scholarly journals Hydropower impact on the river flow of a humid regional climate

2020 ◽  
Vol 163 (1) ◽  
pp. 379-393
Author(s):  
Julian David Hunt ◽  
Giacomo Falchetta ◽  
Behnam Zakeri ◽  
Andreas Nascimento ◽  
Paulo Smith Schneider ◽  
...  
Keyword(s):  
Water Management ◽  
River Flow ◽  
Regional Climate ◽  
Cumulative Impact ◽  
Storage Reservoirs ◽  
Considerable Impact ◽  
Reservoir Construction ◽  
Probability Of Precipitation ◽  
Regional Climates ◽  
Historical Flow

AbstractLand use and water management have considerable impacts on regional climates. This paper proposes that in humid regions with low wind patterns the construction of hydropower storage reservoirs contributes to the increases in the probability of precipitation in the regional climate. This observation has been tested with a methodology that calculates the cumulative influence of reservoir construction in the basins surrounding with a proposed index named Cumulative Impact of Existing Reservoirs, and compares this index with the historical flow of the rivers. It was found that the construction of reservoirs in Brazil had a considerable impact on its river flows.

scholarly journals Desiccation of the Transboundary Hamun Lakes: Natural or Anthropogenic?

2021 ◽  
Author(s):  
Mahdi Akbari ◽  
Ali Mirchi ◽  
Amin Roozbahani ◽  
Abror Gafurov ◽  
Björn Klöve ◽  
...  
Keyword(s):  
Water Management ◽  
River Flow ◽  
Environmental Water ◽  
Economic Stress ◽  
Dust Storms ◽  
Border Region ◽  
Lake System ◽  
Transboundary River Basin ◽  
Before And After ◽  
Reservoir Construction

This paper investigates the hydrologic and water management reasons behind the desiccation of the Hamun Lakes in the Iran-Afghanistan border region. We analysed changes in Hirmand (or Helmand) River flow, the main tributary providing 70% of the lakes’ total inflow, and precipitation during 1960-2016 by calculating standardized indices for precipitation (SPI) and discharge (SDI). Also, we applied Normalized Difference Spectral Indices (NDSIs) using satellite images from 1987 to present to observe monthly areal change of the lakes. The transboundary water body is responding to changes in regional water management, which has severely reduced the lakes’ inflow. Upstream water regulation in Afghanistan coupled with reservoir construction on the Iranian side has caused nearly full desiccation of major parts of the lake system. There is a discernible shift in the relation between the Hirmand River flow at the international border and upstream precipitation over the lakes’ basin before and after 2004. From 1960 to 2003, high river flows were expected to feed the lakes due to high precipitation over the basin. However, the Hirmand River flow at the border declined after 2004 despite large amounts of upstream precipitation, including the largest recorded amounts, especially in the Hindu Kush mountains. Further, environmental water stress caused by anthropocentric water management in Iran by reservoir construction has impacted the area of the lakes. Although a long period of drought from 1998-2004, i.e. climatic driver, decreased the lakes’ area, the lake system is primarily falling victim to anthropogenic flow alterations in the transboundary river basin. The lakes’ shrinkage places socio-economic stress on an already-vulnerable region with important public health implications as the exposed lake beds turn into major sources of sand and dust storms.

Analog Models for Empirical-Statistical Downscaling

2021 ◽  
Author(s):  
María Laura Bettolli
Keyword(s):  
Statistical Downscaling ◽  
Climate Models ◽  
Global Climate ◽  
Regional Climate ◽  
Weather Conditions ◽  
Climate Information ◽  
Analog Method ◽  
Weather Typing ◽  
Regional Climates ◽  
Local Weather

Global climate models (GCM) are fundamental tools for weather forecasting and climate predictions at different time scales, from intraseasonal prediction to climate change projections. Their design allows GCMs to simulate the global climate adequately, but they are not able to skillfully simulate local/regional climates. Consequently, downscaling and bias correction methods are increasingly needed and applied for generating useful local and regional climate information from the coarse GCM resolution. Empirical-statistical downscaling (ESD) methods generate climate information at the local scale or with a greater resolution than that achieved by GCM by means of empirical or statistical relationships between large-scale atmospheric variables and the local observed climate. As a counterpart approach, dynamical downscaling is based on regional climate models that simulate regional climate processes with a greater spatial resolution, using GCM fields as initial or boundary conditions. Various ESD methods can be classified according to different criteria, depending on their approach, implementation, and application. In general terms, ESD methods can be categorized into subgroups that include transfer functions or regression models (either linear or nonlinear), weather generators, and weather typing methods and analogs. Although these methods can be grouped into different categories, they can also be combined to generate more sophisticated downscaling methods. In the last group, weather typing and analogs, the methods relate the occurrence of particular weather classes to local and regional weather conditions. In particular, the analog method is based on finding atmospheric states in the historical record that are similar to the atmospheric state on a given target day. Then, the corresponding historical local weather conditions are used to estimate local weather conditions on the target day. The analog method is a relatively simple technique that has been extensively used as a benchmark method in statistical downscaling applications. Of easy construction and applicability to any predictand variable, it has shown to perform as well as other more sophisticated methods. These attributes have inspired its application in diverse studies around the world that explore its ability to simulate different characteristics of regional climates.

scholarly journals South Asia river-flow projections and their implications for water resources

2015 ◽  
Vol 19 (12) ◽  
pp. 4783-4810 ◽  
Author(s):  
C. Mathison ◽  
A. J. Wiltshire ◽  
P. Falloon ◽  
A. J. Challinor
Keyword(s):  
Water Resources ◽  
South Asia ◽  
River Flow ◽  
Climate Model ◽  
Asian Summer Monsoon ◽  
Regional Climate ◽  
Global Climate Models ◽  
Climate Projections ◽  
The South ◽  
River Flows

Abstract. South Asia is a region with a large and rising population, a high dependence on water intense industries, such as agriculture and a highly variable climate. In recent years, fears over the changing Asian summer monsoon (ASM) and rapidly retreating glaciers together with increasing demands for water resources have caused concern over the reliability of water resources and the potential impact on intensely irrigated crops in this region. Despite these concerns, there is a lack of climate simulations with a high enough resolution to capture the complex orography, and water resource analysis is limited by a lack of observations of the water cycle for the region. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. Two global climate models (GCMs), which represent the ASM reasonably well are downscaled (1960–2100) using a regional climate model (RCM). In the absence of robust observations, ERA-Interim reanalysis is also downscaled providing a constrained estimate of the water balance for the region for comparison against the GCMs (1990–2006). The RCM river flow is routed using a river-routing model to allow analysis of present-day and future river flows through comparison with available river gauge observations. We examine how useful these simulations are for understanding potential changes in water resources for the South Asia region. In general the downscaled GCMs capture the seasonality of the river flows but overestimate the maximum river flows compared to the observations probably due to a positive rainfall bias and a lack of abstraction in the model. The simulations suggest an increasing trend in annual mean river flows for some of the river gauges in this analysis, in some cases almost doubling by the end of the century. The future maximum river-flow rates still occur during the ASM period, with a magnitude in some cases, greater than the present-day natural variability. Increases in river flow could mean additional water resources for irrigation, the largest usage of water in this region, but has implications in terms of inundation risk. These projected increases could be more than countered by changes in demand due to depleted groundwater, increases in domestic use or expansion of water intense industries. Including missing hydrological processes in the model would make these projections more robust but could also change the sign of the projections.

scholarly journals Water storage reservoirs and their role in the development, utilization and protection of catchment

Spatium ◽  
2011 ◽  
pp. 9-15
Author(s):  
Branislav Djordjevic ◽  
Tina Dasic
Keyword(s):  
Water Management ◽  
Sustainable Development ◽  
Development Strategy ◽  
Water Storage ◽  
The Sustainable Development ◽  
Storage Reservoirs ◽  
Development Plans ◽  
The Creation ◽  
Negative Impacts ◽  
Hydrological Regimes

Reasons why water storage reservoirs are necessary in accordance with the sustainable development strategy are described in the paper. The main positive and negative impacts of reservoirs on the environment are analyzed. The most important are: the improvement of hydrological regimes (decreasing maximal and increasing minimal flows), the creation of optimal water management, utilization and protection of water, and the creation of better conditions for river and coastal ecosystems. Negative impacts and measures for its mitigation or elimination are also analyzed. The conclusion is that water storage reservoirs can be harmoniously incorporated into the environment. Serbia has a limited number of locations suitable for the construction of reservoirs, therefore it is necessary to retain these areas for storage in regional development plans and other legal acts.

scholarly journals The 2010–2015 mega drought in Central Chile: Impacts on regional hydroclimate and vegetation

2017 ◽  
Author(s):  
René Garreaud ◽  
Camila Alvarez-Garreton ◽  
Jonathan Barichivich ◽  
Juan Pablo Boisier ◽  
Duncan Christie ◽  
...  
Keyword(s):  
River Flow ◽  
Potential Evapotranspiration ◽  
Regional Climate ◽  
Climate Scenario ◽  
Annual Rainfall ◽  
Central Chile ◽  
Groundwater Levels ◽  
Tree Ring Reconstruction ◽  
Neutral Conditions ◽  
Northern Sector

Abstract. Since 2010 an uninterrupted sequence of dry years, with annual rainfall deficits ranging from 25 to 45 %, has prevailed in Central Chile (western South America, 30–38° S). Although intense 1- or 2-year droughts are recurrent in this Mediterranean-like region, the ongoing event stands out because of its longevity and large spatial extent. The extraordinary character of the so-called Central Chile Mega Drought (MD) was established against century long historical records and a millennial tree-ring reconstruction of regional precipitation. The largest MD-averaged rainfall relative anomalies occurred in the northern, semi-arid sector of central Chile but the event was unprecedented to the south of 35° S. ENSO neutral conditions have prevailed since 2011 (but for the strong El Niño 2015) contrasting with La Niña conditions that often accompanied past droughts. The precipitation deficit diminished the Andean snowpack and resulted in amplified declines (up to 90 %) of river flow, reservoir volumes and groundwater levels along central Chile and westernmost Argentina. In some semiarid basins we also found a conspicuous decrease in the runoff-to-rainfall coefficient. A substantial decrease in vegetation productivity occurred in the shrubland-dominated, northern sector, but a mix of greening and browning patches occurred farther south where irrigated croplands and exotic forest plantations dominate. The ongoing warming in central Chile, making the MD one of the warmest 6-year period on record, may have also contributed to such complex vegetation changes by increasing potential evapotranspiration. The understanding of the nature and biophysical impacts of the MD contributes to preparedness efforts to face a dry, warm future regional climate scenario.

scholarly journals Markov chain analysis of regional climates

2010 ◽  
Vol 17 (6) ◽  
pp. 651-661 ◽  
Author(s):  
S. Mieruch ◽  
S. Noël ◽  
H. Bovensmann ◽  
J. P. Burrows ◽  
J. A. Freund
Keyword(s):  
Markov Chain ◽  
Dynamic Properties ◽  
Regional Climate ◽  
Coarse Grained ◽  
Recurrence Time ◽  
Markov Chain Analysis ◽  
Central Pacific ◽  
Climate Anomalies ◽  
Chain Analysis ◽  
Regional Climates

Abstract. We present a novel method for regional climate classification that is based on coarse-grained categorical representations of multivariate climate anomalies and a subsequent Markov chain analysis. From the estimated transition matrix several descriptors, such as persistence, recurrence time and entropy, are derived. These descriptors characterise dynamic properties of regional climate anomalies and are connected with fundamental concepts from nonlinear physics like residence times, relaxation process and predictability. Such characteristics are useful for a comparative analysis of different climate regions and, in the context of global climate change, for a regime shift analysis. We apply the method to the bivariate set of water vapour and temperature anomalies of two regional climates, the Iberian Peninsula and the islands of Hawaii in the central Pacific Ocean. Through the Markov chain analysis and via the derived descriptors we find significant differences between the two climate regions. Since anomalies are departures from seasonal and long term components, these differences relate to differences in the short term stability of both regional climates.

Public participation to improve water resource management in Uzbekistan

2005 ◽  
Vol 51 (3-4) ◽  
pp. 365-372 ◽  
Author(s):  
G. Khasankhanova
Keyword(s):  
Water Management ◽  
Public Participation ◽  
Rural Areas ◽  
Rural Economy ◽  
Water Resource Management ◽  
River Flow ◽  
Environmental Safety ◽  
Consultation Process ◽  
Integrated Water Management ◽  
Amu Darya

At present Uzbekistan uses about 42 km3 of transboundary river flow and 27 km3 of this is from the Amu Darya. Annual average flow entering the upper reaches of Amu Darya within Uzbekistan is over 60×109 m3, which is already contaminated, but significant adverse water quality changes occur downstream where the river is the main source of drinking water. After independence Uzbekistan made a commitment to transfer management of farms and the rural economy from the public sector to private hands. Living conditions have deteriorated severely throughout Uzbekistan, but rural areas have been hit hardest. Several studies and projects in Uzbekistan have adopted the integrated water management-based environmental approach. A structured public participation and consultation process was followed during these projects including a social and the environmental assessment. This paper presents the two case studies to illustrate the effects of uniting the potential of all interested participants to improve water management and environmental safety. Consultation between the two main groups of stakeholders is essential for the future of the water sector. There is substantial support for WUAs among all stakeholders, at all levels, including among those stakeholders who currently manage the existing system.

Expected Future Runoff of the Upper Jordan River Simulated with a CORDEX Climate Data Ensemble

2016 ◽  
Vol 17 (3) ◽  
pp. 865-879 ◽  
Author(s):  
Gerhard Smiatek ◽  
Harald Kunstmann
Keyword(s):  
Complex Terrain ◽  
River Flow ◽  
Regional Climate ◽  
Climate Data ◽  
Jordan River ◽  
Discharge Rates ◽  
Ensemble Mean ◽  
The Future ◽  
The Mean ◽  
High River Flow

Abstract Data from five different RCMs run in two experiments from the Coordinated Regional Climate Downscaling Experiment (CORDEX) are applied together with the Water Flow and Balance Simulation Model (WaSiM) to assess the future availability of water in the upper Jordan River. Simulation results for 1976–2000 show that the modeling system was able to reasonably reproduce the observed discharge rates in the partially karstic complex terrain without bias correction of the precipitation input. For the future climate in the area, the applied CORDEX models indicate an increasing annual mean temperature for 2031–60 by 1.8 K above the 1971–2000 mean and by 2.6 K for 2071–2100. The simulated ensemble mean precipitation is predicted to decrease by 16.3% in the first period and 22.1% at the end of the century. In relation to the mean for 1976–2000, the discharge of the upper Jordan River is simulated to decrease by 7.4% until 2060 and by 17.5% until 2100, together with a reduction of high river flow years.

scholarly journals Climate Change Projections of Aridity Conditions in the Iberian Peninsula

2021 ◽  
Author(s):  
Cristina Andrade ◽  
Joana Contente ◽  
João Andrade Santos
Keyword(s):  
Climate Change ◽  
Water Management ◽  
Iberian Peninsula ◽  
Radiative Forcing ◽  
Climate Models ◽  
Regional Climate ◽  
Aridity Index ◽  
Agroforestry Systems ◽  
Mitigation And Adaptation ◽  
La Mancha

The assessment of aridity conditions is a key factor for water management and the implementation of mitigation and adaptation policies in agroforestry systems. Towards this aim three aridity indices were computed for the Iberian Peninsula (IP): the De Martonne Index (DMI), the Pinna Combinative Index (PCI), and the Erinç Aridity Index (EAI). These three indices were first computed for the baseline period 1961‒1990, using a gridded observational data (E-OBS), and, subsequently, for the periods 2011‒2040 (short-range) and 2041‒2070 (medium-range) using an ensemble of six Regional Climate Models (RCMs) experiments generated by the EURO-CORDEX project. Two Representative Concentration Pathways (RCPs) were analyzed, an intermediate anthropogenic radiative forcing scenario (RCP4.5) and a fossil-intensive emission scenario (RCP8.5). Overall, the three indices disclose a strengthening of aridity and dry conditions in central and southern Iberia until 2070, mainly under RCP8.5. Strong(weak) statistically significant correlations were found between these indices and the total mean precipitation (mean temperature) along with projected significant decreasing(increasing) trends for precipitation(temperature). The prevalence of years with arid conditions (above 70% for 2041‒2070 under both RCPs) are projected to have major impacts in some regions, such as southern Portugal, Extremadura, Castilla-La Mancha, Comunidad de Madrid, Andalucía, Región de Murcia, Comunidad Valenciana, and certain regions within the Aragón province. The projected increase in both the intensity and persistence of aridity conditions in a broader southern half of Iberia will exacerbate the exposure and vulnerability of this region to climate change, while the risk of multi-level desertification should be thoroughly integrated into regional and national water management and planning.

Enhancing research utilization for integrated water management

1995 ◽  
Vol 31 (8) ◽  
pp. 311-319
Author(s):  
Johan Wisserhof
Keyword(s):  
Water Management ◽  
Policy Analysis ◽  
Research Utilization ◽  
Policy Research ◽  
Integrated Water Management ◽  
Policy Problem ◽  
Additional Input ◽  
Considerable Impact ◽  
Intermediary Role

Water-related research is often performed at significantly lower levels of integration than policymaking for integrated water management. This may limit its utilization in policymaking. Nevertheless, an analysis of strategic policymaking for water management in The Netherlands shows that policy research still has a considerable impact on policy. This is largely due to the integrative intermediary role of policy analysis. (Policy research is the acquisition of knowledge concerning a policy problem. Policy analysis is the appraisal of alternative policies.) However, policy analysis for water management is often restricted to the natural sciences and engineering. An additional input of administrative science may contribute to resolve the current problems in implementation of integrated water policies. Factors of concern in this respect are elaborated.

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