By G. Edwin Battenberg
Rainwater harvesting… the ancient technique of capture, diversion and storage of rainwater. It is useful for landscape irrigation, household cleaning and bathing, drinking and livestock water, among other purposes..
This process was essential for life in earlier times. Rainwater is highly valued for its inherent quality of softness, nearly neutral pH and the absence of metals. It is rapidly gaining ground as an exciting new trend on the domestic front.
Historic concept
The concept of rainwater harvesting may date back 6,000 years in China. Evidence of this technique attests to the capture of rainwater as far back as 4,000 years ago.1
Archeological evidence in Israel confirms rainwater capture as early as 2,000 B.C. Ruins of cisterns built to store runoff from hillsides for agricultural and domestic use are still standing there today.
The ancient Anasazi and other Native American cultures in the southwest US carefully crafted purveyance trenches. These followed the natural contours of the mountains and plateaus to bring water to villages and cliff dwellings for drinking, crop irrigation and livestock watering.
Early pioneers in North America collected rainwater in barrels for use in laundering, bathing and other cleaning operations because of its natural softness. In point of fact, these earlier generations coined the phrase ‘hard water’ because ground water and some surface waters were too hard to work with, hence the term we still use in our industry today. The high mineral content combined with the tallow and fats used in making soap of that era created ‘soap curd’ that hampered laundry, bathing and cleaning chores.
I can still remember the rain barrel my grandparents used for making coffee, tea and ice. My grandmother would boil the water to disinfect it, let it cool and store it in a five-gallon glass bottle that was suspended in a cradle…the same type used for early home and office delivery (HOD).
Designed collection
Lighthouses in remote locations where ground water or public water were not available were designed with catchments to divert rainwater to a cistern. Today, visitors can see how rainwater was collected, conveyed and stored for these facilities located along the coastal and Great Lakes regions of North America.
Some of these cisterns were constructed of wood and, though no longer in use, still hold water after more than 150 years. Most lighthouses that are open to the public, of course, have now been updated with electricity, modern plumbing and public water or a well system.
The most interesting aspects of rainwater harvesting are learning about methods of capture, storage and usage of this natural resource. Construction of these catchments varies widely due to geographic and topographical conditions.
On a recent trip to Japan, I toured an ancient village that was over five hundred years old. The elegantly simple method of a rainwater catchment was built into each structure and stored in barrels with overflows routed to surface ponds and subsequently piped to lower areas where crops were tended.
The grounds of the common area were designed to make excess water flow away from structures via a stone ‘wick’ to reduce flooding. All of the materials used in construction of the rainwater system were gathered locally and constructed with wood from indigenous trees.
Australian mandate
In the Australian Outback, where population densities are very low, rainwater capture is essential to survival where groundwater is either not available or it is too deep to pump to the surface. The use of domestic rainwater tanks has been a long-standing practice throughout Australia and is still common today.
A 1996 survey conducted by the Australian Bureau of Statistics showed that 82 percent of rural populations in southern Australia used rainwater as their primary source of water for drinking and other domestic needs. Rainwater falling on house and/or outbuilding roofs is naturally soft, clear and for the most part, free of microorganisms.
There is, however, the potential for chemical, physical and microbiological contamination during collection and storage. Chemical and physical qualities are relatively easy to maintain with today’s modern treatment processes but the risk of microbiological contamination is more difficult to control.
Renewed popularity
Rainwater harvesting is enjoying a revival in popularity primarily for reducing reliance on municipally treated water. Some US states have no restrictions on rainwater catchment while others provide severe criminal penalties claiming rights to rainfall for use by others, particularly in the west.
Depletion of groundwater sources, poor water quality and high tap fees for isolated property owners make rainwater harvesting an excellent option for domestic use. There are more than 100,000 residential rainwater harvesting systems in use throughout the US.
Demand by urban home gardeners, weekend cabin owners, cattle ranchers and homeowners intent on green building practices — all seeking a sustainable high quality water source — practically guarantees more growth for both the customer and new business start-ups. With this kind of focus, supported by well-established companies catering to these customers, it is no exaggeration to say that there exist ample opportunities for water conditioning dealers to capitalize on this rapidly growing market segment by providing modern treatment methods to control potential microbiological contamination.
In future Flowing Issues segments, we will discuss current trends, state regulations and permit requirements and legal considerations. Suffice it to say that rainwater catchment with all of its different faces may help close the gap between supply and demand with regard to population growth in areas hard hit by drought and dwindling ground water supply. Stay tuned!
Reference
- E. Gould and E. Nissen-Petersen, Rainwater Catchment Systems for Domestic Supply: Design, Construction and Implementation, Stylus Publishing LLC, 1999.
About the author
Gary Battenberg is with Hague Quality Water International located near Columbus, OH, holding the position of Technical Director since 1997. He has over 26 years experience in the field of domestic, commercial and high-purity water treatment processes. Battenberg has worked in the areas of UV sterilization, reverse osmosis and ozone technologies. Contact him at [email protected].