Your search found 18 records
1 Uhlenbrook, S.; Leibundgut, C. 1999. Integration of tracer information into the development of a rainfall-runoff model. In Leibundgut, C.; McDonnell, J.; Schultz, G. (Eds.), Integrated methods in catchment hydrology: Tracer, remote sensing and new hydrometric techniques. Wallingford, UK: IAHS. pp.93-100.
(Location: IWMI-HQ Call no: 551.48 G000 LEI Record No: H027490)
2 Rutenberg, E.; Uhlenbrook, S.; Leibundgut, C. 1999. Spatial delineation of zones with the same dominating runoff generation processes. In Leibundgut, C.; McDonnell, J.; Schultz, G. (Eds.), Integrated methods in catchment hydrology: Tracer, remote sensing and new hydrometric techniques. Wallingford, UK: IAHS. pp.281-284.
(Location: IWMI-HQ Call no: 551.48 G000 LEI Record No: H027513)
3 Uhlenbrook, S.. 2006. Catchment hydrology with satellites, models and rubber boots. Delft, Netherlands: UNESCO-IHE. 22p.
(Location: IWMI-HQ Call no: 551.48 G000 UHL Record No: H039146)
Inaugural address of Stefan Uhlenbrook, Professor of Hydrology, Head of the Hydrology and Water Resources Core at the UNESCO-IHE Institute for Water Education in Delft, The Netherlands
4 Uhlenbrook, S.. 2006. Catchment hydrology with satellites, models and rubber boots. Delft, Netherlands: UNESCO-IHE. 22p.
(Location: IWMI HQ Call no: 551.48 G000 UHL Record No: H040396)
Inaugural address of Stefan Uhlenbrook, Professor of Hydrology, Head of the Hydrology and Water Resources Core at the UNEXCO-IHE Institute for Water Education in Delft, The Netherlands
5 Masih, Ilyas; Uhlenbrook, S.; Ahmad, M. D.; Maskey, S. 2008. Regionalization of a conceptual rainfall runoff model based on similarity of the flow duration curve: a case study from Karkheh River Basin, Iran. [Abstract only]. Geophysical Research Abstracts, 10. 2p.
(Location: IWMI HQ Call no: e-copy only Record No: H041238)
Streamflow data is a prerequisite for planning and management of water resources. However, in many cases, observed streamflow data are not available or the records are too short or of insufficient quality. This undermines the informed planning and management of water resources at a specific site and as well as at the river basin scale. The study examines the possibility of simulating time series of streamflows for ungauged catchments based on hydrological similarity, using the mountainous, semiarid Karkheh river basin (55,000 km2, Iran) as an example. The main research question examined in this paper is whether or not the parameters of a hydrological model applied to gauged catchments can be successfully transferred for simulating streamflows in hydrologically similar ungauged catchments. In this study, the HBV model is applied to simulate daily streamflow with parameters transferred from gauged basin counterparts. Different similarity measures were reviewed and finally the approach based on the shape of the flow duration curve (FDC) was used. FDCs are frequently used for comparing the response of gauged catchments and for estimating hydrological indices for ungauged catchments, but their potential use for the regionalization of conceptual rainfall runoff models to ungauged catchments needs to be explored and is a subject of this paper. FDCs for ungauged basins are defined using developed regional regression relationships between the parameters of a logarithmic FDC model and physiographic catchment characteristics of eleven gauged catchments. The results suggest that the proposed method could be successfully applied for the estimation of ungauged streamflows in the mountainous parts of the Karkheh river basin. Then the estimated ungauged streamflows were used as an input to conduct water balance analysis of main river reaches of Karkheh river system. The utility of this information is demonstrated in closing the water balance, scenario analysis for surface water allocation and identification of river reaches where further hydrological investigations are crucial.
6 Masih, Ilyas; Ahmad, Mobin-ud-Din; Turral, Hugh; Uhlenbrook, S.; Karimi, Poolad. 2008. Understanding hydrologic variability for better surface water allocations in Karkheh Basin Iran. Paper presented at the 13th IWRA World Water Congress on Global Changes and Water Resources, "Confronting the expanding and diversifying pressures", Montpellier, France, 1-4 September 2008. 15p.
(Location: IWMI HQ Call no: IWMI 551.483 G690 MAS Record No: H041523)
Water-limited environments occupy about half of the global land area and are highly sensitive to change due to scarcity and variable distribution of water and nutrients. The Karkheh basin in Iran is in a water limited region which exhibits increasing competition for scarce water resources between irrigation, domestic, hydropower and environmental needs. Increasing demands for water are making sustainable water management more and more difficult particularly because of lack of understanding of basin hydrology and impacts of water resource development on different users across the basin. An in-depth study was conducted to examine the inter-annual and long-term variability of surface water resource using daily stream flow data from 1961 to 2001 at seven key locations across the Karkheh basin. The water accounting at basin scale was carried out using the available information for the water year 1993-94, which is considered in Iran as the reference year for future development and allocation of water resources in the Karkheh basin. The analysis reveals that water allocation planning on the basis of mean annual surface water availability can only provide a supply security of about 45 %, ranging from 40 to 52 percent. Although, the water allocations to different sectors are lower than the available resources and the competition among different sectors of water use is minimal during the study period, it would be extremely difficult to meet the demands in future i.e. by 2025, as planned allocation will reach close to the annual renewable water resources available in an average climatic year. The competition among irrigation and other sectors will keep increasing in future, particularly during dry years. The analysis conducted in this study is helpful in gaining further insights into the hydrological variability of surface water resources and incorporating it into water development and allocation strategies that will contribute in ensuring the sustained productivity from irrigated agriculture and other uses of water in the coming decades.
(Location: IWMI HQ Call no: e-copy only Record No: H041662)
(0.84 MB)
This study provides a comprehensive spatio-temporal assessment of the surface water resources of the semi-arid Karkheh basin, Iran, and consequently enables decision makers to work towards a sustainable water development in that region. The analysis is based on the examination of statistical parameters, flow duration characteristics, base flow separation and trend analysis for which data of seven key gauging stations were used for the period of 1961–2001. Additionally, basin level water accounting was carried out for the water year 1993–94. The study shows that observed daily, monthly and annual streamflows are highly variable in space and time within the basin. The streamflows have not been changed significantly at annual scale, but few months have shown significant trends, most notably a decline during May and June and an increase during December and March. The major causes were related to changes in climate, land use and reservoir operations. The study concludes that the water allocations to different sectors were lower than the totally available resources during the study period. However, looking at the high variability of streamflows, changes in climate and land use and ongoing water resources development planning, it will be extremely difficult to meet the demands of all sectors in the future, particularly during dry years.
8 Verma, Shilp; van der Zaag, P.; Uhlenbrook, S.. 2008. Small reservoirs, big impacts?: exploring alternate models of river basin development. In Humphreys, E.; Bayot, R. S.; van Brakel, M.; Gichuki, F.; Svendsen, M.; Wester, P.; Huber-Lee, A.; Cook, S. Douthwaite, B.; Hoanh, Chu Thai; Johnson, N.; Nguyen-Khoa, Sophie; Vidal, A.; MacIntyre, I.; MacIntyre, R. (Eds.). Fighting poverty through sustainable water use: proceedings of the CGIAR Challenge Program on Water and Food, 2nd International Forum on Water and Food, Addis Ababa, Ethiopia, 10-14 November 2008. Vol.3. Water benefits sharing for poverty alleviation and conflict management; Drivers and processes of change. Colombo, Sri Lanka: CGIAR Challenge Program on Water and Food. pp.1-5.
(Location: IWMI HQ Call no: IWMI 333.91 G000 HUM Record No: H041845)
(0.30 MB)
9 Masih, Ilyas; Ahmad, Mobin-ud-Din; Uhlenbrook, S.; Turral, Hugh; Karimi, Poolad. 2008. Overview of streamflow variability and water accounts for the Karkheh Basin, Iran. In Humphreys, E.; Bayot, R. S.; van Brakel, M.; Gichuki, F.; Svendsen, M.; Wester, P.; Huber-Lee, A.; Cook, S. Douthwaite, B.; Hoanh, Chu Thai; Johnson, N.; Nguyen-Khoa, Sophie; Vidal, A.; MacIntyre, I.; MacIntyre, R. (Eds.). Fighting poverty through sustainable water use: proceedings of the CGIAR Challenge Program on Water and Food, 2nd International Forum on Water and Food, Addis Ababa, Ethiopia, 10-14 November 2008. Vol.3. Water benefits sharing for poverty alleviation and conflict management; Drivers and processes of change. Colombo, Sri Lanka: CGIAR Challenge Program on Water and Food. pp.32-37.
(Location: IWMI HQ Call no: IWMI 333.91 G000 HUM Record No: H041850)
(0.27 MB)
(Location: IWMI HQ Call no: e-copy only Record No: H042660)
(0.53 MB)
This paper examines trends in streamflow and their links with local climate in the Karkheh River and its major tributaries, which originate from the Zagros Mountains, Iran. Streamflow records from five mainstream stations for the period 1961–2001 were used to examine trends in a number of streamflow variables. The studied variables were mean annual and monthly flows, 1 and 7 days maximum and minimum flows, timing of the 1-day maxima and minima, and the number and duration of high and low flow pulses. Similarly, the precipitation and temperature data from seven climate stations for the period from 1950s to 2003 were used to examine trends in climatic variables and their correlation with the streamflow. The Spearman Rank test was used for the detection of trends and the correlation analysis was based on the Pearson method. The results reveal a number of significant trends in streamflow variables both increasing (e.g. December flows) and decreasing (e.g. May flows) for all stations. However, some trends were not spatially uniform. For example, decline in low flow characteristics were more significant in the upper parts of the basin, whereas increasing trends in floods and winter flows were noteworthy in themiddle parts of the basin.Most of these trends could be attributed to precipitation changes. The results show that the decline in April and May precipitation causes the decline in the low flows while the increase in winter (particularly March) precipitation coupled with temperature changes lead to increase in the flood regime. The observed trends at the Jelogir station on the Karkheh River reflect the combined effect of the upstream catchments. The significant trends observed in a number of streamflow variables at Jelogir, 1-day maximum, December flow and low pulse count and duration, point to the changes in hydrological regime of the entire Karkheh River system and are attributed to the changes in climatic variables.
11 Masih, Ilyas; Maskey, S.; Uhlenbrook, S.; Smakhtin, Vladimir. 2009. Assessing the benefits of improved precipitation inputs in SWAT model simulations. In Texas Water Resources Institute. 2009 International SWAT Conference Proceedings, University of Colorado at Boulder, Boulder, Colorado, USA, 5-7 August 2009. College Station, TX, USA: Texas A&M University System. pp.285-292. (Texas Water Resources Institute Technical Report 356)
(Location: IWMI HQ Call no: e-copy only Record No: H042755)
(0.12 MB)
The importance of better input data, model structure and parameterization for good process-based predictions are well recognized in the hydrological modeling. Although the physically based semi-distributed model Soil Water Assessment Tool (SWAT) offers a range of possibility for defining the model structure and input data, the input of climatic data is still very simple. SWAT uses the data of gauge located nearest to the centroid of the catchment, which may not always represent overall catchment climatic conditions. This eventually influences the model parameterization process and quality of the predicted results. This paper uses areal precipitation obtained through interpolation and compares the model performance (observed versus simulated hydrograph) using the normal SWAT precipitation input procedure (station precipitation). The model was applied to mountainous, semi arid catchments in the Karkheh basin, Iran. Daily time series data from October 1987 to September 2001 were used for the model calibration (1987-94) and validation (1994-01). The model performance was evaluated at daily, monthly and annual scales by using a number of performance indicators. The comparison suggests that the use of areal precipitation is likely to improve model performance at smaller spatial scales, i.e., sub-catchments representing tertiary level streams (having drainage area in the range of 600 to 2,300 km2). Whereas reasonably good simulations can be achieved for larger scales representing the Karkheh River and its major tributaries (drainage area of greater than 5,000 km2) under both precipitation scenarios.
(Location: IWMI HQ Call no: e-copy only Record No: H043079)
(1.14 MB)
The study examines the possibility of simulating time series of streamflows for poorly gauged catchments based on hydrological similarity. The data of 11 gauged catchments (475–2522 km2), located in the mountainous semi-arid Karkheh river basin of Iran, is used to develop the procedure. The well-known HBV model is applied to simulate daily streamflow with parameters transferred from gauged catchment counterparts. Hydrological similarity is defined based on four similarity measures: drainage area, spatial proximity, catchment characteristics and flow duration curve (FDC). The study shows that transferring HBV model parameters based on the FDC similarity criterion produces better runoff simulation compared to the other three methods. Furthermore, it is demonstrated that the FDC based regionalization of HBV model parameters works reasonably well for streamflow simulations in the data limited catchments in the mountainous parts of the Karkheh river basin. In addition, it could be demonstrated that the parameter uncertainty of the model has little impact on the FDC based regionalization approach. The methodology presented in this paper is easy to replicate in other river basins of the world, particularly those facing decline in streamflow monitoring networks and with a limited number of gauged catchments.
(Location: IWMI HQ Call no: e-copy only Record No: H043436)
(0.64 MB)
Reduction of input uncertainty is a challenge in hydrological modeling. The widely used model Soil Water Assessment Tool (SWAT) uses the data of a precipitation gauge nearest to the centroid of each subcatchment as an input for that subcatchment. This may not represent overall catchment precipitation conditions well. This paper suggests an alternative – using areal precipitation obtained through interpolation. The effectiveness of this alternative is evaluated by comparing its simulations with those based on the standard SWAT precipitation input procedure. The model is applied to mountainous semiarid catchments in the Karkheh River basin, Iran. The model performance is evaluated at daily, monthly, and annual scales by using a number of performance indicators at 15 streamflow gauging stations each draining an area in the range of 590-42,620 km2. The comparison suggests that the use of areal precipitation improves model performance particularly in small subcatchments in the range of 600-1,600 km2. The modified areal precipitation input results in increased reliability of simulated streamflows in the areas of low rain gauge density. Both precipitation input methods result in reasonably good simulations for larger catchments (over 5,000 km2). The use of areal precipitation input improves the accuracy of simulated streamflows with spatial resolution and density of rain gauges having significant impact on results.
14 Maskey, S.; Bhatt, D.; Uhlenbrook, S.; Prasad, K. C.; Babel, M. S. 2015. Adaptation to climate change impacts on agriculture and agricultural water management - a review. In Hoanh, Chu Thai; Johnston, Robyn; Smakhtin, Vladimir. Climate change and agricultural water management in developing countries. Wallingford, UK: CABI. pp.11-31. (CABI Climate Change Series 8)
(Location: IWMI HQ Call no: IWMI Record No: H047369)
(628 KB)
(Location: IWMI HQ Call no: e-copy only Record No: H049794)
(1.94 MB) (1.94 MB)
The implementation of afforestation programs in arid environments in northern China had modified the natural vegetation patterns. This increases the evaporation flux; however, the influence of these new covers on the soil water conditions is poorly understood. This work aims to describe the effect of Willow bushes (Salix psammophila C. Wang and Chang Y. Yang) and Willow trees (Salix matsudana Koidz.) on the soil water conditions after the summer. Two experimental plots located in the Hailiutu catchment (Shaanxi province, northwest China), and covered with plants of each species, were monitored during Autumn in 2010. The monitoring included the soil moisture, fine root distribution and transpiration fluxes that provided information about water availability, access and use by the plants. Meanwhile, the monitoring of stable water isotopes collected from precipitation, soil water, groundwater and xylem water linked the water paths. The presence of Willow trees and Willow bushes reduce the effect of soil evaporation after summer, increasing the soil moisture respect to bare soil conditions. Also, the presence of soil water with stable water isotope signatures close to groundwater reflect the hydraulic lift process. This is an indication of soil water redistribution carried out by both plant species.
(Location: IWMI HQ Call no: e-copy only Record No: H049609)
(2.04 MB) (37.7 MB)
Building on the information and analyses provided in Chapters 3 through 8, this chapter expands on the interlinkages between the main water use sectors, describing how decisions made by one can have significant repercussions on the others. It highlights the need for a consolidated approach to addressing climate change through water in order to maximize co-benefits and address trade-offs.
(Location: IWMI HQ Call no: e-copy only Record No: H049607)
(5.04 MB) (37.7 MB)
The Prologue provides an overview of the state of the world’s water resources and the potential impacts of climate change on the hydrological cycle, including water availability and quality, water demand, water-related disasters and extreme events, and ecosystems. Knowledge gaps, limitations and uncertainties are also addressed.
18 Timmerman, J.; Connor, R.; Uhlenbrook, S.; Koncagul, E.; Buytaert, W.; Mishra, A.; Zandaryaa, S.; Webley, N.; Amani, A.; Stewart, B.; Hada, R.; Kjellen, M. 2020. Climate change, water and sustainable development. In UNESCO World Water Assessment Programme (WWAP); UN-Water. The United Nations World Water Development Report 2020: water and climate change. Paris, France: UNESCO. pp.30-37.
(Location: IWMI HQ Call no: e-copy only Record No: H049608)
(1.11 MB) (37.7 MB)
This introductory chapter describes the objectives and scope of the report, describing the main concepts related to water and climate, emphasizing the cross-sectoral nature of the challenges and potential responses, and highlighting those that are potentially the most vulnerable.
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