Basin States Modeling Results Matrix Version 6 September 19 2005

• Description: Basin States Modeling Results Matrix Version 6 September 19 2005
• State: CO
• Date: 9/19/2005
• Title: Basin States Modeling Results Matrix Version 6 September 19 2005
• Water Supply Pro - Doc Type: Meeting

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BASIN STATES MODELING RESULTS MATRIX VERSION 6�
QUESTIONS ADDRESSED AND STATISTICAL APPROACH
20 year model runs (2006 to 20025)
➢ 90 hydrologic traces per year
"Point" statistics refer to the probability of occurrence in that particular year, and is
calculated as the number of occurrences divided by 90 possible occurrences
"Period" statistics refer the probability of occurrence any time within a specified
number of years. The approach to obtaining period statistics for each question is
detailed below:
1. What is the probability of incurring a shortage in the 5th, 10th, and 20th year (point),
and at any time over the next 5, 10, and 20 years (period)?
• CRSS -Lite model output slot: "Shortage Total Lower Basin Shortage"
• Output file has 90 traces across the x -axis, 20 years down the y -axis
• For each trace:
o 1 = at least one shortage during the specified time period
o 0 = no shortages during the specified.time period
• Result was 90 values across, either a 1 or 0 for each trace
• Probability = (sum of the 90 values) divided by (90)
2. What is the earliest a shortage occurs?
• CRSS -Lite model output slot: "Shortage Total Lower Basin Shortage"
• Output file has 90 traces across the x -axis, 20 years down the y -axis
• The first year of shortage, regardless of trace number, was observed and noted
• Result was one value for the entire run
What is the maximum shortage volume over the 5th, 10th, and 20th year (point), and at
any time over the next 5, 10, and 20 years (period)?
• CRSS -Lite model output slot: "Shortage Total Lower Basin Shortage"
• Output file has 90 traces across the x -axis, 20 years down the y -axis
• Shortage volume was summed for each trace over the specified time period
• The maximum volume from the resulting 90 values was noted for each period,
divided by 1,000 to convert to thousand - acre -feet (KAF)
4. What is the most probable Mead elevation in the 5th, 10th, and Nth year (point), and at
any time over the next 5, 10, and 20 years (period)?
CRSS -Lite model output slot: "Mead Pool Elevation"
Output file has 90 traces across the x -axis, 20 years down the y -axis
For each time period, the median value was noted
o 5 years = median of 90x5 values
o 10 years =median of 90x10 values
o 20 years = median of 90x20 values
USBR Draft Pagel of 3 9/19/2005