WMOD00274 ‎(2)‎

• Title: Hydro-Climate Index Study - Final Report
• Prepared By: HDR Engineering
• Date: 2/14/2008
• County: Statewide
• State: CO
• Weather Modification - Doc Type: Report

Colorado River Water Conservation District
Hydro-Climate Studies and Predictions
Statement of Work
The scope of HDR’s proposed services focuses on the examining the precipitation and
streamflow trends for a number of watersheds in Colorado and relating these variables
to HydroClimate Indicies (HCI). This proposed scope will address the relationships of
these variables within four basins that have been identified that are identified as having
current or near-term pressures in the arena of water supply. These basins are identified
as:

1.Arkansas River (above Pueblo Reservoir – Tasks A & B)

2.Dolores-San Juan River Basins (Tasks A & B)

3.Rio Grande River Basin (Tasks A & B)

4.Upper Colorado, Gunnison, and Yampa-White River basins (Task B).
All analyses and results described in the Statement of Work will be related to these four
basins and sub-basins (if applicable).

Tasks – Hydro-Climate Definitions and
Relationships

HDR proposes two primary inter-related Hydro-Climate tasks to enhance the
understanding of and the risk assessment of future water supply in these specific basins.
The two tasks have two specific sub-tasks each and are outlined below:
?
Description of the relationships of hydro-climate indices on the basin-specific
precipitation and runoff values and the timing of the runoff values on a seasonal
time scale.
?
Description of the relationships of hydro-climate indices on the basin-specific
precipitation and runoff values on a multi-seasonal basis.
?
Description of the relationships of hydro-climate indices on the basin-specific
demand factors that can affect water demand on seasonal time scales.
?
Description of the relationships of hydro-climate indices on the basin-specific
demand factors that can affect water demand on multi-seasonal time scales.

Task A: Development of the hydro-climate indices
(HCI) - basin response relationships on a seasonal
basis.

?
Supply: Relate the amount of basin average precipitation values during the
October to March period and the April to September volume runoff into the basins
to the following HCI’s. These relationships will be calculated for the Dolores-San
Juan, Rio Grande and Arkansas basins.:

Multivariate ENSO Index (MEI) for the periods of Jul/Sep through Oct/Dec
?
three-month averages and five-month averages.

Pacific Decadal Oscillation (PDO) for similar periods as MEI,
?

North Atlantic Oscillation (NAO) for similar periods as MEI
?
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