Climate Change and Hydrologic Impact Assessment

The Bureau of Reclamation (Reclamation), the US Army Corps of Engineers (USACE) and other water management agencies have an interest in developing reliable, science-based methods for incorporating climate change information into longer-term water resources planning. Such planning assessments must quantify projections of future climate and hydrology. The common practice is to begin by developing relationships between current observed climate and climate projections over the assessment region. Because the spatial resolution and biases of climate projections developed by global climate models is not adequate for local to regional hydrologic assessments, this step relies on some form of spatial downscaling and bias correction, which produces watershed scale weather information to drive simulations of hydrology and other water resource management conditions (e.g., water demands, water quality, environmental habitat).

Water agencies continue to face decisions about the selection of downscaling method(s), the selection and configuration of hydrological models, and of observational datasets. Therefore, there is a critical need to understand the ramification of these methodological decisions, as they affect the signal and uncertainties produced by climate change assessments, and thus the effectiveness of these results to support adaptation planning and decision-making.

The overarching goal of the project is to identify strengths and weaknesses of current techniques used for downscaling climate projections and assessing hydrologic conditions toward better guidance on adaptation planning. Results from this evaluation steer research and development investments to develop improved methodologies.

This project is sponsored jointly by the US Army Corps of Engineers and the US Bureau of Reclamation.