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Chapter 1
Sustainable water use and efficiency
Water efficient approach
Planning and sustainability
Providing water for towns and cities has been a challenge for thousands of years. The residents of Rome and Pompeii were able to enjoy plentiful supplies of good quality water as a result of sound planning and the engineering skills of the Romans (Plate 1.1).
The challenge that is now faced is providing water to meet the increasing needs of communities at a time when demand is increasing and supplies are not only reducing, but there is also a lack of security, due to drought and climate change.
To meet this challenge requires sound planning and an understanding of the water cycle and the water needs of the community.
Water is needed to support human life. This requires good quality water for consumption, and also water to provide hygienic living conditions: for washing, cleaning and ablutions. Water is also needed to support the production of food, goods and services. Electricity generation from thermal power stations, for example, requires a significant amount of water. The standard of living we enjoy is strongly dependent on availability of a water source of high quality and from a secure supply.
The focus of this publication is on urban green space. In recent years, owing to drought, water to support urban environments in Australia has not been available to provide the standards of landscapes that have might have been expected in the past. The changing landscape environment is strongly influenced by the availability of water (Plate 1.2).
Green space in urban areas consists of vegetation, such as residential gardens, parklands, urban forests, sporting grounds, streetscapes, commercial landscapes, public gardens, botanic gardens, golf courses and racetracks.
Planning for sustainable use of irrigation water in urban areas to support green space is essential.
The aim of the approach outlined in this publication is to provide a knowledge base and understanding of all of the key factors and processes that are involved in achieving the efficient use of water in urban landscapes.
Efficiency applies to all processes involved in the management of the landscape. The maintenance of the urban landscape should be carried out efficiently. The use of fertilisers, labour, capital and the application of water all need to be managed astutely and resources used efficiently.
Sustainability – what does it mean?
The aim for all horticultural sites should be that they be sustainable in economic, social and environmental terms: they should be triple-bottom-line positive.
Figure 1.1. Sustainable water management principles
The term sustainable use is now liberally used in water management. A truly sustainable landscape would be one that involves no human-related inputs, including energy, water and chemicals. The purpose or role of most urban landscapes is to provide some form of service or outcome to the community. The space may be used in a passive way, such as a parkland, or it may be an active-use area, such as a sports ground.
A landscape that has no requirement for additional inputs and is in harmony with the environment could be considered truly sustainable. However, the purpose of most urban landscapes is to provide some type and level of service and so some inputs will be required. A landscape that provides a high level of services, such as intense sports activity, would be expected to have a high level of inputs and may not be considered sustainable, in the strict sense of the term.
There needs to be a balance between social benefits and environmental sustainability.
A key characteristic of a sustainable landscape is that it continues to perform and deliver the intended services or outcomes for the medium to long term: 20 to 50 years or more. It is not a short-term objective. A landscape in which water use is managed in a sustainable manner, but the site is degraded or fails, is not a sustainable landscape. An informed and integrated approach ensures that all factors that have an impact on sustainability are taken into account.
Sustainable water use is understood in this publication to mean the use of minimum amount of supplementary water to achieve the desired outcomes and that the use of water and other inputs are carried out in such a way that the environment is protected.
The efficient use of water to maintain a landscape is a critical part of achieving sustainability (Figure 1.1). It ensures that little or no water is wasted and that the impact on the environment is minimised. These core requirements are fundamental to sustainable turf and landscape areas.
Characteristics of sustainable irrigated landscapes
The sustainability of an irrigated area requires consideration of the health of the water source, the impact of the extraction of water on the environment and the health and viability of the irrigated turf and landscape areas.
Some features of sustainable irrigated landscapes include:
- The extraction of water for irrigation does not have a negative impact on the water source and the environment.
- Water security is achieved.
- The irrigated area (landscape) is suited to its intended purpose.
- The inputs (water, chemicals, energy and labour) used are minimised, used efficiently and managed so that environmental health is protected and the maintenance demands are minimised.
- The capacity of the organisation is appropriate to manage the landscape, both in terms of resources used and outcomes or services, to be provided.
- The business and functions of the site are viable.
Core elements of sustainable irrigated landscapes
The following are the core elements of an approach consistent with the achievement of sustainable use of water in urban landscapes.
- The site is designed, including selection of plants, to minimise the demand for supplementary irrigation water.
- The hydrology of the site is assessed and managed to optimise the use of rainfall.
- The amount of supplementary water provided is matched to the site vegetation, soils and weather.
- Irrigation is carried out efficiently.
- An annual irrigation water requirement and water budgets are prepared for the site and used for ongoing monitoring and evaluation.
- A secure non-potable water supply is a planning objective.
- Resource management practices associated with the irrigated site, such as fertiliser and chemical, have no negative impact on the environment (thus protecting soil health and water bodies).
- Water management is carried out to best management practices standards, within a framework, that encourages continual improvement.
The adoption of these core elements provides a sound basis for the achievement of sustainable landscapes.
The first stage in the development of an urban landscape, including turf areas, should be an objective analysis of the purpose and use of the landscape and the assessment of the need for supplementary water. This process should identify not only whether or not the site should be irrigated, but on what scale and to what level.
Landscape outcome
Approach
The starting point in the consideration of the development or ongoing maintenance of any urban landscape area that is proposed to be irrigated should be the identification of the outcome to be provided by the landscape or space (Plate 1.3).
The word ‘outcome’ is used, in this document, to describe the outputs or services of the landscape. These outputs may be aesthetic, functional (e.g. provide shade), active use (e.g. sporting activities), ...
