scholarly journals Assessment of observed and simulated low flow indices for a highly managed river basin

2018 ◽  
Vol 49 (6) ◽  
pp. 1831-1846 ◽  
Author(s):  
Hagen Koch ◽  
Stefan Liersch ◽  
José Roberto Gonçalves de Azevedo ◽  
Ana Lígia Chaves Silva ◽  
Fred Fokko Hattermann

Abstract Droughts and resulting low flows are a threat for society, economy, and ecosystems. Droughts are natural phenomena, but anthropogenic water use can increase the pressure on water resources. To analyze the effects of changing land-use or water management and climate variability/change on water resources, models integrating the most important hydrological processes are needed. These models must account for natural processes and water resources management at different spatial and temporal scales, e.g., reservoir operation, water withdrawals. Low flow indices are analyzed for observed and simulated flows for the highly managed São Francisco river basin in Brazil, showing that during wet, normal, and moderately dry years, the existing reservoir system is able to augment low flows while during strong droughts the system reaches its limits. This effect is also represented in the simulations using the eco-hydrological model SWIM, which was adapted to account for region-specific characteristics of land-use and water management. While good to very good performance was achieved for calibration and validation for most gauges, for some gauges at tributaries only insufficient quantitative criteria are reached. The reasons for the deviation between observations and simulation results are discussed. Overall, the model is able to represent natural discharges and observed, managed discharges.

Water Policy ◽  
2021 ◽  
Author(s):  
Yanhu He ◽  
Zhenjie Gong ◽  
Yanhui Zheng ◽  
Xiaoyan Bai ◽  
Peng Wang

Abstract Since 2011, China has implemented its most stringent water management system to effectively protect water resources and guarantee socioeconomic development. More basin-scale water division schemes have been developed to act as references for basin-scale water resources management. Water dispatching during dry periods is an effective way to guarantee the water supply for the river basin, and is also an important component of basin-scale water resources management. Given this, the present study proposes a framework for the water dispatching of river basins during dry periods under the most stringent water management system in China. This framework mainly consists of the analysis and forecasting of rainfall and inflow, the dispatching requirements for the main water users, major reservoirs, and sections, as well as safeguard measures. The Jian River Basin in South China is presented as a case study. The total discharge of the Gaozhou Reservoir in 2017 was 25 million m3 more than the target discharge specified in the water dispatching scheme, and the total water storage utilization ratio during the dispatch period was 4.7% higher than the target utilization ratio. These factors demonstrate the effectiveness and applicability of the proposed framework. HIGHLIGHT The proposed framework for the water dispatching of river basins during dry periods provides reliable technical support for water use security under the most stringent water management system in China, and is demonstrated to be both effective and applicable.


Author(s):  
V. P. Kovalchuk ◽  
P. I. Kovalchuk ◽  
M. V. Yatsyuk ◽  
R. Yu. Kovalenko ◽  
O. S. Demchuk ◽  
...  

For integrated water management in river basins in Ukraine, there is no toolkit for system modeling and selection of management structure in river basins according to environmental and economic criteria, which corresponds to the creation of water management systems under conditions of sustainable development. Therefore, the urgent task is to develop a system model of integrated water management on the example of the Ingulets River basin. The purpose of the work is to create a system model of integrated water resources management in Ingulets River basin, which provides scenario modeling of technological solutions, their evaluation and optimization of economic criteria for efficient water use under environmental constraints and criteria for achieving a good or excellent ecological status of the river basin. The system model is used as a toolkit, the method of decomposition of the river basin into subsystems, analysis of subsystems and their composition into a holistic model of integrated management by the basin principle. Telecommunication methods are proposed to improve monitoring. A method of scenario analysis is proposed, which performs simulation modeling of prospective management scenarios at the first level of the hierarchy, and at the second level - options are evaluated according to the criteria of cost-effective water use with environmental objectives and regulatory restrictions. For simulation modeling, a system of balance difference equations for the dynamics of water masses, mixing and spreading of pollution in rivers and reservoirs is formalized. A system of combined control for the impulse method of river washing was developed. Multicriteria optimization of variants of the control structure is carried out on the Pareto principle. A system model has been developed for integrated water resources management in the Ingulets River basin that meets the requirements of the EU Water Framework Directive on the establishment of cost-effective water use while ensuring good or excellent ecological status of rivers. The structural and functional diagram of the system model includes the subsystems: the water supply subsystem of the Dnipro-Ingulets canal; a subsystem for flushing the Ingulets River from the Karachunivske reservoir and displacing the saline prism into the Dnipro River; subsystem of environmental safety when discharging pollution into the river Ingulets; subsystem of water supply for irrigation in the Ingulets irrigation system, prevention of soil salinization. A system of technological, economic and environmental criteria for evaluating integrated management by the basin principle has been developed. They include maintaining the water level in reservoirs, displacement of salt water prism and limitation on water quality, ensuring the ecological condition of the river, and the dynamics of water resources consumption. Technological criteria determine the maintenance of water levels in reservoirs. Cost-effective water use is estimated on the basis of the dynamics of water consumption for river washing and irrigation. The formalized integrated management system in the Ingulets River basin includes operational water resources management and structure management. Integrated management is carried out according to subsystems, types of management and a system of criteria. For operational management the balance differential equations of water exchange in reservoirs are formalized. A two-layer model of water masses dynamics, pollutants distribution and mixing when flushing rivers from reservoirs is used. Scenario analysis is offered to select the optimal structure of the management system. Simulation scenarios are being simulated. Scenario optimization is performed on the Pareto principle. An example of evaluating the effectiveness of the proposed system and its comparison with the existing regulations for Ingulets River flushing is given.


2020 ◽  
Author(s):  
Robert Behling ◽  
Sigrid Roessner ◽  
Saskia Foerster

<p>One of the consequences of global climate change is the more frequent occurrence of extreme weather conditions. Semi-arid regions are especially vulnerable since evapotranspiration significantly exceeds precipitation for most of the year and rainfall occurrence is dominantly sporadic and highly variable in amount and spatial extent. Consequently, these regions suffer from droughts of increasing duration and severity, occasionally interrupted by strong rainfall events generating high surface runoff and in part highly destructive floods. In semi-arid regions water retention capability is often further reduced by changes of the original vegetation cover due to conversion into farmland and intensification of land use. The result is widespread land degradation by a decrease in permanent vegetation cover and an increase in soil erosion. Under such conditions sustainable water resources management is of key importance, however, reliable long-term observations describing the water cycle and the resulting water budget are missing for many regions of the world. This situation requires new approaches in improving seasonal forecast for relevant water resources parameters as well as spatiotemporally explicit understanding the of influence of water and land use management on the long-term development of water availability and land surface conditions. <br>The German collaborative research project ‘Seasonal water resources management in semi-arid regions: Transfer of regionalized global information to practice’ (SaWaM) aims at the development of methods allowing the use of global data for deriving information needed for regional water resources management in semi-arid regions by integrating meteorological, hydrological and ecosystem sciences and supported by satellite remote sensing analysis. The performance, practical applicability and transferability of the developed methods are assessed in several semi-arid regions including Brazil, Iran and Sudan. Here, we present our work on the analysis of the seasonal and long-term vegetation dynamics at different spatial and temporal scales using satellite time series data of different spatial and temporal resolution (MODIS and Sentinel-2).  Our goal is linking the derived vegetation dynamics to changes in meteorological conditions, water availability and land use. In this context we put emphasis on the spatiotemporal analysis of bioproductivity related to different land use types and climatic conditions to identify and characterize hotspots of water usage in form of irrigated agriculture as a basis for further evaluation of the underlying water management practices.<br>We perform time series analysis of satellite-derived vegetation indices (VI) using various statistical aggregates, such as maximum, mean and temporal duration related to variable time periods (hydrological year, dry and wet season, growing patterns) as well as additive time series decomposition. Thus, we analyze long-term trends, seasonal deviations from long-term average conditions, and break points in the time series related to land use and water management changes. Moreover, we compare the derived spatiotemporal VI dynamics against the dynamics of hydrometeorological conditions (e.g. precipitation, evapotranspiration, temperature) as well as land use patterns in order to evaluate the impact of hydrometeorological drought conditions on different land use types and water management practices.  In conclusion, we present prototypes for information products supporting decision making of the local experts in the target regions.</p>


2003 ◽  
Vol 47 (7-8) ◽  
pp. 81-86 ◽  
Author(s):  
H. Bode ◽  
P. Evers ◽  
D.R. Albrecht

The Ruhr, with an average flow of 80.5 m3/s at its mouth, is a comparatively small tributary to the Rhine River that has to perform an important task: to secure the water supply of more than 5 million people and of the industry in the densely populated region north of the river. The complex water management system and network applied by the Ruhrverband in the natural Ruhr River Basin has been developed step by step, over decades since 1913. And from the beginning, its major goal has been to achieve optimal conditions for the people living in the region. For this purpose, a functional water supply and wastewater disposal infrastructure has been built up. The development of these structures required and still requires multi-dimensional planning and performance. Since the river serves as receiving water and at the same time as a source of drinking water, the above-standard efforts of Ruhrverband for cleaner water also help to conserve nature and wildlife. Ruhrverband has summed up its environmental awareness in the slogan: “For the people and for the environment”. This basic water philosophy, successfully applied to the Ruhr for more than 80 years, will be continued in accordance with the new European Water Framework Directive, enacted in 2000, which demands integrated water resources management in natural river basins, by including the good ecological status of surface waterbodies as an additional goal.


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