Indicators of Climate Change Impacts on the Water Cycle and Water Management

Managing water is a top social and economic responsibility and is expected to become even
more critical as climate change, in addition to other human activities, alters water availability and
quality. Robust indicators reflecting the effects of climate change on the U.S. and global water
cycles are needed in order to appropriately manage water resources. Here, we describe a suite of
seventeen water cycle and management indicators, which are based on synthesis of available
datasets. These indicators include: average and heavy precipitation, standardized precipitation
index, annual, 7-day low and 3-day high streamflow volume, streamflow timing, snow cover,
snow water equivalent, groundwater level, lake water temperature, stream water temperature,
dissolved oxygen, salinity, Palmer Drought Severity Index, water withdrawals and water use. We
also identify three indicators that could be included in the suite of water cycle and management
indicators with some additional, directed work: snowfall, evapotranspiration and soil moisture.
Our conceptual framework focuses on known water cycle changes in addition to potential effects
on management, and addresses water quantity and quality, as well as water use and related
interactions with freshwater ecosystems, societal impacts, and management. Water cycle
indicators are organized into three categories: (1) hydrologic processes, (2) water quality
processes, and (3) water quality and quantity impacts. Indicators described here are
recommended to serve as critical references for periodic climate assessments. As such, these
indicators support analyses of the effects of global change on the natural environment,
agriculture, energy, and water resources, among other sectors. Additionally, we identify research
gaps and needs that can be addressed to advance the development of future indicators.