Water mill using artesian water at Megali Vryssi, Lamia, Greece

 by Constantinos Balomenos

 

Introduction

   In 1986 I was fortunate enough to meet and interview the last miller of this watermill, namely Giannis Ververis (1921-2002), who described to me everything he knew about it. By that time the mill was in ruins, surrounded by water and copious plant growth, preventing anyone from being able to approach it. Therefore, I necessarily confined myself to the miller's description and along with his help I attempted to sketch how the watermill was built and operated.

 

1.    Some historical facts

   Since the years of the Ottoman Empire, some 3-4 km east of the city of Lamia, there was the Tsifliki (estate) of Megali Vryssi. The estate extended over an area of 30,000 acres, from the foothills of the Othrys mountain range to the shores of the Maliakos Gulf. From 1830, after the creation of the independent Greek state, the farm was bought by the Greeks, Nicholaos Stournaris (1806-1853) and Andreas Fardis (?-1875). Later, from 1871, the whole farm came to Irine Stournari daughter of Nicholaos; she married the Englishman, Charles Edward Prior Merlin.

   Artesian water has sprung up in considerable quantities in a low area of this estate, near the foothills of the mountain range, since long ago. Since the years of the Turkish occupation travellers stopped and drank or watered their pack animals at this place, and the name of the area ‘Megali Vryssi’ (Large Spring) came from this. This same water, via a canal, was used to irrigate the estate grounds and the rest ended up in the Maliakos Gulf. In Act Nr.16 of the Municipality of Lamia (1856) it is stated that: “the estate includes Mills, Fulling Mills, Fulling Tubs and an Hotel”!

   It should be noted that this area, along with the waters in the associated channels, is a designated wetland, home to a fish unique in the world, the Greek pygosteus (or pungitius hellenicus).

 

2.    Water utilization

   Here we have perhaps the only case of a watermill on horizontal ground, which operated from the 19th century (maybe even earlier), using artesian spring water. The point from where the water gushed was enclosed with high masonry walls, approximately triangular at its base (as the last miller told). The walls reached a height of more than 4 m and formed a large cistern (which is here called Cistern 1). Inside there were low partitions (again masonry built), also filled with water, and their overflow led the water through the final outer high wall of the cistern.

 

   At a distance of 3-4 m from Cistern I, another construction was built in the shape of an upright cylinder, again made of stone with a dark coating on the outside, and which had a diameter of 2 m and a height of approximately 3-3.5 m. Internally it was shaped like a funnel and narrowed at the bottom ending in a hole with a pipe for the water to exit (its exact diameter is not known). This construction we will call Cistern 2. The two cisterns were connected by a gently sloping duct (canal) with a rectangular cross-section (80 cm wide and 50 cm deep). A schematic presentation, based on the narrative of the last miller Giannis Ververis, is shown here:

 

    The water level difference inside Cistern 2 created hydrostatic pressure at the lower end, which having a small diameter pipe and nozzle (around 5-6 cm) directed the water at sufficient speed to drive a horizontal water wheel; this was of metal, probably with small troughs. The last miller had never actually seen it because the wheel was ‘out of sight’; in this case, there was no ‘zourio’ (water wheel chamber) as in other horizontal watermills.

    The vertical shaft of the water wheel drove the runner millstone. For the operation of the mill, both cisterns had to be always filled with water. In the summer, when the spring water was dwindling and the water in Cistern 2 was 0.5 m lower, the mill only operated marginally. In normal operation the grinding speed was estimated at between 40-60 rpm (by the last miller). However, he could increase the distance between the millstones, by using a screw, so that the rotation of the shaft would increase. In the evenings, during holidays or when the mill had to be stopped, the water wheel shaft was blocked with the help of an iron or wooden crank.

    Some improvement in the operating parts and construction at the mill must have taken place in the period 1870-80. In the latter period, when Giannis N. Ververis was the last miller, no improvements were made except for some minor repairs to the building (mainly the roof). The mill was in operation until 1946, then abandoned. By the 1950s, after the expropriation that took place in the area, the mill was ruined. Now there are just a few traces among the water-loving plants.

 

3.    Theoretical calculation of power generated

   In this case we have the following data:

Height difference of water level, h = 2.5 to 4 m

Water outlet pipe diameter D = 5-6 cm, so pipe radius r = 2.5-3 cm

 

   Other constants that are useful here are:

The density of pure water, d = 1000 Kg/m³

The acceleration of gravity, g = 10 m/s²

 

   Using standard formulas of mechanics. Specifically:

 

The speed (υ) of water outflow from the siphon:    υ = (2gh) ^½    (1)

 

The cross-section (A), or otherwise the area of the water outlet pipe: A = π·r²    (2)

 

The supply (Π) of the water is calculated from the formula: Π = A·υ(3)

 

The theoretically produced power (P) from the hydraulic installation is:  P = Π.d.g.h   (4)

 

   Substituting the probable range of numerical values into the above formulas (1), (2), (3) and 4) the results are given in the following table:

 

*The last 2 columns give the theoretical output of the watermill in W (watts) and in HP (English horsepower) where 1 HP is equivalent to 746 W.

 

Epilogue

   For the record, it should be remembered that the power of a (horizontal wheel) watermill has been calculated to be equivalent to the power of 15 people. Considering that the average power of a human is 0.1 HP, then the average power of a watermill is 1.5 HP. This simple and ingenious construction, which utilized a source of artesian water to create the necessary head (height difference), was able to produce (theoretically) a power of around 1 HP for a water height of 4 meters. Also, the water mill operated for several decades and served the local area.

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References

 

1.    Interview with John's N. Ververis, the last miller.

2.    Const. Ath. Balomenos: ‘Sydney Merlin and Zaira Theotoki’, newspaper LAMIAKOS TYPOS, sheet 20361, p. 6, May 15, 2013, Lamia.

3.    Const. Ath. Balomenos: ‘Megali Vrissi’sTsifliki’, newspaper LAMIAKOS TYPOS, p. 8, 24 Aug. 2013, Lamia.

4.    Th. Kougioumzelis - S. Peristerakis: "Elements of Physics", volume 1, Mechanics-Thermotis, page 151, Athens, 1960

5.    Const. Ath. Balomenos: ‘Hydrokinesis in Fthiotida (until the end of the 20th century)’. Work from January 2018, as yet unpublished. It is posted at www.amfictyon.blogspot.gr .

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 Constantinos Ath. Balomenos (physicist) can be contacted at: balomenoskostas@yahoo.gr