EP 1130-2-500
27 Dec 96
materials, new repair techniques and innovative designs as well as all reasonable alternative
configurations. The schemes investigated must address and resolve concerns which have led up
to the major rehabilitation proposal, such as declining reliability and consequences of
unsatisfactory performance of the structure or component. Since complete reliability analyses
must be conducted on all alternative schemes, only reasonable and technically feasible
alternatives should be investigated. This requires a screening process to eliminate less
reasonable schemes from consideration. Factors considered in the screening process should
include, but not be limited to, technical feasibility, constructibility, and impacts upon appurtenant
structures. Alternative schemes eliminated during this process for engineering reasons should be
briefly described, along with the factors which resulted in elimination.
(4) Guidance.
(a) Basic reliability principles and an example for a steel miter gate are presented in ETL
1110-2-532, "Reliability Assessment of Navigation Structures", 1 May 1992. Additional
guidance is also presented in ETL 1110-2-321 "Reliability Assessment of Navigation Structures,
Stability of Existing Gravity Structures", 31 December 1993, and ETL 1110-2-354, "Reliability
Assessment of Pile-Founded Navigation Structures", 31 August 1995.
(b) Hydropower. The reliability of turbines and generators, and other
electrical/mechanical equipment may be determined by using "survivor curves. " Estimates of the
initial reliability and the annual rate of change in reliability should be made for both the base
condition and all rehabilitation alternatives. ETL 1110-2-337, Reliability Analysis of
Hydropower Equipment, should be used and the Hydroelectric Design Center (HDC) should be
contacted for guidance in the use of survivor curves and other reliability tools. (See Appendixes
F and H for further discussion.) The reliability of appurtenant structures such as powerhouses,
penstocks, gates, dams, etc. should be determined in accordance with Appendix D.
g. Environmental Considerations.
(1) Environmental Effects. Provide a brief description of the existing affected
environment. Highlight significant resources that are likely to be affected as well as any that are
covered by a specific law (e.g., endangered species, clean air, clean water, cultural and historical,
etc). Identify potential hazardous and toxic wastes concerns, conduct studies and prepare
appropriate reports in accordance with ER 1165-2-132. Identify the location and significance of
impacts and justify any mitigation requirements including the mitigation cost estimate. Indicate
the concurrence or nonconcurrence given by resource agencies on impact assessments and
proposed mitigation plans. Identify any environmental constraints (project stoppers) that would
render an alternative infeasible. Present a matrix of the alternative environmental considerations.
(2) Coordination and Correspondence. Provide a table indicating who was contacted,
their affiliation, and a synopsis of their general concerns. Copies of all pertinent correspondence
should be included in Appendix C of the report.
(3) Reports and Studies. This section summarizes the studies conducted to evaluate the
environmental effects of the rehabilitation plan (e.g., biological, cultural, social, HTRW, studies,
etc.).
(4) The reporting officer will be responsible for determining NEPA documentation (e.g.,
Environmental Assessment, Finding of No Significant Impact, Environmental Impact Statement)
B-8
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