Drying of Floodplain Forests Associated with Water-Level Decline in the Apalachicola River, Florida - Interim Results, 2006

2007 ◽  
Author(s):  
Melanie R. Darst ◽  
Helen M. Light
Keyword(s):  
Water Level ◽  
Floodplain Forests ◽  
Apalachicola River ◽  
Water Level Decline

Vegetation change in response to grazing and water level decline in the Enot Zukim Nature Reserve (En Fescha), Israel

2009 ◽  
Vol 57 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Linda Olsvig-Whittaker ◽  
Margareta Walczak ◽  
Amos Sabach ◽  
Eli Dror
Keyword(s):  
Water Level ◽  
Vegetation Change ◽  
Nature Reserve ◽  
Water Level Decline

scholarly journals Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephan Schulz ◽  
Sahand Darehshouri ◽  
Elmira Hassanzadeh ◽  
Massoud Tajrishy ◽  
Christoph Schüth
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Irrigated Agriculture ◽  
Lake Urmia ◽  
Water Level Decline

Model Test Study on Embankment Instability Induced by Rapid Drawdown of Water Level at Yellow River Downstream

2010 ◽  
Vol 160-162 ◽  
pp. 750-755
Author(s):  
Yu Kun Zhao ◽  
Ji Hong Yang ◽  
Qing An Li
Keyword(s):  
Water Level ◽  
Model Test ◽  
Yellow River ◽  
Digital Camera ◽  
Hydrodynamic Pressure ◽  
Test Methods ◽  
Test Study ◽  
Short Period ◽  
Water Lever ◽  
Water Level Decline

Rapid drawdown of water level is one of the most important factors that influencing the embankment stability. Based on the principle of geomechanical model test and hydroaulic model test methods, the model test was performed to study Yellow River downstream embankment instability induced by rapid drawdown of water level. The slope models with geometric scale of 1:25, 1:45, 1:62.5 were constructed in the transparent plexiglass model box with 1.6m long, 0.8m wide and 0.6m high. Changes on the slope were recorded during water level decline at different velocity by digital camera and slope tracer etc. The model test results showed that during the rapid drawdown process, there was only small cracks and not slippage in advance; when the water level dropped to a certain height, the sliding distance increased suddenly, which showed that the rate of water level decline was behind the river water, and the slope weight and downslope hydrodynamic pressure by the saturation line in slope body were higher than water lever exceeds the sliding force in a very short period of time, which caused landslide; after the sliding body appearing, slide was continuous and not mutation.

Estimation of shallow groundwater evaporation from dried-up areas of Lake Urmia, Iran

2020 ◽  
Author(s):  
Sahand Darehshouri ◽  
Nils Michelsen ◽  
Christoph Schüth ◽  
Stephan Schulz
Keyword(s):  
Water Level ◽  
Salt Lake ◽  
Shallow Groundwater ◽  
Irrigated Agriculture ◽  
Lake Area ◽  
Lake Urmia ◽  
Night Time ◽  
Undisturbed Soil ◽  
Custom Made ◽  
Water Level Decline

<p>Lake Urmia, located in the northwest of Iran, had an initial volume of about 19 km<sup>3</sup> and a surface area of 5,700 km<sup>2</sup> (Alipour, 2006). Once one of the largest hypersaline lakes in the world, this UNESCO Biosphere Reserve site currently shows a remarkable water level decline. About 70% of the lake area (Tourian et al., 2015) and more than 90% of its volume were lost between 2000 and 2014 (Schulz et al., 2020). The lack of a precise water balance of the Lake Urmia catchment is one of the challenges authorities are facing in their efforts to restore the lake to its ecological level. Here, key issues are that lake evaporation rates are mostly assumed and that evaporation of shallow groundwater from dried-up areas (up to 3,000 km<sup>2</sup>) is often ignored. The objective of this study is to obtain evaporation rate estimates for the dried-up parts of the Urmia lake bed. To this end, we set up a laboratory experiment with undisturbed soil columns collected from dried-up areas of the lake. With the help of a custom-made low-cost environmental chamber, the columns were subject to day- and night-time weather conditions typical for the area. Performed measurements comprise water level logging and monitoring of mass losses from the columns due to evaporation. First experimental results will be presented.</p><p> </p><p><strong>References </strong></p><p>Alipour, S., 2006. Hydrogeochemistry of seasonal variation of Urmia Salt Lake, Iran. Saline Systems 2, 9. doi:10.1186/1746-1448-2-9</p><p>Schulz, S., Darehshouri, S., Hassanzadeh, E., Tajrishy, M., Schüth, C., 2020. Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia. Sci. Rep. 1–10. doi:10.1038/s41598-019-57150-y</p><p>Tourian, M.J., Elmi, O., Chen, Q., Devaraju, B., Roohi, S., Sneeuw, N., 2015. A spaceborne multisensor approach to monitor the desiccation of Lake Urmia in Iran. Remote Sens. Environ. 156, 349–360. doi:10.1016/j.rse.2014.10.006</p><p> </p>

scholarly journals Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia?

2020 ◽  
Author(s):  
Stephan Schulz ◽  
Sahand Darehshouri ◽  
Elmira Hassanzadeh ◽  
Christoph Schüth
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Climatic Changes ◽  
Water Withdrawal ◽  
Water Volume ◽  
Irrigated Agriculture ◽  
Agricultural Water ◽  
Lake Urmia ◽  
Data Set ◽  
Water Level Decline

<p>Lake Urmia is one of the largest hypersaline lakes on earth with a unique biodiversity. Over the past two decades the lake water level declined dramatically, threatening the functionality of the lake’s ecosystems. There is a controversial debate about the reasons for this decline, with either mismanagement of the water resources, or climatic changes assumed to be the main cause.</p><p>During this study we gathered an extensive hydro-meteorological data set, information about the reservoirs and the lake bathymetry. This data served for a quantification of the water budget components of Lake Urmia over the last five decades. Interestingly, a comparison of the temporal patterns of the principal natural boundary conditions of streamflow (precipitation and evaporation) with the inflow to the lake revealed that the variability of the inflow can be well explained its natural drivers. With this we can show that variations of Lake Urmia’s water level during the analyzed period were mainly triggered by climatic changes.</p><p>However, under the current climatic conditions agricultural water extraction volumes are significant and often exceed the remaining surface water inflow volumes. This rather simple observation shows that something deeper needs to be dug here. Therefore, we performed a parsimonious hindcast experiment and run a set of development scenarios based on the previously developed water balance. This helped us to better quantify the human impact on the development of the water volume of Lake Urmia. We could show that changes in agricultural water withdrawal would have a significant impact on the lake volume and could either stabilize the lake, or lead to its complete collapse (Schulz et al., 2020).</p><p> </p><p><strong>References</strong></p><p>Schulz, S., Darehshouri, S., Hassanzadeh, E., Tajrishy, M. and Schüth, C.: Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia, Sci. Rep., 10(1), 236, doi:10.1038/s41598-019-57150-y, 2020.</p>

scholarly journals Study on the Causes of the Decline of the Low Water Levels of Poyang Lake, China

2019 ◽  
Vol 117 ◽  
pp. 00014
Author(s):  
Jian-Zhao Guan ◽  
Lei Zhang ◽  
Chun-Ming Fang ◽  
Jun Feng
Keyword(s):  
Water Level ◽  
Poyang Lake ◽  
Dominant Role ◽  
Water Environment ◽  
River Channel ◽  
Water Levels ◽  
Sand Mining ◽  
Channel Erosion ◽  
Main River Channel ◽  
Water Level Decline

The drastic decline in the water level of Poyang Lake during the dry season has close connection with the water environment and lake ecology. The drastic decline has attracted considerable attention, and has led to intense scientific discussions regarding its cause. However, the importance of the different causes of the low water level decline has not been clearly illustrated. To improve the understanding of the reasons for the decline of low water levels in the Poyang Lake Waterway, this paper investigated the contributions of river channel erosion and sand mining to the water level decline. The results show that sand mining mainly occurred on the beaches of the Waterway, and had a relatively small effect on the change in the shape of the main river channel. It was found that the contribution of sand mining to the decline in the low water level was no more than 30%, while the average contribution by natural erosion was about 85%. This indicates that natural channel erosion of the Waterway has been significant, and plays a dominant role in the declining water levels of the Waterway.

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