1987-08-24 Public Hearings and Regular Meeting

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e e rOM, BS thru JA to RTH, RE: Lomax CIP Drainage Improvements, Page 3 . Alternatives I and II were the other approaches studied. Alternative I is a straight-forward solution involving the enlargement of several eXisting Flood Control open channels in Lomax, the construction of four north-south lateral channels, and associated structural improvements at roads, highways, and railroads. Alternative II examines the possibility of constructing a 70-acre detention pond west of Strang Yard to reduce the cost of improvements under and east of Strang Yard. Alternatives I and II can be compared purely on a cost basis. The table below shows that comparison: ALTERNATIVE I ALTERNATIVE II (Million $) (Million $) Galveston Bay to Strang Yard 1.364 1 .064 Strang Yard to EXXON Pipel. Corr. 1 .424 1 .052 West of EXXON Pipel. Corr. 1.384 1.362 Detention Facility and Weir None 2.145 ----- ----- TOTAL CONSTRUCTION COST 4.172 5.623 Pipeline Adjustments 0.400 0.400 Utility Adjustments 0.050 0.050 Channel Right of Way 1. 136 1.060 Detention Pond Site None 1.050 ----- ----- . TOTAL NON-CONSTRUCTION COST 1 .586 2.560 ----- ----- TOTAL PROJECT COST 5.158 8.183 Alternative II results in a $770,000 savings in channel right-of-way acquisition and construction costs. However, the cost of land and construction of the detention pond is estimated to cost $3,195,000. Thus, Alternative II would cost about $2,425,000 more than Alternative I. CONCLUSIONS 1. Diversion of part of Lomax's runoff to Big Island Slough would have substantial downstream impacts on the Slough. Accordingly, Alternates III and IV are not economically feasible options. 2. Alternate II offers no advantage over Alternate I and costs over 40% more. RECOMMENDATION Staff recommends that City Council accept Alternative I, as presented by Flood Control, as the master drainage plan for Lomax. .