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<br />would sustain very little damage provided adequate forecasts of runoff <br />events would permit evacuation of items that would be subject to damage <br />from the storm runoff. Flood forecasting as a management technique, however, <br />is not inexpensive and is not necessarily technologically easily accomplished. <br />In most instances the runoff characteristics of small watersheds are poorly <br />known and as a consequence forecasts are quite unreliable. In addition, <br />the response time of small urban watersheds is so short that adequate fore- <br />cast lead times are virtually impossible. Nonetheless, with increased <br />development of mathematical models and of remote data acquisition, fore- <br />casting systems could well be a useful component of an urban storm drainage <br />system. <br /> <br />Combined Alternatives <br />Combinations of structural and nonstructural measures usually prove <br />to be more optimal than either considered separately. A recent article in <br />Civil Engineering Magazine (lO) describes an approach that is termed <br />"natural drainage" that is proposed for implementation in a newly <br />developing area near Houston, Texas. The overall management approach <br />includes both structural and nonstructural components. The natural drain- <br />age concept considers it essential that the existing flood plains be pre- <br />served as nature's easement tlhich will be made use of at periodic intervals. <br />It also recognizes that urbanization will definitely effect the 'response <br />of the watershed and must therefore be controlled in some fashion. The' <br />specific criteria developed for this particular concept states that no <br />development will be permitted within the 25-year flood plain of the small <br />tributaries, that no development will be permitted within the lOO-year <br />28 <br />