ENVIRONMENTAL STUDIES

Module 6. Social issues and the environment

Lesson 23
URBAN PROBLEMS

23.1 Introduction

Developments in the four target sectors of transport, tourism, energy and industry, and action in the priority themes of air, noise, water and waste have a significant impact on the quality of the urban environment. Activities are importance to develop co-operation between cities in the promotion of local Agenda plans. The local Agenda process by assisting local authorities in developing policy tools and instruments and through awareness rising.

The Sustainable Cities project in 1993, as a follow-up to the discussion that flowed from the 1990 Green Paper on the urban environment. The main aims of the project are to:

• Promote new ideas on sustainability in European urban settings,
• Foster a wide exchange of experience,
• Disseminate good practices on sustainability at the urban level, and
• Formulate recommendations aimed at influencing policy at the EU, Member State, and regional and local level.

Essentially it consists of

• Policy reports and recommendations for institutions,
• Networking activities that are run by the Sustainable Cities campaign launched. The charter calls for increased inter-local authority co-operation and commits its signatories to drawing up long-term action plans for sustainable development with those involved at the local level.

A wide range of human activities affect water availability and quality especially in areas with a high population density, concentrated industrial activity and intensive agriculture.
Only a small fraction of the world's population has access to tap water that is suitable for drinking. In the European Union, this service is taken for granted, and it is forgotten that this is not the case everywhere. The indicators selected by the panels of water experts will give a comprehensive description of the pressures imposed on quality and availability of water resources and of the success of environmental policy to reduce them.

• The prevention of over-exploitation of ground water and surface water for drinking water or industrial or other purposes;
• The prevention of pollution of ground water from diffuse sources; and
• A better ecological quality of surface and marine water.

The indicators formulated by the Scientific Advisory Groups for the policy field Water Pollution & Water Resources go into more detail: nutrients, overuse of ground water resources, pesticides, heavy metals and organic matter are listed as the most important pressures on water. A more general indicator "wastewater treated" is also included as a measure of the efforts invested in the protection of water quality.

23.2 Related to Air Pollution

The term "air pollution" is used to describe substances that are artificially introduced into the air. Air pollution stems from gases and airborne particles which, in excess, are harmful to human health, buildings and ecosystems.

Four major impacts determine the classification of pollutants under the traditional policy field

23.2.1 Air pollution

• The acidification of soil and water by pollutants such as sulphur oxides, nitrogen oxides and ammonia;
• The damage to buildings sensitive to the same acidifying substances;
• The formation of troposphere ozone from so-called ozone precursors, e.g. Volatile organic compounds, nitrogen oxides and carbon monoxide which indirectly affect human and animal health and vegetation;
• Direct effects on human health and ecosystems e.g. through high atmospheric concentrations of particles, and vocs.

Excluded from this chapter are emissions of CO_2, N₂O, CH₄ and CFCs, which are covered in the policy fields Climate Change and Ozone Layer Depletion. Emissions of highly toxic substances are given special consideration under the heading Dispersion of Toxic Substances

Although some of these pollutants are also produced by nature, the main environmental problems result from human activities. Air pollutants are often transported over considerable distances, affecting air quality, ecosystems, lakes and other surface water, groundwater, soils and buildings in adjacent and distant countries.
The following list of indicators selected by the Scientific Advisory Group (SAG) "Air Pollution" comprises four indicators of pressure. The two "background" or "driving force" indicators Consumption of petrol & diesel oil by road vehicles and Primary energy consumption represent the major causes of these pressures.

23.2.2 Water conservation

Water conservation can be defined as:

1. Any beneficial reduction in water loss, use or waste as well as the preservation of water quality.
2. A reduction in water use accomplished by implementation of water conservation or water efficiency measures; or,
3. Improved water management practices that reduce or enhance the beneficial use of water. A water conservation measure is an action, behavioral change, device, technology, or improved design or process implemented to reduce water loss, waste, or use. Water efficiency is a tool of water conservation. That results in more efficient water use and thus reduces water demand. The value and cost-effectiveness of a water efficiency measure must be evaluated in relation to its effects on the use and cost of other natural resources (e.g. energy or chemicals).

The goals of water conservation efforts include as follows:

• Sustainability. To ensure availability for future generations, the withdrawal of fresh water from an ecosystem should not exceed its natural replacement rate.
• Energy conservation. Water pumping, delivery, and waste water treatment facilities consume a significant amount of energy. In some regions of the world over 15% of total electricity consumption is devoted to water management.
• Habitat conservation. Minimizing human water use helps to preserve fresh water habitats for local wildlife and migrating water flow, as well as reducing the need to build new dams and other water diversion infrastructure.

23.2.3 Rain water harvesting

Rain water harvesting is the accumulating and storing of rainwater for reuse before it reaches the aquifer. It has been used to provide drinking water, water for livestock, water for irrigation, as well as other typical uses. Rainwater collected from the roofs of houses and local institutions can make an important contribution to the availability of drinking water. It can supplement the subsoil water level and increase urban greenery. Water collected from the ground, sometimes from areas which are especially prepared for this purpose, is called Storm water harvesting. In some cases, rainwater may be the only available, or economical, water source. Rainwater harvesting systems can be simple to construct from inexpensive local materials, and are potentially successful in most habitable locations. Roof rainwater may not be potable and may require treatment before consumption. As rainwater rushes from your roof it may carry pollutants, such as mercury from coal burning buildings, or bird faeces. Although some rooftop materials may produce rainwater that would be harmful to human health as drinking water, it can be useful in flushing toilets, washing clothes, watering the garden and washing cars; these uses alone halve the amount of water used by a typical home. Household rainfall catchment systems are appropriate in areas with an average rainfall greater than 200 mm (7.9 in) per year, and no other accessible water sources (Skinner and Cotton, 1992). Overflow from rainwater harvesting tank systems can be used to refill aquifers in a process called groundwater recharge; though this is a related process, it must not be confused with rainwater harvesting.

There are several types of systems to harvest rainwater, ranging from very simple home systems to complex industrial systems. The rate at which water can be collected from either system is dependent on the plan area of the system, its efficiency, and the intensity of rainfall (i.e., annual precipitation (mm per annum) x square meter of catchment area = liters per annum yield ex, ... a 200 square meter roof catchment catching 1,000mm PA yields 200 KLPA.)

23.2.4 Watershed management

Watershed management is the study of the relevant characteristics of a watershed aimed at the sustainable distribution of its resources and the process of creating and implementing plans, programs, and projects to sustain and enhance watershed functions that affect the plant, animal, and human communities within a watershed boundary. Features of a watershed that agencies seek to manage include water supply, water quality, drainage, storm water runoff, water rights, and the overall planning and utilization of watersheds. Landowners, land use agencies, storm water management experts, environmental specialists, water use purveyors and communities all play an integral part in the management of a watershed.