Visualization of Lake Mead Surface Area Changes from 1972 to 2009

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.

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Cambios en el paisaje de menorca desde 1975 hasta 2010 mediante teledetección

Latin American Journal of Development ◽

10.46814/lajdv3n5-052 ◽

2021 ◽

Vol 3 (5) ◽

pp. 3305-3318

Author(s):

Emilio Ramírez-Juidías ◽

Francisco Víquez-Urraco

Keyword(s):

United States ◽

Satellite Images ◽

Climatic Factors ◽

The United States ◽

Strong Increase ◽

Tourist Attraction ◽

Territorial Development ◽

Landscape Development ◽

Landsat Satellite

La isla de Menorca, Reserva de la Biosfera, ha originado una fuerte atracción turística a consecuencia de su gran riqueza paisajística. En este estudio, se analizaron 265 imágenes Landsat procedentes del United States Geological Service para el periodo 1975-2010, todas examinadas y clasificadas en un determinado lapso de tiempo con el fin de poder caracterizar correctamente el desarrollo territorial espacial y temporalmente. Los resultados muestran como entre 1975 y 1990 no existe desarrollo del paisaje. Entre 1990 y 2000, hay un gran aumento de la vegetación a consecuencia de la protección recibida por la Unesco. En el periodo 2000-2010, es evidente el efecto del clima en el desarrollo del paisaje. The island of Menorca, Reserve of the Biosphere, has created a strong tourist attraction due to its rich landscape. In this research, 265 Landsat satellite images from the United States Geological Service were analyzed or the 1975 to 2010 eriod, each of which was examined and classified in a certain period of time in order to characterize right way the territorial development both spatially and temporally. The results show how between 1975 and 1990 there is virtually no landscape development. Between 1990 and 2000, there is a strong increase of vegetation as a result of the protection received by UNESCO. In the period 2000-2010, it was evident the effect of climatic factors in the landscape development.

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Lake Mead and Hoover Dam monitoring in Nevada and Arizona states, USA using InSAR

10.5194/egusphere-egu2020-21582 ◽

2020 ◽

Author(s):

Mehdi Darvishi ◽

Georgia Destouni ◽

Fernando Jaramillo

Keyword(s):

Los Angeles ◽

Water Level ◽

Land Surface ◽

Ground Deformation ◽

The United States ◽

Water Levels ◽

Lake Mead ◽

Water Level Changes ◽

Hoover Dam ◽

The Impact

<p>Man-made reservoirs and lakes are key elements in the terrestrial water system. The increased concern about the impact of anthropogenic interventions on and the dynamics of these water resources has given rise to various approaches for representing human-water interactions in land surface models. Synthetic aperture radar interferometry (InSAR) has become a powerful geodetic tool for this purpose, by evidencing changes of ground and water surfaces across time and space. In this research, the Lake Mead and associated Hoover Dam are studied using Small Baseline Subset (SBAS) technique. Lake Mead is the largest reservoir in the United States, in terms of water capacity, supplies water and hydropower for millions of people in Las Vegas, Los Angeles and southwestern part of the USA. In recent years, rising temperature, increasing evaporation and decreasing precipitation have decreased water levels substantially, and probably modified its surrounding groundwater and surface as well.</p><p>This study aims to identify a hydrology-induced ground deformation around the lake Mead and a probable Hoover dam movement displacement. For the reservoir, we used the SBAS technique using 138 SAR data, including ERS1/2, Envisat, ALOS PALSAR and Sentinel-1, covering a time-spam between 1995 and 2019. For the analysis on the dam, we used the SBAS technique from 2014 to 2019 with descending and ascending modes of Sentinel-1A/B imageries. We found two main deformation patterns around the lake associated with the water level changes. Firstly, ERS and Sentinel-1 data evidenced a ground deformation that manifested itself as as a subsidence pattern in 1995 that has gradually changed into an uplift up to 2019. Secondly, the correlation trend between the deformation and water level changes has changed from negative to positive, with a transition point around March 2008. A possible interpretation for this is that the ground has initially reacted to the water fluctuations in the reservoir before March 2008 but after no longer plays a dominant role in the deformation occurring around the lake. The findings will help us to have a better understanding over the changes happened around the lake due to the water level changes and provide the valuable information for more effective management and maintenance of hydraulic structures and facilities near by the lake and water control in the future.</p>

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