NPS: Explore Nature » Reference Manual #77

Freshwater Resources Management

Aquatic Habitat Protection and Management

Introduction

Objectives of this section are to inform superintendents and resource managers of the kinds of park aquatic habitats that must be protected, the ecological factors governing those habitats, and internal and external activities that impact aquatic systems. Wetlands and floodplains are aquatic habitats subject to specific executive and legislative mandates and NPS guidance. Specific inventory, planning, and compliance requirements relating to these habitats are also discussed.

Policy and Objectives

With respect to aquatic habitats in natural areas, the NPS seeks to:

minimize human-induced impacts on aquatic habitats,

limit effects and mitigate damage if impacts are unavoidable,

maintain and restore aquatic habitats to protect their ecological and aesthetic character and dependent animal and plant communities, and

minimize economic costs to developments from flood hazards.

Aquatic Habitats

NPS units are located across a wide latitudinal gradient and within a broad range of physiographic regions. Aquatic habitats thus range from tundra ponds and alpine lakes, which may be ice-free for only a few months each year, to subtropical marshes and swamps that never freeze. Lakes and rivers are obvious aquatic habitats to be protected, while other less conspicuous yet functionally important aquatic habitats may not receive the same consideration. Listed below are major classes of aquatic habitats included in NPS units.

Lakes and ponds, including tundra pools, vernal ponds, inter-dune pools, caldera lakes, kettle lakes and tarns, oxbows and guts, pothole lakes, alkali or inland saline ponds, and playas. Reservoirs created for flood control, water supply, or hydropower are human-made habitats occurring in some parks.

Permanent and intermittent rivers and streams, including subsurface watercourses through caverns, and tidal freshwater and brackish water channels. Waterfalls along river courses create micro-habitats and attract visitor interest in many parks. Canals are human-made habitats occurring in some NPS parks.

Springs and seeps, which are driven by groundwater, include desert spring pools. Many are home to endemic aquatic taxa and some have historic (cultural) significance.

Geysers and hot springs driven by geothermal energy.

Floodplain/riparian habitats, such as bottomland hardwood swamps and cypress swamps.

Other wetlands with tree cover, such as cedar swamps, cypress domes, alder/willow thickets, and lake-shore swamps.

Fresh and brackish water marshes dominated by sedges and grasses, salt marshes, tule marsh, and sloughs.

Northern peatlands (bogs, heaths, and fens), pocosins, and muskeg.

Glaciers and associated subglacial flows.

Coastal floodplains and wetlands.

Physical and Ecological Factors

The nature of aquatic habitats and their biotic dependents is defined by the balance of water quantity and quality characteristics, physiographic and biotic factors, and episodic events such as fire and hurricanes. A shift in the balance of any major governing factors may lead to drastic changes in habitat type, with corresponding changes in the biotic community. The influence of water quality, water quantity, and other factors on aquatic habitats is discussed below.

Water quantity is a primary factor governing aquatic habitats. Hydrologic regimes, that is, the seasonality, quantity, and distribution of water amounts, vary according to changing patterns in rainfall in a watershed. Areal coverage, timing, and duration of inundation (hydropattern) are critical in maintaining marsh, swamp, bog, and lake systems. The water budget, that is, total input and losses of water within a habitat, is closely related to hydropattern. Flow velocity and seasonal water-level requirements must also be considered for river and stream habitats.

Water quality, including both the physical and chemical properties of the water affect the capacity of aquatic habitats to support life. Nutrient and inorganic ion concentrations determine, in large part, the productivity of the system. Sediment load and turbidity affect rates of photosynthesis, quality of spawning sites, success of filter-feeding and sight-feeding organisms, etc. Salinity, pH, dissolved oxygen, and temperature are important in determining animal communities of a habitat. Many constituents are seasonally or annually variable, and many result from the unique combination of physical, geographical, and chemical characteristics of the drainage basin. Natural variability among aquatic habitat types is often extreme. For example, nutrient levels in bog waters are very low compared with a floodplain swamp; sediment load and turbidity are high in streams receiving glacial melt waters compared with levels in Everglades marshes.

Physical aspects of aquatic habitats are shaped by geological and climatic influences. These influences may be prolonged (e.g., weathering or uplifting of landforms), or immediate (e.g., vulcanism, earthquakes, or hurricanes). Processes of stream-channel cutting, weathering and uplifting, storm disturbance, long-shore currents, and tides create or influence habitat characteristics such as stream meanders or braids, riffle/pool complexes, substrate types and locations, and waterfalls. These physical aspects often determine composition of the aquatic biological community, distributions of the organisms, and the location of spawning, nursery, feeding, and wintering sites.

Biotic communities of aquatic habitats also alter habitat characteristics. The vegetation community often creates the substrate of the habitat (e.g., peat formed by sphagnum in bogs or by saw grass in the Everglades). Further, plants may also influence chemical components and fluxes in waters and soils. Animals such as the beaver and alligator modify wetland habitats by damming watercourses or lowering soil elevations, and thus influence other vegetation and animal species. The addition of animals or plants to an aquatic habitat in which they are not native (sometimes termed "species pollution") often changes the ecological balance of the habitat.

Impacts on Aquatic Habitats

Aquatic habitat characteristics must remain within a given range of natural variation to support biotic communities adapted to that range. Human activities that shift these characteristics outside the natural range of variability often cause habitat degradation and changes in species composition or abundance. In addition, recreational and aesthetic qualities of wetlands are related to many of the following factors and are an important contribution to a quality visitor experience. Waterfalls with too little flow because of upstream diversion, former whitewater river rapids drowned by reservoirs, polluted waters, the use of ski boats and jet skis, or scenic views obscured by woody vegetation formerly suppressed by fires lessen visitor enjoyment of the park. This section discusses activities that affect aquatic systems, mechanisms by which they do so, and resultant changes in the system.

Water quality: Nutrients

Nutrient additions within parks may issue from human waste from backcountry operations and campgrounds, sewage-treatment plants, soil erosion, lawn maintenance, garbage dumps, and fish-cleaning sites. External activities include deforestation, storm-sewer drainage, agricultural/urban runoff, sewage treatment outfalls, and landfill leaching. Nutrient additions change animal and plant communities, increase dissolved oxygen demand causing animal mortality, increase organic deposition, and affect aesthetics.

Water quality: Pesticides

Some pesticides accumulate in aquatic habitats where they, or their breakdown products, undergo bio-amplification (i.e., increased concentration as they proceed up the food chain). Pesticides have been shown to cause dramatic declines in some top-level predator populations, and may be responsible for less obvious, chronic effects on wildlife.

Water quality: Atmospheric deposition

Parks are often located in areas where water resources have low buffering capacity, and are subject to damage if acidic atmospheric deposition depletes the natural buffering capability. In the eastern United States, many parks containing significant water resources have received increasing acidic atmospheric loading over the last 40 years, leading to decreased pH and increased sulfate and heavy metals concentrations. In the western United States, many parks contain large numbers of low-alkalinity lakes and streams that often occur in glaciated, high elevation alpine and subalpine zones. In these areas, slopes are typically steep, watersheds are small, soils are often thin and acidic, and the water resources subsequently are sensitive to increasing acidic atmospheric deposition. Acidification not only changes ambient water quality, but may also have far-reaching biological impacts, including reduced fecundity and the elimination of acid-sensitive species in affected waters.

Water quality: Hydrocarbons and toxics

Some hydrocarbons and toxic chemicals are used in fueling and maintenance operations, and result from minerals development both inside and outside of parks. Leaking underground fuel tanks and marina operations may pollute surface and groundwater. Oil spills and acid drainage from mineral-mining sites also cause mortality of plants and wildlife in wetlands and floodplains. Chemicals, including solvents, paints, tars, wood preservatives, and detergents used in maintenance, are often toxic to organisms in aquatic systems.

Water quality: Physico-chemical constituents

Physico-chemical factors in aquatic habitats, such as pH, temperature, dissolved oxygen, and turbidity are often affected by human activities. Activities that increase nutrient input may also result in increased turbidity, as do developments that remove riparian vegetation, such as logging, grazing, road-building, construction, placer mining, and farming. Irrigation in arid areas increases soil salinity and often concentrates chemicals at chronically or acutely toxic levels for vegetation and/or wildlife. Removal of riparian vegetation and tree cover on slopes can cause increases in average water temperatures and sediment loads, and changes in dissolved ion concentrations and photosynthetic rates in aquatic systems. Even when those activities are external, but occur within the watershed of park aquatic habitats, problems should be anticipated.

Water quantity: Hydropattern alterations

Water removal from park aquatic habitats results mainly from external activities. Withdrawals from municipal and agricultural wells may lower area groundwater levels, with subsequent wetland impacts, flow reductions in springs or seeps, or similar impacts in other aquatic habitats. Flow pattern changes may also occur because of land use alterations (e.g., deforestation, development) within a watershed, potentially causing more flash flooding, less groundwater recharge, and sometimes seasonal changes in water availability. In coastal areas, removal of fresh water may allow salt water to intrude into groundwater and soils. Reservoirs in park watersheds withhold and divert waters from parks, change natural flooding cycles, and alter downstream nutrient regimes. Thermal energy developments near park boundaries may impact timing and degree of geyser displays and hot spring flows.

Reservoirs, water control structures, and hydroelectric dams may provide flows to the park at inappropriate times of year or in inadequate or overwhelming quantities, with temperatures or other factors outside of the natural range. Areal distribution of these flows may also be unnatural, thereby affecting inundation patterns, and the flows may even be directed to areas outside of normal drainage basins. Delivery schedules may be maintained such that natural water fluctuations in marshes, swamps, and rivers are stifled, or in the case of lakes, may be exaggerated beyond normal limits.

Internal park activities such as bridge, roadway, and building projects may upset the balance of water flow and hydropattern in aquatic habitats by reducing connections between wetland areas, by direct mortality of wetland animals crossing roadways, by impeding migrations, and by changing current patterns and siltation.

All of these impacts can affect parks and have been shown to cause changes in aquatic communities; some changes have been subtle, and others dramatic, as in the direct mortality of the biota or effects on animal nesting success. Many communities depend upon the predictability of seasonal and annual environmental conditions, so that any activity that interferes with that predictability decreases the ability of the community to respond properly.

Physical modifications

Physical modifications of aquatic habitats issue from actions like streambed channelization, dredge or fill operations, gravel removal and mining, and jetty construction. Those actions produce changes in the physical parameters of aquatic habitats, including water depths, current speed, sediment transport, and turbidity. The results are reduced habitat and species diversity, shifts in organismal abundance and distribution, and changes in the rates and locations of beach-building and erosion. Mineral development in and near parks physically alters floodplain and wetland habitats or changes water flow or circulation patterns by the construction of drilling pads, coffer dams, and placer operations. Timbering along park streams often results in streambed obstruction by fallen trees and slash, which can disrupt fish spawning and migration patterns. Unregulated or improperly placed culverts, dams, and weirs have similar impacts.

Biotic factors

Animal harvest by fishing, hunting, and trapping occurs in many parks. These topics are discussed in this Reference Manual. However, removal of animals from aquatic systems may affect ecosystem function and structure.

Related to harvesting is the purposeful introduction of animals for sport. Nonnative sport fishes and foraging species stocked into waters outside parks by state or federal agencies have often colonized park habitats. Many have been shown to displace native fish species and to disrupt planktonic communities and food webs. A common practice in the past, fish stocking still occurs in a few parks, most commonly where special circumstance areas (often reservoirs) are designated by park legislation for "active fisheries management." Some nonnative species introduced outside of park waters to control aquatic plants have also colonized parks.

Other impacts

The use of recreational vehicles in wetland and riparian habitats disturbs the physical and vegetational structure and often causes direct animal mortality. Disturbances in aquatic habitats may remain visible for decades, affecting habitat aesthetics and function.

Floodplain Management

Floodplains are flood-prone lands that border inland and coastal waters. In the United States there are more than 50,000 square miles of flood-prone land (Dunne and Leopold 1978).

Floodplains are valuable yet often overlooked components of park ecosystems. They serve important functions such as natural moderation of floods, water quality maintenance associated with filtration of waters through vegetation and gravel, sediment control, groundwater recharge, riparian habitat for biota, areas for outdoor recreation and education, and natural beauty.

Floodplains can be divided into three general descriptive categories: riverine, coastal, and special areas (43 FR 6030). Riverine floodplains are valley areas that are periodically inundated by floodwater from adjacent perennial or intermittent streams or rivers of any size. Flooding in river floodplain areas can result from excessive precipitation and runoff, natural or human-made channel obstruction, or reservoir releases. Riverine floodplains are subject to frequent flooding; generally floods that overtop riverbanks occur every one to two years (Leopold et al. 1964).

In addition to conventional flooding in riverine floodplains, changes in floodplains from debris flows in the steep gradient ephemeral channels of some western parks present special situations in floodplain management. Debris flows are not generally predictable using normal flood forecasting procedures, yet they can sometimes exceed floods from runoff in both peak volume and destructiveness.

Stream channels located in glacial outwash areas or in aggrading landscapes such as alluvial fans present additional problems. Streams in these areas often transport enormous amounts of sediment and can rapidly inundate or undermine a site through rapid lateral erosion. Problems with locating roads or facilities near such streams occur in both desert parks (alluvial fans) and in Alaska (glacial outwash).

Coastal floodplains border lakes, estuaries, or oceans. Flooding in coastal floodplains is due to landward flows caused by unusually high tides, waves created from high winds, storm surges, or tsunamis.

Special floodplain areas include sheet flow or shallow flooding areas and wetlands in which the paths of flooding are unpredictable and indeterminate.

Mandates and guidance

Mandates and guidance for National Park System floodplain protection is found in Executive Order 11988, Floodplain Management (42 FR 26951; May 24, 1977). In addition, floodplain guidance is found in the Coastal Zone Management Act, which has certain requirements for consistency with approved state coastal zone management programs; Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act, which require U.S. Army Corps of Engineers' permits for construction and disposal of dredged material in waters of the United States; the Fish and Wildlife Coordination Act, which requires that equal consideration be given to wildlife when proposing to impound, divert, deepen, control, or modify any stream or other water; the Wild and Scenic Rivers Act; and the Endangered Species Act. Procedures for compliance with these laws is presented in DO/RM 12, Conservation Planning, Environmental Impact Analysis, and Decision-making.

Executive Order 11988 was issued in furtherance of the National Environmental Policy Act, the National Flood Insurance Act of 1968, as amended (42 USC 4001 et seq.), and the Flood Disaster Protection Act of 1973. Executive Order 11988 emphasizes the environmental aspects of floodplain management. This Order requires that all federal agencies avoid, to the extent practicable, the adverse impacts associated with the occupancy and modification of floodplains and avoid direct and indirect support of floodplain development if there is a practicable alternative. The preferred method for satisfying this requirement is to avoid actions on the base floodplain (100?year floodplain). If an action must occur on the base floodplain, the Order requires that agencies minimize potential harm to people and property and to natural and beneficial floodplain values. Furthermore, the Executive Order directed federal agencies to develop agency-specific procedures to comply with the Order in a manner consistent with agency missions. The National Park Service Floodplain Management Procedural Manual (hereafter referred to as "Manual") was adopted by the agency on July 1, 1993, by Special Directive 93-4. The Manual articulates the National Park Service policy of preserving floodplain natural resource values and minimizing potentially hazardous conditions associated with flooding and provides a procedure for implementation.

In addition to the Manual, other NPS guidance describes activities and procedures associated with floodplain management. These include:

DO/RM 2 Park Planning. Provides guidance on the preparation of general management plans and other park planning documents. In many cases, the actions proposed in park planning documents require floodplain evaluation.

DO/RM 12, Conservation Planning, Environmental Impact Analysis, and Decision-making. Includes the final procedures concerning compliance with legislative and executive requirements which relate to NPS planning activities, including compliance with Executive Order 11988.

DO/RM 18, Wildland Fire Management. Provides guidance on fire management, which can affect floodplains and freshwater resources.

DO/RM 28, Cultural Resource Management. Provides direction for the management of cultural resources, including guidance for management of cultural resources in floodplains, and flood loss protection for storage of cultural artifacts.

DO/RM 40, Dams and Appurtenant Works. Provides an outline of responsibilities of the NPS in the planning, design, construction, and maintenance of dams and a related discussion on floodplain management.

Natural Resource Inventory and Monitoring in this Reference Manual. Provides guidance on inventorying and monitoring park natural resources, including water resources.

Responsibilities

A detailed listing of NPS responsibilities in regard to floodplain management is presented in the Manual.

Floodplain planning and compliance procedures

The goal of NPS floodplain management is to protect riverine, coastal, and special types of floodplains and floodplain functions, and the natural and beneficial values associated with floodplains, and to protect life and property. A brief summary of procedures outlined in the Manual is given below. The procedures set forth in the Manual conform with the requirements provided in the Executive Order as a minimum and in some cases are more restrictive due to high environmental standards consistent with the mission of the National Park Service.

The generalized procedure is shown in a flow chart in the Manual. In brief, the preferred method of compliance with floodplain management in the NPS is to avoid use of the "regulatory floodplain." The regulatory floodplain for a particular case is determined by the action class that an activity on a floodplain fits into as defined in the Manual. Depending upon the action class, one of three regulatory floodplains applies (100-year, 500-year, extreme). If an action is found to be in the applicable regulatory floodplain and relocating the action to a non-floodplain site is considered not to be a viable alternative, then flood conditions and associated hazards should be quantified as a basis for management decision making, and appropriate prescribed actions taken. If it is decided to locate an action in an applicable regulatory floodplain, a formal statement of findings should be prepared. The statement of findings describes the rationale for selecting a floodplain location (i.e. that no practical non-floodplain locations are available), describes the flood-related risk associated with the chosen location, and provides a description of the how the risk will be mitigated.

If floodplain information is inadequate or not available, the NPS or contractors will develop data sufficient to determine the floodplain dimensions. Proposed actions that might affect park floodplains for which there are no floodplain data will be addressed on a case-by-case basis. It must be determined if a proposed action is located in or could affect a floodplain. For many small projects, the cost of determining precise base floodplain boundaries is prohibitive in relation to the action. For such actions, the NPS can choose to use a worst-case analysis by assuming the project is in or will affect the base floodplain.

Where activities in floodplains cannot be avoided, compliance with both EO 11988 and the Manual can be met by either (1) structural mitigation using berms, dikes, and placement of buildings on pillars, which effectively places the activity outside the floodplain, or (2) nonstructural mitigation such as flood warning systems that will allow sufficient warning time to fully evacuate personnel and allow removal of artifacts. It is recognized that NPS property will someday be lost in the latter case and may be lost under structural mitigation efforts, depending upon the flood frequency design of the structures. In all cases where activities in floodplains cannot be avoided, the NPS should take action to minimize harm to or within the floodplain and preserve natural and beneficial floodplain values.

Where floodplain values have been harmed by previous human activity, NPS resource management plans will include actions to reestablish an environment in which the natural ecological systems of the floodplain can function. Where actions must unavoidably occur in floodplains, the NPS will make every possible effort to maintain the integrity of the natural ecosystem to preserve it and its attendant organisms and physical processes. When the opportunity exists, the NPS will not simply preserve, but will enhance the value of floodplains by using them for their educational, recreational, scientific, and similar purposes that are not disruptive of natural ecological conditions. Resource management plans will include inventory and monitoring programs as necessary to evaluate floodplain mitigation and restoration efforts.

In general, cultural resources located in floodplains will be managed to ensure on-site preservation (DO/RM 28 Cultural Resource Management). Floodproofing measures taken to protect the cultural property from the hydraulic and erosive forces of flooding will be designed so as not to adversely affect the integrity of the site.

Portions of floodplains are classified as wetlands by the Fish and Wildlife Service (Cowardin et al. 1979). Further information on this classification system, on-site evaluation procedures, wetlands compliance, and the National Wetlands Inventory is presented under Wetlands Management, below.

Managing floodplain threats from external sources

Activities outside park boundaries can cause impacts on park coastal, riverine, and special area floodplains. The superintendent will work to minimize potential floodplain impacts through active coordination and involvement in the planning and implementation of actions external to, yet affecting, park floodplain values. Activities external to the park often are federal actions and therefore require environmental impact statements or environmental assessments and the NPS becomes involved through the National Environmental Policy Act (NEPA) process (DO/RM12). Nonfederal actions, for the most part, will also trigger some type of review according to state or local zoning or permit requirements.

Some external actions might occur that would threaten park floodplain systems, but which NPS might not discover until after the fact. Examples include an action that is categorically excluded for NEPA compliance by another agency; inadequate public notice during the NEPA process or state or local review processes; actions on private or Native American lands that do not trigger NEPA or other public review processes; and illegal activities. For these reasons, it is important that NPS managers be alert for actions external to the park that would threaten the natural floodplain values or the health and safety of NPS visitors and facilities.

Flood monitoring and mapping

Most floodplain mapping in the United States has been done near major population centers to provide information for the protection of life and property. For the most part, parks are located far from these urban centers and therefore very little floodplain mapping has been completed in or near parks. When a park needs floodplain information that does not currently exist, it is not always necessary to invest in an expensive, detailed engineering analysis. Often, a determination can be made by a qualified professional that an area is not in the applicable regulatory floodplain. Such determinations can be made based on geomorphology, vegetation type, and other physical evidence. However, when a confident determination cannot be made that an action is outside of the regulatory floodplain, particularly when human life and/or substantial investment is involved, a detailed analysis of flood hazard is necessary. Such studies should adhere to standard accepted engineering procedures and factor-in special considerations such as unstable geomorphology, potential for mud and debris flows, and changing land use and water supply conditions. Where possible, the areal extent of design floods should be plotted on high resolution maps and detailed hydraulic conditions (depth and velocity) defined in important locations. This information serves as the basis for decision making for actions located in and near floodplains.

Park staff can gather useful information immediately after a flood event such as records of debris lines on the ground, trees, and stable reference points; records of high-water marks at stable surveyed reference points where water velocity was low; photo-documentation of post-flood effects, and interviews with people knowledgeable about the flood.

Wetland Management

Introduction

Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. More specifically, wetlands form where these conditions occur with sufficient frequency to support plant and animal communities that require saturated or seasonally saturated conditions for growth and reproduction. These specialized habitats are found in a variety of landscape positions, and include riparian wetlands, salt marshes, bogs, marshes, swamps, and mudflats. As a result, they provide a wide variety of critical ecological functions including rare plant habitat, fish and wildlife habitat, flood and erosion control, water quality enhancement, stream-flow maintenance, and many related functions. Wetlands also provide numerous recreation opportunities and are important components of many cultural landscapes.

Unfortunately, wetlands in the United States have been subjected to extensive drainage, filling, and other impacts, resulting in loss of more than half of the wetland acreage that existed in the lower 48 states prior to European settlement. Although regulatory measures have slowed wetland degradation and destruction, losses continue in the United States at a rate of 150,000-200,000 acres annually. Many important wetland areas have escaped destruction through protection within NPS units; however, infrastructure development; oil, gas, and mineral operations; grazing; and other activities within and adjacent to NPS units have the potential to degrade wetlands if they are not located or managed appropriately. This section provides guidance related to protection of NPS wetland resources as well as restoration of degraded or lost wetlands.

NPS authorities and mandates

Specific authorities for protection of NPS wetland resources are found primarily in the NPS Organic Act, Section 404 of the Clean Water Act, and in Executive Order 11990 (Protection of Wetlands), which directs the NPS to (1) provide leadership and take action to minimize the destruction, loss, or degradation of wetlands, (2) preserve and enhance the natural and beneficial values of wetlands, and (3) avoid direct or indirect support of new construction in wetlands unless there are no practicable alternatives and the proposed action includes all practicable measures to minimize harm to wetlands. Executive Order 11990 further directed the NPS and other federal agencies to develop procedures for implementing the Order. DO 77-1: Wetland Protection and Procedural Manual 77-1: Wetland Protection establish such policies and procedures for protecting and managing wetlands within the National Park System in a manner consistent with Executive Order 11990 and NPS Management Policies.

Responsibilities

NPS responsibilities for wetland protection and management consistent with Executive Order 11990 are explained in DO 77-1: Wetland Protection.

NPS wetland policies, standards, and procedures

DO 77-1: Wetland Protection established NPS policies, requirements, and standards for protecting and managing wetlands in the course of carrying out responsibilities related to:

- acquiring, managing, and disposing of NPS lands and facilities;
- construction and related development activities;
- permitting activities as provided for under NPS regulatory authorities; and
- conducting activities, programs, or planning efforts affecting use of NPS lands.

Following is a summary of DO 77-1, with references made to Procedural Manual 77-1 for more detailed implementation procedures.

No net loss policy
The NPS has adopted a goal of no net loss of wetlands and a longer-term goal of net gain of wetlands servicewide through the restoration of natural wetlands.

Requirement to restore wetlands
Where natural wetland characteristics or functions have been degraded or lost due to previous or ongoing human activities, the NPS must, to the extent appropriate and practicable, restore them to pre-disturbance conditions. (See Restoring Wetlands, below.)

Wetland definition and classification standard
Consistent with Department of the Interior directives, the NPS uses "Classification of Wetlands and Deepwater Habitats of the United States" (Cowardin et al. 1979; U.S. Fish and Wildlife Service Report FWS/OBS-79/31) as the standard for defining, classifying, and inventorying wetlands. Under this system, a wetland must have one or more of the following attributes:

at least periodically, the land supports predominantly hydrophytes (wetland vegetation);
the substrate is predominantly undrained hydric soil; or
the substrate is non-soil and is saturated with water or covered by shallow water at some time during the growing season of each year.

These three attributes encompass wetland areas that fall into five categories:

areas with hydrophytes and hydric soils, such as those commonly known as marshes, swamps, and bogs;
areas without hydrophytes but with hydric soils (for example, flats where drastic fluctuations in water level, wave action, turbidity, or high concentration of salts may prevent the growth of hydrophyte);
areas with hydrophytes but non-hydric soils, such as margins of impoundments or excavations where hydrophytes have become established but hydric soils have not yet developed;
areas without soils but with hydrophytes such as the seaweed-covered portion of rocky shores; and
wetlands without soil and without hydrophytes, such as gravel beaches or rocky shores without vegetation.

Wetland inventory requirement
NPS units must conduct unit-wide wetland inventories to help ensure proper management and protection of wetland resources. U.S. Fish and Wildlife National Wetland Inventory maps are based on the Cowardin et al. (1979) definition and classification system, and should be obtained (if available) to help meet basic inventory needs. More detailed (higher resolution and/or more rigorously ground-truthed) wetland inventories must be conducted in areas that are proposed for development or are otherwise susceptible to degradation or loss due to human activities. As part of the wetland inventory process, any known degradation of NPS-managed wetlands and the causes of this degradation (e.g., drainage, filling, mining, nutrient enrichment) should be recorded and used in developing restoration/management plans. All NPS wetland inventories must use the Cowardin et al. (1979) classification system or be cross-referenced to it. Section 5.1 of Procedural Manual 77-1 and Protecting Wetland Resources from Internal Activities, below, provide additional information about wetland inventories.

Applicability of NPS wetland policies and procedures
If a habitat meets the Cowardin et al. (1979) wetland definition, then in most cases it is subject to the policies and procedures of DO 77-1 and Procedural Manual #7-1. Sections 4.1-4.2 of Procedural Manual 77-1 discuss applicability of these policies and procedures in greater detail.

Avoiding, minimizing, and compensating for wetland impacts
For proposed new development or other new activities, plans, or programs that are either located in or otherwise have the potential for direct or indirect adverse impacts on wetlands, the NPS employs a sequence of (1) avoiding adverse wetland impacts to the extent practicable, (2) minimizing impacts that could not be avoided, and (3) compensating for remaining unavoidable adverse wetland impacts via restoration of degraded wetlands. Compensation for wetland degradation or loss must be at a minimum 1:1 ratio (i.e., an acre of comparable wetland type must be restored to compensate for each acre degraded or destroyed). Section 5.2 of Procedural Manual 77-1 explains procedures for implementing this sequence.

"Statement of findings" requirement and relationship to NEPA
Actions proposed by the NPS that have the potential to have adverse impacts on wetlands must be addressed in an environmental assessment or an environmental impact statement. If the preferred alternative in an environmental impact statement or assessment will result in adverse impacts on wetlands, a "statement of findings" documenting compliance with Director's Order 77-1 and Procedural Manual 77-1 must be completed and attached to NEPA documents (some excepted actions are addressed in section 4.2 of the Procedural Manual). Superintendents oversee preparation of statements of findings, and the Chief of the NPS Water Resources Division certifies (1) the adequacy of wetland-related technical analyses, and (2) consistency with servicewide implementation of the Director's Order and accompanying procedures. Regional directors have final approval authority for statements of findings. Detailed information regarding statement of findings contents, review processes, signature procedures, and relationships to the NEPA process are explained in section 5.3 of Procedural Manual 77-1.

Enhancing wetland values
Where appropriate and practicable, NPS units should enhance natural wetland values by using them for educational, recreational, scientific, and similar purposes that do not disrupt natural wetland functions.

Other authorities and compliance requirements

Section 404 of the Clean Water Act
Compliance with section 404 of the Clean Water Act is mandatory for all actions with the potential to discharge dredged or fill material into waters of the United States, including wetlands. NPS managers should contact the appropriate U.S. Army Corps of Engineers local or district office early in the project planning process regarding necessary permits for such actions. As part of the permit process, the Corps may require compensation for unavoidable wetland impacts. In such cases, NPS managers should work with the Corp to identify potential wetland restoration projects that meet the compensation requirements of both agencies.

Fish and Wildlife Coordination Act and Endangered Species Act
U.S. Fish and Wildlife Service recommendations under the Fish and Wildlife Coordination Act (generally made as part of the 404 permit and NEPA coordination processes) must be considered and implemented to the maximum extent practicable. The Fish and Wildlife Service has the authority to require mitigation measures as appropriate under the Endangered Species Act.

Other federal laws and directives
Activities in or affecting wetlands may also be subject to provisions of the Rivers and Harbors Act (section 10), the Wild and Scenic Rivers Act, the Coastal Zone Management Act, the Coastal Barrier Resources Act, the National Environmental Policy Act, the National Historic Preservation Act, and NPS director’s orders and procedures for implementing Executive Order 11988 (Floodplain Management).

Compliance with state and local laws and regulations
Parks must comply with state and local laws and regulations where these entities have jurisdiction. For example, parks are required to fully comply with state water quality standards. Parks are also required by the Coastal Zone Management Act to ensure that proposed actions are consistent with state coastal zone management plans "to the maximum extent feasible." Even in matters where state and local governments do not have jurisdiction, NPS units should endeavor to ensure consistency with state and local laws and regulations related to wetland protection, to the extent practicable.

Protecting wetlands from external activities

Participate in regional planning and permit review processes
Many actions outside NPS boundaries that affect wetlands within NPS units must go through some form of zoning, permitting, or similar process. NPS managers should investigate and, where possible, actively participate in area planning processes affecting water resources management, development, agriculture, and land management. This may be accomplished by coordinating with other federal agencies such as the Environmental Protection Agency, the Army Corps of Engineers, the Bureau of Land Management, and the U.S. Forest Service; state and local environmental regulatory and planning agencies; regional water boards; etc. The NEPA process for federally funded projects is a particularly important opportunity to see that NPS wetland resources are protected.

It is especially important to be involved in the review processes for the various types of Clean Water Act permits (e.g., section 402 National Pollutant Discharge Elimination System point source discharge permits and section 404 dredged or fill discharge permits). Park managers should be aware that under an agreement between the Department of the Army and the Department of the Interior, the Fish and Wildlife Service serves as the point of contact for the NPS and other Department of Interior agencies regarding 404 permits. In many cases, the Army Corps of Engineers contacts the Fish and Wildlife Service (not the affected park unit) regarding 404 permit applications that could adversely affect NPS resources. Fish and Wildlife Service staff must then determine if there is a potential for an adverse effect on park resources before contacting the park. Therefore, it is important to establish a relationship with the relevant Fish and Wildlife Service office to ensure that the park is informed of any permit applications in the vicinity.

In some areas of the country, the Environmental Protection Agency conducts "advanced identification" programs in which it identifies critical wetland areas where 404 permits are unlikely to be granted. NPS managers can contact the applicable Environmental Protection Agency regional office to inquire about and offer assistance in identifying wetlands outside park borders that, if adversely impacted, may affect park resources.

Ensure that appropriate legal and regulatory protections are in place
Consistent with the Clean Water Act, NPS units should ensure that the highest possible water quality standards are in place to protect park waters. If possible and appropriate, Outstanding National Resource Waters or equivalent designation should be attained for high-quality park waters, and appropriate non-degradation standards should be established. In most cases these water quality standards and "use designations" are developed and implemented by the state or by interstate commissions.

Where water quantity/water rights is an issue with respect to protecting wetlands (e.g., volume, timing, spatial distribution of inflows, or impacts due to withdrawals or drainage), NPS units should use the appropriate planning, regulatory, and legal means to preserve or attain hydrologic conditions necessary to meet mandates for preservation and protection of wetland ecosystems.

Monitor resources
NPS units should ensure that properly designed water resource monitoring stations (quantity and quality) are in place at sites where waters that may be impacted by external activities cross park boundaries into wetland areas. In addition, it may be necessary to monitor biotic resources in wetlands to document existing conditions and evaluate impacts.

Protecting wetland resources from internal activities

Obtain and use wetland inventory data
The first step in avoiding wetland impacts associated with NPS activities is to obtain and use adequate wetland inventory maps. Because of limitations in scale, border resolution, minimum detectable wetland size, limited ground-truthing, and other constraints, standard National Wetland Inventory wetland maps should be considered approximate, and omission and classification errors should be anticipated. While use of this base inventory information is sufficient for avoiding wetland impacts in most initial project planning, a more detailed on-site evaluation should be conducted for each project to locate any unmapped wetlands, to determine wetland borders and characteristics more accurately, and to otherwise ensure that projects will not impact wetlands. Some states or other entities have had the National Wetland Inventory maps digitized. Parks wishing to obtain digital data should contact the Fish and Wildlife Service regional wetland coordinator regarding availability (also available at www.nwi.fws.gov).

If a park has not yet been mapped by the National Wetland Inventory, the Fish and Wildlife Service regional wetland coordinator should be contacted to obtain an estimated date of completion. Several options are available if this date is not sufficiently close to meet NPS wetland protection requirements. One option is to explore a joint effort with the Fish and Wildlife Service to expedite National Wetland Inventory mapping. Parks should contact the NPS Water Resources Division regarding an interagency agreement between the NPS and the Fish and Wildlife Service to facilitate mapping, typically on a fifty/fifty cost- sharing basis. NPS units can decrease omissions and increase classification accuracy by expanding the ground-truthing effort beyond standard National Wetland Inventory protocols and by participating directly in other phases of the inventory process. Expanded ground-truthing is also an excellent opportunity to associate other attributes to mapped and classified wetland polygons, such as dominant species associations, nonnative or rare species observations, threats, impacts, physical habitat characteristics, wildlife observations, and so on. Other advantages include high project priority and savings associated with equipment and trained personnel offered by the Fish and Wildlife Service. (The NPS may be responsible for 100% of costs for digitizing maps or for re-mapping areas already completed for the National Wetlands Inventory.)

Another option is to have contractors conduct other larger scale, more detailed mapping than is possible through the National Wetlands Inventory program. This option has the potential for yielding very high resolution, accurate inventory results geared specifically to the resource management needs of the park. However, it is a more labor intensive and costly option, and may not be practical for conducting many parkwide wetland inventories.

Conduct on-site wetland evaluations at proposed development sites
On-site wetland evaluations should always be conducted at proposed development sites to verify that wetland impacts would, in fact, be avoided or to develop appropriate mitigation measures if wetland impacts cannot be avoided. First, a preliminary wetland analysis should be performed, followed (if necessary) by definitive wetland delineation.

A preliminary analysis should be conducted by persons trained in wetland plant identification and ecology, hydrology, and soil science. The analysis involves a search for "field indicators" of the soil, vegetation, and hydrologic characteristics comprising the Cowardin et al. (1979) wetland definition. If this investigation clearly rules out the presence of wetlands that could be impacted by the project, then no further investigation related to wetland protection or compliance is necessary. However, if this investigation indicates presence of wetlands, or the answer is in doubt, then more definitive wetland delineation work is necessary. The NPS Water Resources Division can provide guidance for conducting the preliminary analysis and in determining the need for formal delineation.

The preliminary analysis should include the following steps.

Any wetlands or other waters near or at the site that were identified in the wetland inventory should be located in the field. The preliminary evaluation for these areas should focus on ensuring that the actual wetland borders do not extend onto the proposed site and that no wetlands will otherwise be impacted by the project via contamination, offsite drainage, or other effects.
The site should be evaluated for areas where wetlands that may have been missed in the inventory are most likely to occur (e.g., small isolated depressions or areas not readily visible from aerial photography due to tree canopy or other obstructions). In many cases, the existence of such wetlands will be immediately clear based upon knowledge of local wetland types or obvious presence of wetland characteristics. (Wetlands adjacent to or downstream from the proposed site should also be noted, and potential impacts should be considered.)
An assessment of disturbance at the site should be made, such as drainage, filling, farming, or other factors that may have altered the soil, hydrology, or vegetative features at the site. Awareness of such disturbance not only will help avoid erroneous interpretation of wetland field characteristics, but will also help identify impacted areas that should be considered for restoration rather than development.

In the rare situation where the preliminary evaluation indicates the possibility of wetland impacts and no practicable alternatives exist for a project, the NPS wetland procedures must be followed and the Army Corps of Engineers must also be contacted to ensure compliance with section 404 of the Clean Water Act. Even if the Army Corps of Engineers determines that a 404 permit is not required, compliance with Director’s Order 77-1 and Procedural Manual 77-1 is still required. In either case, definitive wetland delineation must be performed at the site as discussed in the following section.

Definitive wetland delineations

Wetlands subject to section 404 of the Clean Water Act ("jurisdictional wetlands")
The Army Corps of Engineers uses the 1987 "Corps of Engineers Wetlands Delineation Manual" to determine if a site is a "jurisdictional wetland" (one that meets the regulatory definition of a wetland under Corps' regulations for implementing section 404 of the Clean Water Act). Under the regulatory definition, wetlands are:

"... those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions."

Only about 85-90% of the habitats classified as wetlands under the Cowardin et al. (1979) definition and classification system are also Army Corps of Engineers "jurisdictional wetlands." This is because the Corps definition only recognizes sites as wetlands if they have all three of the diagnostic characteristics (hydrophytic vegetation, wetland hydrology, hydric soil). In contrast, the Cowardin system recognizes that many unvegetated sites (e.g., mudflats, unvegetated stream shallows, playas) or sites lacking soil (e.g., rocky shores) are still wetland habitats, but may lack wetland vegetation or soil characteristics due to natural chemical or physical factors. However, such sites are still recognized by the Army Corps of Engineers as other "waters of the United States" or "special aquatic sites," and are regulated under other provisions of the Clean Water Act.

The Army Corps of Engineers local or district office will determine the need for sending staff to delineate jurisdictional wetlands at the site of the proposed project, and may be able to provide other siting advice to help eliminate wetland impacts. However, backlogs at Corps' offices for field evaluations often cause unacceptable delays in NPS project planning and implementation. In such cases, NPS units may choose to have well-qualified personnel or contractors perform delineations and have the results approved by the Corps. In such cases, the product should include jurisdictional wetlands, other wetlands as defined under Cowardin et al. (1979), and any other waters regulated by the Army Corps of Engineers (e.g., deepwater habitats).

Wetland types or actions NOT subject to section 404 of the Clean Water Act
Even when the preliminary analysis indicates wetland impacts at a site, the Army Corps of Engineers may determine that a 404 permit is not required. This may occur either because the wetland does not meet the regulatory definition or because the action is exempt from 404 regulation. In such cases, the broader wetland protection requirements of Executive Order11990 (as implemented through DO 77-1 and Procedural Manual 77-1) still apply, and delineation is necessary for NPS compliance purposes.

Final siting considerations
In the final siting and design process, NPS units must follow policies and procedures discussed in DO 77-1 and Procedural Manual 77-1, including minimizing unavoidable impacts on wetlands at the site. This should include orienting development layouts to minimize impacts, using "Best Management Practice" for water quality protection, and establishing sufficient buffer areas to protect against adverse impacts on adjacent wetlands. Considerations in determining adequate buffer zones may include minimizing offsite drainage, erosion, or noise impacts, preserving fish and wildlife habitats and migration corridors, protecting recreational or cultural values, and many other factors.

Restoring wetlands
D0 77-1 states, "Where natural wetland characteristics or functions have been degraded or lost due to previous or ongoing human activities, the NPS will, to the extent appropriate and practicable, restore them to pre-disturbance conditions." This may range from relatively straightforward tasks such as removing small amounts of fill to complex tasks such as remediating contaminant spills or completely recontouring and revegetating abandoned gravel mine sites.

The key to most complex restorations is to gain an understanding of the relationships between site hydrology (especially the dynamics of water table fluctuations and flood regimes), desired vegetation communities, soil characteristics, and topography. One of the best ways to accomplish this is to locate appropriate undisturbed reference areas that can serve as models for restoration at the disturbed site. By studying hydrology, plant community, soil, and topographic relationships at the reference area, the disturbed area can be designed to mimic these characteristics. Factors such as fire regime, water quality, adjacent land use, invasive nonnative plants, sedimentation, and rare species are but a few of the additional complexities that must be addressed in many restoration plans. Therefore, "cookbook" approaches to wetland restoration are rarely successful.

Wetland restoration is a relatively new and complex science. Consequently, the failure rate for restoration projects can be quite high unless performed by experienced specialists willing to take great care in the design, implementation, and post-project monitoring and follow-up treatment phases. Some factors to consider in restoration include the following.

Historical aerial photography series and other historical sources often provide critical information regarding pre-disturbance site conditions, responses of the site to disturbance over time, and potential reference sites.
Clear goals related to target plant community types, faunal habitat characteristics, and so on should be established for wetland restoration projects. These goals should be used to assist in design, implementation, monitoring, evaluation of success, and follow-up management prescriptions. Designs should incorporate self-sustainability as a project goal to the maximum extent possible.
Failure to adequately understand and restore appropriate site hydrology is the greatest cause of wetland restoration failure. Therefore, careful attention to hydrology and its relationship to vegetation, soils, and topography is an essential component of restoration design. This information is best obtained by studying these relationships at the target site and reference areas. But, even if this information is obtained and used in design, it is still often prudent to incorporate sufficient topographic variability to account for imperfect understanding or ability to precisely reproduce hydrology-plant-soil relationships.
Site-specific revegetation decisions are also important factors in project success, and should be made by wetland revegetation experts. In some cases it is sufficient to let existing seedbanks and adjacent seed sources provide "natural" recolonization of desired plant communities after hydrologic restoration, recontouring, soil amendments or other measures have been implemented, as necessary. In other cases, such as when erosion or nonnative plant invasion are major concerns or where "natural" recolonization is expected to be limited, contractors with well-documented planting experience and success in wetland restoration may need to be employed. Poor planning in this area may lead to severe nonnative plant problems or wasted money when natural revegetation overwhelms unnecessary plantings or plants die due to poor greenhouse, transportation, or planting techniques.
Careful supervision of earthmoving equipment operators, planting contractors, and other implementation steps must be performed by experienced personnel with the ability to ensure that plans are carried out in the field as designed. In many wetland systems, elevations off by a few inches can result in failure to meet project objectives. Also, most earthmoving contractors have little or no experience in the specific requirements of ecosystem restoration and, for example, may need to be directed to incorporate variability in topography rather than constant grades or flat surfaces common to other types of construction.
Even for the most meticulously designed projects, post-project monitoring and the flexibility to incorporate mid-course or post-implementation adjustments should be incorporated into the overall project design. For example, post-implementation vegetation or hydrologic monitoring may indicate the need for some spot replanting, regrading, changes in prescribed fire regimes, nonnative plant control, or other adjustments.

Sources of additional wetland restoration guidance and methods include Interagency Federal Guidance on Wetland Restoration, Creation, and Enhancement (Interagency Workgroup on Wetland Restoration 1999), Stream Corridor Restoration: Principles, Processes, and Practices (Federal Interagency Stream Restoration Working Group 1998), and Wetland Creation and Restoration: The Status of the Science (Kusler and Kentula 1990). These references not only provide valuable guidance, but also contain expanded lists of references that can direct readers to more specialized or regional information. Internet sources for wetland restoration bibliographies include sites run by the U.S. Geological Survey, Biological Resources Division (www.npwrc.usgs.gov/resource/literatr/wetresto/wetresto.htm), Wetlands International and the Association of State Wetland Managers ( http://www.aswm.org/propub/pubs/aswm-publist.htm), and the National Wetlands Research Center (www.nwrc.usgs.gov/library.htm). The U.S. Environmental Protection Agency also maintains a valuable website for restoration and many other wetland-related topics ( www.epa.gov/owow/wetlands).

Aquatic Resource Restoration

Introduction

Aquatic resources include rivers, streams, lakes, estuaries, oceans/bays, wetlands, riparian zones, aquifers, and the biotic resources they support. Aquatic resource restoration is the reestablishment of aquatic ecosystem structure and function as closely as possible to pre-disturbance conditions. When reestablishment of pre-disturbance or "natural" conditions is not possible or feasible, restoration may involve the recovery of disturbed ecosystem structure and function to a desired condition that reflects many of the elements of the dynamic, self-sustaining pre-disturbance ecosystem. In all cases restoration requires an analysis of the causes of degraded or impaired resource conditions, the establishment of aquatic resource "condition objectives," and the development and implementation of a plan to achieve those objectives. Monitoring is important in determining whether restoration objectives are being achieved and may provide feedback when the responses to restoration actions are uncertain or when restoration is occurring in an "adaptive management" context.

Restoration requires a good understanding of the relationships between the various physical and biological components of the aquatic ecosystem and the reasons for their degraded conditions. Aquatic resource restoration may involve the recovery of (1) hydrologic regimes, including watershed runoff conditions, stream flows, lake levels, and groundwater tables; (2) water quality; (3) fluvial geomorphic processes and associated landscape features; and/or (4) wetland, riparian, and aquatic vegetation conditions and associated native animal populations.

Aquatic ecosystems are dynamic and often very resilient. Restoration may involve nothing more than eliminating or effectively controlling the cause(s) of degraded resource conditions and permitting recovery or "healing" to occur naturally. More active aquatic resource restoration may involve interventions to reestablish physical habitat components, conditions, and processes, and then permitting passive recovery of dependent biological communities and associated ecosystem functions. Direct species interventions may be required in some cases when native species are absent from the aquatic ecosystem or when nonnative species are present.

Restoration of water quality generally is accomplished within the context of state clean water programs (See Water Quality Management under Water Resources Management in this section). Similarly, many laws and policies cover the restoration of native or endangered species, or the management of nonnative species (See Native Fish and Aquatic Biological Communities in this section.) Restoration of surface and groundwater regimes may require the acquisition of water rights (See Water Rights under Water Quantity Management in this section).

Because resource responses to restoration actions may be uncertain, it often is a good idea to implement restoration as part of an "adaptive management" process. Adaptive management requires monitoring to document the response of resource conditions to restoration, and provides the information needed to periodically review and evaluate whether modifications in the restoration program are needed to achieve restoration objectives. Restoration monitoring requires careful experimental design to be effective.

Stream and Riparian Resources

Stream channels and their associated floodplains and riparian zones are strongly interacting and dynamic landscape elements. Stream corridors integrate the attributes, conditions and processes of their watersheds and influence the evolution of landscapes at the local, regional, and watershed scales. As such they are highly vulnerable to degradation stemming both from altered watershed conditions and activities occurring in channels and associated riparian zones. In some parks, stream corridors have been degraded by activities occurring within the park; in other parks upstream watershed activities have resulted in degradation of park stream and riparian systems. The same dynamic, high-energy integrated characteristics that make streams vulnerable to degradation also make many streams resilient and capable of "healing" themselves when the causes of degradation are identified and effectively controlled.

Stream and riparian resource restoration generally involves seven major steps:

Inventory and analysis of present ecological conditions.

Determination of the ecological conditions and processes that existed prior to disturbance of the stream corridor or its watershed and comparison of present conditions to pre-disturbance conditions.

Analysis of the causes of altered or impaired ecological conditions.

Identification of management opportunities and constraints.

Development of quantifiable/measurable stream corridor ecological condition objectives.

Development and implementation of restoration actions.

Monitoring the attainment of restoration condition objectives and using monitoring information to modify restoration actions if necessary.

The symptoms of degraded stream and riparian condition are often easily seen, although they may be subtle and difficult to identify at times. For example, channel incision, accelerated bank erosion, degraded riparian vegetation, and the presence of nonnative fishes may be very evident conditions. However, the challenge in stream and riparian restoration is to adequately understand the causes of stream channel and riparian zone degradation and to factor that understanding into the restoration design. This problem analysis step often requires a sophisticated and interdisciplinary understanding of the many physical and biological interactions within the stream corridor and between the stream and its watershed. For example, accelerated bank erosion may stem from local conditions such as instream modifications or degraded riparian vegetation conditions, or it may stem from changes at the watershed scale in the balance between sediment delivery and flows and sediment transport capacities. Providing protection to an eroding streambank may not be stream restoration but rather may be simply patching a symptom of a larger degradation problem.

There are no standard steps to follow in the analysis of stream corridor structure, function, and condition. The analysis needs to be undertaken as a professional endeavor on a case-by-case basis. It may involve an understanding of:

hydrology and "instream flows,"
erosion, sediment yield, and sediment transport,
floodplain/riparian vegetation,
channel (fluvial) processes and channel-riparian zone interactions,
water quality, and
aquatic and riparian species, habitats, and interactions.

Given effective condition assessments, problem analyses, and the establishment of restoration condition objectives, the task then is to develop and implement a feasible and sustainable set of restoration actions. Restoration actions may be influenced by budgetary realities, political and jurisdictional considerations, legal and regulatory sideboards, or limitations in scientific understanding or restoration technology. In most cases restoration will involve some degree of management or mitigation of the land uses, stream developments, or flow manipulations that resulted in stream corridor degradation. In many park situations, stream corridor restoration may need to focus on the reestablishment of "good condition" streambank and riparian vegetation (and associated instream woody debris). Vegetation restoration may occur passively once the causes of degradation are mitigated, or it may require "nudging" in the form of active seeding or planting. Bioengineering techniques may sometimes be appropriate if habitat conditions are unsuitable for natural revegetation. Restoration of flow regimes modified by diversions, groundwater pumping, or dam operations may be a complex process requiring effective interactions with such things as water law, river system operations processes, and Federal Energy Regulatory Commission (FERC) re-licensing. The restoration of incised or entrenched stream systems presents especially difficult challenges. Often it is tempting to employ engineered structures such as drop structures or check dams to elevate channel base levels. These techniques are difficult to implement successfully, and qualified professionals on a site-specific basis must carefully consider their use. Similarly, the use of instream structures to enhance fisheries habitat has had only very marginal success. Instream habitat structures are vulnerable to high flows, often interfere with natural stream processes and/or induce unintended secondary effects. All structural approaches to stream and riparian restoration need to be considered very cautiously on a case-by-case basis by qualified professionals, and should only be considered after careful, objective problem analysis and the development of restoration condition goals, objectives, and timeframes.There are many sources of information on stream and riparian resource restoration. An integrated compilation of much of this information was prepared by the Federal Interagency Stream Restoration Working Group, 1998, Stream Corridor Restoration Principles, Processes and Practices. This compendium is available online at www.usda.gov/stream_restoration.WetlandsDO 77-1 states: "Where natural wetland characteristics or functions have been degraded or lost due to previous or ongoing human activities, the NPS will, to the extent appropriate and practicable, restore them to pre-disturbance conditions." This may range from relatively straightforward tasks such as removing small amounts of fill to complex tasks such as remediating contaminant spills or completely recontouring and revegetating abandoned gravel mine sites.

Historical aerial photography series and other historical sources often provide critical information regarding pre-disturbance site conditions, responses of the site to disturbance over time, and potential reference sites.
Clear goals related to target plant community types, faunal habitat characteristics, and so on should be established for wetland restoration projects. These goals should be used to assist in design, implementation, monitoring, evaluation of success, and follow-up management prescriptions. Designs should incorporate self-sustainability as a project goal to the maximum extent possible.
Failure to adequately understand and restore appropriate site hydrology is the greatest cause of wetland restoration failure. Therefore, careful attention to hydrology and its relationship to vegetation, soils, and topography is an essential component of restoration design. This information is best obtained by studying these relationships at the target site and reference areas. But, even if this information is obtained and used in design, it is still often prudent to incorporate sufficient topographic variability to account for imperfect understanding or ability to precisely reproduce hydrology-plant-soil relationships.
Site-specific revegetation decisions are also important factors in project success, and should be made by wetland revegetation experts. In some cases it is sufficient to let existing seedbanks and adjacent seed sources provide "natural" recolonization of desired plant communities after hydrologic restoration, recontouring, soil amendments, or other measures have been implemented, as necessary. In other cases, such as when erosion or nonnative plant invasions are major concerns or where "natural" recolonization is expected to be limited, planting contractors with well-documented experience and success in wetland restoration may need to be employed. Poor planning in this area may lead to severe nonnative plant problems or wasted money when natural revegetation overwhelms unnecessary plantings or plants die due to poor greenhouse, transportation, or planting techniques.
Careful supervision of earthmoving equipment operators, planting contractors, and other implementation steps must be performed by experienced personnel with the ability to ensure that plans are carried out in the field as designed. In many wetland systems, elevations off by a few inches can result in failure to meet project objectives. Also, most earthmoving contractors have little or no experience in the specific requirements of ecosystem restoration and, for example, may need to be directed to incorporate variability in topography rather than constant grades or flat surfaces common to other types of construction.
Even for the most meticulously designed projects, post-project monitoring and the flexibility to incorporate mid-course or post-implementation adjustments should be incorporated into the overall project design. For example, post-implementation vegetation or hydrologic monitoring may indicate the need for some spot replanting, regrading, changes in prescribed fire regimes, nonnative plant control, or other adjustments.

Native Fish and Aquatic Biological Communities

NPS Management Policies states "the National Park Service will maintain as parts of the natural ecosystems of parks all native plants and animals"(4.4.1). Management emphasis will be on minimizing human impacts on native animals and the dynamics of natural animal populations. Management of harvested aquatic species will seek to preserve or restore natural aquatic habitats and the natural abundance and distribution of native aquatic species, including fish, together with the associated terrestrial habitats and species (Sec. 4.4.2 – 4.4.3). Resource managers are directed to restore native species to parks whenever all the following criteria can be met:

1. Adequate habitat to support the species either exists or can reasonably be restored in the park, and if necessary also on adjacent public lands and waters, and, once a natural population level is achieved, the population can be self- perpetuating;

2. The species does not, based on an effective management plan, pose a serious threat to the safety of people in parks, park resources, or persons or property outside park boundaries;

3. The genetic type used in restoration most nearly approximates the extirpated genetic type; and

4. The species disappeared, or was substantially diminished, as a direct or indirect result of human- induced change to the species population or to the ecosystem. (Sec. 4.4.2.2).

Aquatic Restoration Concepts

Aquatic biological communities in national park units are often in need of restorative actions due to three main causative factors: (1) physical habitat alteration; (2) the introduction of nonnative species; and/or (3) overuse from recreation or commercial fishing in or outside of parks. If the physical habitat has been altered, restoration of the native aquatic community may be more a function of habitat restoration rather than direct species restoration. If nonnative species encroachment is the problem, actions will need to be focused on control or elimination of the nonnative species. Therefore, understanding the cause of the changes that have occurred in the native fish or aquatic biological community is a critical first step in addressing restoration. This information will direct the type of actions that are needed to restore the native biological components, whether those components of concern are fish, aquatic invertebrates, or vegetation.

Declines in fish populations due to fishery overharvest seldom will require manipulative management actions to restore the population. Reducing harvest through increased regulation and control of harvest activities should allow population recovery if habitat is available and nonnative species competition is not a factor.

Actions taken toward the artificial enhancement of habitat or populations beyond naturally occurring carrying capacities should be entirely avoided as these are in opposition to NPS purposes and mandates.

Restoration due to changed habitat conditions
Physical alteration of stream, river, lake or riparian habitats can and usually will have far reaching affects on biological communities. Physical changes can result in altered water quality and chemistry or changes in the geomorphologic characteristics of the stream due to altered flows, erosion, or watershed level impacts. Streams or rivers can become out of balance due to watershed alterations, riparian area grazing, water diversions, land clearing and/or changes in flow volume and timing. When this occurs, associated changes in water temperature, habitat accessibility, sediment transport, river depositional processes, nutrient transport, and numerous other physical, chemical, and biological processes occur. These changes will change the suitability of the habitat to support specific biological components, particularly in the same proportions or balance as they were previously. Some species may be favored while others are negatively impacted. Physical habitat changes may allow the invasion of species previously not present and the loss of previously occurring species. Physical habitat changes may result in the loss of important spawning substrate, eliminate the ability of insect populations to reproduce, result in the annual stranding of larval or juvenile fish, expose species to predation that would not normally occur, or result in many other negative impacts to the aquatic community.

If the biological community changes within the system are thought to be due to physical alterations that have occurred in the aquatic habitat, efforts should first be directed at restoring the naturally functioning water body (see above sections on Stream and Riparian Resources and Wetlands). The naturally occurring, native biological community cannot be restored if the habitat and water conditions creating that habitat are not suitable and supportive of that community. Once the natural physical attributes of the water body are restored, aquatic community restoration may follow unaided. Generally, makeshift solutions or "mitigating actions" to altered habitat conditions will not be successful.

For example, if stream flow and transport characteristics have been altered such that necessary spawning gravel is no longer available to a fish population, the artificial creation of spawning gravel sites will not be a long-term self-sustaining solution. In this situation, the appropriate management strategy would include a professional evaluation of the river's geomorphological characteristics and restoration of natural stream stability and dynamics, which would result in the natural redeposition and maintenance of the required habitat. Likewise, if instream woody debris and cover have become depleted, mitigative actions involving the artificial placement of structures or material to provide habitat should be avoided as they are not likely to be self sustaining and may alter flow such that additional erosional processes are induced. Instead, the central cause of the loss of habitat should be investigated and restored, as opposed to mitigative actions, if at all possible.

Occasionally, alterations that have occurred within the habitat will allow a species to invade that remains even when the habitat is restored. In such cases, intervention involving physical removal and active restoration efforts as described in the following paragraphs may be required.

Restoration due to influences of nonnative species
The introduction of nonnative species into aquatic environments can result in displacement, competition, predation, or an artificially increased food source for the native biological component(s). NPS Management Policies states that "Exotic species will not be allowed to displace native species if displacement can be prevented." (Sec. 4.4.4). Restoration of native aquatic populations that have been impacted by the introduction of one or more nonnative species will usually require physical intervention, capture, and removal of the nonnative species. Such restoration may also require supplemental restocking of the native species.

Before nonnative species removal or control management programs are launched, careful and full evaluation should be made of the stream, lake, or river habitat conditions. Has the environment been altered such that the nonnative species is favored or able to occur? Is there a critical segment of habitat that the nonnative species requires that is not natural or is not critical to the native species? If a nonnative species can be eliminated through habitat restoration (or in some cases manipulation), habitat restoration should be accomplished prior to attempting direct removal and control measures within the stream community. In either case, professional assistance should be sought if the park staff does not contain a professionally trained aquatic ecologist or fisheries biologist.

Direct restoration measures will usually require severe treatment of the aquatic community either through poisoning of all habitat used by nonnatives within the area to be restored or temporary water diversion and clean-up of the desired habitat. In either case, a high risk of the loss of genetic diversity or integrity of the natural population is likely to occur. NPS Management Policies requires that natural resource managers "strive to protect the full range of genetic types (genotypes) of native plant and animal populations in the parks by perpetuating natural evolutionary processes and minimizing human interference with evolving genetic diversity." (Sec. 4.4.1.2). This requires that a full understanding of the species composition and genetic diversity of the existing aquatic community be obtained before restoration actions begin. An adequate supply of specimens of the desirable native species needs to be collected and retained for recolonization of the habitat following treatment if the same genetic strains are not available from similar habitats in adjacent or local areas. Sufficient expertise should be sought to ensure that the native species of concern can be retained safely and will be available for reintroduction. If one or more native species have become extirpated from the area to be restored, someone with expertise and understanding of the genetics of the species in question should be consulted prior to the introduction of specimens caught elsewhere. NPS Management Policies require that all resource management actions involving planting or relocating species, subspecies, or varieties will be guided by knowledge of local adaptations, ranges, and habitat requirements and detailed knowledge of site ecological histories. (Sec. 4.4)

Permanent reduction or elimination of a nonnative species through control or targeted harvest programs are seldom successful and are not recommended if natural aquatic community restoration is the management goal. Control programs often waste considerable money, time, and effort without ever attaining the goal of full aquatic community restoration.

Restoration considerations
Aquatic resources are often directly linked, and present a continuous pathway of movement and habitat availability with areas outside of the park. This connectivity will often influence the feasibility of restoration actions. Many parks have specific provisions within their enabling legislation directed at fishery or aquatic resources that may call for stocking programs to continue, fishing to continue under state control and direction, or other provisions that will influence the feasibility and legality of undertaking native species restoration actions. Local economic or potential political ramifications need to be seriously considered and these factors balanced against the extent to which current conditions are influencing the overall achievement of park management objectives. Restoration actions will often be controversial, and a good base of resource knowledge and purpose will be needed to support controversial proposals. Consideration should also be given to the likelihood that restored populations or aquatic communities will remain that way once the project is accomplished. For example, if native fish populations have been suppressed due to the introduction of a popular nonnative gamefish species, is this species very likely to be reintroduced illegally by fishermen once restoration has occurred?

When contemplating the need for restorative actions involving aquatic biological communities, the following factors should be considered:

What are the specific legislatively mandated purposes of the park unit, and are there specific provisions within the units enabling legislation that may influence management objectives with regards the aquatic biological community in questions?
What are the park’s jurisdictional authorities and do they have the authority to manipulate the aquatic community to accomplish restoration goals?
To what extent is the altered aquatic community affecting the ability of the park to meet its overall management objectives, and what affect will restoration have on meeting these objectives?
How practical is it to accomplish the desired restoration and can the populations be maintained once restoration is accomplished?
What activities are occurring in waters around and adjacent to the park that may influence the ability of the park to accomplish or maintain the restoration goals?
Are there political ramifications to the proposed restoration and will the project be acceptable to the general public and political interests?
What will be the cost in dollars and is the restoration cost-effective?

As with any natural resource restoration efforts, a successful and logical approach to accomplishing restoration calls for the following steps in implementing the program:

Fully understand and document existing conditions.
Carefully and fully identify conditions desired (project objectives).
Identify the cause of the resource change from the desired conditions.
Identify the actions necessary to remove the cause of change.
Plan steps to necessary to implement the needed restoration actions (this may include public involvement, NEPA assessments, management briefings, political contacts, and cooperative planning with other state or federal agencies).
Implement the actions.
Monitor for success and document results.

A final guideline is that restoration of aquatic biological communities or fish populations will in all likelihood be an interative process and adaptive management approaches may be needed. Monitoring of results is critical to determining success. Aquatic communities or individual fish populations may take five or more years to stabilize following restoration actions, depending on the level of disturbance. Without follow-up monitoring, project success or necessary adaptive actions cannot be determined.

Other Aquatic Resource Restoration Topics

Additional topics related to aquatic resource restoration may include water quality restoration, lake restoration, estuarine restoration, coastal marine resources restoration, and the restoration of groundwater resources. Each of these topics is complex and mitigative approaches are quite often site specific. It is beyond the scope of this document to address all the approaches to these issues, though technical assistance in resolving these issues may be available from the Water Resources Division.

Freshwater Resources Management Table of Contents | RM#77 Table of Contents

TOP OF PAGE