Procedural Manual 77-2: Floodplain Management
This procedural manual applies to all NPS proposed actions, including the direct and indirect support of floodplain development and channel modifications, that could adversely affect the natural resources and functions of floodplains or increase flood risks. If the cost of obtaining precise floodplain information is prohibitive, the NPS will assume the project is within a regulatory floodplain unless the site can be determined beyond reasonable doubt to be outside the floodplain.
This procedural manual will apply to actions implemented prior to the Executive Order (May 28, 1980), including existing developments, when those actions are the subject of regularly occurring updates of official NPS planning documents. This procedural manual also applies to roads and to actions that are functionally dependent upon locations in proximity to water and for which non-floodplain sites are never a practicable alternative. Examples of actions functionally dependent upon water include: marinas, docks, piers, water intake facilities, sewage outfalls, bridges, flood control facilities, water monitoring stations, drainage ditches, debris removal, outdoor water sports facilities, boardwalks to interpret wetlands, and similar water-dependent actions.
While non-floodplain locations may not be a practicable alternative for these types of activities, minimization of impacts to the natural resources of floodplains remains an important requirement.
B. Excepted ActionsThis procedural manual does not apply to historic or archaeological structures, sites, or artifacts whose location is integral to their significance.
This procedure does not apply to certain park functions that are often located near water for the enjoyment of visitors but require little physical development and do not involve overnight occupation. Examples include:
- Picnic facilities, scenic overlooks, foot trails, and small associated daytime parking facilities in non-high hazard areas provided that the impacts of these facilities on floodplain values are minimized;
- Isolated backcountry sites, natural or undeveloped sites along trails or roads, survey and study sites, or other similar activities; and
- Emergency actions essential to protecting property and public health, provided that emergency actions are limited to the minimum required and that all possible steps are taken to mitigate the short and long term adverse impacts of these actions on floodplain values.