The “ability to sustain” is what underpins the term sustainability. However fashionable this word has become in recent years, true sustainability is only possible if the consumption is less than the capacity of production or recovery. For example, if you have a pond on your back yard and use the water from the pond to irrigate your garden this activity will only be sustainable if the amount of water used for irrigation during the dry season is less than the ability of the pond to stock the water during the rainy season. The pond’s water level indicates consumption versus availability. If the pond dries out before the end of the dry season it means the extraction of water for irrigation it is unable to sustain irrigation for the role dry season, summarizing it is unsustainable.