HomeMy WebLinkAboutCOM 0178.004 2006-2008 d'+tv
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Harry Kim Christopher J• Yuen
Mayor Director
Brad Kurokawa, ASLA
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PLANNING DEPARTMENT
101 Pauahi Suee6 Suite 3 Hilo, Hawaii 967203043
(808) 961-8288 FAX (808) 961-8742
March 9, 2007
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Honorable Pete Hoffmann cc
Chair and Presiding Officer
and Members of the County Council
COUNTY COUNCIL
333 Kilauea Avenue, Second Floor
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Hilo, HI 96720
Deaz Chair Hoffmann and Members of the County Council:
SUBJECT: BILL 52 -RELATING TO STORMWATER MANAGEMENT
The council is deferring action on Bill 51, which relates to Chap. 27. The council is also
considering Bill 52, which amends Chap. 23 and 25, and in its previous form, had also
amended Chap. 27. I understand some of the concerns that led to the deferral of Bill 51,
however, I was hoping that the council could act on Bi1152, if it didn't amend Chap. 27.
It is possible to do that by putting the standards fora "site drainage plan" in Chap. 25.
The attached proposed Draft 3 of Bill 52 does that, by including the standards in sec. 25-
2-72(3). To recap: new buildings in commercial, resort, and industrial zones such as
apartment buildings and commercial and industrial buildings need "plan approval". As
part of plan approval, Bill 52 would require them to have a site drainage plan approved
by the Department of Public Works. This site drainage plan would require stormwater to
be drained into a drywell or other approved infiltration device.
The requirement in the proposed Draft 3 would be to handle the expected ten-year, one-
hour storm. I realize that Bi1151 was amended to require drainage to handle the expected
one hundred year storm. The ten year storm is a considerable amount of water. In
Kailua-Kona, it is 2.0" of rain per hour; in Hilo, it is 5.0" per hour. I don't have figures
for the 100 yeaz expected storm but it would be roughly 50% more. This doesn't mean
that the drywell stops working after an hour: it is supposed to continue draining at this
rate. I checked rainfall records for Kailua-Kona from 1949-2000: the maximum rainfall
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Hawaii County is an Equal Opportunity Provider and Employer.
Honorable Pete Hoffmann
Chair and Presiding Officer
and Members of the County Council
COUNTY COUNCIL
Page 2
March 9, 2007
actually recorded in any day was 15.2". I believe DPW will verify that most drainage
problems in urban situations are from older developments which were allowed to
discharge water into the streets rather than from newer developments with drywells.
I will be happy to discuss these issues at the March 9 meeting.
Sincerely„
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CHRISTOPHER J. YU N
Planning Director
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Wpwin60/CHRIS 07/ HOFFMAN -BILL 52 - RELATING TO STORMWATER MANAGEMENT
Attachment