Continuous Holocene Record of Diatom Stratigraphy, Paleohydrology, and Anthropogenic Activity in a Spring-Mound in Southwestern United States

1994 ◽  
Vol 42 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Dean W. Blinn ◽  
Richard H. Hevly ◽  
Owen K. Davis
Keyword(s):  
United States ◽  
Water Level ◽  
Water Levels ◽  
Anthropogenic Activity ◽  
Southwestern United States ◽  
Middle Holocene ◽  
Temperature And Precipitation ◽  
Diatom Stratigraphy ◽  
Diatom Density ◽  
Montezuma Well

AbstractThis study presents the first continuous record of fossil diatoms taken from an open spring-mound in southwestern United States. Diatoms were analyzed from a radiocarbon-dated core taken from Montezuma Well, a near thermally constant spring in northcentral Arizona. Fluctuations in total diatom density, oscillations in the relative abundance of Anomoeoneis sphaerophora, and intermittent deposition of calcite suggest that water levels in Montezuma Well underwent dramatic fluctuations to the degree of being intermittently dry, or at least very shallow, during the middle Holocene (∼8000-5000 yr B.P.). The fluctuations in water level probably correspond to oscillations in regional temperature and precipitation, which regulate hydrologic input and evaporation rates. The dramatic fluctuations in water level during the middle Holocene suggest that the endemic biota of Montezuma Well underwent relatively rapid speciation within the past ∼5000 yr. The appearance of endemic species (Gomphonema montezumense and Cyclotella pseudostelligera f. parva ) at ∼5000-3000 yr B.P. supports this hypothesis. Diatom indicators for organic enrichment (Aulacoseira granulata and A. islandica) closely coincide with the prehistoric native occupation of Montezuma Well.

Tree-ring analysis of wetlands of the upper St. Lawrence River, Quebec: response to hydrology and climate

1996 ◽  
Vol 26 (3) ◽  
pp. 482-491 ◽  
Author(s):  
Martin Jean ◽  
André Bouchard
Keyword(s):  
Water Level ◽  
Tree Growth ◽  
Significant Relationship ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Climatic Fluctuations ◽  
Climatic Variations ◽  
Temperature And Precipitation ◽  
Growth Variation ◽  
St Lawrence River

A dendrochronological analysis of three tree species colonizing a swamp along the St. Lawrence River was undertaken to (a) study the extent to which water-level fluctuations have an impact on tree growth in comparison to climatic variations; (b) compare the responses of three species (Acerrubrum L., Larixlaricina (Du Roi) K. Koch, and Thujaoccidentalis L.) with hydrologic and climatic variations; and (c) examine the duration of the influence of water-level fluctuations on tree growth. Tree cores from 78 stands were cross-dated and verified with COFECHA and a master chronology for each species was produced using ARSTAN. Response function analyses were used to measure the influence of climate (temperature and precipitation) and water level on tree growth. Water-level fluctuations have a significant influence on A. rubrum growth, accounting for 30% of the tree growth variation. A significant relationship exists between L. laricina and water-level fluctuations, but only 9% of the tree growth is explained by hydrology. No significant relationship was found between water levels and T. occidentalis growth. Climatic fluctuations are a more important influence on growth for all three species, accounting for 46% to 51% of the tree growth variation not explained by water levels.

scholarly journals Visualization of Lake Mead Surface Area Changes from 1972 to 2009

2021 ◽  
Author(s):  
K. Wayne Forsythe ◽  
Barbara Schatz ◽  
Stephen J. Swales ◽  
Lisa-Jen Ferrato ◽  
David M. Atkinson
Keyword(s):  
United States ◽  
Water Level ◽  
Surface Area ◽  
Satellite Images ◽  
Strong Relationship ◽  
The United States ◽  
Water Levels ◽  
Lake Area ◽  
Lake Mead ◽  
Landsat Satellite

For most of the last decade, the south-western portion of the United States has experienced a severe and enduring drought. This has caused serious concerns about water supply and management in the region. In this research, 30 orthorectified Landsat satellite images from the United States Geological Service (USGS) Earth Explorer archive were analyzed for the 1972 to 2009 period. The images encompassed Lake Mead (a major reservoir in this region) and were examined for changes in water surface area. Decadal lake area minimums/maximums were achieved in 1972/1979, 1981/1988, 1991/1998, and 2009/2000. The minimum lake area extent occurred in 2009 (356.4 km2), while the maximum occurred in 1998 (590.6 km2). Variable trends in water level and lake area were observed throughout the analysis period, however progressively lower values were observed since 2000. The Landsat derived lake areas show a very strong relationship with actual measured water levels at the Hoover Dam. Yearly water level variations at the dam vary minimally from the satellite derived estimates. A complete (yearly) record of satellite images may have helped to reduce the slight deviations in the time series.

scholarly journals Visualization of Lake Mead Surface Area Changes from 1972 to 2009

2021 ◽  
Author(s):  
K. Wayne Forsythe ◽  
Barbara Schatz ◽  
Stephen J. Swales ◽  
Lisa-Jen Ferrato ◽  
David M. Atkinson
Keyword(s):  
United States ◽  
Water Level ◽  
Surface Area ◽  
Satellite Images ◽  
Strong Relationship ◽  
The United States ◽  
Water Levels ◽  
Lake Area ◽  
Lake Mead ◽  
Landsat Satellite

For most of the last decade, the south-western portion of the United States has experienced a severe and enduring drought. This has caused serious concerns about water supply and management in the region. In this research, 30 orthorectified Landsat satellite images from the United States Geological Service (USGS) Earth Explorer archive were analyzed for the 1972 to 2009 period. The images encompassed Lake Mead (a major reservoir in this region) and were examined for changes in water surface area. Decadal lake area minimums/maximums were achieved in 1972/1979, 1981/1988, 1991/1998, and 2009/2000. The minimum lake area extent occurred in 2009 (356.4 km2), while the maximum occurred in 1998 (590.6 km2). Variable trends in water level and lake area were observed throughout the analysis period, however progressively lower values were observed since 2000. The Landsat derived lake areas show a very strong relationship with actual measured water levels at the Hoover Dam. Yearly water level variations at the dam vary minimally from the satellite derived estimates. A complete (yearly) record of satellite images may have helped to reduce the slight deviations in the time series.

scholarly journals Modeling water level using downstream river water level observations and machine learning methods

2020 ◽  
Vol 163 ◽  
pp. 01009
Author(s):  
Mikhail Sarafanov ◽  
Eduard Kazakov ◽  
Yulia Borisova
Keyword(s):  
Machine Learning ◽  
Linear Regression ◽  
Water Level ◽  
Statistical Models ◽  
Polynomial Regression ◽  
Water Levels ◽  
Learning Methods ◽  
Machine Learning Methods ◽  
Temperature And Precipitation ◽  
Gauging Station

The article presents the results of the development of a model for calculating levels at one gauging station using the levels at another. To link the levels at two gauging stations, the data on levels, temperature and precipitation were used. The use of machine learning methods to solve the problem of predicting water levels made it possible to achieve an accuracy of about 6 cm. At the same time, traditional statistical models (linear regression, polynomial regression) have 14-16 cm error.

AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

2019 ◽  
pp. 95-103
Author(s):  
Krum Videnov ◽  
Vanya Stoykova
Keyword(s):  
Water Level ◽  
Real Time ◽  
Early Warning ◽  
Water Sources ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Level Monitoring ◽  
Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

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