The basic (physical) necessities of life are air, water, food and shelter. We can live only a very short time without air to breathe. Water we need regularly, while we can live for weeks without food, if necessary. Our bodies are mostly water, and water is used to mediate all our bodily exchanges, transporting life-giving nutrients to all our organs and cells, while carrying away toxins and wastes.
Air and water are the great transporting and mixing media of life on planet Earth, that allow plants to thrive, while staying in one place. Air blankets the Earth as an atmosphere of gases, which circulate through the heat of the sun and climate processes. Water circulates through the processes of the hydrological cycle — as water vapour in the air, as liquid water on and under the surface of the Earth, and as solid ice or snow at high latitudes and altitudes.
Air and water are both energised and purified by these circulatory processes, and these processes and the nature of air and water can be adversely affected by the pollution of excess. There is also an essential inter-connection between these physical processes and the ecological systems and networks of life. The nature of the air and the complex states of water on the planet arise from, and are dependent on, living processes and eco-systems. Water can have many ionic states, and form molecular links and networks that reflect the substances in it. Water is the most universal of solvents.
The burning of fossil fuels over the last couple of hundred years, and the accelerating rate at which we have burned them, especially oil in the last 50 years, has changed the gas composition of the atmosphere globally. The cheap energy this has provided has been used to build an industry and urbanisation that spew vast amounts of concentrated wastes and toxic materials into waterways and the oceans. This water pollution is most obvious locally, but there are global impacts through the circulations of rivers, the oceans and the atmosphere, as there is with the pollution of the air.
The vitality, purity and availability of water is directly affected by the loss of forests and the degradation of soils by agriculture — which also affects the air, locally and globally. The loss of riparian vegetation and habitats along the margins of rivers and streams alters the nature of the waterways, and affects the transport of sediments and nutrients, and their exchanges with groundwater and across floodplains.
Natural systems are full of exchanges, transitions from one state to another and storages, level on level, in a repeating and interwoven way. Our human systems, to be healthy and sustainable, must be part of and mimic the natural systems that contain and support us. Thus our water supplies and re-use of ‘waste’ water should consist of multiple systems at different levels, with different types and size of storage and a diversity of re-use through different processes.
Urban areas need some large central supplies and a distribution network, but the supplies should be diverse, including rivers, reservoir storage and groundwater, as well as direct rainfall collection. For a robust water supply the distribution network needs to have in-built redundancy, with looped or multiple primary feeders and mains, connected to the different supply sources spread around the network.
The best storage is natural groundwater, which is facilitated by forests. It provides a vast reservoir and distributes itself, through its flow through the ground. It is a diffuse rather than a concentrated source, which can be taped into for small supplies spread throughout a town or agricultural area. In dry climates and near the coast it is vulnerable to salination, and the removal of forests lowers groundwater levels generally, while also bringing the salts in the soil close to the surface. Groundwater away from forested hills, and especially on alluvial or coastal plains can be very variable in quality.
Storing rainwater directly from hard surfaces in rainwater tanks or storage basins provides small-scale distributed storage, which can be used on gardens and for washing etc. However, hard surfaces should be minimised, and shrub and tree areas maximised. Mulching of gardens increases ground storage by improving rainfall infiltration and the retaining of soil moisture.
Rainwater is slightly acidic and is best used for washing our bodies, as our skin moisture is slightly acidic. The best water for drinking is slightly alkaline (like the water in our bodies) and mineralised. This water is supplied naturally by ‘relief’ springs, which arise from base rock materials as dense cool water, and by the forest enclosed streams that flow from them. Drinking water is then better supplied separately from appropriate sources, and not as part of washing and industrial water.
The re-use of water, following washing and industrial uses, can be diverse and multi-functional, by having distributed and varied re-use at different scales. The type and degree of treatment required before re-use depends on the initial use, for instance when natural and biodegradable cleaners are used, and the re-use. Water used by a single family for washing and then re-used on their own garden has a very low parasite hazard, while the combined washing water from many households sent to a central treatment plant has a much higher health hazard, due to the mixing of microbes from many sources.
Thus, greywater from a household can be simply drained to mulched vegetation beds, following minimal storage for sediment deposition and scum removal. Runoff from roads and paved areas can be directed to grassed or vegetated swales alongside, or to vegetated infiltration areas. Contained wetland areas, with or without naturally contained sand filtration areas, can be used to treat road runoff and the greywater from a group of houses or ‘high quality’ industrial ‘waste’ flows, to allow re-use in community gardens and reserves etc. As far as practical, re-use should be designed around gravity flow systems, with a cascade of ‘units’ along and down the contour.
This re-use fits in very well with the growing of food in towns, in either family or community gardens, and as public ‘orchards’ or food forests along reserve land and waterway corridors.
Toxic waste streams must be carefully treated, being mixed and diluted and then adequately treated before discharge to the natural environment. Loading and the concentration of harmful substances is the critical issue, but in the end it is natural systems, mainly the reducing microbes, in the natural environment that will transform the ‘wastes’ and make them available for re-use again. Maintaining healthy and robust eco-systems to do this is then essential for effective processing and re-use of our output ‘waste’ streams.
Air and water are common ‘resources’, which flow across private property and state boundaries. Their management for our use and enjoyment must, therefore, be handled through community decision-making processes, which allow fair sharing and appropriate care.