scholarly journals The impact of river regulation in the Tigris and Euphrates on the Arvandroud Estuary

2020 ◽  
Vol 44 (6) ◽  
pp. 948-970 ◽  
Author(s):  
Ali Torabi Haghighi ◽  
Mojtaba Sadegh ◽  
Joy Bhattacharjee ◽  
Mehmet Emin Sönmez ◽  
Mojtaba Noury ◽  
...  
Keyword(s):  
Flow Regime ◽  
Iraq War ◽  
River Flow ◽  
Remote Sensing Data ◽  
River Regulation ◽  
Rate Of Change ◽  
The Past ◽  
New Information ◽  
Flow Changes ◽  
The Impact

The Arvandroud river (also known as Shatt-al-Arab) and its estuary have been degraded due to the changing river flow regime in the Tigris and Euphrates. This study assessed changes in flow from the major rivers and the impacts on the estuary. To assess the river flow changes, three major flow regime attributes were computed: timing (TIF), magnitude (MIF), and variability (VIF). By combining these indices, the total flow regime impact factor (IF) was scaled between 0 and 1, and classified into five groups: Low (0.80<IF<1.0), Incipient (0.60<IF<0.80), Moderate (0.40<IF<0.60), Severe (0.2<IF<0.40), and Drastic (0.0<IF<0.20). Flow regime impact maps were then created for 1941–1955, 1960–1970, 1975–1984, and 1990–2000. These revealed that, over time, the impact has extended along the basin from downstream to upstream, with a significant flow regime change from 1941–1955 to 1990–2000 in the Tigris, Euphrates, and Arvandroud. Analysis of remote sensing data revealed that the change in the flow regime has led to land degradation in the Arvandroud estuary during the past 46 years (1972–2018). In addition, the impact of the Iran–Iraq war (based on degradation of vegetation cover between 1985 and 1988) is 5.1 times of mean rate of change during 1972–2018. This study thus contributes new information on estuaries and the impact of upstream land and water use change.

scholarly journals Anthropogenic and Climate Effects on a Free Dam Tropical River: Measuring the Contributions on Flow Regime

2020 ◽  
Vol 12 (23) ◽  
pp. 10030
Author(s):  
Verônica Léo ◽  
Hersília Santos ◽  
Letícia Pereira ◽  
Lilia Oliveira
Keyword(s):  
Climate Change ◽  
Flow Regime ◽  
River Flow ◽  
Human Impacts ◽  
Global Climate ◽  
Rate Of Change ◽  
Hydrologic Alteration ◽  
Tropical River ◽  
Range Of Variability Approach ◽  
Flow Components

The demand for freshwater resources and climate change pose a simultaneous threat to rivers. Those impacts are often analyzed separately, and some human impacts are widely evaluated in river dynamics—especially in downstream areas rather than the consequences of land cover changes in headwater reaches. The distinction between anthropogenic and climate on the components of the flow regime is proposed here for an upstream free dam reach whose watershed is responsible for the water supply in Rio de Janeiro. Indicators of hydrologic alteration (IHA) and the range of variability approach (RVA) combined with statistical analyses of anthropogenic and climate parameters indicated that (1) four river flow components (magnitude, frequency, duration, and rate of change) were greatly altered from the previous period (1947 to 1967) and the actual (1994 to 2014); (2) shifts in the sea surface temperature of the Atlantic correlated with flow magnitude; (3) the cattle activity effects on the flow regime of the studied area decreased 42.6% of superficial discharge; global climate change led to a 10.8% reduction in the same river component. This research indicated that climate change will impact the intensification of human actions on rivers in the southeast Brazilian headwaters.

scholarly journals Marine and anthropogenic controls on the estuary of the Suriname River over the past 50 years

2016 ◽  
Vol 95 (4) ◽  
pp. 419-428
Author(s):  
K. Gersie ◽  
P.G.E.F. Augustinus ◽  
R.T. Van Balen
Keyword(s):  
Tidal Current ◽  
River Flow ◽  
Sediment Load ◽  
Anthropogenic Activities ◽  
Fluvial Systems ◽  
Sediment Fluxes ◽  
Fine Grained ◽  
The Past ◽  
The Impact ◽  
Strong Tidal Current

AbstractHumans have played an important role in fluvial systems because of the impact of their land-use activities, frequently leading to degradation of environmental conditions. Rivers, which are the primary agents in sediment transport, have thus been subject to changes in sediment fluxes. The Suriname River has been affected by anthropogenic activities since colonial times, and has experienced strong discharge and sediment-load changes since the construction of the Afobaka Dam in 1964. The river's estuary sediments largely consist of fine-grained sediments, originating, ultimately, from the Amazon River and transported by the strong tidal current. The influence of this tidal current is diminished at the head of the estuary, allowing the river flow to become dominant. Also remarkable is the interaction of the Suriname River and the westward-migrating mudbanks which is evident in the changing magnitude and volume of Braamspunt, a mudcape located at the mouth of the estuary. The regulated discharge of the river results in a change of the river's morphology, resulting, among other things, in the growth of river bars.

scholarly journals Calibration of hydrological models for ecologically relevant streamflow predictions: a trade-off between fitting well to data and estimating consistent parameter sets?

2020 ◽  
Vol 24 (3) ◽  
pp. 1031-1054 ◽  
Author(s):  
Thibault Hallouin ◽  
Michael Bruen ◽  
Fiachra E. O'Loughlin
Keyword(s):  
Flow Regime ◽  
River Flow ◽  
Freshwater Ecosystems ◽  
Living Environment ◽  
Rate Of Change ◽  
Low Flow ◽  
Hydrological Models ◽  
Flow Conditions ◽  
Local Flow ◽  
Trade Off

Abstract. The ecological integrity of freshwater ecosystems is intimately linked to natural fluctuations in the river flow regime. In catchments with little human-induced alterations of the flow regime (e.g. abstractions and regulations), existing hydrological models can be used to predict changes in the local flow regime to assess any changes in its rivers' living environment for endemic species. However, hydrological models are traditionally calibrated to give a good general fit to observed hydrographs, e.g. using criteria such as the Nash–Sutcliffe efficiency (NSE) or the Kling–Gupta efficiency (KGE). Much ecological research has shown that aquatic species respond to a range of specific characteristics of the hydrograph, including magnitude, frequency, duration, timing, and the rate of change of flow events. This study investigates the performance of specially developed and tailored criteria formed from combinations of those specific streamflow characteristics (SFCs) found to be ecologically relevant in previous ecohydrological studies. These are compared with the more traditional Kling–Gupta criterion for 33 Irish catchments. A split-sample test with a rolling window is applied to reduce the influence on the conclusions of differences between the calibration and evaluation periods. These tailored criteria are shown to be marginally better suited to predicting the targeted streamflow characteristics; however, traditional criteria are more robust and produce more consistent behavioural parameter sets, suggesting a trade-off between model performance and model parameter consistency when predicting specific streamflow characteristics. Analysis of the fitting to each of 165 streamflow characteristics revealed a general lack of versatility for criteria with a strong focus on low-flow conditions, especially in predicting high-flow conditions. On the other hand, the Kling–Gupta efficiency applied to the square root of flow values performs as well as two sets of tailored criteria across the 165 streamflow characteristics. These findings suggest that traditional composite criteria such as the Kling–Gupta efficiency may still be preferable over tailored criteria for the prediction of streamflow characteristics, when robustness and consistency are important.

Nitrogen concentrations in flow separated river water

2020 ◽  
Author(s):  
Jørgen Windolf ◽  
Hans Thodsen ◽  
Henrik Tornbjerg ◽  
Brian Kronvang ◽  
Peter B. Sørensen
Keyword(s):  
Coastal Waters ◽  
Stream Water ◽  
Base Flow ◽  
Rate Of Change ◽  
Data Set ◽  
Flow Component ◽  
The Past ◽  
N Concentration ◽  
N Removal ◽  
The Impact

&lt;p&gt;Nitrogen (N) loads and concentrations have been successfully reduced in most Danish streams during the last 30 years. Thereby also reducing the impact of the main driver of marine eutrophication in Danish coastal waters. However, the trend in N-loads and concentrations vary substantially among the monitored streams. The understanding of this variation are of great importance and interest for the evaluation of measures implemented to combat N eutrophication and for forecasting of effects of further measures.&lt;/p&gt;&lt;p&gt;River hydrographs can be split into base flow and quick flow components and the N concentrations in these two components can, thereafter, be calculated. The N concentration in the two components varies over time showing both longer term and seasonal variation. The quick flow component typically having a high variation reflecting present days leaching of N from fields and this strata has been significantly reduced during the last 3 decades due to a more sustainable farming practices.&lt;/p&gt;&lt;p&gt;During base flow conditions, stream water typically holds less nitrogen due to N removal in groundwater. Reductions in agricultural nitrogen leaching over the past three decades has reduced concentrations in the quick flow component and reduced the load to ground water aquifers. As groundwater aquifers are often large with a capacity of several years of recharge, the response in base flow N-concentrations is expected to be slow compared to the response in quick flow. The low response of the N-concentrations in base flow have implications on the rate of change of the river concentrations and consequently riverine N-loads to coastal waters. In some cases, the base flow N-concentration might still be influenced by the larger N-leaching of the past (1960-1990).&lt;/p&gt;&lt;p&gt;We have analyzed a national data set for developments in N-concentrations during base flow and quick flow. The data set covers the in country range in catchment size, land use and geology. The data set spans 29 years covering the period 1990 &amp;#8211; 2018. In addition, measurements from a few streams monitored for a longer period have been included in the analyses&lt;/p&gt;

Integrating reservoirs in a landscape-based hydrological model to understand the impact of the reservoir on flow regime in the Cauvery river basin, India

2020 ◽  
Author(s):  
Anjana Ekka ◽  
Saket Kesav ◽  
Saket Pande ◽  
Pieter van der Zaag ◽  
Yong Jiang
Keyword(s):  
Flow Regime ◽  
River Basin ◽  
River Flow ◽  
Calibration Method ◽  
Reservoir Model ◽  
Cauvery River ◽  
River Landscape ◽  
Cauvery River Basin ◽  
The Impact ◽  
Gauging Station

&lt;p&gt;As economic development continues to expand, rivers resources are exploited for power generation, flood control, and irrigation, which substantially impacts the river hydrology and surrounding ecosystem.&amp;#160; Reservoir construction is one of the major contributors to such changes. &amp;#160;Around the world, the long free-flowing rivers are impaired due to reservoirs and their downstream propagation of fragmentation and flow regulation, which impacts the structural and functional connectivities of the entire basin. The extent of interdependence and interactions of biophysical, social, and economic characteristics determine hydrological behaviour and thus define the sustainability of the river ecosystem. In this regard, the topography driven rainfall-runoff modeling (Flex-Topo model) approximates the river landscape hydrological behaviour by delineating the catchment into three functional hydrological units (HRUs).&amp;#160; However, these HRUs are natural and do not take anthropogenic factors into account. Therefore, the present study aims to understand the effects of the integration of reservoirs into a Flex-Topo model to assess model transferability in predicting the river flow regime in ungauged basins.&lt;/p&gt;&lt;p&gt;The Cauvery river basin in India is chosen as a case study. The construction of reservoirs in the Cauvery basin helped to expand irrigated areas, securing water availability during water stress conditions. Nevertheless, it aggravates the water allocation between upstream and downstream states leading to conflict among states sharing the river basin. Based on size and storage capacity, four large reservoirs are selected for the study. At first, the watershed area is delineated based on the gauge location. For adding reservoirs, two different flex-models are created for the watershed&amp;#8217;s areas upstream and downstream of the reservoirs. A separate reservoir model is created for each reservoir. The reservoir model is integrated into the flex-model following operation rule curves to simulate the reservoir based on different reservoir yield. It is assumed that the response of the upstream catchment will serve as an input to the reservoir, and the outflow of the reservoir will be an input to the downstream catchment. These three subunits are connected, and river flow is simulated at the gauge station located at the downstream of the reservoir. Three different procedures are adopted to calibrate the model. First, the integrated flex reservoir model is calibrated using the downstream gauging station. In the second calibration method the reservoir is calibrated first, then keeping the parameters of the reservoir fixed the integrated model is calibrated using downstream gauging station. Third, both the reservoir model and flex model are calibrated separately. The modelled runoff from each parameter sets are compared using Nash-Sutcliffe Model Efficiency and Mean Absolute Error with the observed.&lt;/p&gt;&lt;p&gt;Results indicate that the second calibration method performed the best and improved the overall performance of the Flex-Topo model. Further, results are compared across the four reservoirs in order to develop a generalized understanding of transferring a integrated flex model to basins where data on reservoirs is unavailable. The proposed method therefore provides a way to simulate both biophysical constraint and anthropogenic modifications simultaneously in river landscape and enhance understanding of impact of reservoirs on river flow regime.&lt;/p&gt;

The Impact Analysis of Subsidence on Vegetation Growth in Songzao Mining

2013 ◽  
Vol 448-453 ◽  
pp. 805-809
Author(s):  
Gang Gu ◽  
Ai Guo Wang ◽  
Chen Cheng Hu ◽  
Hai Chao Liang
Keyword(s):  
Vegetation Index ◽  
Impact Analysis ◽  
Remote Sensing Data ◽  
Self Healing ◽  
Vegetation Growth ◽  
The Past ◽  
Grassland Ecosystems ◽  
Wide Range ◽  
Index Changes ◽  
The Impact

In this paper, to gradually comprehensive analyze the impact of coal exploration to vegetation growth, Chongqing Songzao Mining was selected as the study area, vegetation index changes of the past decade were analyzed from a macro perspective using three remote sensing data, and then species composition and community structure of different times collapse area was analyzed using microscopic samples investigate. This paper argues that Songzao Mining exploitation of coal resources affected the local forest and grassland vegetation, but not on a wide range of forest and grassland ecosystems adversely affected, the area of forest and grassland ecosystems can carry local failure, and through the self-healing approach ultimately make forest grass ecosystem to stabilize.

scholarly journals Assessment of Climate Driven Changes in Flow Series of Alpine Basin: A Case Study of Danube River Basin

2018 ◽  
Vol 8 (6) ◽  
pp. 3505-3507
Author(s):  
A. N. Laghari ◽  
A. Rajper ◽  
G. D. Walasai ◽  
A. R. Jatoi ◽  
N. B. Jalbani ◽  
...  
Keyword(s):  
Flow Regime ◽  
River Flow ◽  
River Regulation ◽  
Snow Accumulation ◽  
Danube River ◽  
Groundwater Extraction ◽  
Snow Storage ◽  
Major Increase ◽  
Reduced Water

This study was carried out in order to analyze the climate change driven influence on mean monthly flow series of Danube River and its tributaries during the last century. The study confirms some signs of climate driven alterations in monthly river flow series along with change in flow seasonality during the last century. In spite of this, man-made interference in the basin like i.e. groundwater extraction, irrigation, river regulation, land use alteration and urbanization, has significantly changed Danube flow regime in most areas of the catchment. The analysis of Achleiten station demonstrates that average annual flow regime is a little bit increased. Major increase is observed in winter and autumn months and decrease in summer months. These seasonal alterations clearly signal a future glimpse of reduced water availability in alpine basins. This will mainly occur due to the change in the form of precipitation in winter, from snow to rain and the consequent less snow accumulation, and the early melt of snow storage, less precipitation and high evaporation rate in summer.

Circassia: Remembering the Past Empowers the Future

2019 ◽  
Vol 23 (2) ◽  
pp. 199-215
Author(s):  
Charlotte Hille ◽  
Renée Gendron
Keyword(s):  
Direct Result ◽  
North Caucasus ◽  
The Third ◽  
The Past ◽  
The North ◽  
New Information ◽  
The Future ◽  
The Impact

This article recounts the story of how the Circassians have been able to raise awareness of their deportation in the 1860s during the Caucasian Wars. After a brief methodology the authors provide an overview of the Circassian history. The second section analyses the period when the Circassian population came under Russian rule after the 1860s. The third part focuses on three broad approaches or strategies used by several Circassian groups to increase the awareness of the Circassian subjugation in the 1860s. The last two sections discuss some of the changes that have occurred as a direct result of the work undertaken by Circassian organisations. The authours argue that the Circassians have created lieux de mémoire, especially since the beginning of the 1990s, what does not always overlap with the dominant Russian perception of history in the North Caucasus. The analysis demonstrates how the Circassians have (re)discovered their story and the impact of this new information on their actions.

scholarly journals Do roads lead to grassland degradation or restoration? A case study in Inner Mongolia, China

2011 ◽  
Vol 16 (6) ◽  
pp. 751-773 ◽  
Author(s):  
Xiangzheng Deng ◽  
Jikun Huang ◽  
Qiuqiong Huang ◽  
Scott Rozelle ◽  
John Gibson
Keyword(s):  
Remote Sensing ◽  
Inner Mongolia ◽  
Satellite Remote Sensing ◽  
Remote Sensing Data ◽  
Rate Of Change ◽  
Grassland Degradation ◽  
High Quality ◽  
Sensing Data ◽  
The Impact

AbstractWe use satellite remote sensing data of grassland cover in Inner Mongolia, China to test whether the existence of and the size of roads in 1995 is associated with the nature of the grassland in 2000 and/or if it affects the rate of change of the grassland between 1995 and 2000. The regression results show that the impact of roads on grassland cover depends on the nature of the resource. When the grassland is composed of relatively high quality grassland, roads lead to degradation, whereas when grassland resources are sparse, access to a road results in the restoration of the resource.

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