SE, respectively for maximum temperature. Similar trend of values is found for minimum temperature by using SSVM. On the other hand, SDSM is found slightly less efficient for the downscaling of daily precipitation but SSVM is found considerably efficient than that of SDSM. Aforementioned parametric values depict that the SSVM is more suitable for the downscaling of climate variables by using GCMs. In contrast to calibration, over the validation period both models are found to be slightly less efficient, as expected. In case of APHRODITE data products such as precipitation and mean temperature, the obtained results show that both models are highly efficient to downscale climate variables at local data series. This data product is helpful to overcome scarce data issues in climate change studies. As, the variance (E), R 2 and standard error (SE) alone are not evaluate the efficiency of both models for downscaling of precipitation during calibration and validation it is therefore, means daily (mm/day), standard deviation (mm/day), percentile (95%), percent wet, maximum dry and wet spell length were also utilized as performance descriptors. The thresh hold for wet condition was set to 1 mm. Table 4.4 explains the difficulty of SDSM for downscaling of local precipitation from regional scale predictors using NCEP data compared with SSVM during calibration and validation. Table 4.4 is used to compare SSVM and SDSM by taking average of all statistics estimated from daily baseline precipitation including observed and APHRODITE and NCEP downscale data in term of bias, that is, difference between baseline and NCEP downscaled values. The maximum number of shaded values are clearly indicates the superiority of SSVM over SDSM for precipitation downscaling in both calibration and validation period.
With respect to most of the waterresources indicators, the projected land use changes until 2050 balance each other out, and the net effect is only marginal. Land use projections for Slovenia until 2050 show a substantial increase of forested area at the expense of arable land and semi-natural vegetation. Urban land use is expected to increase by roughly 22% as compared to present day; industrial land use is expected to increase by roughly 27%. For Croatia, forest areas are expected to increase substantially between 2010 and 2050 until 50% of the country’s land surface is forested. Areas of arable land and semi-natural vegetation are expected to decrease substantially. Industrial and urban land uses are expected to increase by respectively 22% and 1%. Effects on waterresources would be more significant with increased irrigation to increase the crop yield of e.g maize. This would lead to an increase in water demand from 2216 Mm3/year to 3337 Mm3/year. Overall water demand in the Sava basin would further increase to around 6000 Mm3/year if we combine both increased irrigation and climate projections until 2100. The average simulated maize yield could increase from 5.7 tons/ha at present conditions to 9.9 tons/ha in case of increased and optimum irrigation. These substantial increases in irrigation, which would lead to substantial crop yield increases as well, would lead to water scarcity in parts of the Sava basin. Also, there just is not sufficient water to irrigate all areas which are water-limited for crop growth. Existing irrigation plans and irrigating the areas which were previously equipped for irrigation (according to FAO) seems more feasible from a waterresources perspective.
The Pearl River in southern China provides important waterresources for agriculture, industry, hydropower generation and domestic use within its drainage basin. Particularly, it plays a key role for water supply to large cities in the Pearl River Delta, such as Macau, Hong Kong, Guangzhou. Population growth and socio-economic development have increased pressure on waterresources in the Pearl RiverBasin (PRB). This situation is likely to be aggravated by decreasing wateravailability due to climate change. Allocating water is critical to meet human and ecosystem needs in the PRB now and in the future. However, waterresources allocation in the PRB is being challenged by uncertainties associated with climate change and socio- economic development. This study assessed the combined effects of climate change and socio- economic development on water supply and use in the PRB, and identified water allocation plans, which are robust to climate change and socio-economic development in this basin. This study first assessed the impact of climate change on seasonal discharge and extreme flows in the PRB (Chapter 2). The variable infiltration capacity (VIC) model driven by bias-corrected results of five different climate models under the IPCC scenarios RCP4.5 and 8.5 was used for the assessment. Results indicate a reduction in average low flow under the five climate models. The reduction varies across the basin and is between 6 and 48% for RCP4.5. For RCP8.5, low flows show a 22 - 72% decrease. High flows are projected to decrease in the upstream part of the basin and to increase in the central part under both RCP4.5 (-6 to 20%) and 8.5 (-16 to 31%). River discharge in the dry season is projected to decrease throughout the basin. In the wet season, river discharge tends to increase in the middle and lower reaches and decreases in the upper reach of the PRB. The variation of river discharge is likely to aggravate water stress. Especially the reduction of low flow is problematic as already now the basin experiences temporary water shortages in the delta.
Abstract: The aim of the presented study is to assess the impacts of climate change on hydropowerproduction of the Toce Alpine riverbasin in Italy. For the meteorological forcing of futurescenarios, time series were generated by applying a quantile-based error-correction approach to downscale simulations from two regional climate models to point scale. Beside a general temperature increase, climate models simulate an increase of mean annual precipitation distributed over spring, autumn and winter, and a significant decrease in summer. A model of the hydropower system was driven by discharge time series for futurescenarios, simulated with a spatially distributed hydrological model, with the simulation goal of defining the reservoirs management rule that maximizes the economic value of the hydropowerproduction. The assessment of hydropowerproduction for futureclimate till 2050 respect to currentclimate (2001–2010) showed an increase of production in autumn, winter and spring, and a reduction in June and July. Significant change in the reservoir management policy is expected due to anticipation of the date when the maximum volume of stored water has to be reached and an increase of the reservoir drawdown during August and September to prepare storage capacity for autumn inflows.
It is clear from the information shown in those tables and figures that all the models and scenarios project negative effects on flow in the basin, on the volume of water stored in the reservoir and on the generation of hydropower by the end of the 2010-2039 period. The projected supply yield for the different scenarios for the year 2039 is presented to cover the supply requirement or demand for the same year (636.1 millions of cubic meters -MCM- for all scenarios, see Table V) and the ratio for unmet demand is specified for each case. The new scenarios developed in this report are based specifically on the current or baseline scenario and the future weighted average scenario (see Table III), for the purposes of the proposed analyses.
Previous studies highlighted the connection between rainfall variability and vegetation cover, as well as range- land greenness in semi-arid ecosystems. For instance, ac- cording to Adler and Levine (2007), under the ever increasing environmental changes, vegetation productiv- ity, basal cover, and species composition in arid and semi-arid rangelands were strongly associated with rain- fall availability. Moreover, the alteration of rainfall distribution associated with long-term climate change/ variability is expected to influence plant productivity and species diversity in semi-arid areas (Cheng et al. 2011). As a result, the rangeland vegetation cover and its po- tential productivity could be limited by the long-term rainfall variability and its distribution in arid and semi- arid ecosystems (Cheng et al. 2011). Accordingly, for the sustainable utilization and management of rangelands, as main feed resources for both domestic and wild her- bivores, monitoring of climatic risk through the develop- ment of rangeland water requirement and satisfaction index is very crucial in arid and semi-arid ecosystems (Peter and Sandro 2012). Therefore, rangeland WRSI is defined as the amount of water required to replenish water that is lost through evapotranspiration (ET) pro- cesses, and it is calculated using a water stress index scheme to determine whether a given rangeland vegeta- tion has sufficient water to achieve its potential yield or not in a particular season (Peter and Sandro 2012; Senay et al. 2011).
Additionally, hydrological deficits were evident in both studies. In a longitudinal, system-wide view, the stability of fish habitat is massively affected due to poor cover avail- ability and changing water levels. In a vertical and lateral perspective, the transient changes in water level are not limited to the river itself, but also measurable in the near- river aquifer. This type of disturbance is likely to produce more serious ecological effects if the lateral connectivity is improved by rehabilitation measures such as river widening. Rehabilitation scenarios are therefore facing conflicting boundary conditions. The fishes’ ecological situation can be significantly improved by effective rehabilitation of the longitudinal habitat structure. This success generally achieved by widening is also positive in terms of removing the siltation of the riverbank. River–groundwater interac- tions are reestablished, resulting in benefits for the epigean fauna [ 11 , 72 ], spawning conditions for fish [ 35 ] as well as the replenishment of the adjacent aquifer for flood con- trol [ 34 ]. In the river Rhone, as a formerly braided system widening is a rehabilitation measure that deserves special consideration.
Abstract. Mismanagement and uneven distribution of water may lead to or increase conflict among countries. Allocation of water among trans-boundary river neighbours is a key issue in utilization of shared waterresources. The bankruptcy theory is a cooperative Game Theory method which is used when the amount of demand of riparian states is larger than total available water. In this study, we survey the application of seven methods of Classical Bankruptcy Rules (CBRs) including Proportional (CBR-PRO), Adjusted Proportional (CBR-AP), Constrained Equal Awards (CBR-CEA), Constrained Equal Losses (CBR-CEL), Piniles (CBR-Piniles), Minimal Overlap (CBR-MO), Talmud (CBR-Talmud) and four Sequential Sharing Rules (SSRs) including Proportional (SSR-PRO), Constrained Equal Awards (SSR-CEA), Constrained Equal Losses (SSR-CEL) and Talmud (SSR- Talmud) methods in allocation of the Euphrates River among three riparian countries: Turkey, Syria and Iraq. However, there is not a certain documented method to find more equitable allocation rule. Therefore, in this paper, a new method is established for choosing the most appropriate allocating rule which seems to be more equitable than other allocation rules to satisfy the stakeholders. The results reveal that, based on the new propose model, the CBR-AP seems to be more equitable to allocate the Euphrates Riverwater among Turkey, Syria and Iraq.
In order to divert water from rivers or lakes for any economic activity (urban water supply, industry, irrigation), one must get a water use permit from the corresponding authorities. In Brazilian law these water use permits are known as “outorga”. The outorga is a discretionary decision taken by the State, and its concession depends on water use efficiency and wateravailability. In other terms, the concession of a new outorga must not harm other users with water use rights in the same basin, i.e. multiple uses must be assured. Moreover, water uses must be efficient according to pre- established standards, otherwise the water rights can be cancelled. Irrigation corresponds currently for around 69% of total water rights allocated in Brazil (National Water Agency 2005).
Abstract. The objective of this study was to analyze the changes and uncertainties related to wateravailability in the future (for the purposes of this study, the period be- tween 2011 and 2040 was adopted), using a stochastic ap- proach, taking as reference a climate projection from cli- mate model Eta CPTEC/HadCM3. The study was applied to the Ijuí Riverbasin in the south of Brazil. The set of methods adopted involved, among others, correcting the cli- matic variables projected for the future, hydrological sim- ulation using artificial neural networks (ANNs) to define a number of monthly flows and stochastic modeling to gen- erate 1000 hydrological series with equal probability of oc- currence. A multiplicative type stochastic model was devel- oped in which monthly flow is the result of the product of four components: (i) long-term trend component; (ii) cyclic or seasonal component; (iii) time-dependency component; and (iv) random component. In general, the results showed a trend to increased flows. The mean flow for a long pe- riod, for instance, presented an alteration from 141.6 m 3 s −1 (1961–1990) to 200.3 m 3 s −1 (2011–2040). An increment in mean flow and in the monthly standard deviation was also observed between the months of January and October. Be- tween the months of February and June, the percentage of mean monthly flow increase was more marked, surpassing the 100 % index. Considering the confidence intervals in the flow estimates for the future, it can be concluded that there is a tendency to increase the hydrological variability during the period between 2011 and 2040, which indicates the possibil- ity of occurrence of time series with more marked periods of droughts and floods.
The primary challenge in waterresources management is to balance water supply with the ever increasing demand. One option to balance supply and demand is to increase supply by augmenting the currentwaterresources. This often involves large scale water resource projects such as the North–south Carrier in Botswana, the Great Man Made River in Libya, the Lesotho Highlands Water Project in South Africa and the National Water Carrier in Israel (Butler and Memon 2006; Rahm et al. 2006; Wheida and Verhoeven 2007). Though the supply enhancement projects can solve water shortage problems for time being, they are not enough to meet the increasing water demand caused by rapid economic development and population growth (Wang et al. 2011a, b, 2012). The development of society and intensive human activities has lead to extensive depletion of water sources throughout the world. Recently, water resource depletion has accelerated due to the large- scale population growth, urbanization, socioeconomic development and climate change (Butler and Memon 2006; WHO 2006; Wheida and Verhoeven 2007; Wang et al. 2008).
pertinent with the new focus on stream restoration activities and the urgency in developing water-quality criteria for sediment. Eco-region concept was employed by using the historical flow and suspended flow data. It was discussed that channel forming discharge represents long term sediment transport conditions and designated this flow as potential metric for sediment transport conditions. It was further mentioned that “flow of a given frequency and recurrence interval is perhaps more appropriate to integrate suspended-sediment transport rates for the purpose of defining long term transport conditions at sites from diverse regions”. In this study bank-full discharge and effective discharge have been used interchangeably.
The daily climate data were collected from the Department of Hydrology and Meteorology (DHM), Government of Nepal. Meteorological data used in this study include daily precipitation, daily maximum temperature and daily minimum temperature of Kyanging Langtang snow and glacier hydrology station temperature. The products of scenarios generated by using CGCM3 temperature and precipitation data were used with the HBV (Hydrologiska Byråns Vattenbalansavdelning) light 3.0 hydrological model for the calculation of future discharge from Langtang Khola catchment at Syaprubesi. Seibert (2005) describes the model as follows: daily discharge is simulated by HBV light 3.0 using daily rainfall, temperature and potential evaporation as input. In this study, seasons in Nepal are classified as: winter (DJF) December of the previous year to February; spring (MAM) March to May; summer (JJAS) June to September; and autumn (ON) October to November. Four applications of computer software programs are applied in this study: (1) SDSM for generating daily climate temperature and precipitation scenarios (SDSM 4.2), developed by Wilby and Dawson (2007) in the UK, is chosen for developing daily climate scenario study, (2) hqrating model (developed by the Department of Hydrology and Meteorology, Government of Nepal) to develop the rating curve, (3) ArcGIS 9.3 for glacier area delineation, and (4) HBV Light 3.0 for discharge modelling (Seibert 2005).
This study was aimed to compare the uncertainty of two hydrological models in discharge modeling and their performance and catchment hydrological response to climate change in Megech river catchment. In this study, large scale regional climate model (REMO) output was downscaled statistically to metrological variables at a daily resolution using SDSM model version 5.11. The two hydrological models, HBV-Light and GR4J, were successfully calibrated (1991-1995) and validated (1998-2000) using current climatic inputs and observed river flows. The overall performances of the two models in reproducing historical records were good at daily and monthly time scale both on calibration and validation (NSE=0.91 for HBV and NSE=0.88 for GR4J). The models results in predicting hydrological response of changed climate (2015-2050) was simulated using statistically downscaled 20 ensembles climate scenario data for both A1B and B1 scenarios. Both model results showed a reduction of the peak discharge in August and September The total annual discharge for future period (2015-2050) showed a decreasing trend for HBV-Light simulation and an increasing trend for GR4J simulation. More studies using different hydrological models on different catchments need to be carried out in order to provide more general conclusions about the reliability of the model output.
While natural resources management may be an ally of geography, it has evolved as a divergent field of enquiry, drawing techniques from many fields. Johnston (1983) explored the links between natural resources management, resource analysis, as well as human and physical geography, but he commented that these links were yet to be proven. Geography has drawn from other fields of enquiry (e.g. hydrology, waterresources engineering, and economics) and has provided a spatial perspective on the management of natural resources. Initially, much of the collaborative effort was focused on the assessment of waterresources potential for riverbasin development. These efforts included the estimation of physical potential, determination of technical and economic feasibility, and evaluation of social desirability (Chorley and Kates, 1969).
Futureriver flows have been estimated using the hydrological model, Simplified Hydrolog (SIMHYD), which is integrated with data from three different general climate models and emission scenarios. In this study, two different representative concentration pathway (RCP) emission scenarios RCP 4.5 and RCP 8.5 were selected to obtain downscaled future precipitation and potential evapotranspiration data from government agencies for the period of 2016 to 2100. Data from the two emission scenarios show an anticipated warmer and drier climate for the Murrumbidgee catchment. Runoff in the Murrumbidgee catchment is controlled by various dams and weirs, which yields positive results in runoff even when monthly rainfall trend was negative. The overall runoff simulations indicated that impact of climate change is short and intense.
Water is the main element for development since it defines and limits the op- portunities for growth and economic development. The lack of water will in- crease constantly owing to the increase of the economic activities, social re- quests, environmental damage, and the climate changes. The research has as purpose to build an indicator of wateravailability, in the lower Basin of Guayalejo-Tamesi River in Tamaulipas, Mexico. Considering a quantitative methodology that provides the application of mathematic models through a hydrologic simulation software and scenarios of climate change (WEAP) (MA- GICC); and the qualitative that represents a major economic engineering challenge to convert complex variables such as the human development, the rise of the economic activity, and the increase of the social-demographic in water requirement. Bearing in mind that the valley is one of the most impor- tant hydrological systems of the State of Tamaulipas that provides to produc- tive areas; the chemical industry, petrochemical, energetic, agricultural and livestock such as the domestic. Which makes relevant to apply and analyze the IDA, being a new experience at the regional level that needs to be abroad in a general way by the binding instances to the development of these areas which will allow a better social usage and economic of the hydrological system in a sustainable integral environment.
Caldwell (2010) found that RCMs tend to over-predict precipitation estimates and that, contrary to expectations, “improved resolution does not translate into improved simulation….” For this study, the author investigated performance of gridded observational datasets, RCMs, and GCMs ranging in spatial resolution from 1/12 th of a degree up to 4.5 degrees in terms of their ability to reproduce wintertime precipitation (Pr) over the state of California. The author looked at the ability of the various methods to capture mean precipitation, precipitation distribution, and temporal variability. A total of 24 different models and gridded observation datasets were collected and investigated. The author concluded that all models with resolution finer than three degrees were able to accurately reflect observed conditions “in the sense that the California mean for these models is essentially independent of the averaging method” (Caldwell, 2010). The author notes that the removal of bias from the climate models is “critical” and observes that, in regards to the RCMs investigated, there exists a “wet bias [that] seems to be associated with strong Pr events, while Pr frequency is generally under-predicted” (Caldwell, 2010). The author suggests further investigation of both of these findings.
As noted above, the operating policies of the CRB reser- voir system are dictated by the Law of the River. In CRRM, like CRSS, these laws have been simplified so that the main regulations affecting operations are a mandatory release of 10.2 BCM per year from Glen Canyon Dam (for the Lower Basin’s 9.2 BCM/yr entitlement and one-half of Mexico’s 1.9 BCM/yr) and an annual release from the Lower Basin to Mexico of 1.9 BCM. CRRM, again like CRSS, requires the release from Lake Powell regardless of the reservoir level rel- ative to its minimum power pool; only when it is not physi- cally possible to release water (dead storage) are releases to the Lower Basin curtailed. CRRM shortage delivery opera- tions were updated in CRRM relative to the version of the model used in Christensen et al. (2004) to reflect the “basin states alternative” (BSA) which is likely to be adopted as the basis for water deliveries in the future. The BSA has three different shortage levels (494, 617, and 740 MCM/yr that are imposed at Lake Mead elevations of 327.66, 320.05, and 312.42 m, respectively. The BSA also stipulates a hard protect of the Southern Nevada’s Water Authority (SNWA) intake at an elevation of 304.80 m. At this elevation deliv- eries to the lower basin will be reduced, to zero if need be, to ensure no further reduction of elevation. The first three reductions are weighted 79% to CAP, 17% to Mexico, and 4% to SNWA. The BSA does not stipulate how shortages are allocated after the 740 MCM/yr level; however CRRM fol- lows the Law of the River and recognizes CAP’s allocation to be junior to the MWD, which in turn is junior to the Im-