WSP08408

• File Number: 8210.140.20.A
• Description: Colorado River Basin Organizations/Entities - CRBSF - Colorado River Board of California
• Date: 5/28/2001
• Author: CRBC
• Title: Colorado River Water Report
• Water Supply Pro - Doc Type: Report/Study

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June 1, 2001 Preliminary Forecast of Colorado River Flow into
Lake Powell (1) (Million Acre-feel)

Change From Last
USBR and National Weather Service Month's Forecast
APril-July Water Year 2001 April-July Wat Yr 2001
Maximum (2) 7,300 10,666 -0,800 -0,824
Mean 5,300 * 8.266 ** -0,500 -0,524
Minimum (2) 3,300 5,866 -0,300 -0,324

. This month's A-J forecast is 69% of the 30-year A-J average shown below,
.. This month's A-J forecast is 71 % of the 30-year W-Y average shown below,

Comparison with past records
of Colorado River
inflow into Lake Powell
(at Lee Ferry prior to 1962)

April-July Flow Water Year Flow
Long-Time Average (1922-2000) 8,018 11,869
30-yr, Average (1961-90) 7,735 11.724
10-yr. Average (1991-2000) 7.434 11 .403
Max, of Record 15.404 (1984) 21,873 (1984)
Min of Record 1,286 (1977) 3,663 (1977)
Last Year (2000) 4352 7,310

(1) Under conditions of no other Upper Basin reservoirs,

(2) USBR and NWS forecasts indicate the probability of 19 chances out of
20 that the actual flow will not exceed the maximum value, and will not be
less than the minimum value.

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