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October 27, 2005 Page 2 channel was two miles long and terminated in one three acre and two twenty acre retention basins. This drainage improvement cost $4.5 million. Its cost is spread over the expected X30 residential units within this project. The allocated cost per unit is $6,zoo. In other words, each unit within this development is "charged with" this amount to address offsite drainage infrastructure. Remember, this is in an area that receives about 30" rain per year! Also, the ground slope in this area is only about t% - z%, with deep soil ground conditions. So, the land characteristics are very conducive to an economic and cost effective drainage design. In its tz years of existence, water flow in the drain channel has never exceeded 3" in depth (for an 8' deep channel) and water has never reached either of the two 20 acre retention basins. I have attached a few photos, to show you what this drain channel and retention basins look like. In addition, the requirement to address the too-year storm has been expanded beyond the modification of FEMA designated flood zones and is proposed to also apply to the alteration of any water course. Can you imagine what impacts these proposed requirements would have on the planned Waikoloa Workforce/Unidev Housing project in Waikoloa? That drainage basin is probably zo,ooo to 30,000 acres, as it starts at the summit of Mauna Kea and fans in the Westerly direction towards Waikoloa Village. The cost to contain all rainfall from atoo- year storm would be astronomic! We ask that you and your colleagues on the Council revise Bi115r back to its original intent and content as presented by the Hawaii County Department of Public Works. Sincerely, / ,~j . r ~ 2~ 1 Riley W. Smith, P.E. (#4959) Vice President Land & Asset Management Attachments: Photos I-~i~ Al.un.il.ih~~.~ H~~~c, I~.unucl,~., Hlz~.ui -~i~--Fi Irl.: r,80g) 88~-7~1 ! ~ Fus; IR03!SR~-`60'_ ~ «~ti~~.purl:crraitah.~rm