Evaluating strategies of conjunctive use of surface water and groundwater in a canal command area: a case study in the Srisailam Right Branch Canal, Andhra Pradesh, India

Conjunctive use of surface water and groundwater for irrigation is increasingly recognised as a means of coping with unreliable surface water supply under variable climate in water-scarce environments, both in India and globally. Achieving a harmonious balance between the use of surface water and groundwater requires careful consideration of physical, environmental and economic benefits, impacts and trade-offs. In an irrigation command area, where interactions between surface water and groundwater are high, conjunctive use management can play a significant role in increasing water availability, improving equitable distribution of water while also maintaining long-term sustainability of groundwater resources. The Srisailam Right Branch Canal (SRBC) command area in a drought- prone part of Andhra Pradesh in South India with a command area of 76,900 ha providing livelihood to over 35,000 farmer households, was used as a case study, to quantify and evaluate the impacts of conjunctive use strategies. Following the commissioning of the SRBC project and release of canal water in 2004, this study has revealed that the improved water availability has been quickly followed by a looming threat of water-logging conditions in many villages, with some of them likely to face adverse impacts within the next five years. Further, inequities of water availability exist between the head and tail-end of the canal and its distributaries. A simple integrated simulation model fully incorporating surface water-groundwater interactions was developed here and applied to characterise current and predevelopment conditions and to model alternative scenarios of conjunctive use. Results of modelling indicate that there is surplus water available within the system in the form of excess canal water that is lost as drainage as well as under- utilised groundwater potential.' By more carefully regulating canal supplies to levels that prompt sustainable groundwater extraction, and by improving distribution efficiency, it is possible to realise up to 4.0 TMC or 113 GL of water savings in a year. This surplus water would be enough to support a gross irrigated area of roughly 24,000 ha, which could boost the livelihoods of an estimated 12,000 households. It could be allocated to downstream blocks or to alternative higher value uses. Any such change to prevailing conditions involves trade-offs that can affect the delicate balance between salt and water, between groundwater sustainability and equity of water distribution. There is a need for quantification and evaluation of impacts and trade-offs before such changes are implemented. A conceptual and modelling framework is presented, that effectively captures the current state of the system, is capable of forecasting impacts of alternative CU scenarios, and gives output results that can be easily interpreted and thus enable informed decision making by operators and managers of the system

Adaptive irrigation infrastructure — linking insights from human-water interactions and adaptive pathways

Irrigation systems face unforeseeable changes in climate, technologies, and societal preferences during their lifetime, potentially rendering them obsolete or inadequate. To remain functional, irrigation systems need to be adaptive to changes as the future unfolds. Past approaches to irrigation system design were largely informed by engineering or economic criteria. This is increasingly recognised as insufficient. We provide examples of contemporary irrigation systems in Australia to highlight the need for planning and design approaches that recognise the complex interactions between human and water systems and embrace unknowns. We review literature on hydro-social interactions and dynamic adaptive pathways to provide insights for the development of adaptive irrigation systems.</p

Integrating cost and benefit considerations with supply- and demand-based strategies for basin-scale groundwater management in South-West India

Efforts to reverse groundwater depletion in hard-rock regions by enhancing aquifer recharge with valuable surface water present complex challenges and trade-offs related to upstream-downstream interactions and equity. Here, groundwater modelling is used in combination with economic valuation techniques to assess the effectiveness of alternative supply and demand measures under different climate change scenarios in an upper sub-basin of the Krishna River basin in India. It is found that aquifer recharge provides benefits for the sub-basin that are not apparent at the basin scale.Water recharged or crops selected in upper catchments should aim to generate economic benefits that outweigh losses faced downstream

Ways forward for resilience thinking: lessons from the field for those exploring social-ecological systems in agriculture and natural resource management

Resilience thinking appears to offer a holistic approach that can be used by social researchers to interpret past and contemporary conditions and identify possible futures for social-ecological systems (SES). Resilience thinking is shaping contemporary environmental policy and its implementation in Australia, Europe, and North America. At the same time, social researchers have raised concerns about the limitations of resilience thinking, particularly in its handling of human agency, power relationships, social thresholds, and the social construction of SES definitions. We argue for a reflexive turn in resilience thinking as a way to address these concerns. We draw on lessons from three Australian case studies where a reflexive application of resilience thinking generated insights for research and practice. We propose six areas for reflexive inquiry: (1) focal scale and level, (2) SES definition, (3) narratives of change, (4) processes of knowledge production, (5) social transition trajectories, and ( 6) social thresholds. In so doing, the assumptions of resilience thinking are politicized and problematized, which improves its theoretical analytical utility, and in practice generates new insights into social processes. Reflexivity offers opportunity for greater cross-disciplinary dialogue between resilience thinking and the social sciences, while allowing methodologies with differing ontologies and epistemologies to be applied in a complementary manner

Integrated modeling framework to evaluate conjunctive use options in a canal irrigated area

In canal irrigated areas, where interactions between surface water and groundwater are high, the conjunctive management of surface water and groundwater can play a significant role in improving water availability in time and space, thereby promoting more equitable distribution of water while maintaining long-term availability of groundwater resources. Achieving a harmonious balance between the use of surface water and groundwater requires careful consideration of the associated benefits, impacts, and trade-offs. In this study, a simple, integrated framework was developed and implemented to characterize and quantify interactions between surface water and groundwater in a canal irrigated area; this framework was used to evaluate the impacts of alternative levels of conjunctive use under varying climate and cropping conditions. Applying the model to a case study area of the Srisailam Right Branch Canal project in Andhra Pradesh, India, indicated that regulating canal supplies to optimum levels can prompt sustainable groundwater use and save up to 48% of allocated canal water; these water savings could be reallocated elsewhere within the irrigated area to promote equity

The social learning potential of participatory water valuation workshops : A case study in Tasmania, Australia

Participatory water valuation workshops are useful for their valuation outcomes, but can they also foster social learning? Social learning involves changes in understanding through social interactions between actors, which go beyond the individual to become situated within wider social units. Participatory water valuation workshops involve dialoguing about knowledge, perspectives, and preferences, which may be conducive to social learning. In this paper, we assess the social learning potential of a participatory valuation workshop, based on a case study in Tasmania, where farmers, water managers, and a policy maker shared their personal perspectives on the past, current and future values of irrigation water. To assess the social learning potential of a single participatory valuation workshop, we analyzed drivers—that is, factors positively influencing social learning—and outcomes—that is, indications that social learning occurred. Data were collected through an exit survey, in-workshop reflections and semistructured interviews following 3 weeks and 6 months after the actual workshop. The results indicate that the workshop provided the drivers for social learning to occur. In addition, participants indicated to have learned from and with others, and that the workshop provided improved and extended networks. According to the participants, the workshop led to a shared concern about increasing prices for water licences and induced substantive outcomes related to the use, management, and governance of irrigation water. We conclude that participatory valuation workshops, such as the one analyzed here, can foster social learning.</p