FLOOD02837

• County: Jefferson
• Stream Name: Buffalo Creek
• Basin: South Platte
• Title: Buffalo Creek Mitigation Plan Project Notebook
• Date: 6/11/1998
• Floodplain - Doc Type: Flood Documentation Report

Oct-29-96 10:50 HENZ METEOROLOGICAL SRVC. 303-458-5309

P.02

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BENZ METEOROLOGICAL SERVICES
Meteorological Consu1~ and Weather Forecasting

Mr. Tom Browning 28 October 1996
Colorado Water Conservation Board
1313 Sherman
Denver, Colorado 80203

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Dear Mr. Browning:

Henz Meteorological Services ( HMS ) would like to propose the re-constitution
of the rainfall for six heavy rainfall events which affected the town of Buffalo
Creek and adjoining basins from June through September 1996. HMS will rely
on the following data to prepare the re-constitution of the rainfall:

1. Digital data files of the 0.5 degree elevation angle base reflectivity from
the National Weather Service WSR.-88D located at Watkins, Colorado
which will be used to give quantitative aerial, temporal and intensity
definition to the storms,

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2. 5-minute ALERT rain gauge data of the Urban Drainage & Flood Control
District which will be used to ground-truth the radar re-constitution

3. ERL Mesonet observations of surface temperature, dew point, wind
direction and speed which will be used to assist in the "atmosphere-
truthing" of the radar-rainfall relationship, and

4. Conventional surface and upper air observations of the National
Weather Service which will assist In the quantification of the rainfall.

HMS has archived the above identified data during the past summer during its
Flash Flood Prediction Program (F2P2) managed for the Urban Drainage &
Flood Control District. No additional data costs will be incurred in the production
of the rainfall re-constitutions,

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HMS proposes to prepare the 5-minute rainfall intensity, aerial coverage and
storm total rainfall for each of the three events. The aerial coverage of the data
will be for the entire drainage basins affected in southern Jefferson County which
impact the Buffalo Creek drainage areas. The WSR-88D radar will allow the
calculations to be performed for areas roughly "0.5mile by 0.5 mile grid squares".
The data will allow 5-minute rain maps to be prepared in a spreadsheet format
similar to the one in Figure 1 which was prepared last summer for the Marston
Lake urban flooding event.

2480 West 26th Ave., Suite 310B, Denver, Colorado 80211 Ph. [phone] Fax [phone]
"Good science serving engineering, forensics, business, government and operational forecasting"