WSP00251

• File Number: 8220.200.05.P
• Description: Hoover Dam/Lake Mead/Boulder Canyon Project
• Basin: Colorado Mainstem
• Date: 7/29/1968
• Author: USACOE
• Title: Title 33--Navigation and Navigable Waters Part 208--Flood-Control Regulations Hoover Dam and Lake Mead Colorado River Nev-Ariz
• Water Supply Pro - Doc Type: Report/Study

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Reservoir
Lake Powell - - _ _ _ _
Navajo _ _ _ _ _
Blue Mesa - - - - - _
Flam1ng Gorge _ _ _ _ _ _

Creditable storage space
Acre -feet
- 3,850,000
- - 1,036,100
- - - 148,500
- - 1,501,200

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(b) Releases trom Lake Mead shall be restricted to quantities that
will not cause a flow in excess of 40,000 cubic feet per second at the
gaging station, Colorado River below Davis Dsm, insofar as possible.

(c) F~he period January 1 to August 1, m1nimum releases rrom
~e Mead tn RttiiTn'-Hip-A';g,"7';t-:i-:nciOsf.;contr-,,1"- ~-pA'ct prejic'::1P~ii,.1n...~-
j!!Jlh (a) of this section shall be-determined-r1=om-tabies 1 throU8b 6
of the Tables of Minimum Average Releases for Flood-Control Purposes
currently in force for various conditions of available storage space in
Lake Mead and Lake Powell and of maximum rorecasted inflow to Lake Mead.
The Tables of Min1mUIII Average Releases for Flood-Control Purposes cur-
rently in force as of the promulgation of this section are those dated
July 8, 1968. Pertinent info~tion on inflow forecasts and on permis-
sible changes in the releases indicated in tables 1 through 6 of the
Tables Of Minimum Average Releases for Flood-Control Purposes currently
in force is given in subparagraphs (1), (2), (3), and (4) of this
paragraph.

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(1) All inflow forecasts used in carrying out the provisions of
the regulations in this aection shall be prepared by the Bureau of
Reclamation and shall be for the flow of the Colorado River at Grand
Canyon, Ariz. gaging station. Basic forecasts of natural flow, for
conditions of no Colorado River Storage Project reservoirs, shall be
adjusted for tranBmountain diversions and effective storage space in
upstream reservoirs (excluding Lake Powell). The maximum forecast for
any specified runoff period is defined as the estimated inflow volume
(acre-feet) that, on the average, will not be exceeded 19 times out
of 20.

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(2) Effective storage space in each upstream reservoir is the
lesser of the actual space available, or the usable space available.
The usable space 1& the difference between the min1mUIII forecasted inflow
vol.ume (acre-feet) for any specified nmoff' period and expected no~l
releases. '!'he min1mum forecast is defined as the estimated inflow
volume (acre-feet) that, on the average, will be exceeded 19 t1mes out'
of 20.

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(3) When minimum relealles for the periods April 1 to August 1,
May 1 to August 1, or June 1 to August 1 as given in tables 4, 5, or
6 are between 20,000 cubic feet per second and 40,000 cubic feet per

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