WSP05133

• File Number: 8210.140.20.A
• Description: Colorado River Basin Organizations/Entities - CRBSF - Colorado River Board of California
• Date: 6/28/2002
• Author: CRBC
• Title: Colorado River Water Report
• Water Supply Pro - Doc Type: Report/Study

001331 '"

-

July 4. 2002 Preliminary Forecast of Colorado Riyer Flow into
Lake Powell (1) (Million Acre-feet)

Change From Last
USBR and National Weather Service Month's Forecast
Aoril-JulY Water Year 2002 Aoril-July Wat Yr 2002
Maximum (2) 1,900 4,437 -1.550 -1 .434
Mean 1,300 * 3.437 ** -0,150 -0,034
Minimum (2) 0,700 2.437 1,250 1,366

* This month's A-J forecast is 16 % of the 30-year A-J average shown below,
** This month's WY forecast is 29 % 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)

Lon9-Time Average (1922-2001)
30-yr. Average (1961-90)
10-yr. Average (1992-2001)
Max, of Record

Min, of Record

Last Year (2001)

April-July Flow

Water Year Flow

8,018
7,735
7,672
15.404 (1984)
1,286 (1977)
4,301

11,869
11,724
11,739
21,873 (1984)
3.663 (1977)
6,955

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

(2) USSR 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,

-5-

"