greatly influence these limits. Most large shore protection projects require 

 floating construction equipment. 



X. ENVIRONMENTAL CONSIDERATIONS 



Shore protection measures by their very nature are planned to result in 

 some modification of the physical environment. However, thorough planning and 

 design require that the full impact of that modification on the ecological 

 and esthetic aspects of the environment be fully considered and understood. 

 If there is potential for a significant adverse effect to any environmental 

 feature, the design analysis of a shore improvement project should include 

 alternatives for avoiding or mitigating that adverse effect. Therefore, the 

 design analysis should include a multidiscipline appraisal of the total impact 

 of the project, which includes environmental quality as well as economic 

 benefits. The necessity for this appraisal at the planning and design stage 

 is apparent and required by law. If there is a probability for conflict 

 between planned construction and environmental quality, a final decision by 

 appropriate authority based on social, technical, and economic analysis will 

 be required. 



In recent years the question of total environmental quality has reached 

 high levels of public concern. Published technical information on this 

 question is scattered through many disciplines, and the lack of quantifiable 

 base-line data precludes reliable quantitative forecasting of most environ- 

 mental and ecological changes resulting from manmade structures. Two works 

 that specifically address this question are Rounsefell (1972) on the eco- 

 logical effects of offshore construction and Thompson (1973) on ecological 

 effects of offshore dredging and beach nourishment. Both works include state- 

 of-the-art evaluations, from the ecologist's perspective, and extensive 

 bibliographies with some entries annotated. Both describe and discuss direct 

 and indirect effects of several categories of coastal protective works, and 

 both discuss procedures for evaluating those effects. The two agree that it 

 is of utmost importance to obtain necessary data on probable environmental 

 impact of proposed construction at an early stage of the project planning. 

 An accurate assessment of preproject environment is essential, not only for 

 initial planning and design, but also for later design modification or alter- 

 natives that could bear on either mitigation or environmental change or 

 enhancement of other aspects of the environment. Rounsefell and Thompson's 

 works suggest that the methods of shore protection discussed in this manual 

 would generally not result in long-term undesirable ecological changes for 

 individual projects. However, this opinion is qualified to the extent that 

 cumulative effects of numerous works of certain types could conceivably result 

 in some detrimental long-term changes. A further requirement is recognized 

 for additional baseline data and knowledge of the quantitative ecological- 

 physical relationships. This information can be developed by monitoring 

 before-, during-, and after-construction effects on coastal projects. 



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