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8. Provision and rehabilitation of housing
2. Environmental impacts and protective measures
2.1 Development of areas of new housing
2.2 Rehabilitation of housing
2.3 Locational factors and planning
3. Notes on the analysis and evaluation of environmental impacts
4. Interaction with other sectors
5. Summary assessment of environmental relevance
The object of providing housing is to satisfy the basic need for shelter. What shelter means and how the basic need for it is actually met will very much depend on local conditions and traditions and on how advanced the society is. Broadly speaking, what is meant by the provision of housing, in the narrow sense, is creating, maintaining and rehabilitating living accommodation and making available the items required for this purpose, namely building land, infrastructure (e.g. roads and railway lines etc., mass transport facilities, telecommunications, drinking water, facilities for disposing of waste and wastewater, and energy), building materials, construction technology, and finance. However, the provision of housing is not confined solely to making the actual accommodation available but also includes measures to create an environmentally acceptable residential habitat and the setting up of the other social, cultural and welfare facilities required (schools, health-care facilities, places of public assembly, shops, etc.)
In a wider sense, anything done to enable the inhabitants to play a fuller part in the social and economic life of the society helps to improve housing conditions. In particular, this includes steps taken to support self-help organisations, to establish secure rights where previous ownership is uncertain, to introduce amended rules and regulations and to promote employment and create sources of income.
Under existing economic and demographic conditions and in the light of current development trends, providing reasonable housing for urban populations is becoming a major problem. Today, a large number of families already live in unacceptable housing conditions. Though there may be local differences, the common factors which can be identified are these:
- inadequate protection against the elements (e.g. rain, storms, solar radiation, cold), against hazards from the environment (e.g. noise, fire, pathogens, air pollution), and against expulsion,
- a residential habitat generating severe environmental stresses,
- overcrowding, leading to stressful situations, aggression and accidents and encouraging the spread of sickness and disease,
- building stock which is low-grade or presents health risks (dilapidated old buildings and slums, squatter settlements and dwellings constructed from scrap material or flimsy wood) and,
- a non-existent or inadequate technical and social infrastructure (e.g. an inadequate supply of drinking water, uncontrolled disposal of waste and wastewater, inadequate provision for schooling and medical care).
In cases where towns undergo massive growth, this growth is often subject to only inadequate control by the authorities. Often there are no viable schemes for regional and urban development.
Programmes for providing housing are based on data on population growth, income distribution, size of households, distribution of population, etc. Inaccurate figures for population growth, for the size and state of the housing stock and for building by the private sector make it difficult to determine what need there is for housing to be built or rehabilitated.
In many countries, the growth of towns has not been evenly spread geographically. Internal growth and an increasing influx of migrants has meant a sudden spiralling in the demand for housing in conurbations. Where housebuilding policy has concentrated on meeting the demand by building new housing it has proved particularly bad at meeting the growing demand for low-cost housing. The ever larger supply-side shortfall in the field of low-cost housing has therefore caused existing towns to become overpopulated and slums to be created, particularly in long-established areas of old houses. At the same time there has been an extensive wave of illegal occupation of land combined with the erection of shanty housing.
Today, the main aims in providing housing are not only to create fresh accommodation within the framework of regional and urban development but also to deal with seriously bad housing conditions by upgrading the housing stock. In rehabilitating housing, another of the goals being pursued is to slow down changes in the social mix, which in the areas concerned normally tend to be in one direction only, and in this way to achieve a better social balance.
2. Environmental impacts and protective measures
Projects aimed at providing or rehabilitating housing have an impact on the environment through the building activities to which they give rise; certain important aspects of these are outlined below.
2.1 Development of areas of new housing
There are problems that are difficult or even impossible to solve when housing is being rehabilitated and these are the problems that have to be anticipated when planning new housing. The techniques and planning measures required for this purpose are familiar and well established; the main ones and their accompanying environmental impacts are briefly outlined below.
Allocating areas for building normally entails a change in the existing land use and a rise in the consumption of raw materials; hence, land suitable for agriculture, areas of forest and woodland, and ground covering mineral deposits should not be built on if at all possible. Farmland in peri-urban areas often serves to supply the needs of the urban population and should not be adversely affected by steps taken to develop the towns. Areas of forest and woodland close to towns represent a valuable resource deserving of protection. Such areas perform climatic and hydrologic functions, act as a recreational resource and often form a source of supply for fuel, building materials and drinking water.
The physical location of public utilities and sources of employment is dealt with in other environmental briefs such as
- Planning of Locations for Trade and Industry
- Public Facilities - Schools, Health Care, Hospitals.
Particularly for housing, closeness to jobs is often an important location determinant.
Cheap building land will often be available well away from towns. This however not only means a change to the existing use of the land but also creates a problem in that more transport services will be needed. Once built on, such land may, often quite deliberately, create a need for land to be switched to other industrial or commercial uses. This being the case, land-use regulations will be needed as part of planning law to control possible emissions and the demand for land.
New areas of housing mean a redistribution of the demand for water, but they may equally well give rise to increases in this demand, to greater amounts of wastewater and solid wastes and to a need for the appropriate infrastructure to be provided. There will also be a rise in the volume of traffic. When planning new areas of housing, the regional supply and disposal facilities will need to be considered.
Insects, which act as vectors of many diseases, constitute a major risk to the health of inhabitants. Poor sanitation, standing wastewater, and even open water tanks produce ideal breeding grounds for insect pests. Insects can be successfully combatted at lower cost by preventative action than by the use of chemicals for example. The organised collection of solid waste, regular maintenance of open drains and suitable domestic sanitary systems such as ventilated latrines will reduce health risks in this way. Protection against insects inside buildings can be obtained by, for example, extra nets covering doors and windows. Apart from the question of funding for reasonable supply and disposal facilities, another question of crucial importance is keeping them in good working condition (maintenance).
Personal and household hygiene is another prerequisite for reducing disease. As well as the physical requirements mentioned above, public information on the importance of hygiene can play a major role in improving health; in this connection it should be remembered that, depending on the country, between 30 and 60% of the heads of households in slum areas and squatter settlements are women. In buildings, it is in the areas of food preparation and storage and number of occupants that important hygienic requirements have to be satisfied. Where possible there should be a separate kitchen with an adequate supply of good quality water and good facilities for wastewater drainage.
Animal raising is common in urban areas and forms a source of extra income. However, animals can also transmit disease; children in particular should be prevented from coming into contact with dung, and animals should be kept away from areas used for utilities and other services or for disposal purposes, such as rubbish dumps for example.
Polluted air is another thing that puts human health at risk. Pollution sources in urban areas are domestic heat and energy production (particularly where coal is burnt), the burning of solid waste, road traffic, and industrial emissions. Selecting suitable locations for areas of new housing and analysing possible ways of improving the local habitat (e.g. planting of vegetation, aeration) for rehabilitation projects are some of the ways in which improvements can be effected.
Like air pollution, noise too is a health risk but it is one that is rarely given its proper weight. Soundproofing, in buildings for example, is expensive. Where the source cannot be eliminated or its output reduced, viable noise-protection options are ensuring adequate separation from the source of the noise and, where required, breaking the transmission path by erecting embankments.
2.2 Rehabilitation of housing
The purpose of rehabilitation projects is restrained urban renewal. They are carried out to improve living conditions in existing uncontrolled settlements and slums. In so doing, they avoid demolition and re-settlement wherever possible and instead take advantage of the existing social structures and housing to initiate or accelerate the process of building an integrated community.
Poor sanitation is a major problem in many existing settlements. Hence the improvement of hygiene conditions must be a priority task; this includes providing and developing a reliable supply of water and ensuring controlled disposal of solid waste and wastewater. Although such projects do, in the main, improve the environmental situation in settlements, they need to be carefully planned and their running needs to be meticulously monitored if they are not to damage the environment. The following environmental briefs in particular offer detailed planning notes for this purpose:
- Urban Water Supply
- Wastewater Disposal (and rainwater) - collection, treatment, disposal, removal)
- Solid Waste Disposal - collection, treatment, disposal.
While it is true that high-density housing has beneficial effects on infrastructural costs, land uptake, etc., it also creates problems, such as greater surface runoff and hence the risk of flooding, problems with water supply and disposal of wastewater and solid waste, aggravation of the consequences of natural disasters, and a less satisfactory habitat and hence less satisfactory hygiene conditions.
Another objective of rehabilitation projects is to improve the housing stock. Dilapidated old buildings and above all the buildings in squatter settlements are often a health risk. Preference should be given to using local building materials, which may also create jobs. For self-built housing, not only is the flexible application of planning and building standards necessary but advice from building consultants is needed to prevent hazards and additional costs.
Raising the standard of the infrastructure in residential settlements also includes the putting down of facilities for public movement such as roads, footways, squares, flights of steps, etc.; such operations increase the sealed ground surface and hence contribute to greater surface runoff. Theses areas need to be drained. The provision of a road infrastructure increases traffic in areas where there may not have been much previously. In this case regulations to limit, say, motorised private transport may be considered for the purpose of cutting immissions. However, given the importance people attach to private transport, there are severe constraints on whether such regulations can in fact be introduced (see the environmental brief Transport and Traffic Planning).
It will often be necessary to work towards providing lower standards of development, such as only a single access road per block for the fire services and refuse collection rather than a fully developed system of roads.
2.3 Locational factors and planning
It is in the areas of location selection, design of settlement and infrastructure, and type of dwelling that the environmental impacts of housing projects lie. Not only natural factors but also the activities of planners need to be considered. Often, in the very areas which are out of the question for development or the building of new dwellings, there may already be (illegal) squatter settlements and hence a requirement for rehabilitation.
Many countries are situated in zones subject to earthquakes, volcanic eruptions, floods, and landslips caused by erosion. The regions where the majority of such natural hazards occur are known; seldom however can their occurrence be predicted. Early warning times of a few days are exceptional; it is often a matter of hours. It is therefore important to have regional monitoring systems, for appropriate protective precautions to have been taken, and for expertise in disaster prevention and rescue to be readily available.
Many large towns are particularly at risk because, for historical reasons, they are often situated on estuaries, at river crossings, on deltas, or in basin-like depressions. When this is the case, locations where the geomorphological situation is better should be sought, at least when satellite settlements are going to be established. Possible consequences of earthquakes, volcanic eruptions and storms are the destruction of buildings and parts of the infrastructure, earth slips, floods and fire (e.g. as a result of damage to electrical systems). Locations at risk from natural phenomena should be avoided wherever possible for housing projects. Where this is not possible or where built-up areas already exist, special precautions should be taken in respect of design of settlement and infrastructure and types of dwelling. When the layout of the settlement is being decided, high-density housing should be placed in low-risk areas, and the plans must provide adequate access for rescue vehicles. Parts of the infrastructure particularly at risk such as the water supply, the wastewater discharge system and the electricity supply should be designed to be hazard-resistant to local standards where these exist; in some cases this will make them considerably more expensive.
The buildings should have hazard-resistant structures and where possible structural provisions of this kind should be incorporated into the existing buildings. Examples of such provisions are wooden frames and solid roofing with no sharp edges; when blown off in storms, sharp-edged sheet metal roofing creates a further hazard. However, such provisions must be weighed against the cost involved, particularly when applied to existing buildings.
Although hilly country offers greater protection from flooding there is still the risk of landslides and mud flows. Slopes in zones subject to erosion and river banks are often a favourite location for uncontrolled settlements; in such cases the financial impact of reducing the risk has to be weighed against the cost of opting for an alternative location. Buildings on steep slopes will need to be suitably anchored and supported.
Where build-up areas are sited on a rocky subgrade, this creates drainage problems. It costs more to lay the services infrastructure underground and sanitary systems are more difficult to install because of the need for machinery to be used.
On wetlands or in lake-side areas (where elevated pile foundations will be needed), building costs go up, and such areas should not be considered as possible locations. Wetlands have to be drained or filled; as well as the ecological consequences of doing this, additional costs will be incurred for suitable machinery and the opportunities for self-help are limited. Considerable problems will also arise with hygiene.
As well as the possible adverse nature of the ground described above, another problem that particularly affects the siting of dwellings is old pits and dumps for the disposal of solid waste and abandoned industrial sites, collectively called contaminated sites. Hazards that exist at places like these are subsidences due to inadequate compacting, fires or explosions resulting from methane release, unpleasant odours and contamination of water. For such areas to be used for lightweight building or rehabilitation, comprehensive appraisals of the potential hazards will be needed.
Floods are a seasonal phenomenon caused both by heavy precipitation and by storms and their effects are aggravated by the sealing of the ground surface which is a necessary part of settlement. They result in contamination of drinking water, overflow of the private and public discharge and drainage infrastructure, erosion, damage to buildings, an increase in the breeding grounds for disease-carrying insect pests, and, in the worst case, fatalities. Though cheap, land subject to periodic flooding requires large investments in drainage systems and protective structures. Incorrect drainage may lead to groundwater pollution. Open drains for surface water, though simple to lay, can easily be blocked by the sediment load, plant growth and uncontrolled waste disposal; constant cleaning of the drainage system is also necessary on health grounds. Individual buildings can be protected from flooding by building them on platforms or elevated piles.
Vectors of infectious diseases (attracted by human and animal excrement and wastewater), toxic chemicals (from local industry), and natural constituents such as very high salt or metal contents are causes of water pollution. The requisite cleaning techniques, though known, are often impossible to finance due to their high running costs. What is important is for drinking water to be adequately protected from pollution at source, in the pipes and at the takeoff points.
Land allocation has an important part to play in dealing with the environmental aspects of housing projects. By suitably allocating land to uses that do not interfere with one another or do so to only a minor degree, or by separating mutually intrusive uses in rehabilitation projects, it is normally possible to reduce problems with immissions. By selecting appropriate locations for communal amenities and businesses and by planning transport capacities to match, it is possible to reduce the transport services required and hence energy consumption and immissions.
Building density is an important factor in housing projects and one that creates environmental problems. The closer together the buildings, the smaller the amount of unoccupied space left for grassed areas, trees or other plant cover. This affects the local microclimate, the hydrologic cycle and the quality of the air. The setting aside of ground for open spaces is thus an effective way of improving the environmental situation in residential areas, especially in hot and humid climates. However, there are costs involved because the open spaces take up land that could otherwise be built on and they have to be looked after if they are to go on performing their function.
A widespread practice in building projects is to remove existing trees from land for dwellings in the construction phase. This should be avoided as far as possible.
Climatic design principles, based on natural ventilation, should be carefully applied in residential buildings and buildings for other purposes. If there is no way of avoiding air-conditioning systems, then care must be taken to see that substitutes are used for hydro-chloro-fluoro-carbons (HCFC's).
The use of energy in homes will depend on disposable income and the energy resources available. For high and middle income groups, the most widely used forms of energy are electricity and gas bottles. In areas where incomes are low, traditional energy resources such as wood, kerosene, charcoal, refuse and dung are widely used. These however are a major source of air pollution. The burning of firewood and charcoal is one of the main causes of deforestation and subsequent problems with erosion. One radical alternative to such fuels is the use of solar energy, which can be employed for heating, cooking or, via solar cells, for generating electricity. There is vast potential here for use in urban areas too (see also the environmental brief Renewable Sources of Energy).
To avoid existing or anticipated bottlenecks in the supply of building materials, to increase productivity in terms of finished dwellings and to cut costs, thought should be given to what building materials and techniques are going to be used. Metal roofs for example, though easy to install and maintain, create climatic problems in buildings and, where they have to be imported, tie up foreign currency. The use of suitable local materials may help to improve housing conditions and will boost the local economy. The point at which the unrestricted use of local materials becomes unacceptable is where resources become over-exploited or where it may create health risks, such as when asbestos-containing materials are used. Although there is very little that individual projects can do to influence product ranges, any opportunities that occur to do so should be exploited to the full.
The gearing of buildings and rooms to the cultural customs of the population, and the aesthetic standards of such buildings and rooms, are important factors that may cause social impacts. Studies of the cultural values, ways of life and physical and functional requirements of the target group (not just the way in which areas in the settlement are allocated to uses such as residential, shops and religious activities, but also the functional layout of apartments or houses) will provide pointers in the above respects for shaping the project.
Changing the use of an area always has impacts on neighbouring areas; these need to be catered for by means of precautionary planning. Where for example there are areas at risk from erosion close to areas of new housing, the latter areas will need protection. The same will be true where there are areas of forest or woodland situated close to residential areas where the residents produce their energy in traditional ways.
Of all the members of a family, women, often in the capacity of head of the household, spend the most time working in the home and they are thus the main beneficiaries of improvements in housing. This is why special consideration must be given to their interests in the course of planning and implementation.
3. Notes on the analysis and evaluation of environmental impacts
German planning law and building regulations, together with the complementary rules and regulations governing immissions, plus the body of law relating to nature and landscape preservation and water/wastewater and solid waste, form a comprehensive legal armoury; but to operate successfully they need control mechanisms and sanctions. These however are very complicated and expensive and it is therefore impossible for them to be adopted in many countries when even the basic legal framework is lacking.
Nevertheless, they are based on principles of planning which do not alter with different geographical zones and here are some of these principles:
- bring together uses that do not interfere with one another or do so to only a minor degree,
- keep a distance between uses that do interfere with one another,
- prevent, reduce and recycle solid waste.
(see the Bundesimmissionsschutzgesetz [Federal Immission Control Act], the Abstandserlaß [separation decree] of the state of North-Rhine/Westphalia, the body of law relating to solid waste, etc.). Yet even German law, comprehensive though it is, confines itself to general statements in certain areas where no universally applicable guideline values or standards exist and where a verdict has to be reached in the light of the individual circumstances. A typical example of this is the sensible allocation and mixing of land for building and land for open spaces. There is no question that this should be done, but it may be difficult to achieve in practice because there is no provision for it in the law. This is particularly important in countries where the land does not have the benefit of a legal framework to protect it.
It is often the case that, though the World Health Organization (WHO) guideline values may be adopted as reference parameters for appraisals of air quality or the basic need for a supply of hygienically acceptable water, nothing is done to ensure that these values are met. Not just in the areas of land and water but in that of flora and fauna too, what are crucial are national laws and, where in place, international conventions. From them can be extracted basic requirements for use in assessing housing projects.
Where they exist, relevant local planning regulations are an essential prerequisite for environmentally acceptable housing provision. Urban development guidelines, housebuilding schemes, the stated objectives of rehabilitation programmes, town planning law and the local building regulations often include a large number of provisions relevant to the environment. A further point that should be made is that received behavioural norms often correspond to coded form, and express modes of behaviour that are in tune with the environment and they may thus be accorded a standing equivalent to that of guidelines. Ways of life, settlement practices and types of economic activity all have a crucial bearing on modes of behaviour of this kind.
4. Interaction with other sectors
Cross-sectoral projects such as housing provision affect planning in many other sectors. Cross references have already been made at the appropriate points in the text.
In the same way, housing projects are included in master planning schemes that may have repercussions on the organisation of the projects. This is the case with, for example, spatial and regional planning, overall energy planning and water framework planning.
5. Summary assessment of environmental relevance
The need for shelter is a basic need which, due to economic constraints, may not be acceptably met for certain sections of the population. Projects to rehabilitate housing settlements and the allocation of land for areas of new housing both involve many environmental impacts and the environment may likewise affect such projects in many ways. With projects of this type, it is not a question of looking for radical alternative solutions in order to achieve the given goals. What is important is that in planning and executing housing projects, full allowance should be made for the areas of potential conflict with the environment described above in order to determine how the projects can be executed with the least harm to the environment. It is particularly important that programmes for providing housing with utility and other services should be embodied in a scheme for balanced spatial and housing development that includes the promotion of regional centres.
In the past, provision of housing by the state often concentrated mainly on overcoming housing shortages in large towns, caused amongst other things by the flight from the land and the lack of jobs in the towns. This was done by mass producing dwellings on the lines adopted in the industrialised countries, but often no thought was given to analysing the risks involved and to heading off any secondary effects (such as the need to dispose of wastewater and solid waste). In so doing it started processes of change in the natural environment and in human society which led to serious undesirable developments. The results of an unbalanced housing provision policy of this kind were not only greater uptake of land and extensive pollution of the soil, water and air but also social erosion, greater poverty, more crime and the destruction of traditional ways of life.
Where housing is provided by the state, programmes for modernising and maintaining the housing stock and for rehabilitating residential areas must allow opportunities and avenues for staving off undesirable developments in society and reducing environmental stress. An employment policy which acknowledges self-help in the provision of housing as an effective way of reducing material poverty can be of considerable assistance in providing housing and protecting the environment.
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