WWA Activities Relating to Hydrology

Reconciling Projections of Future Colorado River Streamflow: The goal of this project is to reconcile future Colorado River streamflow projections by evaluating the various methodologies and models being used in projections and to understand why different modeling approaches produce varying flow reduction amounts. The second component of this project entails identifying a common subset of appropriate climate scenarios and models in development of future projections of streamflow; and using these scenarios and models to generate a consistent suite of Colorado River streamflow projections by the mid to late 21st century. Results will directly apply to the needs of water planners across the western U.S., and similar mid-latitude continental regions where water resources are heavily dependent on snowmelt runoff from mountainous headwater areas. Nick Graham (HRC), Dan Cayan (CAP), Dennis Lettenmaier, Andy Wood (CIG), Robert Webb, Brad Udall, (WWA) Martin Hoerling (NOAA-WWA), Jonathan Overpeck, Holly Hartman (CLIMAS).

WWA and NOAA comment on EIS for Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lakes Powell and Mead. For more information on the EIS see: http://www.usbr.gov/lc/region/programs/strategies.html

Appendix U: Climate Technical Work Group Report, Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lakes Powell and Mead

South Platte Regional Assessment Tool (SPRAT)
Draining the northeast quadrant of Colorado, the South Platte River Basin covers approximately 20 percent of the state and houses roughly 70 percent of its population, including the Denver-Metro area and Front Range cities to the north. SPRAT models the movement and allocation of water throughout the Basin, allowing users to make relative comparisons of the water supply and demand impacts associated with various population growth, climate/hydrologic, and agricultural land-use scenarios, and by allowing the merits of various water management alternatives (adaptations) and infrastructure changes to be similarly compared. Chris Goemans, Colorado State University.

Reservoir Management Decision Calendar.
Graphically depicts the annual decisions of reservoir operators based on whether they relate to planning, operations or may be affected by climate and weather forecasts .Andrea Ray, ESRL, NOAA, Robert Webb, NOAA.

TreeFlow: Tree-ring reconstructions of streamflow for Colorado.
Provides information about how tree rings are used to extend hydrologic records, and provides access to 20 reconstructions of streamflow gagaes across Colorado. For more information, also see the WWA Tree-ring reconstructions of streamflow pages. Connie Woodhouse, University of AZ, Jeff Lukas, INSTAAR, Robert Web, NOAA