scholarly journals Hydrological modeling in glacierized catchments of Central Asia: status and challenges

Author(s):  
Yaning Chen ◽  
Weihong Li ◽  
Gonghuan Fang ◽  
Zhi Li

Abstract. Glaciers are one of the most important water supplies of glacierized catchments in Central Asia. Therefore, the effects of climate change on glaciers, snow cover and permafrost will have increasingly significant consequences for runoff. Hydrological modeling has become an indispensable research approach to water resources management in large glacierized river basins, but there is a lack of focus in the modeling of glacial discharge. This paper reviews the status of hydrological modeling in glacierized catchments of Central Asia, discussing the limitations of the available models and extrapolating these to future challenges and directions. After reviewing recent efforts, we conclude that the main sources of uncertainty in assessing the regional hydrological impacts of climate change are the unreliable and incomplete datasets and the lack of understanding of the hydrological regimes of glacierized catchments of Central Asia. Runoff trends indicate a complex response of catchments to changes in climate. For future variation of water resources, it is essential to quantify the responses of hydrologic processes to both climate change and shrinking glaciers in glacierized catchments, and scientific focus should be on reducing these uncertainties.

2017 ◽  
Vol 21 (2) ◽  
pp. 669-684 ◽  
Author(s):  
Yaning Chen ◽  
Weihong Li ◽  
Gonghuan Fang ◽  
Zhi Li

Abstract. Meltwater from glacierized catchments is one of the most important water supplies in central Asia. Therefore, the effects of climate change on glaciers and snow cover will have increasingly significant consequences for runoff. Hydrological modeling has become an indispensable research approach to water resources management in large glacierized river basins, but there is a lack of focus in the modeling of glacial discharge. This paper reviews the status of hydrological modeling in glacierized catchments of central Asia, discussing the limitations of the available models and extrapolating these to future challenges and directions. After reviewing recent efforts, we conclude that the main sources of uncertainty in assessing the regional hydrological impacts of climate change are the unreliable and incomplete data sets and the lack of understanding of the hydrological regimes of glacierized catchments of central Asia. Runoff trends indicate a complex response to changes in climate. For future variation of water resources, it is essential to quantify the responses of hydrologic processes to both climate change and shrinking glaciers in glacierized catchments, and scientific focus should be on reducing uncertainties linked to these processes.


Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1313
Author(s):  
George Akoko ◽  
Tu Hoang Le ◽  
Takashi Gomi ◽  
Tasuku Kato

The soil and water assessment tool (SWAT) is a well-known hydrological modeling tool that has been applied in various hydrologic and environmental simulations. A total of 206 studies over a 15-year period (2005–2019) were identified from various peer-reviewed scientific journals listed on the SWAT website database, which is supported by the Centre for Agricultural and Rural Development (CARD). These studies were categorized into five areas, namely applications considering: water resources and streamflow, erosion and sedimentation, land-use management and agricultural-related contexts, climate-change contexts, and model parameterization and dataset inputs. Water resources studies were applied to understand hydrological processes and responses in various river basins. Land-use and agriculture-related context studies mainly analyzed impacts and mitigation measures on the environment and provided insights into better environmental management. Erosion and sedimentation studies using the SWAT model were done to quantify sediment yield and evaluate soil conservation measures. Climate-change context studies mainly demonstrated streamflow sensitivity to weather changes. The model parameterization studies highlighted parameter selection in streamflow analysis, model improvements, and basin scale calibrations. Dataset inputs mainly compared simulations with rain-gauge and global rainfall data sources. The challenges and advantages of the SWAT model’s applications, which range from data availability and prediction uncertainties to the model’s capability in various applications, are highlighted. Discussions on considerations for future simulations such as data sharing, and potential for better future analysis are also highlighted. Increased efforts in local data availability and a multidimensional approach in future simulations are recommended.


Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3358
Author(s):  
Patrik Sleziak ◽  
Roman Výleta ◽  
Kamila Hlavčová ◽  
Michaela Danáčová ◽  
Milica Aleksić ◽  
...  

The changing climate is a concern with regard to sustainable water resources. Projections of the runoff in future climate conditions are needed for long-term planning of water resources and flood protection. In this study, we evaluate the possible climate change impacts on the runoff regime in eight selected basins located in the whole territory of Slovakia. The projected runoff in the basins studied for the reference period (1981–2010) and three future time horizons (2011–2040, 2041–2070, and 2071–2100) was simulated using the HBV (Hydrologiska Byråns Vattenbalansavdelning) bucket-type model (the TUW (Technische Universität Wien) model). A calibration strategy based on the selection of the most suitable decade in the observation period for the parameterization of the model was applied. The model was first calibrated using observations, and then was driven by the precipitation and air temperatures projected by the KNMI (Koninklijk Nederlands Meteorologisch Instituut) and MPI (Max Planck Institute) regional climate models (RCM) under the A1B emission scenario. The model’s performance metrics and a visual inspection showed that the simulated runoff using downscaled inputs from both RCM models for the reference period represents the simulated hydrological regimes well. An evaluation of the future, which was performed by considering the representative climate change scenarios, indicated that changes in the long-term runoff’s seasonality and extremality could be expected in the future. In the winter months, the runoff should increase, and decrease in the summer months compared to the reference period. The maximum annual daily runoff could be more extreme for the later time horizons (according to the KNMI scenario for 2071–2100). The results from this study could be useful for policymakers and river basin authorities for the optimum planning and management of water resources under a changing climate.


2021 ◽  
Author(s):  
Zarina Saidaliyeva ◽  
Veruska Muccione ◽  
Maria Shahgedanova ◽  
Sophie Bigler ◽  
Carolina Adler

<p>The mountains of Central Asia, extending over 7000 m a.s.l. and accommodating diverse and complex natural and managed systems, are very vulnerable to climate change. They support valuable environmental functions and provide key ecosystem goods and services to the arid downstream regions which strongly depend on the melting snowpack and glaciers for the provision of water by the transboundary rivers starting in the mountains. Strong climate change adaptation (CCA) action is required to increase resilience of the vulnerable, low-income communities in the region. Our knowledge of the CCA actions in the mountains of Central Asia is limited in comparison with other mountainous regions. The aim of this study is to assess the existing adaptation projects and publications and to identify gaps in adaptation efforts by conducting a systematic review of the peer-reviewed literature published in English language. To be selected, the papers had to comply with the following criteria: (i) publication between 2013 and 2019; (ii) explicit focus on CCA in the mountain ranges of Central Asia; (iii) explanation of adaptation options; (vi) a clear methodology of deriving suitable adaptation options. Following the initial screening and subsequent reading of the publications, complying with the specified criteria, 33 peer-reviewed articles were selected for final analysis. This is considerably lower than the number of publications on the European Alps, Hindu-Kush – Himalayas, and the Andes. The number of publications on Central Asian mountains has declined since 2013.</p><p>The research is heavily focused on the problem of water resources, especially water availability at present and in the future 70 % of the analysed papers addressing these issues. These are followed by the papers considering adaptation in agriculture and in managing biodiversity. A critical finding is the lack of publications on adaptation to hazards and disasters including glacier outburst floods, mudflow, and landslides which are common and comparatively well-researched hazards in the Central Asian mountains, experiencing rapid deglaciation. About 50 % of the papers address the transboundary nature of the impacts of climate changes on water resources and land management reflecting the transboundary nature of the Central Asian catchments and the tensions which exist across the region but are especially prominent in the Aral Sea basin.</p><p>We conclude that while there is ample evidence of climate change and its impacts in the mountains of Central Asia and many publications mention the need for adaptation, a very limited number of publications explicitly focus on CCA and how it can be delivered.</p>


2018 ◽  
Vol 11 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Yang Yu ◽  
Yuanyue Pi ◽  
Xiang Yu ◽  
Zhijie Ta ◽  
Lingxiao Sun ◽  
...  

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1201 ◽  
Author(s):  
Pantelis Sidiropoulos ◽  
Georgios Tziatzios ◽  
Lampros Vasiliades ◽  
Nikitas Mylopoulos ◽  
Athanasios Loukas

Groundwater quantity and quality degradation by agricultural practices is recorded as one of the most critical issues worldwide. This is explained by the fact that groundwater is an important component of the hydrological cycle, since it is a source of natural enrichment for rivers, lakes, and wetlands and constitutes the main source of potable water. The need of aquifers simulation, taking into account water resources components at watershed level, is imperative for the choice of appropriate restoration management practices. An integrated water resources modeling approach, using hydrological modeling tools, is presented for assessing the nitrate fate and transport on an over-exploited aquifer with intensive and extensive agricultural activity under various operational strategies and future climate change scenarios. The results indicate that climate change affects nitrates concentration in groundwater, which is likely to be increased due to the depletion of the groundwater table and the decrease of groundwater enrichment in the future water balance. Application of operational agricultural management practices with the construction and use of water storage infrastructure tend to compensate the groundwater resources degradation due to climate change impacts.


2018 ◽  
Vol 4 (0) ◽  
Author(s):  
Valentine Mukanyandwi ◽  
Lamek Nahayo ◽  
Egide Hakorimana ◽  
Aboubakar Gasirabo ◽  
Shinebayar Otgon

Water is important for human health, industry, agriculture and ensuring the integrity and sustainability of the ecosystem. The water resources are the top affected by climate variability and population growth. The current population of Rwanda is about 12 million heading to about 25 million in 2050 under the changing climate, where since 1970 temperature rose by 1.4°C and is predicted that in 2050 to be about 2.5°C with severe effects on water resources in Rwanda. Thereby, this study reviewed the status and causes of water quality problems and suggested appropriate options to undertake for sustainable water resources access, employ and management in Rwanda. It was noticed that among others, the key threats to water quality in Rwanda, include not limited to climate change causing rainfall patterns which generated flooding, landslides and periodic droughts, which loaded pollutants into water. In addition, water quality is jeopardized by the rapid population growth, agrochemicals, industrialization, urbanization, soil steepness and land mismanagement. Accordingly, the reviewed water quality indicate that the water quality pollution likelihood is increasing over time. These facts reveal that the water quality soon or late will be highly polluted and calls for further adaptation and management measures.


Author(s):  
Naga Coulibaly ◽  
Talnan Jean Honoré Coulibaly ◽  
Ziyanda Mpakama ◽  
Issiaka Savané

In the context of climate change in West Africa characterized by a reduction of precipitation, this study was conducted to evaluate the impact of climate change on water resources from now to the end of the 21st century in the transboundary watershed of the Sassandra River shared by Guinea and Côte d’Ivoire. Historical and future climate (Representative Concentration Pathways or RCPs 4.5 and 8.5 scenarios) data were projected with the model. The Abdus Salam ICTP RegCM4 was used. The hydrological modeling of the river basin was carried out with the conceptual hydrological model, GR2M. This model is a monthly time steps model that allows the assessment of the discharge of the Sassandra River for each climate scenario according to the 2030 (2021–2040), 2050 (2041–2060), 2070 (2061–2080), and 2090 (2081–2100) horizons. The results showed a reduction of the annual discharge when compared to the baseline (1961–1980). For the RCP 4.5, the observed values went from –1.2% in 2030 to –2.3% in 2070 and rose to –2.1% in 2090. Concerning the RCP 8.5, we saw a variation from –4.2% to –7.9% in the 2030 and 2090 horizons, respectively. With the general decrease of rainfall in West Africa, it is appropriate to assess the impact on water resources on the largest rivers (Niger, Gambia, and Senegal) that irrigate the Sahelo-Saharian zone.


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