On the left, a modern staff gauge structure on the Nile (photo credit Mansour Mordos) and on the right the ancient nilometer at Elephantine Island.

Forty Centuries of Water Monitoring

On the left, a modern staff gauge structure on the Nile (photo credit Mansour Mordos) and on the right the ancient nilometer at Elephantine Island. Note that the design element on the right is incorporated into the modern gauge as an homage to the ancient gauge.

A team of hydrologists and hydrographers with the Ministry of Water Resources, Irrigation and Electricity (MWRIE) in Sudan recently took part in some AQUARIUS training where I had the chance to learn about their monitoring program. In this age of rapidly advancing hydrometric technology, it is fascinating to think about the changes that have occurred since the birth of modern hydrometry in the 12th dynasty of Egypt when flood stages of the Nile were carved into the cliffs between Semneh and Kumneh (e.g. one of the inscriptions reads “this is the height of the Nile in the 14th year of the reign of His Sanctity King of Amenemhet the Third, still flourishing,” thus recording the flood stage for the year 1827 B.C.).

Before 1900 all water stage recorders in the United States were called Nilometers (one type was known as the Wyoming Nilometer), a clear tribute to the early Nilometers such as the one on Roda Island opposite Gizeh. The Roda gauge is an octagonal column of white marble in a stilling well with connection to the Nile by two tunnels. The gauge is marked in cubits each divided into 24 kirats. Ni-Yarouou, also known as Wafaa El-Nil (the feast of the rivers), was the day the Nile reached 18 cubits. It is celebrated as the New Year and hence is the origin of our New Year’s greetings. The whole wealth of the region was created by the fertile silt deposited by floods. However, extreme floods would scour the top soil and destroy the mud-walled dwellings resulting in famine and disease. Land taxes (called kharag) were imposed based on the level reached by the Nilometer.

Fast forward to the present and we have the Merowe dam development on the Nile and once again the wealth of the region is highly dependent on the results of water monitoring, which brings us to Mansour Mordos and his dedicated team of hydrologists and hydrographers. High quality, reliable data are needed to support hydropower generation and irrigation needs while ensuring environmental sustainability. Mansour’s enthusiastic, highly-skilled and well-trained team is using cutting-edge technology to undertake an ancient task.

Their monitoring challenges are significant. The scale of water and sediment flow in the Nile is staggering – 11,000 m3/s flow and 15 g/l sediment concentration. The MWRIE Water Center was established (under the management of Mr. Sighairoon) to deal with these challenges. The Water Center has chosen the best available equipment and procedures for measurements, monitoring, and data management to run a network with 19 weather stations, 30 level and flow stations, and 3 water quality stations. Field work involves a team of 6 – often working from a purpose-built survey boat – and cooperatively solving monitoring challenges with hard work, perseverance, and innovative solutions.

You know you are doing something right when the thing that you are doing withstands the test of time.

Modern staff gauges that are the primary reference reading for the latest electronic wizardry differ from the early nilometers primarily by the choice of units (meters rather than cubits). Forty centuries is a pretty good affirmation that we are right in what we are doing and that we are doing it right!

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