Fluctuations of Lake Orta water levels: preliminary analyses

While the effects of past industrial pollution on the chemistry and biology of Lake Orta have been well documented, annual and seasonal fluctuations of lake levels have not yet been studied. Considering their potential impacts on both the ecosystem and on human safety, fluctuations in lake levels are an important aspect of limnological research. In the enormous catchment of Lake Maggiore, there are many rivers and lakes, and the amount of annual precipitation is both high and concentrated in spring and autumn. This has produced major flood events, most recently in November 2014. Flood events are also frequent on Lake Orta, occurring roughly triennially since 1917. The 1926, 1951, 1976 and 2014 floods were severe, with lake levels raised from 2.30 m to 3.46 m above the hydrometric zero. The most important event occurred in 1976, with a maximum level equal to 292.31 m asl and a return period of 147 years. In 2014 the lake level reached 291.89 m asl and its return period was 54 years. In this study, we defined trends and temporal fluctuations in Lake Orta water levels from 1917 to 2014, focusing on extremes. We report both annual maximum and seasonal variations of the lake water levels over this period. Both Mann-Kendall trend tests and simple linear regression were utilized to detect monotonic trends in annual and seasonal extremes, and logistic regression was used to detect trends in the number of flood events. Lake level decreased during winter and summer seasons, and a small but statistically non-significant positive trend was found in the number of flood events over the period. We provide estimations of return period for lake levels, a metric which could be used in planning lake flood protection measures.

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Historical and prehistorical water levels of Mormon Lake, Arizona as a measure of climate change on the southwest Colorado Plateau, USA

Quaternary Research ◽

10.1017/qua.2020.92 ◽

2020 ◽

pp. 1-20

Author(s):

Richard Hereford ◽

Lee Amoroso

Keyword(s):

Climate Change ◽

Lake Level ◽

Climate Models ◽

Colorado Plateau ◽

Water Levels ◽

Lake Levels ◽

Average Precipitation ◽

Hydrologic Balance ◽

Endorheic Basin ◽

Historical Levels

Abstract Mormon Lake, elevation 2166 m with maximum historic surface area of 31.4 km2, lies in a forested endorheic basin covering 103 km2. It is the largest unaltered freshwater body on the 337,000 km2 Colorado Plateau. Prehistorical (before AD 1878) highstands were ca. 9 and 24 m relative to depocenter datum. These levels likely occurred during four multidecadal episodes of cool, wet conditions between ca. 3.55 and 0.20 ka BP. Maximum historical levels (early 1900s) were up to 7.9 m, whereas modern (post-1941) levels were frequently zero or relatively low. Historical climate records indicate reconstructed lake levels correlate directly with annual precipitation and inversely with temperature. Early highstands were associated with above average precipitation and the lowest temperatures of the 116 yr record. The lake receded after 1941; thereafter, frequent drying and low-water levels resulted from recurrent drought and steadily increasing temperatures. Consequently, a wet episode from the 1970s to the 1990s had precipitation like the early 1900s, but highstands were only ca. 3.8 m. The historical lake-level chronology is consistent with changes of hydrologic balance predicted by climate models, that is, reduced effective precipitation (precipitation minus evaporation). These changes, particularly aridification, apparently began in the 1970s or earlier. Global oceanic and atmospheric climate modulate lake levels and regional hydroclimate.

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Long-term variations in the net inflow record for Lake Malawi

Hydrology Research ◽

10.2166/nh.2016.143 ◽

2016 ◽

Vol 48 (3) ◽

pp. 851-866 ◽

Cited By ~ 4

Author(s):

K. Sene ◽

B. Piper ◽

D. Wykeham ◽

R. T. McSweeney ◽

W. Tych ◽

...

Keyword(s):

Lake Level ◽

Lake Malawi ◽

Flood Events ◽

Lake Levels ◽

Hydropower Generation ◽

Unobserved Component ◽

Periodic Behaviour ◽

Component Approach ◽

Long Term Trends

Lake Malawi is the third largest lake in Africa and plays an important role in water supply, hydropower generation, agriculture and fisheries in the region. Lake level observations started in the 1890s and anecdotal evidence of variations dates back to the early 1800s. A chronology of lake level and outflow variations is presented together with updated estimates for the net inflow to the lake. The inflow series and selected rainfall records were also analysed using an unobserved component approach and, although there was little evidence of long-term trends, there was some indication of increasing interannual variability in recent decades. A weak quasi-periodic behaviour was also noted with a period of approximately 4–8 years. The results provide useful insights into the severity of drought and flood events in the region since the 1890s and the potential for seasonal forecasting of lake levels and outflows.

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A Conflict between Traditional Flood Measures and Maintaining River Ecosystems? A Case Study Based upon the River Lærdal, Norway

Water ◽

10.3390/w13141884 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1884

Author(s):

Ana Juárez ◽

Knut Alfredsen ◽

Morten Stickler ◽

Ana Adeva-Bustos ◽

Rodrigo Suárez ◽

...

Keyword(s):

Remote Sensing Data ◽

Freshwater Ecosystems ◽

River Channel ◽

Flood Mitigation ◽

Mitigation Measures ◽

Flood Events ◽

Protection Measures ◽

River Ecosystems ◽

Hydraulic Models

Floods are among the most damaging of natural disasters, and flood events are expected to increase in magnitude and frequency with the effects of climate change and changes in land use. As a consequence, much focus has been placed on the engineering of structural flood mitigation measures in rivers. Traditional flood protection measures, such as levees and dredging of the river channel, threaten floodplains and river ecosystems, but during the last decade, sustainable reconciliation of freshwater ecosystems has increased. However, we still find many areas where these traditional measures are proposed, and it is challenging to find tools for evaluation of different measures and quantification of the possible impacts. In this paper, we focus on the river Lærdal in Norway to (i) present the dilemma between traditional flood measures and maintaining river ecosystems and (ii) quantify the efficiency and impact of different solutions based on 2D hydraulic models, remote sensing data, economics, and landscape metrics. Our results show that flood measures may be in serious conflict with environmental protection and legislation to preserve biodiversity and key nature types.

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Productivity of Ospreys, Pandion haliaetus, Affected by Water Levels Near Loon Lake, Saskatchewan, 1975-2002

The Canadian Field-Naturalist ◽

10.22621/cfn.v124i3.1077 ◽

2010 ◽

Vol 124 (3) ◽

pp. 219

Author(s):

C. Stuart Houston ◽

Frank Scott ◽

Rob B. Tether

Keyword(s):

Breeding Success ◽

Water Levels ◽

Lake Levels ◽

The West ◽

Canadian Data ◽

Human Use ◽

The Town ◽

Western Half ◽

Eastern Half

Between 1975 and 2002, diminished breeding success of Ospreys was associated with drought and falling lake levels in the western half of our study area near the town of Loon Lake, west-central Saskatchewan. Only 46% of nest attempts were successful in the west compared to 72% in the east, producing 0.88 young per accessible nest in the west and 1.42 in the east. Breeding success was greater in the eastern half, where water levels were stable, in spite of increased human use of the resort lakes there. Our unique long-term Canadian data base results support Ogden's 1977 prediction that Osprey productivity may decrease when water levels drop and fish populations are reduced.

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Variations in Lake Levels during the Holocene in North America: An Indicator of Changes in Atmospheric Circulation Patterns

Géographie physique et Quaternaire ◽

10.7202/032598ar ◽

2007 ◽

Vol 39 (2) ◽

pp. 141-150 ◽

Cited By ~ 38

Author(s):

S. P. Harrison ◽

S. E. Metcalfe

Keyword(s):

North America ◽

General Circulation ◽

Lake Level ◽

Data Bank ◽

Relative Depth ◽

Lake Levels ◽

Regional Patterns ◽

Air Mass ◽

The Holocene ◽

Lake Status

ABSTRACT Fluctuations in the extent of closed lakes provide a detailed record of regional and continental variations in mean annual water budget. The temporal sequence of hydrological fluctuations during the Holocene in North America has been reconstructed using information from the Oxford Lake-Level Data Bank. This data base includes 67 basins from the Americas north of the equator. Maps of lake status, an index of relative depth, are presented for the period 10,000 to 0 yr BP. The early Holocene was characterised by increasingly arid conditions, which led to widespread low lake levels in the mid-latitudes by 9,000 yr BP. By 6,000 yr BP this zone of low lakes extended from 32o to 51oN. Many of the features of the present day lake-level pattern, particularly high lake levels north of 46oN and along the eastern seaboard, were established by 3.000 yr BP. Four distinctive regional patterns of lake behaviour through time are apparent. Histograms of lake status from 20,000 to 0 yr BP are presented for each of these regions. They illustrate the temporal patterns of lake-level fluctuations on a time scale of 103 — 104 yr. Changes in lake status over North America are interpreted as indicating displacements in major features of the general circulation, specifically the zonal Westerlies and the Equatorial Trough, as reflected by changes in air mass trajectories and hence the position of air mass boundaries over the continent.

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Cosmogenic10Be dating of raised shorelines constrains the timing of lake levels in the eastern Lake Agassiz-Ojibway basin

Quaternary Research ◽

10.1017/qua.2017.40 ◽

2017 ◽

Vol 88 (2) ◽

pp. 265-276 ◽

Cited By ~ 7

Author(s):

Pierre-Marc Godbout ◽

Martin Roy ◽

Jean J. Veillette ◽

Joerg M. Schaefer

Keyword(s):

Lake Level ◽

Time Interval ◽

Lake Levels ◽

Lake Agassiz ◽

Cosmogenic Isotopes ◽

Exposure Dating ◽

Group 3 ◽

Lake Stage ◽

Lake Ojibway

AbstractSurface exposure dating was applied to erosional shorelines associated with the Angliers lake level that marks an important stage of Lake Ojibway. The distribution of 1510Be ages from five sites shows a main group (10 samples) of coherent10Be ages yielding a mean age of 9.9±0.7 ka that assigns the development of this lake level to the early part of the Lake Ojibway history. A smaller group (3 samples) is part of a more scattered distribution of older10Be ages (with 2 outliers) that points to an inheritance of cosmogenic isotopes from a previous exposure, revealing an apparent mean age of 15.8±0.9 ka that is incompatible with the Ojibway inundation and the regional deglaciation. Our results provide the first direct10Be chronology on the sequence of lake levels in the Ojibway basin, which includes the lake stage presumably associated with the confluence and subsequent drainage of Lakes Agassiz and Ojibway. This study demonstrates the potential of this approach to date glacial lake shorelines and underlies the importance of obtaining additional chronological constraints on the Agassiz-Ojibway shoreline sequence to confidently assign a particular lake stage and/or lake-level drawdown to a specific time interval of the deglaciation.

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Quantifying recent lake level changes in Patagonia (Argentina and Chile): Back to the future?

10.5194/egusphere-egu21-8467 ◽

2021 ◽

Author(s):

Daniel Ariztegui ◽

Clément Pollier ◽

Andrés Bilmes

Keyword(s):

Water Level ◽

Lake Level ◽

Satellite Images ◽

Meteorological Data ◽

Tierra Del Fuego ◽

Water Level Fluctuations ◽

Lake Levels ◽

The Past ◽

Rainfall Variations ◽

The Impact

Lake levels in hydrologically closed-basins are very sensitive to climatically and/or anthropogenically triggered environmental changes. Their record through time can provide valuable information to forecast changes that can have substantial economical and societal impact.Increasing precipitation in eastern Patagonia (Argentina) have been documented following years with strong El Ni&#241;o (cold) events using historical and meteorological data. Quantifying changes in modern lake levels allow determining the impact of rainfall variations while contributing to anticipate the evolution of lacustrine systems over the next decades with expected fluctuations in ENSO frequencies. Laguna Carrilaufquen Grande is located in the intermontane Maquinchao Basin, Argentina. Its dimension fluctuates greatly, from 20 to 55 km2 water surface area and an average water depth of 3 m. Several well-preserved gravelly beach ridges witness rainfall variations that can be compared to meteorological data and satellite images covering the last ~50 years. Our results show that in 2016 lake level was the lowest of the past 44 years whereas the maximum lake level was recorded in 1985 (+11.8 m above the current lake level) in a position 1.6 km to the east of the present shoreline. A five-years moving average rainfall record of the area was calculated smoothing the extreme annual events and correlated to the determined lake level fluctuations. The annual variation of lake levels was up to 1.2 m (e.g. 2014) whereas decadal variations related to humid-arid periods for the interval 2002 to 2016 were up to 9.4 m. These data are consistent with those from other monitored lakes and, thus, our approach opens up new perspectives to understand the historical water level fluctuations of lakes with non-available monitoring data.&#160;Laguna de los Cisnes in the Chilean section of the island of Tierra del Fuego, is a closed-lake presently divided into two sections of 2.2 and 11.9 km2, respectively. These two water bodies were united in the past forming a single larger lake. The lake level was&#160; ca. 4 m higher than today as shown by clear shorelines and the outcropping of large Ca-rich microbialites. Historical data, aerial photographs and satellite images indicate that the most recent changes in lake level are the result of a massive decrease of water input during the last half of the 20th century triggered by an indiscriminate use of the incoming water for agricultural purposes. The spectacular outcropping of living and fossil microbialites is not only interesting from a scientific point of view but has also initiated the development of the site as a local touristic attraction. However, if the use of the incoming water for agriculture in the catchment remains unregulated the lake water level might drop dangerously and eventually the lake might fully desiccate.These two examples illustrate how recent changes in lake level can be used to anticipate the near future of lakes. They show that ongoing climate changes along with the growing demand of natural resources have already started to impact lacustrine systems and this is likely to increase in the decades to come.

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Kabul River Flow Prediction Using Automated ARIMA Forecasting: A Machine Learning Approach

Sustainability ◽

10.3390/su131910720 ◽

2021 ◽

Vol 13 (19) ◽

pp. 10720

Author(s):

Muhammad Ali Musarat ◽

Wesam Salah Alaloul ◽

Muhammad Babar Ali Rabbani ◽

Mujahid Ali ◽

Muhammad Altaf ◽

...

Keyword(s):

Machine Learning ◽

Water Level ◽

River Flow ◽

Early Stage ◽

Moving Average ◽

Weather Prediction ◽

Maximum Level ◽

Information Criterion ◽

Water Levels ◽

Kabul River

The water level in a river defines the nature of flow and is fundamental to flood analysis. Extreme fluctuation in water levels in rivers, such as floods and droughts, are catastrophic in every manner; therefore, forecasting at an early stage would prevent possible disasters and relief efforts could be set up on time. This study aims to digitally model the water level in the Kabul River to prevent and alleviate the effects of any change in water level in this river downstream. This study used a machine learning tool known as the automatic autoregressive integrated moving average for statistical methodological analysis for forecasting the river flow. Based on the hydrological data collected from the water level of Kabul River in Swat, the water levels from 2011–2030 were forecasted, which were based on the lowest value of Akaike Information Criterion as 9.216. It was concluded that the water flow started to increase from the year 2011 till it reached its peak value in the year 2019–2020, and then the water level will maintain its maximum level to 250 cumecs and minimum level to 10 cumecs till 2030. The need for this research is justified as it could prove helpful in establishing guidelines for hydrological designers, the planning and management of water, hydropower engineering projects, as an indicator for weather prediction, and for the people who are greatly dependent on the Kabul River for their survival.

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Lake Levels and Sedimentary Environments During Deposition of the Trego Hot Springs and Wono Tephras in the Lake Lahontan Basin, Nevada, USA

Quaternary Research ◽

10.1016/j.yqres.2009.08.001 ◽

2010 ◽

Vol 73 (1) ◽

pp. 118-129 ◽

Cited By ~ 8

Author(s):

Kenneth D. Adams

Keyword(s):

Lake Level ◽

Hot Springs ◽

Silty Clay ◽

Lake Levels ◽

Sediment Sources ◽

Sedimentary Environments ◽

Depositional Settings ◽

Significant Difference ◽

Predictable Pattern ◽

Lake Size

The Wono and Trego Hot Springs (THS) tephras are widespread in the Lahontan basin and have been identified in a variety of sedimentary environments at different elevations. Davis (1983) reported lake level to be at about 1256 m when the THS tephra was deposited, an interpretation questioned by Benson et al. (1997) who interpreted lake level to be ≤1177 m at that time. This is a significant difference in lake size with important implications for interpreting the climate that prevailed at that time. Based on new interpretations of depositional settings of the THS bed at multiple sites, the larger lake size is correct. Additional sites containing the Wono tephra indicate that it was deposited when lake level was at about 1217 m in the western subbasins and at about 1205 m in the Carson Sink. Sedimentary features associated with progressively deeper paleowater depths follow a predictable pattern that is modulated by proximity to sediment sources and local slope. Fine to coarse sands with wave-formed features are commonly associated with relatively shallow water. Silty clay or clay dominates in paleowater depths >25 m, with thin laminae of sand and ostracods at sites located adjacent to or downslope from steep mountain fronts.

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