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<br />t <br />~t <br />-----1 <br />I <br />I <br />, <br />\ <br />~ <br />t <br />\ <br />( <br />\ <br />( <br />( <br />( <br />( <br />( <br />( <br />\ <br />" <br />( <br />\ <br />\ <br />( <br />( <br />i <br />, <br />\ <br />, <br />\ <br />t <br />f <br />t <br />\ <br />\ <br />( <br />\ <br />~ <br />i <br />, <br />l <br />( <br />I, <br />( <br />i <br />L <br />! <br />! <br />i <br />i <br />i <br />,. <br />i <br />\ <br />" <br />I <br />( <br />r <br />, <br />, <br />I <br />,. <br />( <br />r <br />r <br />( <br />( <br />i <br />i <br />( <br />i <br />I <br />r <br />( <br />( <br />r <br />{ <br />I' <br />I <br />I <br />,. <br />( <br />" <br />, <br />I, <br />i <br /> <br />CHAPTER 2 <br />CHARACTERISTICS OF NONSTRUCTURAL MEASURES <br /> <br />,his Chapter discusses some of the characteristics which distinguish nonstructural measures <br />from structural. It may seem trite to say that there are differences, butthis fact is often forgotten <br />and misunderstandings develop as to the role nonstructural measures play in flood plain <br />management. Each type measure - whether structural or nonstructural - has its appropriate <br />place in the present and future management of our nation's flood plains. When a measure is <br />evaluated for a situation for which it is not suited, it is unfair to generalize and say the measure is <br />ineffective or too costly in all situations. A reservoir may be appropriate to protect several <br />cOn1munities on a main stem river, but inappropriate to protect a subdivision on a tributary. <br />Similarly, providing temporary or permanent closures for doorways n1ay be appropriate where <br />shallow flooding occurs, but inappropriate where the velocity and depth are high. A levee <br />protects existing development, and toning seeks to protect future development. One measure <br />may be desired by the community or individual homeowner, another measure may not be <br />desired. Each measure has its appropriate place and the principal task is to find the most <br />appropriate measure for each specific flood hazard and community situation. <br /> <br />Local/Individual Nature <br />Most nonstructural measures are actions taken to individual structures or to land in or around <br />a community. Structures are protected by keeping water out, elevating in-place, constructing a <br />small wall or levee, relocating contents, moving the structure and/or contents, building a <br />structure higher, or using water resistant materials. Specific areas of land are regulated or <br />acquired in fee or easement. Even evacuation, which may be part of a regional forecast/warning <br />system, requires individual action to save life and property. Flood insurance also requires <br />individual, as well as local community action. In each of these cases action is taken on individual <br />structures or to specific plots of land and because of this it is necessary to know the specific <br />characteristics. This should include location, type, condition, use, and depth and frequency of <br />flooding. By way of contrast, reservoirs, levees, diversion works, and channel modifications <br />protect property without modifying individual structures, and until recently did not attempt to <br />regulate land use. Frequently structural measures are not even visible to the individuals being <br />protected - they are over there, or upstream. They deal with the flood, rather than with the <br />structures being protected. Protection is provided not by modifying the structure, but by <br />storing, diverting, or channeling flood waters. <br /> <br />One of the fundamental questions raised by this local/individual characteristic is that of <br />federal intwest. Should the Federal Government be investigating ways to alter individual <br />structures? This question is addressed here because the answer determines our willingness to <br />investigate the feasibility of nonstructural measures. There are two answers to the question- <br />both positive. Since the law requires that Federal flood control planning consider nonstructural <br />alternatives and since nonstructural alternatives means investigating ways to protect individual <br />structures there is no choice but to get down to the level of individual or small groups of <br />structures. Whether or not the Federal Government implements any conclusions or <br />recommendations regarding nonstructural measures is another question. The law states they <br />should be considered. The information can be passed on to the local government or individual <br /> <br />5 <br />