Developing and applying uncertain global climate change projections for regional water management planning (original) (raw)

A Statistical Tool to Generate Potential Future Climate Scenarios for Hydrology Applications

Scientific Programming

Global warming associated with greenhouse emissions will modify the availability of water resources in the future. Methodologies and tools to assess the impacts of climate change are useful for policy making. In this work, a new tool to generate potential future climate scenarios in a water resources system from historical and regional climate models’ information has been developed. The GROUNDS tool allows generation of the future series of precipitation, temperature (minimum, mean, and maximum), and potential evapotranspiration. It is a valuable tool for assessing the impacts of climate change in hydrological applications since these variables play a significant role in the water cycle, and it can be applicable to any case study. The tool uses different approaches and statistical correction techniques to generate individual local projections and ensembles of them. The non-equifeasible ensembles are created by combining the individual projections whose control or corrected control s...

Robust analysis of future climate change impacts on water for agriculture and other sectors: a case study in the Sacramento Valley

Climatic Change, 2008

As part of the 2006 Climate Change Report to Governor Schwarzenegger and the California Legislature, an application of the Water Evaluation and Planning (WEAP) system in the Sacramento River Basin was deployed to look at the impact of climate change on agricultural water management and the potential for adaptation. The WEAP system includes a dynamically integrated rainfall runoff hydrology module that generates the components of the hydrologic cycle from input climate time series. This allows for direct simulation of water management responses to climate change without resorting to perturbations of historically observed hydrologic conditions. In the Sacramento River Basin, the four climate time series adopted for the 2006 Climate Change Report were used to simulate agricultural water management without any adaptation and with adaptation in terms of improvements in irrigation efficiency and shifts in cropping patterns during dry periods. These adaptations resulted in lower overall water demands in the agricultural sector, to levels observed during the recent past, and associated reductions in groundwater pumping and increases in surface water allocations to other water use sectors.

Use of climate scenarios to aid in decision analysis for interannual water supply planning

2007

This work addresses the issue of climate change in the context of water resource planning on the time scale of a few years. Planning on this time scale generally ignores the role of climate change. However, where the climate of a region has already shifted, the use of historical data for planning purposes may be misleading. In order to test this, a case study is conducted for a region, the Australian Capital Territory, where long term drought is raising concerns of a possible climate shift. The issue is cast in terms of a particular planning decision; the option to augment water supply in the next few years to hedge against the drought persisting. A set of climate scenarios are constructed for the region corresponding to the historical climate regime and to regimes where progressively greater levels of change are assumed to have already taken place (5%, 10%, 20% reductions in mean rainfall). Probabilities of the drought persisting are calculated for each of the scenarios. The results show substantial increases in the probability of the drought persisting for even moderate reductions in mean rainfall. The sensitivity of the decision to augment supply to the scenario results depends ultimately on the planners tolerable thresholds for the probability of the drought persisting. The use of different scenarios enables planners to explore the sensitivity of the decision in terms of their risk tolerance to ongoing drought and to their degree of belief in each of the scenarios tested.

Predicting plausible impacts of sets of climate and land use change scenarios on water resources

Applied Geography, 2012

Our world is changing at an unprecedented rate in terms of climate and land use, but these changes can affect our water resources. Hence, we need a methodology that can predict both their individual and agglomerative ramifications. Using the Little Miami River (LMR) watershed as a case study, this paper describes a spatial analytical approach integrating mathematical modeling and geographical information sciences to quantitatively examine the relative importance of the separate and combined hydrologic and water quality impacts of climate and land use changes.

Application of Climate Information and Predictions in Water Sector: Capabilities

Climate variability and climate change have a large impact on water resources since fundamental drivers of the hydrological cycle get affected. It is beneficial to understand the processes driving these changes, the sequences of the changes and their manifestation at different spatial and temporal scales. The purpose of this paper is to explore strategies to improve water management by tracking, anticipating and responding to seasonal to interannual climate variability and climate change. Sound water management is built upon long-term hydrological and meteorological monitoring networks that provide robust, accurate, timely and consistent data that can be used to develop and access tools needed to quantify uncertainty, forecast change and create the multi-phase, multi-level climate scenarios providing reasonable and relevant management of water resources. Several water management options might be considered in consultation with hydro-climatic and social scientists and stakeholders (decision-makers) to facilitate adaptation under climate variability and/or climate change and these are illustrated with suitable examples.

Selecting Stochastic Climate Realizations to Efficiently Explore a Wide Range of Climate Risk to Water Resource Systems

There are significant computational requirements for assessing climate change impacts on water resource system reliability and vulnerability, particularly when analyzing a wide range of plausible scenarios. These requirements often deter analysts from exhaustively identifying climate hazards. This technical note investigates two approaches for generating a subset of stochastic climate realizations that efficiently explore a range of risk to water supply systems. In both methods, a large ensemble of stochastic weather time series is generated to simulate the natural variability of the local climate system, and a selected subset of these sequences is used in the impacts assessment. Method 1 selects the subset by first passing the entire ensemble through a rainfall-runoff model and then screening the hydrologic sequences using the sequent peak algorithm. Method 2 selects a subset of climate sequences based on climate statistics alone, prior to hydrological modeling. Both methods provide insight for identifying the climate statistics that best relate to the vulnerability of the water system and can be used to reduce the computational burden of modeling climate variability and change impacts.

The effects of climate model similarity on probabilistic climate projections and the implications for local, risk-based adaptation planning

Approaches for probability density function (pdf) development of future climate often assume that different climate models provide independent information, despite model similarities that stem from a common genealogy (models with shared code or developed at the same institution). Here we use an ensemble of projections from the Coupled Model Intercomparison Project Phase 5 to develop probabilistic climate information, with and without an accounting of intermodel correlations, for seven regions across the United States. We then use the pdfs to estimate midcentury climate-related risks to a water utility in one of the regions. We show that the variance of climate changes is underestimated across all regions if model correlations are ignored, and in some cases, the mean change shifts as well. When coupled with impact models of the hydrology and infrastructure of a water utility, the underestimated likelihood of large climate changes significantly alters the quantification of risk for water shortages by midcentury. STEINSCHNEIDER ET AL. INTERMODEL CORRELATION AND RISK 5014 Citation: Steinschneider, S., R. McCrary, L. O. Mearns, and C. Brown , The effects of climate model similarity on probabilistic climate projections and the implications for local, risk-based adaptation planning, Geophys.