Water Sustainability under Near-term Climate Change: A Cross-Regional Analysis Incorporating Socio-Ecological Feedbacks and Adaptations
Cross-regional differences in water availability and infrastructure, water regulations, and biodiversity across the Sunbelt of the US provide a compelling platform for understanding freshwater sustainability under population growth and near-term (10-30 years) climate change. Recent studies suggest that uncertainties in climate change projections are the lowest at decadal time scales, which is a critical planning horizon for watershed management. The main objective of the proposed research is to understand, identify, and quantify uncertainties related to freshwater sustainability under near-term climate and population change by incorporating adaptive responses and feedbacks of hydro-ecological and human-environmental systems through a cross-regional synthesis. Using retro-analyses involving AR5 climate change hindcasts, we will revisit how freshwater sustainability could have been better achieved over the past five decades in cities in several fast-growing basins in the Sunbelt. Findings from the retro-analyses will evaluate and recommend societal options (i.e., supply augmentation vs. demand reduction) for promoting future (2015-2034) freshwater sustainability over the region.
Intellectual Merit: The proposed research develops an interdisciplinary framework incorporating societal feedbacks and adaptations for freshwater sustainability under near-term change and growth. Retro-analyses focusing on target basins with different levels of water stress will provide a basis for water resource planning under uncertain climate and future growth. Downscaled (both hindcasts and future) hydroclimatic projections using asynchronous regression and multimodel combinations will provide reduced uncertainty in targeted streamflow attributes. Incorporating the downscaled streamflow projections will quantify the expected changes in reliability, resilience, and vulnerability (e.g., severity of drought/flood risk) of water supply systems (reservoirs/groundwater) over the 10-30 year period under increased demand. Downscaled streamflow projections linked mechanistically to fish community data by virtue of a novel application of time series methods in which spectral anomalies in streamflow are used as covariates in multivariate autoregressive models (MAR), which in turn provide estimates of reliability (persistence across the spectrum of flow extremes), resilience (adaptability to flow variation), vulnerability (µ extinction) and covariation between persistence and the magnitude of low- and high-flow anomalies of native species in fish communities. Cross-regional synthesis of policies and media sources for the targeted basins will identify de/centralized adaptive strategies that have been employed independently and collectively to maintain flows, increase supplies, or reduce demands. To couple the hydroclimatic and hydro-ecological system dynamics with water users and policy-makers, a two-level agent-based modeling framework will explicitly simulate adaptive behaviors and feedbacks of policy and consumers. Historical timelines of hydro-ecology, climate and water decisions, along with linked sociopolitical interactions (e.g., disputes) from the retro-analysis will provide both qualitative and quantitative information and tools to advance social and ecological sustainability of water systems across the region.
Broader Impacts: The proposed research will promote incorporating near-term climate change information in water infrastructure planning by setting up an ASCE Task committee as part of the EWRI Conference. The proposal will contribute to the training of four postdocs (two of them PIs), graduate and undergraduate graduate students. In addition, we propose an online ‘distributed’ seminar in which Honor’s, MS and PhD students from three Universities with collectively interdisciplinary backgrounds will produce a policy-oriented white-paper based on the key findings. Based on the white-paper, PIs will distribute a suite of podcasts on water sustainability and climate change to middle and high-school students in the science program over three States. Podcasts, developed data, tools and publications will be disseminated through main project portal at NCSU, National Climate Change Assessment and ASU’s Central Arizona–Phoenix LTER websites. The white paper on water sustainability and climate will also be disseminated through key water and policy institutions across the region and in targeted conferences. PIs will also demonstrate the findings on adaptations to climate change from the retro and future analyses to water and ecosystem managers, policy experts and user community. Other broader impacts include interdisciplinary, cross-cutting publications on water sustainability and climate change to top journals in geosciences, water management, ecological and social sciences.