BOARD02588

• Board Meeting Date: 5/24/1999
• Description: Directors' Reports
• Board Meetings - Doc Type: Memo

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First Regular Session

Sixty-second General Assembly

LLS NO. R99-0835,OI Bart Miller

STATE OF COLORADO

BY SENATORS Andrews, Evans, and Lamborn;
also REPRESENTATIVES Clapp, Nunez, and Spence,

SENATE JOINT RESOLUTION 99-023

CONCERNING AN INDEPENDENT PEER REVIEW OF THE FEDERAL
NATIONAL WEATHER SERVICE PROBABLE MAXIMUM PRECIPITATION
STUDY USED BY THE UNITED STATES ARMY CORPS OF ENGINEERS IN
THEIR REDESIGN STUDY RELATING TO THE CHERRYCREEK DAM.

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WHEREAS, The terms "probable maximum flood" and "probable maximum
precipitation" as used by the United States Army Corps of Engineers are misleading
terminology because they are both improbable events with respect to the Cherry Creek
Basin; and

WHEREAS, The United States Army Corps of Engineers has assumed the Cherry Creek
Dam will fail following an extraordinarily improbable chain of events; and

WHEREAS, The probable maximum precipitation is a theoretical maximum only and has
somewhere between a one in one million to a one in one billion chance of occurring in
any single year; and

WHEREAS, The. site specific probable maximum precipitation study completed for the
United States Army Corps of Engineers by the National Weather Service has erroneously
applied meteorological procedures and fails to include documented historical paleo flood
evidence; and

WHEREAS, This error is further compounded by the erroneous assumption that the
topographic effects of the Palmer Divide will increase the rainfall in the Cherry Creek
Basin; and

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WHEREAS, The probable maximum flood used by the United States Army Corps of
Engineers is more than twice the flood estimates prepared by other dam safety officials;
and

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