Donor Basin Research Articles

Hanjiang River Runoff Change and Its Attribution Analysis Integrating the Inter-Basin Water Transfer

The Hanjiang River, as a water donor basin, plays a fundamental role in supporting water supply security in northern China while maintaining the health and stability of ecosystems within the basin. However, the combined influence of climate change and anthropogenic interference has resulted in a significant change in the flow regime of the basin, challenging the sustainability of the river system. In order to understand the impact of the above factors on the river runoff, we analyzed the temporal and spatial pattern of runoff and climate factors in the basin and quantitatively assessed the contribution of climate change and human activities to the change in runoff using the elasticity coefficient method. Our results indicate that annual runoff has experienced a significant downward trend over the past 60 years, which is projected to continue into the future. It is also found that the temporal pattern of the runoff regime differed upstream and downstream of the Danjiangkou Reservoir due to the joint operation of the reservoir and China’s Middle Route Project of South-to-North Water Diversion (MRP-SNWD). A significant decrease in runoff was primarily attributed to human activities, followed by precipitation. In contrast, evapotranspiration had the least effect. In particular, the MRP-SNWD was a significant anthropogenic factor, contributing to about 20.3% of the total change in runoff. Our results highlighted the unfavorable effects of human activity on the hydrological system in the Hanjiang River and provided some constructive suggestions to turn vulnerability into resilience.

Ichthyofauna on the move: fish colonization and spread through the São Francisco Interbasin Water Transfer Project

Abstract Projects on river basin integration are keen social-economical drivers in dry regions like the Brazilian semiarid, however, there are concerning ecological impacts implied in those projects. In a long-term analysis, ichthyofauna colonization and spread through the East Axis of the São Francisco River Integration Project (SFIP) was monitored to assess possible impacts on the receiving Paraíba River basin. The fish were collected semiannually (2012 to 2021) from 19 sites in the São Francisco (SF) and Paraíba (PB) basins. A total of 69 fish species were recorded, with distinct fish assemblages between SF (n = 50), PB (n = 35), and the SFIP artificial reservoirs (n = 25). The SFIP reservoirs were colonized by species from the donor basin (SF). In a pioneer finding, Anchoviella vaillanti was recorded for the first time in the receiving basin and it is in the process of establishment. The two SF species that reached PB through the SFIP canals (A. vaillanti and Moenkhausia costae) may be using their year-round reproduction and wide diet to successful spread and colonize the new environment. Since we detected species with potential to reach the receiving basin and became invasives, the implementation of barriers to contain their spread are recommended.

Ictiofauna dos reservatórios do Projeto de Integração do Rio São Francisco

Abstract Artificial impoundments are frequently built to mitigate the water scarcity in the drylands such as the Caatinga region in Brazil. The São Francisco Interbasin Water Transfer (SF-IWT) megaproject implemented many artificial reservoirs for that purpose. A checklist of fish species from the SF-IWT reservoirs is provided based on samples from eight years of monitoring. The collections were conducted semiannually at 28 reservoirs divided into three groups: the East Axis, North Axis, and Agreste Branch. The SF-IWT reservoirs presented a total of 47 species, 46 were recorded in the North Axis, 27 in the East Axis, and only seven in the Agreste Branch. Characids and cichlids represented most of the species. The three analyzed groups of reservoirs presented distinct communities and the reservoirs’ age, richness and abundance were relevant variables responsible for fish composition. The SF-IWT reservoirs present a diverse and heterogeneous ichthyofauna, typical of lentic environments. The main colonizers of the SF-IWT reservoirs were fish from the São Francisco donor basin, invasive species anthropically released in those sites, and eventual species from the surrounding receiving basins. As the accumulation curves suggested, a continuous effort could reveal additional species, patterns in long-term colonization, and contribute to data on the reservoirs’ future stabilization phase. Since invasive species were present in most reservoirs, along with donor-basin native species with potential to disperse to the receiving basins, a continuous and detailed monitoring is key for management planning and possible impacts assessment.

Application of e-TOPSIS for Ground Water Potentiality Zonation using Morphometric Parameters and Geospatial Technology of Vanvate Lui Basin, Mizoram, NE India

Abstract Morphometric analysis is the mathematical analysis of a watershed. Groundwater storage is directly related to the morphometry of a watershed. Remote sensing and GIS gives an opportunity for the scientific and empirical investigation towards groundwater potentiality. The utilization of RS/GIS for scientific investigation into ground water potentiality is quite innovative for the hilly state of Mizoram of India, which faces acute water shortage during the winter season. Vanvate Lui basin of Mizoram was thus chosen for the present study. It is an important source of water for a significant number of rural villages like Zote, Chhipphir, and Lungmovi. The present study analyzed the groundwater potentiality of Vanvate lui basin and undertook groundwater potentiality zonation of Vanvate lui basin using eTOPSIS model. eTOPSIS is an intregated knowledge-based multi-criteria decision-making model assimilating TOPSIS objective weighting method and Shannon Entropy. Areal, relief and linear morphometric aspects of Vanvate lui basin were extracted from ALOS PALSAR DEM for conducting MCDM. It was found that sub-basins 1, 6, 8 and 2 have high potentiality for groundwater storage. Similar, studies were also done on the Donor basin adjacent to the study area for model validation. After applying e-TOPSIS in the Donor basin, it was found that the result of the study matches the groundwater data of Donor basin as provided by the PHE department, Mizoram. The zones found to be under high potential of groundwater in the sub-basins 14, 9, 2, 11, 6 and 5 are the ones where the ground water depth is less than 70 meters as measured by the ground water department of Mizoram state. The present study will help the policymakers, village governance system, district development authorities and P.W.D of Mizoram to take proper steps towards developing the rural life quality, identifying suitable groundwater storage and ensuring proper steps towards watershed management. It is hoped that the research work will help in mitigating the water scarcity problem of the study area during the dry winter season.

Benthic macroinvertebrates assemblages of glacial-fed (Bheri) and rain-fed (Babai) rivers in western Nepal in the wake of proposedinter-basin water transfer.

BackgroundBenthic macroinvertebrates, encompassing large taxonomic groups of invertebrate organisms, are important components of aquatic ecosystems and play crucial roles in aquatic food webs. These organisms are also extensively used in water quality assessments as bioindicators for a range of stressors. Inter-basin water transfer (IBWT) is the transfer of water from a donor basin to a recipient basin and such transfers have both beneficial as well as adverse environmental and socio-economic impacts. This study attempts to generate baseline information on macroinvertebrates assemblages in glacial-fed (Bheri) and rain-fed (Babai) rivers of west Nepal, where Nepal’s first ever inter-basin transfer is in progress and the data can be used to assess the impact of inter-basin water transfer on water quality and aquatic biodiversity after completion.New informationThe dataset includes the records on the taxonomic diversity of macroinvertebrate in the Bheri and the Babai River systems. A total of 56 families of macroinvertebrates belonging to eight classes and four phyla were observed. A significant variation between the glacial-fed and rain-fed and seasons were observed reflecting different ecological zones and abiotic variables in the rivers and their catchments. Hydropsychidae and Baetidae were reported to be the most abundant taxa in the Bheri River system, whereas Gyrinidae, Physidae, Chironomidae and Hydropsychidae were most abundant taxa in the Babai River system.

A Tale of Two Dams: The Impact of Reservoir Management on Rural Depopulation in Central Spain

In rural areas, depopulation is mainly due to a lack of economic and employment opportunities. In this context, the reservoirs already built can be a source of socioeconomic development based on tourism and outdoor leisure activities. The condition for this development to materialize is that reservoir management considers these activities. In Central Spain, a process of rural depopulation has been generated in the municipalities around the reservoirs at the Upper Tagus River, as water management allows water transfers from the Tagus to the Segura River without taking into account regulations that prioritize and protect donor basin users. Through the comparison of reservoir water management and demographic data of two rural areas close to the reservoirs, this article reveals the direct relationship between reservoir management that enables recreational uses with its consequent socioeconomic development and the maintenance of the population in the territory. Consequently, reservoir water management based on the socioeconomic development of reservoir banks is necessary and a priority over transfers to another basin.

Importance of the informative content in the study area when regionalising rainfall-runoff model parameters: the role of nested catchments and gauging station density

Abstract. The setup of a rainfall-runoff model in a river section where no streamflow measurements are available for its calibration is one of the key research activities for the Prediction in Ungauged Basins (PUB): in order to do so it is possible to estimate the model parameters based on the hydrometric information available in the region. The informative content of the dataset (i.e. which and how many gauged river stations are available) plays an essential role in the assessment of the best regionalisation method. This study analyses how the performances of regionalisation approaches are influenced by the “information richness” of the available regional dataset, i.e. the availability of potential donors, and in particular by the gauging density and by the presence of nested donor catchments, which are expected to be hydrologically very similar to the target section. The research is carried out over a densely gauged dataset covering the Austrian country, applying two rainfall-runoff models and different regionalisation approaches. The regionalisation techniques are first implemented using all the gauged basins in the dataset as potential donors and then re-applied, decreasing the informative content of the dataset. The effect of excluding nested basins and the status of “nestedness” is identified based on the position of the closing section along the river or the percentage of shared drainage area. Moreover, the impact of reducing station density on regionalisation performance is analysed. The results show that the predictive accuracy of parameter regionalisation techniques strongly depends on the informative content of the dataset of available donor catchments. The “output-averaging” approaches, which exploit the information of more than one donor basin and preserve the correlation structure of the parameter, seem to be preferable for regionalisation purposes in both data-poor and data-rich regions. Moreover, with the use of an optimised set of catchment descriptors as a similarity measure, rather than the simple geographical distance, results are more robust to the deterioration of the informative content of the set of donors.

Alleviating Water Scarcity in the Central Rift Valley Lakes through an Inter-Basin Water Transfer, Ethiopia

Demand for fresh water, as one of the major natural resources, is increasing rapidly with increasing development and environmental degradation. The continued abstraction of water from Lake Ziway and its main feeder rivers Meki and Katar for irrigation indicates that the water demand may soon exceed the supply. To illustrate disparities in spatial distribution of water resources, the Upper Awash sub-basin, which shares a water-divide with the CRVL sub-basin, has large flow volumes particularly in the rainy season and suffers with seasonal flooding. The rationale behind regaining the water in CRVL relies on this non-uniform spatial distribution of fresh water, calling for a balance between water surplus and deficit regions. For this reason, Inter Basin Water Transfer (IBWT) is suggested as a viable option to augment utilizable water resources of the Upper Awash sub-basin to reduce the significant pressure on the water supply of the rapidly developing urban and irrigation areas in the CRVL sub-basin. A water evaluation and planning (WEAP) model was used to quantify the amount of surplus water in the donor basin, when examining the hydrological dynamics of the basins. Furthermore, optimal flow diversion scenarios were generated by maintaining two baseline scenario constraints. The estimated surplus water in the rainy season is expected to contribute 18 million cubic meters (mcm), 88 mcm and 192 mcm in months June, July and August respectively under average conditions. The optimal amount of diverted water could potentially stabilize the environmental degradation of Lake Ziway and Lake Abijata by compensating for development-driven abstraction and surface water evaporation respectively.

Streamflow regionalization using a similarity approach in ungauged basins: Application of the geo-environmental signatures in the Karkheh River Basin, Iran

Reliable estimation of streamflow especially in ungauged basins is most important for environmental management and planning. Regionalization of streamflow using either the physical attributes or spatial proximities of linked gauged and ungauged basins are considered to be standard techniques for estimating streamflow in ungauged basins. Unfortunately, regionalization of modeling parameters based solely on physical similarities or spatial proximity between gauged and ungauged basins is not always adequate. The hydrologic similarities between basins are related to the basin's response to precipitation, which it is referred to various conditions of basins, so considering the comprehensive characteristics from basins is very important to achieve a knowledge of the hydrology of the basin. Therefore, this study aimed to consider a comprehensive set of signatures with the fuzzy clustering approach. Similar basins were determined by considering key geo-environmental signatures, including topographical/morphological characteristics, soil properties, land use types, remote sensing (RS)-based indices, and climate indices. Redundancy in the selected geo-environmental signatures was assessed using factor analysis. Parameters of lumped and semi-distributed rainfall-runoff models were calibrated in the most similar donor basin (DB) to the ungauged basin (UB) and validated by matching them to the pseudo ungauged basin (PUB). Streamflow estimation results from the pseudo ungauged basins demonstrated that the applied procedure and semi-distributed rainfall-runoff model was an efficient method to estimate streamflow in the ungauged basins.

Climate change effects on the hydrology of the headwaters of the Tagus River: implications for the management of the Tagus–Segura transfer

Abstract. Currently, climate change is a major concern around the world, especially because of the uncertainty associated with its possible consequences for society. Among them, fluvial alterations can be highlighted in basins whose flows depend on groundwater discharges and snowmelt. This is the case of the headwaters of the Tagus River basin, whose water resources, besides being essential for water uses within this basin, are susceptible to being transferred to the Segura River basin (both basins are in the Iberian Peninsula). This work studies the possible effects that the latest climate change scenarios may have on this transfer, one of the most important ones in southern Europe. In the first place, the possible alterations of the water cycle of the donor basin were estimated. To do this, a hydrological model was calibrated. Then, with this model, three climatic scenarios were simulated, one without climate change and two projections under climate change (Representative Concentration Pathways 4.5 (RCP 4.5) and 8.5 (RCP 8.5)). The results of these three hydrological modelling scenarios were used to determine the possible flows that could be transferred from the Tagus River basin to the Segura River basin, by simulating the water resource exploitation system of the Tagus headwaters. The calibrated hydrological model predicts, for the simulated climate change scenarios, important reductions in the snowfalls and snow covers, the recharge of aquifers, and the available water resources. So, the headwaters of the Tagus River basin would lose part of its natural capacity for regulation. These changes in the water cycle for the climate change scenarios used would imply a reduction of around 70 %–79 % in the possible flows that could be transferred to the Segura basin, with respect to a scenario without climate change. The loss of water resources for the Segura River basin would mean, if no alternative measures were taken, an economic loss of EUR 380–425 million per year, due principally to decreased agricultural production.

Quantitative assessment of the impact of an inter-basin surface-water transfer project on the groundwater flow and groundwater-dependent eco-environment in an oasis in arid northwestern China

Inter-basin water transfer projects (IBWTPs) can involve basins as water donors and water receivers. In contrast to most studies on IBWTPs, which mainly impact the surface-water eco-environment, this study focuses on the impacts of an IBWTP on groundwater and its eco-environment in a water donor basin in an arid area, where surface water and groundwater are exchanged. Surface water is assumed to recharge groundwater and a groundwater numerical simulation model was constructed using MODFLOW. The model was used to quantitatively evaluate the impact of an IBWTP located in the upstream portion of Nalenggele River (the biggest river in the Qaidam basin, Northwest China). The impact involved decrease in spring flow, drawdown of groundwater, reduction in oasis area, and an increase in species replacement of oasis vegetation in the midstream and downstream of the river. Results show that the emergence sites of springs at the front of the oasis will move 2–5 km downstream, and the outflow of springs will decrease by 42 million m3/a. The maximum drawdown of groundwater level at the front of the oasis will be 3.6 m and the area across which groundwater drawdown exceeds 2.0 m will be about 59.02 km2, accounting for 2.71% of the total area of the oasis. Under such conditions, reeds will gradually be replaced by Tamarix, shrubs, and other alternative plant species. These findings have important implications for the optimization of water resource allocation and protection of the eco-environment in arid regions.

Modeling Groundwater Flow System of a Drainage Basin in the Basement Complex Environment of Southwestern Nigera

Abstract. This study attempted to model the groundwater flow system of a drainage basin within the Basement Complex environment of Southwestern Nigeria. Four groundwater models were derived from Vertical Electrical Sounding (VES) Data, remotely sensed data, geological information (hydrolineaments and lithology) and borehole data. Subsequently, two sub-surface (local and regional) flow systems were delineated in the study area. While the local flow system is controlled by surface topography, the regional flow system is controlled by the networks of intermediate and deep seated faults/fractures. The local flow system is characterized by convergence, divergence, inflow and outflow in places, while the regional flow system is dominated by NNE-SSW and W-E flow directions. Minor flow directions include NNW-SSE and E-W with possible linkages to the main flow-paths. The NNE-SSW regional flow system is a double open ended flow system with possible linkage to the Niger Trough. The W-E regional flow system is a single open ended system that originates within the study area (with possible linkage to the NNE-SSW regional flow system) and extends to Ikogosi in the adjoining drainage basin. Thus, the groundwater drainage basin of the study area is much larger and extensive than its surface drainage basin. The all year round flowing (perennial) rivers are linked to groundwater outcrops from faults/fractures and contact zones. Consequently, larger percentage of annual rainwater usually leaves the basin in form of runoff and base flow. Therefore, the basin is categorized as a donor basin but with suspected subsurface water input at its northeastern axis.

Joint risk of interbasin water transfer and impact of the window size of sampling low flows under environmental change

Constructing a joint distribution of low flows between the donor and recipient basins and analyzing their joint risk are commonly required for implementing interbasin water transfer. In this study, daily streamflow data of bi-basin low flows were sampled at window sizes from 3 to183days by using the annual minimum method. The stationarity of low flows was tested by a change point analysis and non-stationary low flows were reconstructed by using the moving mean method. Three bivariate Archimedean copulas and five common univariate distributions were applied to fit the joint and marginal distributions of bi-basin low flows. Then, by considering the window size of sampling low flows under environmental change, the change in the joint risk of interbasin water transfer was investigated. Results showed that the non-stationarity of low flows in the recipient basin at all window sizes was significant due to the regulation of water reservoirs. The general extreme value distribution was found to fit the marginal distributions of bi-basin low flows. Three Archimedean copulas satisfactorily fitted the joint distribution of bi-basin low flows and then the Frank copula was found to be the comparatively better. The moving mean method differentiated the location parameter of the GEV distribution, but did not differentiate the scale and shape parameters, and the copula parameters. Due to environmental change, in particular the regulation of water reservoirs in the recipient basin, the decrease of the joint synchronous risk of bi-basin water shortage was slight, but those of the synchronous assurance of water transfer from the donor were remarkable. With the enlargement of window size of sampling low flows, both the joint synchronous risk of bi-basin water shortage, and the joint synchronous assurance of water transfer from the donor basin when there was a water shortage in the recipient basin exhibited a decreasing trend, but their changes were with a slight fluctuation, in particular at shorter window sizes. The decreasing magnitude of individual water shortage risk in the recipient basin was significantly greater than that of joint bi-basin water shortage risk at all window sizes. Although the donor basin had much rich water, but its individual risk accounted for more than 25.3% within a window size of 30days provided that its instream flow was maintained. In practical design and management of interbasin water transfer, impacts of the window size of sampling low flows under environmental change on the joint distribution of bi-basin low flows and the individual risk of water shortage in the donor basin should be paid more attention.

Dynamic management of water transfer between two interconnected river basins

This paper analyzes the dynamic interaction between two regions with interconnected river basins. Precipitation is higher in one river-basin while water productivity is higher in the other. Water transfer increases productivity in the recipient basin, but may cause environmental damage in the donor basin. The recipient faces a trade-off between paying the price of the water transfer, or investing in alternative water supplies to achieve a higher usable water capacity. We analyze the design of this transfer using a dynamic modeling approach, which relies on non-cooperative game theory, and compare solutions with different information structures (Nash open-loop, Nash feedback, and Stackelberg) with the social optimum. We first assume that the equilibrium between supply and demand determines the optimal transfer price and amount. We show that, contrary to the static case, in a realistic dynamic setting in which the recipient uses a feedback information structure the social optimum will not emerge as the equilibrium solution. We then study different leadership situations in the water market and observe that the transfer amount decreases toward a long-run value lower than the transfer under perfect competition, which in turn lays below the social optimum. In consequence, the water in the donor's river-basin river converges to a better quality in the presence of market power. Finally, we numerically compare our results to the Tagus-Segura water transfer described in Ballestero (2004). Welfare gains are compared for the different scenarios. We show that in all dynamic settings, the long-run transfer amount is lower than in Ballestero's static model. Further, we show that the long-run price settles at a lower level than in Ballestero's model, but is still higher than the average cost-based price determined by the Spanish government.

A stochastic model for optimal operation of inter-basin water allocation systems: a case study

This paper presents a new methodology for optimal operation of inter-basin water transfer systems by conjunctive use of surface water resources in water donor basin and groundwater resources in water receiving basin. To incorporate the streamflow uncertainty, an integrated stochastic dynamic programming (ISDP) model is developed. In the ISDP, the monthly inflow to the reservoir in the water donor basin, the water storage of the reservoir, and the water storage of the aquifer in the water receiving basin are considered as state variables. A water allocation optimization model is embedded in the main structure of ISDP and a new ensemble streamflow prediction model based on K-nearest-neighbourhood algorithm is also developed and linked to the ISDP. By using a new reoptimization process, the ISDP model provides monthly policies for water allocation to users in water donor and receiving basins. As water users can form a coalition to increase their benefits, several solution concepts in cooperative game theory, namely Nash–Harsanyi, Shapley, Nucleolus, Weak Nucleolus, Proportional Nucleolus, Separable Costs Remaining Benefits (SCRBs) and Minimum Costs Remaining Savings are utilized to determine the profit of each water user. In the last step, stakeholders make negotiation over these solution concepts using the Fallback bargaining theory to reach a unanimous agreement on the final distribution of the total benefit. The methodology is applied to an inter-basin water transfer project and the results show that the Shapley and SCRB solutions concepts can provide better distributions for the total benefit and the total benefit of water users is increased by a factor of 1.6 when they participate in a grand coalition.

Streamflow prediction in ungauged basins through geomorphology-based hydrograph transposition

Geomorphology-based rainfall–runoff models are particularly helpful for predicting hydrology in ungauged basins. The robustness, generality and flexibility of the modelling approach make it able to deal with a wide variety of processes, events and scales. It allows a rainfall–runoff transfer function to be estimated for any basin without needing to measure discharge. The aim of this study is to transpose hydrological observations from gauged to ungauged basins to predict streamflow hydrographs. It considers pairs of nested and neighbouring basins, the first one providing information for the second ungauged one. A time-series of the donor basin's discharge is deconvoluted by inverting its geomorphology-based transfer function to assess the time-series of net rainfall. The latter is then transposed to the receiver basin, where it is convoluted with the reciever basin's transfer function to predict the hydrograph therein. The methodology was implemented with virtual and real rainfall–runoff events on a set of basins in temperate Brittany, France. Different time scales and spatial configurations were tested. Goodness-of-fit of model predictions varied by basin pair. High prediction accuracy was observed when transposing hydrographs between nested basins differing greatly in size. Several ways to improve the approach are identified by relaxing simplifying assumptions.

Modelling catchment inflows into Lake Victoria: regionalisation of the parameters of a conceptual water balance model

The goal of this study was to evaluate regionalisation methods that could be used for modelling catchment inflows into Lake Victoria. WASMOD, a conceptual water balance model, was applied to nine gauged sub-basins in Lake Victoria basin in order to test the transferability of model parameters between the basins using three regionalisation approaches. Model calibration was carried out within the GLUE (generalised likelihood uncertainty estimation) framework for uncertainty assessment. The analysis was carried out for the period 1967–2000. Parameter transferability was assessed by comparing the likelihood values of regionalised simulations with the values under calibration for each basin. WASMOD performed well for all study sub-basins with Nash–Sutcliffe values ranging between 0.70 and 0.82. Transferability results were mixed. For the proxy-basin method, the best performing parameter donor basin was Mara with four proxy basins giving acceptable results. Sio, Sondu, Gucha and Duma also performed well. The global mean method gave acceptable performance for seven of the nine study basins. The ensemble regionalisation method provides the possibility to consider parameter uncertainty in the regionalisation. Ensemble regionalisation method performed best with an average departure of 40% from the observed mean annual flows compared to 48 and 60% for proxy-basin and global mean methods, respectively.

An Interval Parameter Model for Cooperative Inter-Basin Water Resources Allocation Considering the Water Quality Issues

In this paper, a new methodology based on interval optimization and game theory is developed for optimal operation of an inter-basin water transfer system considering efficiency, equity and sustainability criteria. A linear version of the agricultural water production function is proposed and used for incorporating deficit irrigation. The interval programming and cooperative game theory are utilized for equitable reallocation of benefits to water users in both water donor and receiving basins. To assess the sustainability of water allocation policies, water quality and environmental flow in the donor basin and groundwater table drawdown in the receiving basin are taken into consideration. The effectiveness of this methodology is examined by applying it to a large scale case study of water transfer from the Karoon river basin in south-west to the Rafsanjan plain in the central part of Iran.

Geological and environmental issues of the proposed link canal (Inchampalli to Nagarjunasagar) of Godavari to Krishna Rivers adopting remote sensing and geographical information system (GIS)

Extremely erratic rainfall, unevenly distributed and very heavy precipitation in short time resulting in flash floods and inundation in India became a usual phenomena in recent years. At every event, a huge quantity of water is being wasted into the sea as run-off quite frequently due to inadequate harvesting structures. This huge run-off / surplus water can be harvested through the proposed linking of river basins envisaged by National Water Development Agency (NWDA). Out of the total mega projects, the NWDA suggested three link canals from Godvari to Krishna basin, to harvest the surplus water as well as to transfer flood water from Godavari. The Godavari (Inchampalli) - Krishna (Nagarjunasagar) link canal and its possible impact on the socio-economic and infrastructural forms the present study. The link canal of length 299 km (including a tunnel of 9.150 km) is proposed in the upper reaches connecting Godavari and Krishna basins succeeded by two other links towards their downstream. It takes off from the foreshore of the Inchampalli reservoir and joins the existing Nagarjunasagar via Musi reservoir. IRS-1D, LISS-III data is analysed for morphological, geological and land use/land cover information. Geology, geomorphology and soil base maps were obtained and updated with remote sensing data and their aerial distribution in the study area was discussed. The study includes 10 km buffer area on either side of the alignment and the proposed canal command area (5157.48 Sq km) spread in Warangal and Nalgonda districts. The canal command area is occupied by dry land and wasteland classes. Pediplain weathered is the main landform that occupied major part of the study area. The study area in Warangal district is mostly occupied by unclassified crystalline rocks of Archean age. Fine to medium grained, granite gneisses and migmatities of older metamorphics from chainage 102 km to the end point of the canal. Deep loamy soil, deep clayey soil, deep clayey calcareous soil and gravelly clay soils are dominant in the canal study area. Clayey and loamy soils are suitable for wet / dry crops and gravely calcareous for plantations and dry crops. The study revealed that 23 villages are to be rehabilitated while executing the canal and about 816 villages would benefit from it by way of drinking water / groundwater in addition to crop requirements. Key words: Link canal, donor basin, command area, geomorphology.

A game theoretic approach for interbasin water resources allocation considering the water quality issues

In this paper, a new game theoretic methodology is developed for interbasin water transfer management with regard to economic, equity, and environmental criteria. The main objective is to supply the competing users in a fair way, while the efficiency and environmental sustainability criteria are satisfied and the utilities of water users are incorporated. Firstly, an optimization model is developed to proportionally allocate water to the competing users in water donor and receiving basins based on their water demands. Secondly, for different coalitions of water users, the water shares of the coalitions are determined using an optimization model with economic objectives regarding the physical and environmental constraints of the system. In order to satisfy water-quality requirements, the impacts of decreasing the instream flow in donor basin are estimated using a water-quality simulation model, and the required treatment levels for effluents discharged into the river, downstream of the water transfer point are determined. Finally, to achieve equity and to provide sufficient incentives for water users to participate in the cooperation, some cooperative game theoretic approaches are utilized for reallocation of net benefits to water users. This model is applied to a large-scale interbasin water allocation problem including two different basins struggling with water scarcity in Iran. The results show that this model can be utilized as an effective tool for optimal interbasin water allocation management involving stakeholders with conflicting objectives subject to physical and environmental constraints.