Regulatory Guide 4.11

Terrestrial Environmental Studies for Nuclear Power Stations

ML003739930
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Issue date:	08/31/1977
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Revision 1 August 1977 U.S. NUCLEAR REGULATORY

COMMISSION

REGULATORY

GUIDE OFFICE OF STANDARDS

DEVELOPMENT

REGULATORY

GUIDE 4.11 TERRESTRIAL

ENVIRONMENTAL

STUDIES .FOR NUCLEAR POWER STATIONS

A. INTRODUCTION

The Nuclear Regulatory Commission's policy and procedures for preparing and processing en vironmental impact statements and related docu ments pursuant to Section 102(2)(C)

of the National Environmental Policy Act of 1969 (Public Law 91 190, 83 Stat. 852) are set forth in 10 CFR Part 51, "Licensing and Regulatory Policy and Procedures for Environmental Protection." Regulatory Guide 4.2, "Preparation of Environmental Reports for Nuclear Power Stations," identifies the information needed by the NRC staff in its assessment of the potential en vironmental effects of a proposed nuclear facility.

This regulatory guide provides technical information for the design and execution of terrestrial en vironmental studies for nuclear power stations.

The information resulting from the studies, as they relate to ecological aspects of site selection, assessment of terrestrial effects of station construction and opera tion, and formulation of related monitoring ac tivities, may be appropriate for inclusion in the appli cant's environmental report.This guide is intended to reflect current practice, i.e., the siting of up to several power plants at a single site. Prior consultation with the staff is recommended if larger-scale "Energy Centers" are contemplated.

Although there is a need for a thorough evaluation of environmental impacts, it is important that effort not be needlessly dissipated on programs of limited value. The need for accurate evaluation and timely review of the environmental report makes it essential to focus quickly on meaningful issues and to avoid exhaustive analyses not directly related to station im pacts. This guide recommends site selection assess ments, resource management, source control, and control of effects as means for protecting the ter*Lines indicate substantive changes from previous issue.restrial ecology. The approach recommended for ter restrial surveys begins with broadly based land-use and biotic inventories and then focuses on a limited number of significant environmental issues.

B. DISCUSSION

It is important that environmental assessments provide the information needed to estimate and limit potential environmental impacts of nuclear power station construction and operation.

If important en vironmental impacts are identified prior to site preparation and station construction, these impacts can be reduced to acceptable levels by selecting an ap propriate site, revising the station design, or modify ing operating procedures.

In this guide, environmental studies are divided into five phases: site selection, baseline studies, decommissioning studies, construction monitoring, and operational monitoring.

Table 1 shows the organization for terrestrial studies and identifies ma jor tasks and their approximate time schedules.

Adverse impacts on terrestrial organisms or ecological systems have historically resulted from loss or modification of habitat, release of minerals or tox ic chemicals into the environment, and direct destruc tion of biota. A biological effect may be expressed at the level of the individual organisms or through the collective response of organisms at the system level. Examples of effects on individual organisms include death, reduction of health or vitality, accumulation of toxic substances, and alteration of reproductive success. Examples of ecological system effects include changes in birth or death rates; changes of toxic ele ment concentrations throughout entire food webs; and changes in population size, habitat, or com munity structure.

USNRC REGULATORY

GUIDES Comments should be sent to the Secretary of the Commission, US. Nuclear Regu latory Commission, Washington, D.C. 20555, Attention:

Docketing and Service Regulatory Guides are issued to describe and make available to the public methods Branch. acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate techniques used by the staff in evaluating specific problems The guides are issued in the following ten broad divisions or postulated accidents.

or to provide guidance to applicants.

Regulatory Guides are not substitutes

[or regulations, and compliance with them is not required.

1. Power Reactors 6. Products Methods and solutinons different from those set out in the guides will be accept- 2. Research and Test Reactors 7. Transportation able if they provide a basis for the findings requisite to the issuance or continuance

3. Fuels and Materials Facilities

8. Occupational Health of a permit or license by the Commissaon.

4. Environmental and Siting 9. Antitrust Review 5. Materials and Plant Protection

10. General Comments and suggestions for improvements in these guides are encouraged at all Requests flor single copies of issued guides (which may be reproduced)

or for place times, and guides will be revised, as appropriate, to accommodate comments and ment on an automatic distribuation list for single copies of future guides in specific to reflect new information or experience.

This guide was revised as a result of divisions should be made in writing to the U.S. Nuclear Regulatory Commission, substantive comments received from the public and additional staff review. Washington.

D.C. 20555, Attention:

Director, Division of Document Control.*I

TABLE 1 OPERATION, TERRESTRIAL

ENVIRONMENTAL

STUDIES RELATED TO THE SITING, CONSTRUCTION, AND DECOMMISSIONING

OF NUCLEAR POWER STATIONS Phase Site selection Baseline studies at the proposed site Decommissioning studies Construction monitoring at the approved site Operational monitoring at the approved site MajorTask Regional land-use analysis Ecological analysis Local land-use analysis Ecological analysis Biological inventories Planning station design and construction prac tices to reduce impacts Reclamation analysis Planning station design and construction prac tices to reduce impacts Monitoring of construc tion practices Problem-oriented monitor ing (short-term and con tinuing programs)Time When Task Performed*

Prior to application for CP when candidate areas are being selected Prior to application for CP when preferred site is being selected Prior to application for CP when ER is being pre pared; may continue into construction period. Prior to application for CP when ER is being prepared During period between CP issuance and OL issuance After OL is issued* CP = construction permit ER = environmental report OL = operating license (

Most plant and animal populations have sufficient reproductive capacity to make up for losses of a few individuals without changes in average population sizes or community structure.

When the loss of in dividuals becomes sufficiently great, however, the population as a whole may cease to function as a self sustaining, renewable resource.

The population may then be overstressed, and species extinction or un desirable shifts in community structure may become possible.

Excessive population stresses have resulted from natural phenomena, hunting, trapping, draining of wetlands, harvesting forests, plowing prairies, widespread dispersion of toxic substances, and other activities.

This does not imply that these activities are always incompatible with the well-being of natural systems. Experience has shown that good manage ment often permits the coexistence of desired ecological systems with various human enterprises.

Site Selection The results of site selection surveys are useful in identifying potential impacts of station siting, con struction, and operation on terrestrial ecological systems and permit evaluation of alternatives that could reduce adverse effects. In this guide, the sug gested site selection procedures'

are limited to ter restrial environmental considerations.

Site selection surveys may be descriptive in nature. In describing biota, emphasis is generally placed on ecologically significant, groupings of organisms and management of resources rather than on ecological detail. It is important, however, that the investiga tions rapidly focus on matters of special sensitivity, rather than retaining a broad and diffuse approach.

Site selection surveys can be conducted in two phases: regional land-use analysis and local land-use analysis.

Regional land-use analysis is used in con junction with engineering surveys to select candidate areas for the nuclear station. Local land-use analysis is directed to candidate sites and is used in conjunc tion with engineering considerations to select a preferred site. Site selection surveys of terrestrial ecology are coordinated with preliminary engineering studies. The information needed could be obtained from such sources as aerial photographs, topographic maps, reconnaissance, literature, and regional or local zoning and planning data. Site selection surveys are performed with. the objective of providing data for resource analysis, rather than for detailed func tional analysis of ecosystems.

'See also Regulatory Guide 4.7, "General Site Suitability Criteria for Nuclear Power Stations." Terrestrial criteria at the regional level that are needed in the selection of candidate areas include the extent of prime and unique farmland 2 in the region and the alternatives available for siting on land of lower utility; the occurrence and extent of critical wildlife habitat' in the region and alternatives to its use; and the extent of valuable forests, prairies, wetlands, and deserts in the region and alternatives to their use. Also needed is information on the current status of land-use and zoning plans within the region. This may be done through the use of maps, aerial photographs, and tabulations within the region. Identification of major categories such as agricultural land, forest land, urban areas, parklands, highways, and airports is useful.The selection process examines reasonable oppor tunities for using sites that have minimal impact on the diversity of regional land use, present and future. Preservation of a range of options for land use is im portant for the consideration of biologically rare or unique areas. A unique or critical wildlife habitat may be undesirable for a site since to use it could foreclose opportunities for propagation of wildlife, scientific study, natural history study, recreation, and public enjoyment of wildlife.

Federal, State, regional, and local planning authorities are logical sources to be consulted to determine the existence and location of areas within the region that have been dedicated to the public in terest or areas in which siting would be in conflict with preexisting zoning'plans.

Examples of such areas include dedicated parks and forests; productive farmland;

places where specialty crops are produced;

unique but as yet undedicated forests and wildlife habitats;

scenic areas; wetlands;

and unique mineralogical, paeleontological, or geological areas. More specific land-use classes are needed in the local surveys than in the regional surveys, but they should be based on information obtained by recon naissance rather than detailed biological inventory.

Land-use categories may include farms; fields; secon dary successional areas (indicating dominant species);

forests; and residential, industrial, and com mercial areas. If aerial photographs are used for local land-use analysis, it is important that their scale is sufficient to present views of the candidate sites and their immediate environs.

Soil association data for each site being considered should be supplied.

Soil Conservation Service offices :The terms unique and prime farmland, as used in this guide, are discussed in "Land Inventory and Monitoring Memorandum-3," Soil Conservation Service, United States Department of Agriculture, October 15, 1975. 'The terms critical habitat and endangered species, as used in this guide, are defined in the "Endangered Species Act of 1973" (16 U.S.C. 1531-1543, 87 Stat. 884).4.11-3 I

are usually able to supply sufficient information.

In formation may be furnished as a soil association map that is keyed to a table of descriptive information which includes a listing of soil management capabilities.

The selection of a cooling method for the proposed plant is an important consideration in site selection.

Cooling reservoirs may require loss of land, which may be unacceptable compared to the uges of cooling towers in some regions. However, cooling towers could be objectionable in scenic areas where a cooling lake could be an asset. Visible plumes from cooling towers could be more objectionable environmentally at some sites than at others because of ground fogs or icing. Table 2 is an example matrix that could be used in balancing the above factors.

TABLE 2 FACTORS CONSIDERED

IN THE SELECTION

OF SITES AND COOLING METHODS Environmental Once-Through Variable Cooling Cooling Lake Cooling Spray Tower Canals Table 3 is an example matrix that could be used in weighing and balancing alternative sites. Site selec tion is dependent on a wide range of factors other than those relating to terrestrial ecology. In some cases, the weighing and balancing of all factors may result in a selection that is less than optimum by ter restrial ecological criteria.

In these cases, the need for subsequent monitoring programs may be greater than in the case of more nearly optimum choices.

However, the candidate sites should not be located in critical, unique, or highly valuable habitat areas if it can be avoided.

The goal of the regional and local land-use surveys is the selection of a preferred site the use of which has minimal environmental impact and does not conflict with other societal uses. Any site selected, of course, will result in the loss of some habitat and its as sociated residents.

This loss is assessed through an in ventory of species present. Societal uses are balanced by consultation with planning bodies and by reference to pertinent statutes and regulations.

TABLE 3 Farmland Woodland Wasteland Coastland Wetland Special Wildlife Habitats Preserves and Parks Esthetic Impacts For the local studies, it is important to establish whether there are obvious differences among sites with respect to endangered species, game animals, or other impQrtant species or habitats.

The assessment for each site should include consideration of the areas of preferred habitat of important species (see Section 2.2 of Regulatory Guide 4.2) that would be adversely affected.

Information required for transmission corridors is similar in nature to that for candidate site selection.

4 Detailed corridor routes will not be known at this stage. Nevertheless, consideration needs to be given to probable corridor length, natural barriers, impact on land use, opportunities for combining new trans mission lines with preexisting routes, and esthetic ef fects in the selection of candidate sites. 'The Commission has under review a petition for rulemaking filed on September

15, 1975, requesting that the Commission amend its regulations to clarify the extent of the Commission's regulatory authority over the construction and routing of transmission lines, and to clarify the extent to which the environmental impact of such lines and equipment must be considered in the environmental im pact of the licensing of a particular nuclear facilit

y. Factor SELECTION

OF SITES: TERRESTRIAL

FACTORS6 Site A Site B SiteC Land Use Farmland Woodland Wildlife Habitat Unique or Rare Habitats Area of Site Transmission Corridors Terrestrial Ecology Important Species Present Endangered and Threatened Species Present Baseline Studies Baseline studies of the preferred site, including transmission corridors, are needed to fully describe the site and to establish a basis for predicting the im pact of construction or operation.

Baseline studies may be used for comparison with later construction or operational studies as well as during decommis sioning of the station.

Biological studies of the proposed site are made in advance of station construction or operation.

The 'Units should be quantitative whenever appropriate:

however, judgmental entries are acceptable if needed.4.11-4 qualitative notations of plant and animal abundance included in the baseline inventory are normally suf ficient. Quantitative measurement of population den sity is not usually needed as part of the species inven tory unless qualified professional judgment based on -' field study leads to a reasonable conclusion that one or more populations of important species could be adversely affected by station construction or opera tion. This judgment should be based on examination of each species using the criteria cited here and on professional biological interpretation.

Considera tions include the biological reason for importance and the link between the nuclear station and the organism.

The species considered important are those that meet the definition in Regulatory Guide 4.2 and that are linked adversely to the station in some reasonable way. These may require further quan titative effort in the baseline studies and in the con struction and operational monitoring surveys.

It is important that judgment be exercised in selecting the time for initiating quantitative popula tion studies if they are needed. Where construction effects are anticipated, quantitative studies should begin in the baseline phase. Where an effect of station operation is expected, it would be best to defer quan titative studies until some time prior to operation to ensure reasonable compatibility with the operational studies. It will usually be adequate to bracket the period of anticipated impact within I or 2 years of prior studies and an appropriate term of following studies that would be determined in consultation with the staff. Properly designed studies will avoid placing undue emphasis on certain easily accessible groups of organisms.

Most species of insects, for example, are ecologically important in local food webs. However, species that cannot reasonably be judged threatened by the nuclear station or that are not likely to become of economic or public health significance because of station construction or operation need not be studied quantitatively beyond the initial inventories.

Rodents are also ecologically important food web organisms.

However, quantitative population measurements are not needed as long as there is no reason to believe that station construction or operation will have an ef fiect on their populations beyond that caused by the loss of habitat.

Certain station sites and designs have required special environmental assessment effort. These in clude sites with large cooling lakes or reservoirs and plants having cooling towers, particularly if the water source is seawater or brackish water. These are dis cussed in n;ore detail in the following sections.

It is important that the baseline studies of power stations having proposed man-made cooling lakes consider physical and chemical relationships between the watershed and lake; use of a new habitat by birds, insects, and other animals of both beneficial and adverse aspects; and the potential for successful rehabilitation of the lake basin if the station is decommissioned.

Both beneficial and adverse effects of the lake on the environment should be considered.

Water quality of the artificial lake may be in fluenced not only by source water quality but also by relationships with soils and the surrounding land scape. Development of a watershed management plan is needed as well as an estimate of the amount of runoff of dissolved substances and soil into the lake from the surrounding landscape.

A new reservoir forms a new habitat for plants and animals and results in a loss of existing habitat.

Waterfowl may be attracted in substantial numbers during their normal migration, and their migration habits may be altered, e.g., by overwintering in a northern climate on a warm-water lake. Waterfowl attracted to a lake may cause economic loss to agriculture by their feeding activities, degradation of water quality, and other adverse effects. In addition, the birds themselves may suffer adversely from such effects as disruption of migrational patterns.

These and other factors need to be discussed.

Evaporative cooling towers affect ecosystems by deposition of drift containing dissolved minerals on the landscape or by production of fog. Drift may be beneficial or adverse depending on the chemical com pounds and elements being deposited and the amounts of deposition.

The baseline program is designed to evaluate the potential effects of drift and to establish reference measurements for comparison with later operational monitoring observations by determining the amounts and kinds of airborne chemicals being deposited on the site prior to cooling tower operation.

Acceptable data could be obtained from existing sources of information or from monthly sampling of collectors that collect both dry and wet fallout. If a monitoring program is used, it is normally continued for at least 1 year. Table 4 sug gests chemicals that are usually considered in plan ning the program.

Drift from saltwater or brackish-water cooling towers contains NaCI and other salts. The baseline chemical measurements establish the Na and C I con tent of soils and plants in the expected drift field of cooling towers that use seawater or brackish water. Baseline soil measurements normally include the con ductivity of saturated extracts and pH of samples ob tained from the expected drift field. If the drift from either freshwater or saltwater towers is likely to contain toxic substances, their con centrations are measured unless it is clear that the amounts and concentrations are sufficiently low to 4.11-5 TABLE 4 ELEMENTS AND COMPOUNDS

OF POSSIBLE CONCERN IN CHEMICAL MONITORING

PROGRAMS FOR TERRESTRIAL

SYSTEMS Group Macronutrient Micronutrient Chemicals commonly found in environ ment, some required by animals Toxic Biocides added to. cooling waters Chemical Substances

+ -.3 .2 NH 4 , NO ,PO 4 SO 4 , Ca, Mg, K Cu,Zn,B,Mo,V,Mn,Fe-I -2 Na.C,F,HCO ,CO 3 ,Co,I Pb,Hg,Cd,Cr,As,Ni All Relative Biological Hazard Minor or no risk except in extremely large quantities.

No hazards within the range of concentrations found in nature. Toxicity possible if concentrations are moderate.

Minor risk at ordinary concen tration. Risk from halogens dependent on chemical form. Carbonates usually innocuous.

Sodium salts have high-risk osmotic effects on plants at high concentration.

Presumed high biological risk at all concentrations above those normally found in nature. Presumed high biological risk if present in cooling-tower drift.(I (i preclude both short-term and cumulative adverse ef fects. Adverse biological effects can usually be ruled out with reasonable certainty for most elements and compounds found in nature when the expected addi tions combined with preexisting levels would not raise the concentration of the toxic substance outside the range of variation normally found in the biota or soils of the region. Chemical analyses of soils, plants, and animals in the drift field of freshwater cooling towers are not usually needed when all of the following apply: (1) the dominant salts are harmless mixtures of biological nutrients as shown in Table 4, (2) the ex pected peak deposition beyond the site boundary is less than 20 kg/ha-yr (no more than 50% in any 30 day period during the growing season) of mixed salts, 6 and (3) the drift does not contain toxic ele ments or compounds in amounts that could be hazar dous to plants or animals either by direct or indirect exposure over the expected lifetime of the facility.

Usually, reference specimens of soils, plants, and animals for possible future analysis are retained in cases where it is determined that drift presents a chemical hazard to the environment.

The specimens may consist of subsamples of materials that were col lected prior to tower operation and analyzed for baseline data. Such stored samples should be ade quately protected for analytical purposes.

Construction Monitoring If unavoidable construction practices cause a threat to some natural population or ecosystem that could extend beyond the bounds of the area actually dedicated to construction or associated activities, conscientious construction practice control coupled with systematic inspection is usually sufficient but sometimes biological monitoring of important species is necessary.

In such cases, it is reasonable that studies be designed to document the impact and develop possible corrective actions.

Decommissioning Consideration should be given to the potential for reclamation of the plant site, impoundment basins, and transmission corridors upon decommissioning of the station (see Regulatory Guide 4.2). Operational Monitoring Monitoring after commencement of station opera tion is intended to determine whether or not there are adverse biological effects attributable to operation.

This monitoring program is outlined in detail in the technical specifications that are issued in connection with the station operating license. The scope of these 'Interim value based on staff experience to date.studies is determined by the degree of direct linkage between the proposed station and the terrestrial ecosystem.

It is not necessary to hypothesize vague effects or to undertake a program to measure a phenomenon that has no reasonable relationship to station operation.

However, when an adverse relationship between station operation and a ter restrial community is reasonably thought to exist, a thorough evaluation is necessary.

This evaluation should begin I to 2 years prior to station operation.

Consultation with the NRC staff is recommended to determine the appropriate scope and term of any fol lowup studies.

There may be cases in which no important impact on the terrestrial ecological community is an ticipated.

When such cases are adequately supported, there may be no necessity for terrestrial monitoring during operation.

There also may be cases in which no significant impacts are detected by the required monitoring programs.

In such cases, after review and approval by the staff, these programs may be eliminated.

It should be noted that some minimal effort programs may be designed for detection of long-term impacts or unanticipated changes and thus should not be- eliminated.

C. REGULATORY

POSITION 1. It is important to coordinate all the programs discussed in Regulatory Guides 4.1, "Programs for Monitoring Radioactivity in the Environs of Nuclear Power Plants," and 4.2, "Preparation of En vironmental Reports for Nuclear Power Stations." Since precise predictions and assessments of impacts on terrestrial ecological systems are not always possi ble, reasonable professional interpretations should be made when quantitative prediction is impossible.

2. Adequate assessment of current land-use status should show (by a table, for example) major land-use categories and areas devoted to each category along with aerial photographs showing the same categories.

When data are not available from existing records, an acceptable means of acquiring them would be through the use of aerial photographs in conjunction with ground reconnaissance.

The scale of photographs should be appropriate to the degree of detail required.

Federal, State, regional, and local planning authorities should be consulted to deter mine the existence of present or planned areas dedicated to the public interest or in which siting would be in conflict with preexisting zoning plans. Such contacts should be documented.

3. Discussion of soils should include association names, capability classes, 7 and percentage of site coverage by each association.

When numerous as sociations of minor extent are present, it is acceptable

'U.S. Department of Agriculture I-VIII System should be used.4.11-7 to account for 10 to 15% of the total area in a miscel laneous category, except for areas of unique value. Detailed consideration of soils and their production potential is necessary for sites located in areas that are especially productive of agricultural or forestry products.

4. Biological monitoring programs should be in itially devised to be screening procedures to detect undesirable effects. If adverse biological effects are detected, detailed quantitative biological and ecological analyses may be required to determine causes and to devise remedies.

If adverse effects are not detected, quantitative studies are not needed. The species inventory of the site should include im portant habitats and normal seasonal variations.

Locally prominent or important vascular plants, mammals, birds, reptiles, amphibians, insects, and other plants and animals should be included.

The in ventory should be reasonably complete but may be terminated when additional field effort no longer yields significant numbers of previously unobserved species.

Insect surveys should provide information on im portant species such as disease vectors, pests, and pollinating insects. Interpretation of insect data should include consideration of the possibility of adverse consequences to animals, vegetation, or humans that might be caused by construction or operation of the station. Adverse consequences can usually be determined by consultation with State agricultural authorities.

Normally, detailed field sur veys of insect populations are not needed. Protection of terrestrial systems is usually adequate when it can be shown that (I) habitat losses or altera tions of important species' are small with respect to the amount available within the regional or local con text, (2) chemical emissions from the station are suf ficiently small to permit reasonable assurance that no adverse effect will occur, and (3) no mechanism ex ists for causing unintended destruction of organisms, or its occurrence is infrequent enough to give reasonable assurance that whole populations will not be adversely affected.

Environmental protection should be achieved by control of common sources of environmental effects.

These include soil erosion, siltation, use of herbicides, dust and noise during construction, and others. Biological consequences can usually be prevented or reduced to acceptable levels through proper manage ment. If cooling towers are being considered, the mineral content of the cooling water supply should be deter"The term important species, as used in this guide, is defined in Regulatory Guide 4.2.mined in the baseline studies. An estimate should be made of the amounts and dispersion of salts expected to be deposited from the towers. The estimate should be based on the cooling water quality, manufacturer's specifications for drift release from the towers, con centration factors, and prevailing meteorological conditions at the site. Meteorological dispersion models are useful to obtain estimates of drift deposi tion. Estimated drift deposition from cooling towers may be plotted on a base map or graph centered on the towers and showing isopleths of salt deposition.

The maps should have a radius sufficient to show the points at which the amounts of drift from the tower fall within the normal range of annual variation of background deposition from other sources. They should also show the vegetation types that occur in the drift field. Reconnaissance and inspection of biota in the drift field before and after cooling tower operation is a means recommended for detection of possible adverse effects of drift. The baseline inspection should be carried out by specialists in biology work ing systematically from checklists of possible adverse effects in the community.

Seasonal aerial and ground-level photographs in color or infrared false color of permanent vegetation plots are often useful aids. Quantitative chemical analysis of plants, animals, and soils are needed if chemical deposits are expected to exceed toxic or injurious thresholds.

Population monitoring of selected species could also be needed in such cases. The assessment of cooling lakes and transmission and access corridors should include detailed con sideration of the effects of land diversion on local, regional, and State agricultural production, forest production, or recreational uses. The assessment should include both adverse and beneficial aspects.

Where a cooling lake is proposed, the baseline studies should include a preliminary assessment of the poten tial for reclamation of the lake bottom for agricultural, ecological, or forestry use after decom missioning.

It is not necessary, however, to prejudge future use of the lake site. It is sufficient to establish whether the option exists to reclaim the site for other productive uses or whether the creation of the lake constitutes an irretrievable change in land use. The assessment should also include a report of the number of hectares of the lake site that will remain undisturbed during construction, the number of hec tares and vegetation that will be disturbed, the source of "borrow" material for dike construction, and the management of topsoil removed during construction.

Use of topsoil stripped from the lake bottom for vegetative stabilization of dikes and for ultimate replacement on the lake bottom for rehabilitation should be considered.

4.11-8 When soil disruption during construction at the site or in transmission corridors is expected to expose substrates or a proposed lake is to be built on sub strates having a potential for affecting water quality, chemical analyses of the substrates should be per formed. The elements to be measured depend on the nature of the substrate.

If the substrate is formerly fertilized farmland, analysis for elements common to chemical fertilizers is needed. If the substrate is land of some special history, such as strip-mine land, ap propriate chemical assessment of the water-soluble and exchangeable components of the substrate should be made to obtain an estimate of chemical in put to water bodies. Special attention is given those elements that could reach toxic concentrations in water, accumulate to toxic levels in food webs, or af fect the pH of water bodies. The chemical analyses should be performed on appropriate chemical ex tracts of the soil material.

The characterization of soil material should also include determination of ex change capacity, organic matter, pH, and textural class. When a reservoir is proposed, the baseline studies should include reasonable predictions of the number of birds (especially waterfowl)

expected to use the lake on an annual basis, their expected residence time, the expected impact on farmlands, and all other impacts either on the birds themselves or on the sur rounding area due to their presence.

The estimates should be the best obtainable based on known flyways, estimates of farm acreages nearby, literature, or local evidence of bird utilization of other reser voirs under similar conditions.

5. Information needed for transmission and access corridor assessment is generally similnr to that for sites; however, certain considerations apply specifically to corridors.

Detailed land-use informa tion along corridors is needed. The description should include the distance transversed and locations of principal land-use types such as forests, permanent pastures, cultivated crops, parks, preserves, water bodies, recreation areas, and housing areas. Special features such as historic sites; monuments;

archaeological sites; caves; mineralogical, paleon tological, or geological areas of special interest;

stream crossings;

and road crossings should be iden tified and their locations specified.

Information may be presented in the form of land-use maps that are keyed to descriptive text. It is often useful to sub divide long corridors into convenient segments con taining similar land-use types for descriptive pur poses. It is usually adequate to describe biotic com munities in terms of principal vegetative associations such as oak-hickory forest. The animals most likely to be found along corridors may be determined from literature studies, local experts, or field reconnais sance. Emphasis should be placed on "important" species as defined in Regulatory Guide 4.2. Comprehensive field inventories of biota along tran smission corridors are not usually needed. The potential occurrence of threatened or en dangered plants and animals or their critical habitat adjacent to or within the proposed corridors should be .investigated.

Local, State, and Federal authorities (e.g., the U.S. Fish and Wildlife Service and State wildlife agencies)

should be consulted to determine protected species that reasonably

'could be expected to occur and the locations of possible occurrences along corridors.

If potential areas are identified, field inspection of these areas may be necessary to verify, the presence or absence of the protected organisms.

If proposed transmission corridors could add to the further endangerment of a protected species, realign ment in the critical areas might be required.

6. When adverse effects of construction or opera tion can be reasonably inferred from information ob tained during the baseline phase, quantitative studies that can be compared with later studies during con struction or operational phases should be initiated.

Such studies include measurements of population densities of endangered species, chemical measure ments of soils and biota within the potential drift field of a cooling tower, or annual aerial photography, for example.

The preferred method of biological protection on many construction sites is direct control of potential ly injurious work practice.

Systematic inspection dur ing construction at the site, along corridors, and in adjacent areas should be used to detect injurious or unauthorized activities.

Examples of items that may be checked are: a. Traffic Control -Vehicles should be confined to authorized roadways and stream crossings.

b. Dust Control -Dust should be controlled by such means as watering, graveling, or paving. Areas subject to wind erosion should be controlled by mul ching, seeding, or the equivalent.

c. Noise Control -Noise should be monitored at site boundaries.

d. Smoke Control -Open slash burning of plant material should be conducted in accordance with local and State regulations.

e. Chemical and Solid Waste Control -Cement, chemicals, fuels, sanitary wastes, lubricants, bitumens, flushing solutions, or other potentially hazardous materials should be salvaged or dis charged safely in accordance with existing regula tions. Spills should be cleaned up before they become a hazard.4.11-9 f. Soil Erosion and Sediment Control -Erosion should be controlled by piped drainage, diversion dikes, flumes, sediment control structures, ground covers, or other appropriate means.

g. Dewatering

-Dewatering should be confined to the area needed for construction;

test wells or preexisting wells should be monitored for changes in the water table. If, after analysis of the inventory of species and consideration of potential effects of the nuclear power station, a conclusion is warranted that there will be no adverse impact on biota, there may be no need to carry out biological monitoring programs at the construction and operational stages. Special studies could be necessary if adverse effects on biota are detected and there is no obvious ex plapation or remedy for the effect. In the usual case, however, if habitat loss or alteration, chemical emis sions, or direct destruction of organisms do not con stitute a threat to a population of an important species, the effect need not be studied further.

D. IMPLEMENTATION

The purpose of this section is to provide informa tion to applicants regarding the NRC staff's plans for using this regulatory guide. This guide reflects current NRC staff practice.

Therefore, except in those cases in which the appli cant proposes an acceptable alternative method for complying with specified portions of the Commis sion's regulations, the method described herein is be ing and will continue to be used in the evaluation of submittals for operating license or construction per mit applications until this guide is revised as a result of suggestions from the public or additional staff review.4.11-10

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