March 18th, 2011 – National Weather Service Reports used to estimate precipitation are 30-40 years old

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From: Nicholson, Thomas
Sent: Friday, March 18, 2011 4:01 PM
To: See, Kenneth; Dion, Jeanne
Cc: Randall, John; Kanney, Joseph; Ott, William; Chokshi, Nilesh; Raione, Richard
Subject: Revision to PMP Narrative


I just spoke to John England, U.S. Bureau of Reclamation concerning our response to the NRO information request. He would like a one-word addition to the narrative to say the Southeast U.S. rather than just the U.S.

This is his suggested wording:

Some of the Reports from the National Weather Service used to estimate the design precipitation are 30-40 years old.

Are these estimates still valid?

The NRC has funded research by the U.S. Bureau of Reclamation to review the information and methods developed by the National Weather Service and the U.S. Army Corps of Engineers (HMR 51), focusing on South and North Carolina. To date, reviews of precipitation records from extreme storm events (e.g., tropical storms, hurricanes) since the publication of HMR 51 does not indicate any exceedance or potential for exceedance of those precipitation (PMP) estimates in this region. We have not seen any information or data that would indicate that HMR precipitation (PMP) estimates for the Southeast U.S. have been exceeded.

Please make whatever changes are possible at this time.

Thanks ………. Tom

Thomas J. Nicholson, Senior Technical Advisor
U.S. Nuclear Regulatory Commission
Office of Nuclear Regulatory Research
Mail Stop CSB 2-A07
11555 Rockville Pike
Rockville, MD 20852
Tel: (301) 251-7498
Fax: (301) 251-7422
E-mail: Thomas. Nicholsonc,

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