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Whole Systems Approach to Ecological Design Organic Agriculture and Local Food Appropriate Technology: Energy Green Building & Retrofitting |
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The Hydrological CycleFresh water comes from rain, which evaporates from the oceans. The rain precipitates on land, flows into rivers and lakes, recharges groundwater, is retained in the soil, with a portion running back to the ocean (see picture The Hydrological Cycle). Water is used by agriculture, industry and municipalities. Unsustainable extraction from aquifers lowers the groundwater level. Within a bioregion it is good to assess the water budget – inflows and outflows. Sustainable communities can then ensure they are using water from sustainable sources and conserving wherever possible (see picture Conceptual Water Budget). Too often water is channelled off the landscape as quickly as possible. This does not allow the water to be retained for use throughout the year. Also polluted water is frequently moved away from the area and downstream.
The sustainable approach is to store rainfall in the landscape, grow forests, instal check dams, minimise water pollution, treat polluted water close to the source of pollution and recycle within the region. This maintains the social and ecological integrity of the community.
The climate is changing and in many places the monsoons are becoming less predictable. This reservoir in India was full in the previous year. Notice there is no forest in the landscape. Restorative land practices are explored in a later part of this module. |
The Hydrological Cycle
Click on image to enlarge
Indian reservoir |
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