ASA Glossary: Key Terms & Definitions for Developers and Consultants

ASA Key Terms & Definitions

Anadromous Fish: Fish species that migrate from the ocean to freshwater streams and rivers to spawn, such as salmon, steelhead, and some species of char and trout. The Alaska Anadromous Fish Act specifically protects these fish and their habitats. (AS 16.05.871)

Anadromous Fish Habitat: Spawning, rearing, and migratory habitats of anadromous fish, including streams, rivers, and lakes. These habitats are protected under the Alaska Anadromous Fish Act. (AS 16.05.871)

Anadromous Waters Catalog: A comprehensive list of water bodies in Alaska that have been identified as being used by anadromous fish, maintained by the Alaska Department of Fish and Game. The catalog is used to determine which water bodies are subject to the permitting requirements of the Alaska Anadromous Fish Act. (AS 16.05.871(a))

Best Management Practices (BMPs): Methods, measures, or practices designed to prevent or reduce water pollution, including structural and nonstructural controls and operation and maintenance procedures. BMPs are often required as a condition of permits issued under the Alaska Anadromous Fish Act. (AS 16.05.871(d))

Compensatory Mitigation: The restoration, establishment, enhancement, or preservation of wetlands, streams, or other aquatic resources to offset the adverse impacts of development activities on anadromous fish habitats. Compensatory mitigation may be required as a condition of permits issued under the Alaska Anadromous Fish Act. (AS 16.05.871(d))

Critical Habitat Area: A specific geographic area that contains features essential to the conservation of an endangered or threatened species and that may require special management and protection. The Alaska Anadromous Fish Act requires the identification and protection of critical habitat areas for anadromous fish. (AS 16.05.871(c))

Culvert: A structure that allows water to flow under a road, railroad, trail, or similar obstruction. Culverts can impede the passage of anadromous fish if not properly designed and installed. The Alaska Anadromous Fish Act requires that culverts be designed to allow for the efficient passage of anadromous fish. (AS 16.05.841)

Dam: A barrier constructed to hold back water and raise its level, forming a reservoir. Dams can obstruct the passage of anadromous fish and alter their habitat. The Alaska Anadromous Fish Act requires that dams be designed to include fishways or other structures to allow for the efficient passage of anadromous fish. (AS 16.05.881)

Fishway: A structure that allows fish to pass around or through an obstruction in a stream or river, such as a dam or culvert. The Alaska Anadromous Fish Act requires that any dam or other obstruction built across an anadromous fish stream must include a fishway, unless the commissioner of the Alaska Department of Fish and Game determines it is not necessary. (AS 16.05.881)

Habitat Alteration: Any change in the physical, chemical, or biological characteristics of anadromous fish habitat that could potentially harm or disturb the fish. Habitat alterations may include changes in water flow, water quality, substrate composition, or riparian vegetation. The Alaska Anadromous Fish Act regulates activities that could result in habitat alterations. (AS 16.05.871(a))

Habitat Permit: A permit issued by the Alaska Department of Fish and Game under the Alaska Anadromous Fish Act that authorizes activities that may affect anadromous fish habitat. The permit may include conditions to minimize impacts on fish habitat and ensure compliance with the Act. (AS 16.05.871(b))

Habitat Protection: The conservation and management of anadromous fish habitat to ensure the long-term sustainability of fish populations. Habitat protection measures may include restrictions on development activities, requirements for mitigation or restoration, and monitoring and adaptive management strategies. The Alaska Anadromous Fish Act is designed to provide for the protection of anadromous fish habitat. (AS 16.05.871)

In-stream Flow: The volume and timing of water flow in a stream or river that is necessary to support aquatic life and maintain the ecological functions of the stream. The Alaska Anadromous Fish Act requires that in-stream flows be maintained at levels sufficient to protect anadromous fish habitat. (AS 16.05.871(d))

Mitigation: The avoidance, minimization, or compensation for the adverse environmental impacts of a development project. Mitigation measures may be required as a condition of permits issued under the Alaska Anadromous Fish Act. (AS 16.05.871(d))

Navigable Waters: Waters that are subject to the ebb and flow of the tide and/or are presently used, or have been used in the past, or may be susceptible for use to transport interstate or foreign commerce. The Alaska Anadromous Fish Act applies to activities that may affect anadromous fish habitat in navigable waters. (AS 16.05.871(a))

Ordinary High Water Mark (OHWM): The line on the shore established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas. The Alaska Anadromous Fish Act regulates activities that occur below the OHWM of anadromous fish streams. (AS 16.05.871(a))

Permit Conditions: Requirements or restrictions included in a habitat permit issued under the Alaska Anadromous Fish Act that are designed to minimize impacts on anadromous fish habitat and ensure compliance with the Act. Permit conditions may include mitigation measures, monitoring requirements, or other provisions. (AS 16.05.871(d))

Restoration: The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. Restoration may be required as a condition of permits issued under the Alaska Anadromous Fish Act to mitigate the impacts of development activities on anadromous fish habitat. (AS 16.05.871(d))

Riparian Area: The area adjacent to a stream or river that is influenced by the presence of water and supports unique vegetation and ecological functions. Riparian areas provide important habitat for anadromous fish and are protected under the Alaska Anadromous Fish Act. (AS 16.05.871(a))

Spawning Habitat: The specific areas within a stream or river where anadromous fish lay their eggs. Spawning habitat typically consists of gravel or cobble substrates with appropriate water flow and quality conditions. The Alaska Anadromous Fish Act protects spawning habitat from disturbance or alteration. (AS 16.05.871(a))

Stream Crossing: A structure that allows a road, pipeline, or other development to pass over or under a stream or river. Stream crossings can alter anadromous fish habitat and impede fish passage if not properly designed and installed. The Alaska Anadromous Fish Act regulates the construction and maintenance of stream crossings. (AS 16.05.841)

Substrate: The material that forms the streambed, such as gravel, cobble, sand, or silt. The composition and quality of the substrate are important factors in determining the suitability of a stream for anadromous fish spawning and rearing. The Alaska Anadromous Fish Act prohibits the removal of gravel or other substrate materials from anadromous fish habitat without a permit. (AS 16.05.871(a))

Turbidity: The cloudiness or haziness of water caused by the presence of suspended solids, such as silt or clay particles. Increased turbidity can harm anadromous fish by reducing visibility, clogging gills, and smothering eggs and larvae. The Alaska Anadromous Fish Act regulates activities that may increase turbidity in anadromous fish habitat. (AS 16.05.871(d))

Water Diversion: The removal or redirection of water from a stream or river for various purposes, such as irrigation, hydroelectric power generation, or industrial use. Water diversions can alter the natural flow regime of a stream and adversely affect anadromous fish habitat. The Alaska Anadromous Fish Act prohibits water diversions that obstruct or change the natural flow of anadromous waters without a permit. (AS 16.05.871(a))

Water Quality: The chemical, physical, and biological characteristics of water that determine its suitability for aquatic life and other uses. The Alaska Anadromous Fish Act requires that water quality be maintained at levels sufficient to support healthy populations of anadromous fish. (AS 16.05.871(d))

Watershed: The land area that drains water, sediment, and dissolved materials to a common outlet, such as a stream, river, or lake. The Alaska Anadromous Fish Act recognizes the importance of protecting entire watersheds to maintain the integrity of anadromous fish habitat. (AS 16.05.871(a))