Prepared by a firm of consulting engineers, this booklet outlines the procedural "whys and hows" of assessing environmental impact, particularly for the construction industry. Section I explores the need for environmental assessment and evaluation to determine environmental impact. It utilizes a review of the National Environmental Policy Act and federally required environmental impact statements. Section II suggests a procedure for environmental assessment and evaluation by enumerating the characteristics of environmental quality, human well-being, and proposed development activity. Matrix charts are included to visualize these aspects more completely. Section III offers a procedure for the development of an environmental impact statement. It requires a four-step approach employing (1) an Environmental Impact Index, (2) an Alternative Proportional Value, (3) a Functional Impact Value, and (4) an Environmental Impact Assessment. Sequence and flow charts for the different steps in this process are drawn to show development of the final product, an Environmental Impact Statement. This statement ultimately will serve to organize and detail the available data, make the necessary projections, and present professional judgements. Appended material includes a resume of the background of National environmental policy development; legislative, administrative, and judicial requirements for environmental impact statements; and some additional considerations. (BL)