The planet's fresh water supplies are limited, climate change is adding to periods of intense rain and subsequent drought and the structure of the earth’s subsurface is easily damaged if the water table is not able to remain relatively consistent or to be replenished. The installation of deep wells contributes to the lowering of the water table, impacting on plants and animal life and contributing to the occurrence of landslides.
The Alam Santi design team have been working with the UN, governments, businesses and local communities to design rainwater harvesting systems that can be used by everyone to help replenish natural fresh-water resources.
The team have worked out a system for both calculating the size of tank needed to store water, to remove debris and to filter the water itself, ready to store and deliver with a pump by demand. They recommend the use of traditional, corrugated steel cladding and a maximum roof length for optimal drainage. Their calculator for working out the size of the system needed per household or per building is easily adapted for different environments. Their design further specifies materials needed to build and install the system.
Alam Santi’s work makes recommendations for devices to reduce water use by adapting shower and tap heads and by installing specially designed toilets that extract urine with separate flushes for faeces or urine. The latter allows for water with diluted urine to be reused in irrigation and to add additional nutrients to plants.
Combined with simple technology (like perforated bamboo pipes inserted next to trees and plants to ensure water reaches their roots directly) and landscaping and storm drains designed to capture and use any water run-off, the planet’s limited freshwater supplies can be conserved and used most effectively.
IMPACT ON PEOPLE
Heightening public awareness of the water they use and the difference they are able to make
Ensuring water is more equitably shared and available for all sections of the population
Enabling people to reuse and recycle water in order to cultivate gardens and produce their own food
IMPACT ON PLANET
Prevents the desertification of land caused by lowering the water table through excessive drilling of wells
Limits the landslides caused when the water table is unable to be replenished
Provides irrigation (and urine fed irrigation) for plants and vegetables avoiding excessive use of pesticides or GM crops
Water harvesting, at individual household, community, or state level brings together a range of techniques that contribute to the regeneration of the environment and prevents the degeneration caused by excessive human populations.
Effective use of water and careful harvesting of rainfall show the close interaction between humans and their environment and illustrates how, when working together, communities and environments can thrive. It illustrates an approach to meeting the human need and right for clean water without depleting or stealing from the natural world.
SCALABILITY & REPLICABILITY
As a series of techniques that can be used at different levels and in different contexts, water harvesting can be introduced at any scale of human settlement. The drilling and digging of deep wells have for several decades been a core part of international development’s response to water scarcity in an attempt to reduce water borne disease and the daily trek to carry water experienced by many village populations. While good intentioned, these can add to the degeneration of an area and future livelihoods, in the attempt to alleviate human suffering in the short term.
In contexts of disaster and displacement, shelter and water have to be provided in a hurry and is often trucked in with drinking water provided in bottles and wash facilities constructed rapidly.
The existence of an integrated design approach, the construction of emergency buildings and facilities that allow for harvesting and recycling of grey water or diluted urine and the promotion of water harvesting habits will mean that such a settlement is viable in the longer term without unnecessary damage to the environment or health risk to the community. Such settlements can then include green spaces and vegetable gardens and become thriving places for humans and the natural world.