Water Resource Planning Under Future Climate and Socioeconomic Uncertainty in the Cauvery River Basin in Karnataka, India

Abstract

Decision‐Making Under Uncertainty (DMUU) approaches have been less utilized in developing countries than developed countries for water resources contexts. High climate vulnerability and rapid socioeconomic change often characterize developing country contexts, making DMUU approaches relevant. We develop an iterative multi‐method DMUU approach, including scenario generation, coproduction with stakeholders and water resources modeling. We apply this approach to explore the robustness of adaptation options and pathways against future climate and socioeconomic uncertainties in the Cauvery River Basin in Karnataka, India. A water resources model is calibrated and validated satisfactorily using observed streamflow. Plausible future changes in Indian Summer Monsoon (ISM) precipitation and water demand are used to drive simulations of water resources from 2021 to 2055. Two stakeholder‐identified decision‐critical metrics are examined: a basin‐wide metric comprising legal instream flow requirements for the downstream state of Tamil Nadu, and a local metric comprising water supply reliability to Bangalore city. In model simulations, the ability to satisfy these performance metrics without adaptation is reduced under almost all scenarios. Implementing adaptation options can partially offset the negative impacts of change. Sequencing of options according to stakeholder priorities into Adaptation Pathways affects metric satisfaction. Early focus on agricultural demand management improves the robustness of pathways but trade‐offs emerge between intrabasin and basin‐wide water availability. We demonstrate that the fine balance between water availability and demand is vulnerable to future changes and uncertainty. Despite current and long‐term planning challenges, stakeholders in developing countries may engage meaningfully in coproduction approaches for adaptation decision‐making under deep uncertainty.

The Impact of Climate Change on Crop Production in Uganda—An Integrated Systems Assessment with Water and Energy Implications

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Usable Science for Managing the Risks of Sea‐Level Rise

“…Over the past few decades, different approaches have emerged to assist policymakers in the formulation of adaptive decision mechanisms in changing coastal environments (Bhave et al, ). These efforts have concentrated on understanding the nature of uncertain hazards, exposure, and vulnerability—which together constitute risk in the sense used by the Intergovernmental Panel on Climate Change (Lavell et al, )—as well as the translation of research into practice (Bhave et al, ; Dessai et al, ; Hallegatte, ). Decision frameworks fall into two major categories: traditional “prediction‐first” economic perspectives, such as benefit‐cost analysis, cost‐effective analysis, and multi‐criteria analysis; and more policy‐driven approaches, such as robust decision making and Dynamic Adaptive Policy Pathways (Dittrich et al, ; Gorddard et al, ; Haasnoot et al, , ; Lempert et al, ; Lempert, ; Wise et al, ).…”

Building narratives to characterise uncertainty in regional climate change through expert elicitation

“…Our research cross-checked the relationship between expert-elicited key drivers (moisture availability and strength of flow) and catchment precipitation using observations and re-analysis data. This climate analysis made two important contributions: (1) the good agreement between the expert elicited judgments underlying the narratives and the empirical relationships in the observational and reanalysis data gives confidence in the method developed and supports its wider application; (2) the empirical relationships between moisture flux and observed precipitation enable the translation of qualitative narratives into illustrative quantitative time series of precipitation change which can serve as input to climate impact models (see supplementary information 4 and Bhave et al 2018).…”

“…Climate process-based expert elicitation and narratives have an important role to play in informing regional and local risk assessments and adaptation decisions when future climate uncertainty is large. Bhave et al (2018) have, for example, used qualitative narratives and associated quantitative time series of precipitation change to examine long-term water resources planning in the CRBK. Expert judgment techniques need to be more widely applied to characterise uncertainty in regional and local climate change.…”