted land surface and sedge/grass meadow demonstrated that accuracy of lake level as a predictor of area of sedge/grass meadow is dependent on topography/bathymetry. Our results regarding relations of plant-community response to hydrology are applicable to other Great Lakes wetlands.

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