Alternative water supplies

© Bob Denton, 2016
Advance to Early civilizations –  Back to First settlements
Forward to S S and S

Early human communities did not need to rely solely on rainwater, rivers and lakes for their water supplies.  There were alternative natural or fabricated sources that they learned could be drawn upon – springs, oases, cenotes, aquifers, wells, cisterns, dams and qanats.

Springs

Water in rivers, lakes and even cisterns were often spoiled by mud and minerals or polluted by animal and human waste, so an underground spring was a much cherished alternative source. Springs were often cooler and purer than surface water, originating in underwater aquifers and rising through cracks and fissures in the rock.

Today springs are classified by the amount of water they discharge, the technical term is their ‘resurgence’. This ranges from the first magnitude that emits over 100 cu feet per second (2,800 litres/second) to the eighth magnitude that trickles out at just a pint per second (8 millilitres/sec).

Natural spring
Source: www.wqpmag.com

[P]

Because groundwater tends to maintain its temperature their water is cool in the summer and does not freeze in the winter, providing a regular supply throughout the year.

Their huge value to a community has often led springs to be considered as sacred (holy wells) and in turn this has prompted a raft of spring folklore and mythology, spirits and gods.

Oases

Oases are naturally-occurring aquifers and underground rivers that either reach the surface of their own accord or do this through human intervention.

An oasis is a type of spring which reveals itself as a patch of vegetation located in otherwise desert areas, the greenery indicating the presence of a water supply. Date palms are often found at an oasis and these tall trees helpfully provide an upper canopy to shade other vegetation below.

Al-Kufra oasis
Source: www.theglobalattitude.com

Migrating birds made use of oases since they first overflew deserts and this in turn attracted human attention to these locations. Their very nature gave oases an automatic human strategic and economic value, becoming staging points for trade routes and for desert caravans.

The oasis of Awjila, in today’s north-eastern Libya, was mentioned by Herodotus (fifth-century BCE) as an important waypoint across the Sahara and as a source of excellent date fruits. It handled both east-west traffic from Egypt to Libya and north-south from Benghazi to Lake Chad/Darfur. Herodotus talks of nomadic Nasamones making ten-day journeys between the oases of Siwa and Awjila.

The oasis of Ghadames (aka Cydamus), in today’s western Libya, was settled by 4,000 BCE and its city wall is today a UNESCO World Heritage Site #362.

The oasis of Kufra, in today’s south-eastern Libya, is located on a strategic high-point that dominates the lower-lying areas around it. It is in fact a series of six oases and featured strategically during WWII. It is also considered a holy place for one Sufi sect. Sadly today it has reputedly become a way-point in a major people-trafficking route.

Kufra oasis viewed from space, showing cultivated areas
Source: Wikimedia Commons

Cenotes

The Mayan civilisation lacked any rivers, streams and wells yet was able to flourish in the Yucatán Peninsula of Mexico from 2,000 BCE because its land was peppered with sinkholes known as cenotes, access holes to underground freshwater supplies. The cenote acts to all intents and purposes as a well yet it is not one.

A cenote is created by rain water that has been filtered through the rocks in the ground, mostly limestone or coral. The fresh water then creates what is called a ‘lens aquifer’, sitting on top of the underlying sea water. Different characteristics of the salt and fresh water menisci maintains a virtual diaphragm and they do not mix. Depending on the rainfall and the location this freshwater can be almost negligible to being up to seventy metres deep.

Cenote at Chichén Itzá, Mexico
Source: Wikimedia Commons

The famous Mayan monument’s named Chichén Itzá is derived from chi or ‘mouth’ and ch’e’en or ‘of the well’ so it literally means ‘the mouth of the well of the Itzá’.

Some cenotes were naturally formed, others were hewn out by mankind. Together these proved sufficient fresh water to found a tradition for corn farming upon what is otherwise pretty sparse and arid soil. But the Mayans did more. They found natural surface recesses or ones created by their removal of clay for house-building and used these as aquados – ponds or reservoirs. They also captured rainwater in chultuns or cisterns hewn into the limestone. Some of these had quite small entrances, then widened beneath the surface forming a wine-bottle-shaped profile that minimised airborne corruption. In more recent times both aguados and chultuns have been lined with stone or plaster to secure their contents more securely.

Artesian aquifers

Artesian well
Source: flickr.com

Artesian or confined aquifers are where water is located underground and under pressure. Often in a defile or valley where hydrostatic equilibrium has yet to be reached, meaning the water has not yet found its own level (see later how this siphon effect was used by Romans with their aqueducts). Digging or drilling a well into an artesian aquifer brings the water to the surface naturally. It overflows at the surface until equilibrium is attained.

BRIEFER: In the 12th century Carthusian monks in the French province of Artois created many wells using this principle, Artois was the derivation of the term artesian.

Remarkably artesian aquifers are often present under deserts. In the late 1950s the Nubian Sandstone Aquifer System was discovered beneath the Sahara, it had accumulated there back in the ice age and led to the Gaddafi government in Libya developing its Great Man-Made River Project (see later) supplying 6,500,000 cubic metres of fresh water each day to the cities of Benghazi, Tripoli and Sirte.

We’ve all heard of the Great Barrier Reef, but few have heard about Australia’s Great Artesian Basin. Discovered in 1878 it is the largest and deepest such basin in the world covering 660,000 sq m spreading across almost a quarter of Australia’s massive land-mass. It contains 64,900 cubic kilometres (15,600 cubic miles) of groundwater and is the source of much of the fresh clean water for the continent. It has been used by Aussies to develop farmland at long distances from any river course.

BRIEFER: The Dragon’s Breath Cave system in Namibia is another such underground system. Notable for being the habitat of a rare fish species, the golden cave catfish.

Wells

Neolithic settlements have been found on Cyprus that date back to 9,000 BCE. It had always been something of a crossroads, a stopping-off place for seaborne migrants. One PPNB group settled on the island along its south-west coast at Kissonerga-Mylouthkia, showing some knowledge and sophistication by digging two wells to achieve their water supply.

Kissonerga-Mylouthkia, Cyprus site of the earliest wells
Source: www.archaeological.org

In 2011 these wells were uncovered and proved to be the oldest wells discovered to date anywhere in the world. The well had evidently dried up and was filled with debris. Their early age (8,500 BCE) was determined by radiocarbon dating the accumulated rubbish and particularly the skeleton of a young girl that had been discovered in one of them.

Well in the Jezreel Valley, Israel
Source: Bloomberg Businessweek

The world’s third-oldest well (to-date) was discovered in Israel’s Jezreel Valley.  It was uncovered when the National Roads Company was widening a highway. It was also found to contain two 6,500 BCE skeletons at its base, an older male and a 19-year-old female. The well was attached to an early farming community as evidenced by flint tools, sickle-shaped flint blades and arrowheads at its base. The quarrying work to create the well suggests a long-term community effort had been undertaken to conceive and create it.

Well discovered near Leipzig Source:
www.sci-news.com/archaeology/article00788.html
 

Wells dating back to 5,000 BCE were discovered near Leipzig in Saxony, eastern Germany, making them the oldest in Europe and the oldest wooden wells in the world. The four wells led to archaeologists rethinking the capabilities of our ancestors.  These well-builders were part of a migration from the Great Hungarian Plain some 7,500 years ago, their trail able to be traced by their distinctive Linear Band Ware pottery – cups, bowls, vases, and jugs without handles (though later versions added lugs). This Linear Pottery was made between 5,600 and 4,900 BCE.

The wells were created by farmers, evidently adept at carpentry too. The scientists discovered over one hundred-and-fifty oak timbers used to line the seven-metre deep wells. They were jointed and assembled in a way that has withstood seven centuries beneath ground and kept archaeologists and dendrochronolgists busy. The oak trees were shown to have been felled between 5,206 and 5,098 BCE, so it is claimed as the world’s oldest discovery of any form of wooden architecture. Tool marks discovered on the wood are helping scientists to investigate the woodworking approaches that were used back then.

Other remains found in the wells indicate that local humans’ staple foods were two sorts of wheat, supplemented by lentils and peas, with apples, hazelnuts, raspberries, strawberries and sloe, there were also traces of oils taken from linseed and poppies. Add a little meat and these well-diggers would have enjoyed a good and varied diet.

Cisterns and Step wells

Another approach adopted by early communities from as early as 3,000 BCE was to store water in fabricated cisterns, capturing rainwater in some form of container for later use.

These would also serve a defensive purpose, because if you created cisterns inside your city walls then you could withstand a siege for longer periods. For example the cisterns in the acropolis of Pergamon have been calculated to have been large enough to supply its 20,000 people for over a year.

Pergamon arches
Source: www.handdrawnea.com/Turkey.html

The Harrapan civilization in the Indus Valley of India/Pakistan (more later) developed a number of early and innovative approaches to water storage and use. Here stepped wells were relatively common, subterranean water storage systems built from c.3,000 BCE.

Rani-ki Vav stepwell Source: www.ngu.ac.in/center/dias/morepatan.htm

In western India, Dholavira, excavations revealed the country’s largest and most elegant reservoirs to date. The pictured one is 10m deep, 73 metres long and 29 metres wide. In 2014 another stepwell dating from 3,000 BCE was discovered nearby.

Vishnu shown reclining on Shesha, the thousand-hooded serpent Shesha Source: http://asi.nic.in/asi_monu_tktd_gujarat_ranikivav.asp

UNESCO has recognised Rani-ki Vav, Patan Town in Gujarat as a World Heritage Site #922 for its remarkable stepwell, which has the sobriquet ‘The Queen of Stepwells’. Patan was built during the Solanki dynasty as the Gujarat capital city from 960-1243 CE, a time when Gujarat controlled a major part of the Indian Ocean trade. It became one of the largest cities in India, able to support some 100,000 inhabitants.

Rani-ki Vav Unesco Heritage Site
Source: http://www.cpreecenvis.nic.in

The step-well is one of the biggest found in the region at 64m long x 20m wide x 27m deep. It was constructed by the orders of Rani Udayamati (1022-63 CE) of the Chalukya Dynasty in memory of her husband. She planned it as an inverted temple to water.

It has four storeys each with sculpted pillars and compartments, staircases at the side walls connect the levels. It has bricks faced with stone with the side walls decorated by some five hundred major relief sculptures and a thousand minor ones. They depict for example the ten incarnations of Vishnu (including Buddha), plus Ganesh and the other gods in the Hindu pantheon. The stairwell was invaded by the Saraswati River and filled with silt until the 1980s, which fortunately meant that the sculptures survived intact.

Greek history during the late Bronze Age between 1,600 and 1,100 BCE is called Mycenaean. Mycenae was one of its major city strongholds set high upon a rocky hill. In mythology it was claimed to be founded by Perseus and features in both the influential epic poems. The Iliad and The Odyssey.

Underground cistern entrance at Mycenae
Source: www.vist-ancient-greece.com

At its peak the citadel of Mycenae could house 30,000 people. They built a 360-metre underground tunnel or syrinx from the Perseia spring (named for Perseus) to supply a cistern beneath the citadel that would sustain them during a siege. The city walls were later extended (c 1,200 BCE) to enclose the spring itself and an 86-step staircase led down 18 metres to retrieve the water.

Dams

Another way of accumulating water resources was to build a dam.

Remains of the Jawa Dam Source: www.simscience.org

The world’s first dam (discovered to date!) was built In the Black Desert of today’s Jordan. Using earth and masonry, the Jawa Dam was built c 4,000 BCE to create a store of water for irrigation purposes.

Sadd el Kafara dam, south of Cairo
Source: alchetron.com

The next oldest dam discovered was in Sadd el-Kafara some 30 kilometres south of Cairo, Egypt. This was built between 2,900 and 2,700 BCE with earth and a limestone masonry facing of up to 14 metres high. It was built to protect structures in the valley below rather than to store water. This was a period when pyramid construction was still in its formative stage and their technique for this dam proved inadequate. It did not last very long, its lack of a spillway (channel to run off excess water) meant that a flood simply carried it away.

Remains of Orontes Dam, Syria
Source: pbase.com

The oldest dam still in use today was built c 1,300 BCE on the Orontes River in today’s Syria. Assyrians, Babylonians and Persians built dams between 700 and 250 BCE, these were used both for water supply and for irrigation. In today’s Yemen, the Ma’rib dam was built in the southern Arabian Peninsula at around the same time.

The dam as a water storage device spread or was simultaneously developed in Sri Lanka, India and China as we entered the Classic era.

Qanats

The earliest type of aqueduct was created, known as a qanat.

A qanat
Source: www.azimuthproject.org

Qanats were tunnelled manually through rock and soil from an aquifer in order to supply a community. The tunnels were usually just a little larger than the person digging it and constructed with a gradual downward slope. Every thirty metres or so a vertical shaft was sunk which provided ventilation, but was also used for lifting out the spoil during construction and was a handy access for repairs and routine clearance.

Qanat and kariz at Niavaran
Source: Wikimedia Commons

The qanat uses gravity with no equipment required to deliver the water, and when gouged through rock the water losses through the tunnel prove minimal. Their downside is that the flow is constant and potentially therefore wasteful at periods of low usage.

Qanat in Tanuf, Oman
Source: William James, University of Guelph, Ontario, Canad

The Assyrian King Sargon II refers to seeing one in Persia in 7,000 BCE, his son would later build a famous one at Nineveh. The city of Zarch has the oldest and longest extant qanat, being 3,000 years old and 71 kms (44 miles) long. As with the one illustrated here, qanats frequently terminated at a kariz or well.

The notion of qanats was transmitted along the Silk Route and again later by the Roman and Islamic empires.

Chinese karez Source: www.cits.net

In quite recent times in Turpan, China adopted the qanat principle, though they called it a karez, which means ‘well’ in the Uyghur language. The water source was from nearby mountains and some 1,000 wells were supplied by this gravity-fed approach.

© Bob Denton, 2016
Advance to Early civilizations –  Back to First settlements
Forward to S S and S