|
<br />I
<br />I
<br />I
<br />I
<br />I
<br />
<br />is $l,089,600 with an average annual damage reduction of $956,700; the
<br />
<br />annualized improvement cost without channelization between 24th and 28th
<br />
<br />H. PROJECT RECOMMENDATIONS
<br />
<br />Streets is $l, 192,900 with an average annual damage reduction of $944,400.
<br />
<br />The annual cost without the proposed channel between 24th and 28th
<br />
<br />Streets exceeds the annual cost with this channel. Required flood
<br />
<br />The modified Plan II I approach downstream of 17th Street to 55th Street
<br />
<br />together with channelization between 24th Street and 28th Street has a
<br />
<br />benefit/cost ratio of 1.71 It is recommended that an analysis of the
<br />
<br />proofing cost without the proposed channel outweigh the cost of channel
<br />
<br />construction~
<br />
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />
<br />impacts of sediment and debris in this area, both with and without
<br />
<br />the proposed modifications, be conducted. If the sediment and debris
<br />
<br />analysis does not reveal any major weaknesses, it is recommended that
<br />
<br />An estimated breakdown of benefits and costs in dollars allocated to the
<br />
<br />the modified Plan I II approach downstream of 17th Street to 55th Street
<br />
<br />selected alternative both with and without channelization between 24th
<br />
<br />and 28th Streets is as follows:
<br />
<br />REACH
<br />
<br />Canyon Mouth to 6th
<br />
<br />6th to 9th
<br />
<br />9th to Broadway
<br />
<br />Broadway to l7th
<br />
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />
<br />l7th to 24th
<br />
<br />24th to 28th
<br />with channelization
<br />
<br />24th to 28th
<br />without channeli-
<br />zation
<br />
<br />28th to 30th
<br />
<br />30th to 55th
<br />
<br />CONSTRUCTION
<br />COST
<br />
<br />ROW
<br />COST
<br />
<br />ANNUAL
<br />o & M
<br />COST
<br />
<br />19,700
<br />l4,300
<br />26,000
<br />32,700
<br />46,000
<br />
<br />15,600
<br />
<br />11,200
<br />
<br />800
<br />
<br />5,900
<br />
<br />ANNUAL
<br />NET
<br />BENEFIT
<br />
<br />-ll6,400
<br />36,500
<br />-l90,400
<br />- 93,000
<br />
<br />24,100
<br />
<br />- 87,200
<br />132,400
<br />152,300
<br />
<br />together with channelization between 24th Street and 28th Street be
<br />
<br />implemented.
<br />
<br />BENEFIT
<br />COST
<br />RATIO
<br />
<br />The Plan II approach from the canyon mouth to l7th Street has a benefit/
<br />
<br />633,800
<br />597,900
<br />
<br />250,000
<br />
<br />-0-
<br />
<br />cost ratio of 0.55.
<br />
<br />0.166
<br />
<br />It is recommended that a modified Plan II I approach including flood-
<br />
<br />l,373,100
<br />5,649.400
<br />1 ,155,800
<br />
<br />-0-
<br />
<br />0.295
<br />
<br />proofing, improved crossings over Boulder Creek, and minor channel work
<br />
<br />lOl,500
<br />-0-
<br />
<br />616,300
<br />
<br />-0-
<br />
<br />0.57
<br />0.276
<br />
<br />be studied for the reach upstream of 17th Street to the Canyon mouth.
<br />
<br />2,065,900
<br />547,500
<br />
<br />-0-
<br />
<br />-0-
<br />
<br />I.
<br />
<br />ACKNOWLEDGEMENTS
<br />
<br />1 ,00l, 100
<br />
<br />-0-
<br />
<br />1. 405
<br />
<br />This report was prepared under the auspices and direction of Urban
<br />
<br />0.45
<br />4.33
<br />
<br />Drainage and Flood Control District (UO&FC).
<br />
<br />2.97
<br />
<br />Topographic mapping prepared by Continental Engineers Inc. for the
<br />
<br />United States Army Corps of Engineers in 1970 was updated in the im-
<br />
<br />mediate vicinity of Boulder Creek by Bell Mapping Company under a sepa-
<br />
<br />Totals
<br />
<br />Without channeli-
<br />zation (24th-28th) l3,024,500
<br />
<br />351,500
<br />
<br />with channel i-
<br />zation (24th-28th) 11 ,574,900
<br />
<br />35l,500
<br />
<br />l56,600
<br />
<br />161,000
<br />
<br />-165,800
<br />
<br />+8,600
<br />
<br />0.792
<br />
<br />rate contract with UD&FC for use in this study.
<br />
<br />0.88
<br />
<br />Field survey information was provided by the City of Boulder.
<br />
<br />1 1
<br />
|