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3. Standards for influences on the environment
3.1 Waste water
3.2 Waste heat
3.3 Emission of gases and dusts
3.4 Solid wastes
3.5 Chemical aids
3.6 Changes in land-use
3.7 Removal of soil
3.8 Action influencing the water balance
3.9 Action influencing the surface configuration
3.10 Noise emission
The term "waste water" refers to water entering the sewerage system in the form of water whose character has been changed as a result of domestic or industrial use (particularly water which has been polluted in some way) and rainwater run-off from developed land. It also includes water contaminated as a result of agricultural use and water issuing from dumps.
The harmfulness of waste water is determined by specific properties which (both individually and together) can change the quality of a body of water. These include
- the content of the water in respect of particular substances (concentration)
- the pollutant quantity discharged into the water within a specific period (pollution load)
- certain properties and effects of the waste water (e.g. oxygen depletion).
Discharge of waste water into surface water may impair the quality of the latter, i.e. it may cause contamination or lead to other adverse changes in the water's physical, chemical and biological properties. Emission standards are used in monitoring waste water at the discharge site; they are intended to preserve the water quality necessary for various forms of use and to protect aquatic organisms.
Existing standards for the constituents of waste water apply to
- discharges into sewerage systems with sewage treatment plant and/or
- discharges into bodies of water and into sewerage systems without sewage treatment plant.
Emission standards essentially aim to ensure that waste water is pretreated or the pollution load reduced before waste water is discharged into surface waters.
Waste water disposal regulations, which are generally laid down in national water protection legislation, are backed up by guidelines or minimum requirements concerning discharge of waste water into surface waters. Waste water pretreatment is usually required whenever the monitoring value concerned is frequently and significantly exceeded in the untreated waste water at the point of discharge.
However, it is not always reasonable or feasible for industrial and municipal dischargers to realise waste water treatment measures, for example on account of the degree of treatment-plant utilisation, extent of connection to treatment plants, frequency of sampling etc.
The regulations governing the constituents of waste water require that maximum concentrations not be exceeded (mg/l, m g/m3, mmol/m3). Standards in industrialised countries are laid down in line with "recognised engineering practice" or the like, which is based on specific waste water treatment methods rather than local conditions, the volume of waste water produced or the capacity of the receiving water.
Emission standards may be modified on the basis of
- the purpose for which a body of water is predominantly used
- the ratio of discharge to gravitational flow into receiving water
- directives issued by local authorities.
Measuring procedures for determining the flow and constituents of waste water relate to constituents relevant to water quality on account of the size of the pollution load which they represent or because of their specific harmfulness. Apart from overall limits in the form of summation parameters (settleable solids, BOD5, COD, toxicity to fish), particularly harmful substances or substance groups must be covered individually (e.g. dissolved metals, organic halogen, phosphorus or tin compounds, carcinogenic substances). A distinction must be made between general qualitative standards in the form of discharge bans (or restrictions) and parameter-specific standards.
1. Agriculture
Agriculture generates waste water on account of the activities involved in the production of feed, meat and milk. Agricultural waste water essentially comprises the following:
- Liquid manure
- Silo seepage water
- Whey
- Livestock farming wastes
- Waste water from irrigation
2. Transport
The major types of waste water originating from the transport sector are the waste water discharged directly during construction and operation of transport systems and the pollutants contained in rainwater run-off.
3. Municipal waste water disposal
Municipal waste water comprises the waste water from residential areas and towns which is collected and removed by a system of channels or pipes. It stems primarily from
- households
- facilities such as hostels, hotels, hospitals and authorities
- refuse incineration plants
- small industries
- surface run-off
- sanitary landfills
and may enter the receiving water either directly or following treatment.
Municipal waste water discharges are characterised by considerable fluctuations in terms of composition (washing water, bathing water, slop water and faecal water), quantity and time of discharge. Domestic waste water contains suspended matter, sludges, colloids and dissolved substances such as urine, salts and detergents. These substances contain oxygen-depleting constituents which are fairly readily degradable and are therefore likely to putrefy if there is an oxygen shortage.
Sewerage systems for residential areas may take the form of separate or combined systems. In the former the sewage and the rainwater run-off are removed in separate sewers, while in the latter system they are removed together. Depending on the frequency, duration and quantity of overflow, some of the waste water may enter surface waters without passing through the treatment plant if there is increased run-off on account of wet weather. Substances deposited in the sewer during periods of dry weather are picked up again on account of the increased tractional force resulting when flow is heavy and may reach concentrations far in excess of the original discharge concentration. Separate systems too can cause sizable pollution loads to be carried into the receiving water by the rainwater.
An analysis of standards shows that in many countries direct discharge of waste water from residential areas into surface waters requires a special permit or is banned altogether. In the vast majority of cases, such qualitative standards apply in countries where legislation on water pollution control is in force. The relevant EC directives can be taken as a yardstick (see separate section).
4. Energy supply
Waste water from energy supply facilities essentially consists of process water (generally cooling water) contaminated with biocides. Such substances are used to maintain water purity, remove algae from the water and protect the cooling system. Particular attention must be drawn in this connection to chlorine and chlorine compounds (see Register of Substances).
5. Manufacturing industry
Industrial waste water comprises contaminated water which has been used as a raw material, solvent or means of transportation, for cleaning, sanitary purposes and the like.
Industrial waste water
- often has a one-sided composition, i.e. specific groups of chemical substances predominate;
- contains inhibiting, non-degradable and toxic substances;
- is subject to considerable variations in composition and concentration;
- contains substances which, for example as a result of bacterial conversion, may be a primary or secondary source of considerable odour nuisances.
On the basis of the above-mentioned properties, industrial waste water is often subdivided into
- waste water which can be discharged into the sewerage system or into surface waters without reduction or pretreatment
- waste water which may be discharged only after reduction and pretreatment
and
- waste water which must not be discharged.
Standards for waste water discharge are either specified directly or must be derived from general, industry-specific or locality-specific requirements.
6. Mining/Raw-material recovery
Types of waste water occurring in this sector include polluted mine water and waste water produced during extraction or recovery of raw materials (further processing falls under manufacturing industry). The harmful nature of such waste water generally stems from high concentrations of individual substances (e.g. arsenic, lead, zinc, mercury).
Waste heat is generally introduced into surface waters through the discharge of cooling water and heated process water by industrial plants and power stations.
The discharge of waste heat can interfere with the natural thermal condition of bodies of water, thereby adversely affecting water quality and living conditions for aquatic fauna and flora. The consequences of a rise in temperature in the vicinity of the discharge point include:
- a decrease in oxygen content (on account of the reduced solubility of oxygen at high temperatures and a rise in oxygen demand resulting from the organisms' increased metabolism)
- adverse effects on individual organisms and changes in the spectrum of species
- reduction of the surface water's pollution load capacity and jeopardisation of its self-purification.
Standards for discharge of waste heat into surface waters are generally not legally binding. As in Germany, however, they may be used as a basis for licensing procedures.
Relevant plant-specific standards for waste-heat discharge include the following:
- limits on the temperature of the water to be discharged (in °C)
- limits in respect of the maximum temperature rise, evaporation losses and the maximum quantity of dissolved oxygen
- limits on the temperature of the surface water
The last-mentioned limits are immission standards, or ambient quality standards (see Section 4). The permissible temperature rise for a body of water indicates whether additional waste-heat discharges into the receiving water are permitted. Parameters relating to waste heat are generally set out in water-related guidelines (see register of EC environment treaties).
In order to assess the adverse effects on a body of water resulting from the discharge of heat, a whole series of data must be recorded and correlated with regard to application of the emission standards:
- volume and temperature of the cooling water discharged
- natural temperature and existing temperature of the surface water. A guideline can be provided by the average maximum temperature over a period of several years or the most unfavourable annual value ("summer value") on the basis of local flow and weather conditions
- flow rate during the annual cycle
- BOD and COD
- presence of aquatic fauna and flora; biotope function
By means of calculations it is possible to produce temperature forecasts for a receiving water covering various flow rates, times of year, weather conditions and heat discharges and thus determine the thermal loading capacity of a receiving water as a whole or certain sections of it ("thermal load plan"). Calculating the temperature profile in this way is a complicated procedure. No standards specific to project activities are in existence.
3.3 Emission of gases and dusts
Gaseous and dust emissions are generated, directly or indirectly, by almost every form of human activity. Distinctions must be made between the following categories:
- concentrated emissions
- diffuse emissions
- drifting
- emissions occurring as a result of accidents
Depending on the nature of the materials processed, the techniques used and the extent of the emission control measures, industrial projects can give rise to emissions on a considerable scale. Emissions affecting employees at the workplace must also be taken into account.
In the agricultural sector, gaseous or dust emissions may result from use of fertilisers or tillage of the soil. Infrastructure facilities give rise to considerable emissions both during the construction phase and in the course of their use. The emissions generated by mining and raw-material projects generally take the form of dust; they may occur during open-cast mining, during handling of intermediate products or as a result of drifting from heaps. Finally, it should be remembered that households and small enterprises often constitute the principal source of emissions.
Existing emission standards are generally not based on the demands of nature conservation and environmental protection. Instead, they are determined by technical feasibility (recognised engineering practice, state-of-the-art) and by the extent to which they can be enforced in the sector or plant in question (economic position); they must thus be viewed as political and technical compromises.
Measurement of emissions is a complex process in which numerous marginal conditions play a role. The principal difficulty lies in the fact that most emissions are of a diffuse nature and may result from use of non-enclosed equipment in production facilities, drifting from heaps and the like. Measurement is easier in cases where emissions are concentrated through the use of covers, extraction systems or flues, e.g. encapsulated aluminium production facilities and furnace flues. As emissions are of widely varying types, the complexity of the process involved in measuring them increases in proportion to the number of pollutants to be covered. The current operating condition of a plant and the ambient conditions (temperature, wind) must always be taken into account when measuring emissions.
The measuring techniques themselves are complex and are continuously undergoing further development. Sampling conditions and certain disturbance factors have a considerable influence on results. The measuring techniques and procedural requirements for recording gaseous and dust emissions are described by a variety of sources. Details of the measuring specifications and the equipment to be used are contained in individual directives (Germany's Technical Instructions on Air Quality Control, TA-Luft EC directives etc.). Compilations of internationally used methods may be found in WHO publications (1990).
The link between emission and immission is formed by the dispersion calculation, which permits quantitative determination/forecasting of the likely immission on the basis of the causal relationship between emission and immission/deposition using models representing this relationship. There are various ways of elaborating a dispersion calculation, each of which is based on different mathematical models. The following marginal conditions are among those which must be taken into account and included in the model:
- physical distribution of sources
- changes in emission rates and emission composition over time
- dispersion conditions and changes in these over time and area
- physico-chemical processes in the atmosphere
- deposition effects (particle size, precipitation)
Regulations laying down details of emission/immission measuring programmes, along with the equipment and analysis methods to be used, must fulfil demanding requirements, which may include recommending suitable equipment. Continuous emission monitoring is stipulated for certain types of plants. Additional requirements are imposed in certain cases, particularly with regard to measuring specifications for measurements performed in connection with licensing procedures.
Gaseous and dust emissions are known to have environmental impacts and increasing efforts are therefore being made to reduce them. The first step involves formulating guidelines which lay down emission standards for what are known to be the principal emission sources.
A specific deadline is generally laid down for achieving compliance with these guidelines. After this date the monitoring authority may take coercive measures in order to ensure compliance.
The industries concerned can comply with such guidelines by modifying the processes which they use or by implementing emission control measures. The manufacturers of emission-control equipment gear their products to existing technical conditions and statutory requirements and can generally offer appropriate solutions.
The development of emission control technologies is in a permanent state of flux and is continuously being brought into line with new findings. Emission control measures are combined with material and energy recovery wherever this is technically feasible and desirable. Emission standards relate in most cases to individual substances or groups of substances emanating from individual plants or sites.
Emission standards are given as mass limits in waste gas [mg/m3], as pollutant output per unit of time ([kg/h] or [g/h]) or in the form of emission factors referenced to the mass of the products manufactured or processed ([kg/t] or [g/t]). Waste gases must not be diluted by adding additional air in order to achieve compliance with standards. In some cases, emission standards may be given in the form of a mass concentration graduated according to the mass flow of the substance in question (e.g. 75 mg/m3 at 3 kg/h or more).
Geoecological conditions are not taken into account when emission standards are determined; instead, the figures are based on what is possible given current production and emission control technologies (recognised engineering practice). Only when future standards are being specified are possible improvements in processes taken into consideration. Some countries take account of geoecological and meteorological conditions, as well as pre-existing pollution levels, by designating specific areas in which, for example, tougher standards are to apply under certain conditions. In most countries the standards for new plants are more stringent than those for existing ones (with no transitional provisions).
The introduction of emission standards also has economic impacts in that it may affect the operating results of an entire industry or give rise to a completely new market for emission control technology. When standards are laid down, attention is usually paid to ensuring that they are reasonable from the business-economics viewpoint (for the industry as a whole rather than in microeconomic terms). Countries which lack effective monitoring agencies may introduce standards "just for show" or take over unsuitable emission standards from other countries. The cumulative effect of emissions and the geoecological conditions are taken into consideration in determining ambient air quality standards or immission limits (see same) and compliance with them.
Agriculture gives rise to atmospheric emissions through mechanical tillage of the soil (dust) and application of fertilisers, pesticides or animal faeces (ammonia).
Methane is produced by cattle and by swamp-rice fields, while activities such as burning of vegetation give rise to nitrous oxide emissions. For reasons of plant physiology, application of fertilisers and animal faeces is restricted to specific times; the same applies to use of pesticides, which can likewise lead to gaseous and particulate emissions.
Although all such measures are the subject of recommendations concerning their execution and the quantities to be used, no restrictions in the form of emission standards exist.
In some countries, other measures such as burning-off of fields or banks are restricted to specific times or banned altogether, both in order to prevent emissions and to protect small fauna in particular.
Intensive livestock husbandry is particularly likely to give rise to emissions (especially odour nuisances). There are no standards limiting such emissions; instead, animals are required to be kept at least a stipulated minimum distance away from neighbouring properties. Liquid manure can be stored in closed containers or pits, while solid manure is usually left in the open.
The emissions generated by agriculture are in most cases mixtures of different substances which are extremely difficult to measure.
1. Transport (road, rail, water, air)
In considering the emissions produced by transport systems, a distinction must be made between the construction phase and the operating phase.
Gaseous and dust emissions are likely to be produced on a large scale during the construction phase on account of the use of heavy construction machinery and vehicles and the necessary earth-moving operations. On large construction sites, haul-away operations and storage of the required materials also give rise to emissions. There are no emission standards covering activities in this area.
Standards relate to the actual means of transport (vehicle, aircraft etc.) and compliance with them may be a requirement for operation under certain conditions (e.g. authorisation to operate vehicles in smog conditions, smog regulations).
Vehicle-specific standards are a subject of permanent debate in industrialised nations (manufacturing countries), where a wide variety of organisations endeavour to influence the establishment of standards and dates for their introduction (e.g. vehicle manufacturers, oil industry, environmental protection associations, governments). The outcome is ultimately a compromise between what is feasible in technical terms and what is reasonable from the economic viewpoint. In industrialised countries, compliance with emission standards for road vehicles is often monitored by means of regular vehicle checks. The measuring procedures developed for this purpose have been standardised, in some cases on an international basis, and are relatively quick and easy to perform.
2. Municipal waste disposal
Gaseous and dust emissions may be produced during disposal of solid wastes or waste water, particularly where large quantities of solid waste are involved. Both domestic and industrial wastes can play a part in generating emissions. The principal sources of emissions are sanitary landfills, refuse incineration plants, composting plants and sewage treatment plants.
Where an organised waste disposal system exists, solid wastes are generally deposited on landfill sites or incinerated, in some cases with use being made of the heat generated during the process. Landfill sites can give rise to problems on account of unpleasant odours, production of sanitary landfill gas and scattering of waste material by the wind. Systems for the collection, treatment, and disposal of waste water may also create odour problems, particularly where the chemical and biological treatment stages are concerned.
In industrialised countries, only refuse incineration plants are required to comply with specific standards regarding gaseous and dust emissions. These standards are based on the extremely heterogeneous composition of the refuse and on the related pollutants to be found in the flue gas. The range of standards is being continuously expanded in line with detection possibilities and scientific findings on the effects of individual substances or substance groups. It is also possible that the thermal conversion process itself may produce new substances. The standards specified are geared to the possibilities offered by emission control technology, which is continuously undergoing further development. Other efforts focus on keeping certain substances out of sanitary landfills or incineration plants altogether.
3. Energy supply
Energy supply facilities are power stations which convert solid, liquid, or gaseous fuels into heat and/or electricity. The make-up of their emissions depends to a very large extent on the nature and composition of the fuels used. Apart from the main products of combustion, namely CO2 and H2O, the air may be polluted by CO, SO2, NO, NO2, heavy metals and incompletely converted hydrocarbons. Use of solid and liquid fuels will additionally give rise to emissions of fine dust, consisting of soot, SO2 compounds and halogen compounds. As well as the type of fuel used, a plant's design and mode of operation also have a major influence on the nature and quantity of the emissions which it produces. Emission standards are therefore specified according to plant service condition and capacity.
The actual limit values stipulated are based on the pollutant content of the fuels and on the level of technical development attained in furnace and emission-control technology. Emission standards may also be graduated according to power stations' thermal capacity. Emissions can be reduced by means of fuel-related measures such as use of low-pollution fuels or fuel preparation. Other possibilities include optimising plant management and realising measures to reduce emissions in the flue-gas flow. Foremost among such emission-reduction measures are those involving dust separation, flue-gas desulphurisation and nitrogen removal. The substances covered by Germany's Technical Instructions on Air Quality Control ("TA-Luft") can be regarded as the most important where standards are concerned (see Register of Substances).
4. Manufacturing industry
Industrial operations cover an extremely wide range of fields. The volume and composition of gaseous and dust emissions are thus dependent on the process technology, raw materials and auxiliary materials used.
The emission standards introduced in a variety of countries relate in particular to SO2, NOx, constituents containing dust and components containing acid. The limits for dust emissions pertain above all to dusts containing heavy and non-ferrous metals. Emission standards have also been laid down for a variety of substances which constitute a health hazard or an odour nuisance.
Emissions are produced primarily during open mechanical processing operations and chemical/thermal conversion processes. The standards are based on the state-of-the-art with respect to processing, production and emission control technologies (in Germany standards of the German Association of Engineers VDI and DIN standards are used). It is a well-known fact that in some countries there is a considerable discrepancy between the standards laid down and the actual emission situation. The substances covered by Germany's Technical Instructions on Air Quality Control ("TA-Luft") can also be regarded as the most important where industrial emissions are concerned (see Register of Substances).
5. Mining/Raw-material recovery
Gaseous and dust emissions likely to affect the environment are produced during the following operations:
- extraction (dusts, release of gases)
- transportation
- dressing, further processing, preprocessing
- stockpiling, storage (drifting, gas emissions)
For the most part, there are no standards relating to the primary operations involved in mining and raw-material recovery; regulations in this sector are concerned primarily with safety. Such standards as do exist relate to emissions produced during further processing, transportation and handling; they are based on the state-of-the-art as regards dust collection and enclosure technology, as well as on the concentration in the raw gas. Important qualitative standards include general requirements intended, for example, to restrict drifting during transportation and stockpiling, as well as grassing/recultivation measures.
Solid wastes can be classed both under "chemical substances and substance groups" and - to a large extent - under "non-specific substance categories", which cover substances, substance groups, products, active ingredients, waste materials or general "waste" that cannot be clearly defined. Germany's Technical Instructions on Waste Management ("TA-Abfall") of 10 April 1990 contains information on the disposal of over 300 types of wastes requiring special monitoring. Particular attention must be drawn to the international agreements on the dumping and transportation of solid wastes. An analysis of existing standards reveals that no quantitative standards covering the "production" of solid waste exist for any type of project activity (primarily agriculture, municipal waste disposal, energy supply, manufacturing industry, mining/raw-material recovery). Efforts are made instead to reduce quantities of solid waste by means of specific waste management measures such as mandatory recycling, deposit systems, obligations requiring manufacturers to take back products at the end of their useful life and so on. Extensive monitoring of production, storage, use, transportation and dumping is intended to preclude the possibility of health risks or adverse impacts on the environment, particularly where hazardous wastes or waste materials are involved.
With regard to project activities, particular note should be taken of regulations or recommended values applying to the following areas:
a) Agriculture
- storage of solid and liquid manure
- disposal of solid wastes from large-scale livestock farming operations
- spreading of sewage sludges on agricultural land
- spreading of solid and liquid manure on the groundb) Municipal waste disposal
- frequency and form of disposal, mandatory disposal (local by-laws)
- procedural regulations (sanitary-landfill guidelines)
- mandatory recycling
- separate disposal systems for various types of refusec) Manufacturing industry
- obligation to record specific types of solid waste and solid wastes originating from specific plants (in Germany: the Waste Avoidance and Waste Management Act [Abfallgesetz] and administrative provisions)
- Various types of mandatory recycling
The term "chemical aids" refers to chemicals such as pesticides, fertilisers, growth regulators, thawing salts and the like which are introduced into the environment for a specific purpose. They are used above all in agriculture and forestry to improve or modify growing conditions and to control pests, as well as in the transport sector to remove vegetation from roadsides and railway tracks.
Chemical plant protection uses effective substances in order, for example, to eliminate crop pests and thereby ensure optimum growing conditions for the crops. However, use of such substances for purposes other than those covered by their designated field of application can result in adverse effects on groundwater, surface water, fauna, flora and soil quality. A particularly significant role is played by the high persistence of many substances in soil and water and by unknown toxic effects resulting from additive and synergistic processes.
Pesticides, fertilisers and growth regulators are covered by quantitative standards in the form of recommendations and regulations concerning
- field of application (crop, pest)
- form of application (granules, emulsion, powder)
- time of application (e.g. as from a specific economic threshold)
- waiting periods (before harvesting or consumption).
Restrictions covering the above-mentioned aspects are laid down by the manufacturers at the direction of high-level authorities (e.g. Biologische Bundesanstalt [Federal Biological Research Centre for Agriculture and Forestry] in the Federal Republic of Germany, Health and Welfare Secretariat in Mexico) and are generally substance-specific (see Register of Substances).
Recommendations on use of fertilisers are influenced primarily by yield-determining factors. They are not generally geared to geoecological conditions, although certain attempts are made to take such conditions into account. Under tropical climatic conditions, for example, even large-scale use of such substances is accompanied by limiting factors which automatically restrict agricultural production to a level well below that possible in comparable crop-growing regions in temperate latitudes and the subtropics.
Recommendations on pesticide use and the waiting periods to be observed following application are based on toxicological considerations relating to the maximum residue levels permitted by law. However, the relevant ordinances apply only to foods of plant origin and not to animal fodder. Sometimes irreparable damage can be caused by the hitherto unconsidered combined effects of numerous substances which can be re-assessed only gradually.
The extent to which it is possible to enforce regulations on the use of chemicals is limited by a number of factors:
- language problems
- financial aspects
- acceptance problems
- training problems
- opportunities for monitoring
The FAO Code of Conduct (one example of standards governing conduct in this field) is intended to improve the situation.
The term "changes in land-use" refers here to the process of
- making land-use more intensive
- making land-use more extensive
- or changing the form of land-use
and to the related changes in surface cover.
Changes in the intensity of land-use are most likely to be realised in the agricultural and forestry sectors, with the aim of increasing the amount of land used for production purposes or raising production on existing agricultural and forestry land. Other measures sometimes taken in connection with changes in the intensity of land-use, e.g. use of pesticides and fertilisers, irrigation and drainage, are discussed in the pertinent sections.
Changes in vegetation cover may have negative effects on
- soil usability
(e.g. erosion, compaction, nutrient leaching)- availability of agricultural and forestry land
(e.g. reduction in size of forest stand, steppe formation, increase in waste land, desertification)- living conditions for flora and fauna
(e.g. alteration and destruction of biotopes)- climatic conditions
(e.g. change in wind velocity and pollution rate)- water resources
(e.g. change in groundwater recharge rate and run-off conditions)
Standards for measures affecting vegetation and changes in the intensity of land-use could take the form of mandatory requirements or bans in respect of particular types of land-use, or recommendations/guidelines for site-specific and region-specific forms of land-use management which are not merely geared to short-term economic interests but are also designed to preserve and enhance
- the long-term usability of key economic resources (particularly soil and drinking-water supplies)
- the ecological functions of the land (particularly with regard to climate, water balance, fauna and flora)
and to ensure the resultant optimum or desirable combination of land-use forms in a particular region (land-use structure).
Mandatory requirements and bans covering land-use include "standards" such as the following:
- Designation of areas performing protective functions
(water protection areas, nature reserves, closed forests etc.) in which specific forms of use or changes in land-use are not permitted- Land-use management obligations
(e.g. adherence to specific construction methods, continuation of arable farming)- Regulations limiting forest clearance
(only a specific proportion of the forest area may be cleared; such regulations exist in countries such as Uruguay and Brazil)- Official authorisation necessary to transform forest into arable land/grassland or vice versa
(e.g. in some Laender of the Federal Republic of Germany)
Common to all these land-use requirements and bans is the fact that they are largely dependent on local and regional geoecological conditions and thus generally cannot be simply taken over in other regions or countries. This does not apply, however, to the methods, ecological considerations and planning principles on which they are based.
Other changes in land-use stem above all from construction schemes (settlements, infrastructure facilities, industrial plants etc.) or specific functions (protected areas, rights of use etc.).
1. Agriculture
For the purpose of raising production (particularly in regions with moderate to low yields), the intensity of land-use in agriculture may be changed by
- enlarging cropping areas
- transforming forest and grassland/bush into arable land
- making the existing form of land-use more intensive/extensive
- livestock husbandry.
In order to lay down standards for changes in the intensity of land-use and for the ecologically and economically optimum form of farming, regulations and recommendations geared to local and regional geoecological and economic conditions could be elaborated for the areas to be used. The farming recommendations drawn up by many national and regional agricultural authorities are generally oriented to economic interests and can thus be drawn upon to only a limited extent for the purpose of environmental studies. In some cases, however, ecological considerations have now begun to feature in land-use management (particularly in certain pilot projects).
2. Forestry
Changes in land-use occurring in the forestry sector comprise the following:
- Deforestation, clear cutting
- Afforestation
- Intensification of forest management systems
- Introduction of trees etc. not native to the site
Standards can take the form of recommendations and guidelines for site-specific forest management, e.g.
- clearance permits (to be made contingent upon afforestation measures)
- felling quotas
- specified rotation periods
- recommendations on selection of suitable tree species etc.
3. Other project-specific aspects
A role is also played by changes in the basic purpose for which land is used and the related changes in - or removal of - the vegetation cover; in the broader sense, this also includes changes in function. Such developments are usually the result of construction schemes or administrative measures (e.g. designation of protected areas or special areas).
Depending on their nature and scope, construction measures and other changes in land-use can significantly impair environmental quality in that they may affect water resources, microclimate, biotope conditions and availability of agricultural and forestry land.
Removal of soil comprises the excavation and displacement of soil necessitated by all types of construction measures. Large-scale removal of soil occurs in particular during extraction of raw materials near the surface by means of open-cast mining (gravel, coal, bauxite etc.) and construction of roads. Erosion is not treated here, as it must be regarded as an impact (see Section 5).
As a rule, neither removal and displacement of soil during open-cast mining nor filling work (e.g. in connection with road construction) takes any account of the soil's suitability for use or the function which it performs in respect of plants and the local water balance.
Virtually no soil-specific standards exist, as in most countries there is no executive agency responsible for the soil in its function as a scarce resource that can be easily destroyed. If the aspect of "soil conservation" features at all, it is usually covered by regulations on land-use (see preceding section). Worthy of special note are a number of regulations and guidelines which aim to protect the topsoil (humus) against construction measures and the like.
A Soil Protection Act (Bodenschutzgesetz) is currently in preparation in Germany. It is to form the basis for Technical Instructions on Soil Protection (TA-Boden), which will lay down binding soil standards; the emphasis will be on precautionary measures and provisions for averting risks.