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<br />design will probably ensue based on the analysis performed. Table I presents
<br />a summary of results of selected optimization runs, An important revelation
<br />from this application was that it is possible to quantitatively determine a measure
<br />of the effect of a number of interesting system conditions, e.g., land-use controls.
<br />Also, the range of component sizes that are optimum under a variety of assumed
<br />conditions was limited in most instances so that considerable confidence was
<br />developed in system component sizes. The studies indicated a meaningful role
<br />for land-use controls as a component of an urban flood-control system and,
<br />to a limited extent, quantified its contribution and explicitly evaluated its role.
<br />No additional development work is contemplated before the technique is applied
<br />to the Harding Ditch area. It should be possible in the Harding Ditch study
<br />
<br />?
<br />
<br />TABLE 1.-Summary of Selected Optimization Runs. Blue Waters Ditch. in thousands
<br />of dollars
<br />
<br /> All
<br /> pump, EF, EF, EF, EF, EF,
<br /> PT = 100, PT = 100, no PT, PT = 100, PT = 100,
<br /> System 6-7/8% 6-7/8% 6-7/8% 6-7/8% 3-1/4%
<br />condition at 50, NS' at 50, NS at 50, NS at 50, MS at 100, NS
<br /> (1) (2) (3) (4) (5) (6)
<br />System capital cost 24,600 16,880 13,229 24,800 17,000
<br />Amortized capital cost 1,777 1.204 944 1,771 578
<br />Operation, maintenance,
<br />power. and replacement
<br />cost 94 61 45 66 61
<br />Total annual cost 1,870 1,265 988 1,838 639
<br />Existing annual damages 1.085 1,085 1,085 1,085 1,085
<br />Residual annual damages 25 49 106 23 50
<br />Annual damage reduction 1.060 1,036 979 1,062 1,035
<br />System net benefits -811 -229 -9 -776 396
<br />Optimum Goose Lake
<br />storage 200 acre-ft 800 acre-ft 1,800 acre.ft 600 acre-ft 800 acre-ft
<br />Optimum Blue Waters
<br />storage 400 acre-ft 1,400 acre-ft 1,700 acre-ft 1,200 acre-ft 1,400 acre-ft
<br />Optimum Pump capacity 7;000 cfs 2,600 cfs 1,l00cfs 3,300 cfs 2,600 cfs
<br />
<br />. Pumping is emphasized by requiring all flow to be pumped that is in excess of the natural capability
<br />of existing system to provide lOO-yr protection.
<br />Note: EF = existing land use assumed for future; CF = controlled future land use; PI = exceedence
<br />interval performance target; N~ = natural storage; MS = excavation in detention areas that modify
<br />the storage.
<br />
<br />to further test the methodology as to its value in plan formulation and evaluation
<br />studies, If the results of the initial application in the Blue Waters .Ditch plan
<br />formulation studies are an indication of its utility, it will have considerable
<br />value in studies where a range of alternative systems with a number of components
<br />are to be studied.
<br />
<br />'2
<br />
<br />INFORMATION REQUIREMENTS AND OUTPUT RESULTS
<br />
<br />The technique has been designed to be consistent with plan formulation
<br />strategies in use by many Corps of Engineers offices that are studying urban
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