Page 51 - Highway Engineering Handbook Building and Rehabilitating the Infrastructure

34 CHAPTER ONE

Floodplain Involvement (Executive Order 11988). Executive Order 11988 require addi-
tional steps in the environmental review process for actions that encroach on floodplains.
Specifically, the public must be given the opportunity for early review and comment, and
notices must reference potential encroachments on the base floodplain. In addition,
floodplain-only-practicable-alternative finding must be prepared for actions involving a
significant encroachment (see FHWA Technical Advisory T6640.8A). This finding must
be included in the final environmental document.
A floodplain evaluation must be prepared and summarized in the environmental docu-
ment in accordance with federal regulation (23 CFR 650, Subpart A). This floodplain eval-
uation should contain a project description, including a map of the project showing the base
floodplain and all project encroachments, as well as alternatives to encroachment. A dis-
cussion should be provided of the practicality of alternatives that would avoid longitudinal
or significant encroachments.
The floodplain evaluation should be summarized in the EA or EIS. The portions of the
evaluation pertaining to fish and wildlife, vegetation, wetlands, growth inducement, etc.,
are to be included in the respective sections of the EA or EIS. Summaries involving flood-
plains in general, as well as hydraulics and risk, are to be included in a section entitled
Floodplains.

Safe Drinking Water Act. The Safe Drinking Water Act (SDWA) was enacted in 1974 to
protect the nation’s drinking water supply and protect public health through appropriate water
treatment technologies. The SDWA applies to all of the more than 160,000 public water sys-
tems in the United States. SDWA establishes maximum contaminant levels (MCLs), or stan-
dards for the maximum safe levels of specific constituents in potable water. Important to
highway engineers is the provision of SWDA that mandates protection of sources of drinking
water. The SDWA requires the protection of drinking water and its sources: rivers, lakes,
reservoirs, springs, and groundwater wells. The location of these resources, therefore,
becomes an early consideration in the siteing and design phases of a project.

Federal Endangered Species Act. The Federal Endangered Species Act of 1973 (16 USC
§§1531–1543) provides a means whereby the ecosystems upon which endangered species
and threatened species depend may be conserved. It also provides a program for the con-
servation of such endangered and threatened species. Section 7 of the act requires each fed-
eral agency, in consultation with the Secretary of the Department of the Interior, to ensure
that actions authorized, funded, or carried out by a federal agency do not jeopardize the
continued existence of any endangered or threatened species or result in the destruction or
adverse modification of habitat of such species unless such agency has been granted an
exemption for such action.
For federal highway projects, a request is made to the U.S. Fish and Wildlife Service
(FWS) regarding whether any species listed or proposed as endangered are present in the
project area. If so, a biological assessment must be completed and reviewed by the FWS.
The FWS will make a determination as to the impacts on critical habitat or on the species
itself and whether the impacts can be mitigated or avoided. An exemption from the
Endangered Species Act must be obtained where a project would result in impacts to
endangered species.
The level of involvement with the endangered species process can vary widely from
project to project, but will generally involve the following steps:
• Establish an area of potential environmental impact (APEI) and potential for conflict
with endangered species.
• Once preliminary alternatives are selected, determine whether a request for a species list
from the FWS is required and then request a list, through FHWA, if required.