WMOD00593 - Laserfiche WebLink

Home Browse Search

APPENDIX A , I I System , 1./ Explanation of Rating For each discrete component of the environment con- sidered as a receptor of ar impact of precipitation management, numbered ratings for each of four characteristics are tabula~ed and presented imme- diately following the subj~ct heading. The purpose of this tabulation is to ffcilitate comparison of the essential characteristics and their relative importance among the variohs receptor components and to avoid tediously rep~titious explanations in the text. ' The first tabulated characteristic is the strength of the relationship betwee~ precipitation manage- ment and the environmental! component under con- sideration, without refere~ce to whether the impact may be beneficial, harmfull or neutral in value. The relationship is calledlstrong if precipitation management controls most of the variance of the environmental component and weak if it is largely ineffectual as a control. I The particular defini- tions used are: I . I Precipitation management has no direct telationship with the environ~ental component and any indirect relationship is weak or disturbed. Correlation is not signifi~ant by classical tests. There may be speculation about possibl~ effects but no con- sensus 1s to choice between alterna~ive speculations. I Precipitation management has a direct br indirect relationship with th4 environmental component that can be traced with a signi- ficant degree of confidence; the cortelation is significant by classicdl tests. However, con- trol of :changes in the environ- mental component by precipitation management is subordinate to at least one other factor and usually ,to a number of other f ac"tors,' either na tur al or artific~al, so that precipitation management accounts for less than 20 perc~nt of the variance. As a "lever ~f management," precipi- tation management is present but inconsp~cuous. o 2 ~, I , 1/ Ineffectual Very weak , Precipi~ation management has a direct olr indirect relationship with th~ environmental component, more or ,less comparable in strengt~ to other relationships governi~g changes in the compon- ent. It, generally accounts for 20 percent or more of the total varianc~ of the environmental componen:t, but always less than 50 percent. Among the "levers of manag:ement," precipitation , U.S. Bureau of Recllamation. Skywater. In presis. Moderately weak From 3 Moderately strong management holds rank subordinate to at least one other natural or artificial control, and usually to several. Precipitation management is the single most important determinant of variation of the environmental component, even though the combined effect of other controls may at times outweigh it. Among the "levers of management," precipi- tation management is the most influential, though other "levers" may be, and usually, are important. Precipitation management has greater influence on changes in the environmental component than any other factor. Among the "levers of management," it is the overriding one. The second tabulated characteristic estimates the P?tential value of the impact, whether good, bad, mlxed, or indifferent. A moderate, gentle rain breaking a summer drought might be seen as an unalloyed good for thirsty crops, but most impacts will be a mixture of good and bad, with one or the other predominating. Indifference characterizes some cases, such as that of a field from which the crop is newly harvested. The particular definitions used are: 17 Precipitation management nearly always causes a significant amount of beneficial change in the en- vironmental component. In a given setting, the component is in a situation to benefit from precipi- tation management more than 80 percent of the time during an operational period. Situations during a period when effects would be harmful are infrequent and relatively insignificant. Precipitation management fre- quently causes a significant amount of beneficial change in the environmental component, but there may also be frequent times when the benefit is inconsequential or there may be infrequent times when it is significantly harmful. The regular application of pre- cipitation management would affect the environmental component, on the whole, more beneficially than harmfully. In a given set- ting, the environmental component is in a situation to benefit from precipitation management more than 50 percent of the time, and beneficial effects are, in general, more consequential than ha rmful eff ec ts . Programmatic draft environmental impact statement for Project 4 Very strong +3 Strongly beneficial +2 Moderately beneficial