The promotion of better-designed facilities which facilitate water-saving will become a new trend among the public and designers, because of concerns for environmental protection。 The water conservation index was also designed to encourage utilization of the rain, recycling of water used in everyday life and use of water-saving equipment to reduce the expenditure of water and thus save water resources。
2。2。 Methodology for efficient use of water resources
Some construction considerations and building system designs for effective use of water resources are described below。
2。2。1。 Use water-conservation equipment
A research of household tap-water consumption revealed that the proportion of the water used in flushing toilets and in bathing, amounts to approximately 50% of the total household water consumption, as given in Table 1。 Many construction designers have tended to use luxurious water facilities in housing, and much water has thus been wasted。 The use of water-saving equipment to replace such facilities is certain to save a large amount of water。 For example, the amounts of water used in taking a shower and having a bath is quite different。 A single shower uses around 70l of water, whereas a bath uses around 150l。 Furthermore, current construction designs for housing in Taiwan tend to put two sets of bathtubs and toilets, and quite a few families have their own massage bathtubs。 Such a situation can be improved only by removing the tubs and replacing them with shower nozzles, so that more water can be possibly saved。 The commonly used water-saving devices in Taiwan now include new-style water taps, water-saving toilets, two-sectioned water closets, water-saving shower nozzles, and auto-sensor flushing device systems, etc。 Water-saving devices can be used not only for housing, but also in other kinds of buildings。 Public buildings, in particular, should take the lead in using water-saving devices。
2。2。2。 Set up a rain-storage water supply device
The rain-storage water supply device stores rain using natural landforms or man-made devices, and then uses simple water-cleaning procedures to make it available for use in houses。 Rain can be used not only as a substitute water supply, but also for re control。 Its use also helps to decrease the peak-time water load in cities。 The annual average rainfall in Taiwan is about 2500 mm, almost triple better than the global average。 However, due to geographic limitations, we could not build enough water storage devices, such as dams, to save all the rain。 It is quite a pity that annually about 80% of the rain in Taiwan is wasted and flows directly into the sea, without being saved and stored。 The rain-storage water supply system is used with a water-gathering system, water-disposal system, water-storage system and water-supply system。 First, the water-gathering system gathers the rain。 Then, the water flows to the water-disposal system through pipes, before being sent to the water-storage system。 Finally, it is sent to the users’equipment through another set of pipes。 Using the drain on the roof of a building, leading to the underground water-storage trough, is considered an effective means of gathering rain。 The water, after simple water-disposal processes, can be used for chores such as house cleaning, washing floors, air-conditioning or watering plants。
2。2。3。 Establishing the intermediate water system
Intermediate water is that gathered from the rain in cities, and includes the recycled waste-water which has already been disposed of and can be used repeatedly only within a certain range, but not for drinking or human contact。 Flushing the toilet consumes 35% of all water。 If everyone were to use intermediate water to flush toilets, much water could be efficiently saved。 Large-scale intermediate water system devices are suggested to be built up regularly with in a big area。 Each intermediate water system device can gather, dispose and recycle a certain quantity of waste-water from nearby government buildings, schools, residences, hotels, and other buildings。 The obtained water can be used for flushing toilets, washing cars, watering plants and cleaning the street, or for garden use and to supplement the water of rivers or lakes。 A small-scale intermediate water system gathers waste-water from everyday use, and then, through appropriate water-disposal procedures, improves the water quality to a certain level, so that finally it can be repeatedly used for non-drinking water。 There are extensive ways to use the intermediate water。 It can be used for sanitary purposes, public fountains, watering devices in gardens and washing streets。 In order to recycle highly polluted waste-water, a higher cost is needed for setting up the associated water-disposal devices, which are more expensive and have less economic benefits than the rain-utilization system。 Except for the intermediate water-system set within a single building, if we build them within large-scale communities or major construction development programs, then it is sure to save more water resources efficiently and positively for the whole country as well as improve the environmental situation。