Abstract

In the 18th century, the practice of drying up the wetlands, marshy or stagnant water areas expanded throughout Europe in order to avoid the malaria fevers that the population periodically suffered and to recover land for farming. This communication describes the current knowledge about the history of the process of drying in various hydrological basins as well as the works in the endorheic lake close to the village of L'Estany, located in the district of the Moianès (Catalonia), in the northeast of Spain. The drying began in the 16th century with drainage channels driven by the Monastery of Santa Maria de L'Estany, and culminated in the 18th century with the construction, using the dry stone technique, of a 425 m long, 2.14 m high and 1.20 m wide drainage mine that diverted water to the basin of the Llobregat River. Now the mine and the canals are conserved for use in times of rain as well as a touristic objective that complements the cultural and religious concerns of the Monastery of Santa Maria with its magnificent Romanesque cloister.

INTRODUCTION

The aim of this communication is to explain the technical aspects of the drainage of L'Estany, which started in the 16th century and finished in the 18th century. We will describe the hydraulic works (mainly the construction of a gallery using the dry stone technique) and highlight the importance that this drainage had for the development of the population and the monastery in L'Estany village. We will also present a panoramic view over the incidence in the Mediterranean areas of Spain, of the periodic fever outbreaks in humid areas and wetlands drying processes. Work has been done through surveys in the field, bibliographical search, and consultation of historical archives and reports. We have taken as reference materials the extensive and complete information of the Centre de Visitants (Centre for Visitors of L'Estany) (Centre de Visitants 2015) and the work done by Morros & Puigferrat (2010) on the occasion of the rehabilitation of the main hydraulic work of the L'Estany drainage, a gallery (mina in the Catalan language).

SITUATION

The village of L'Estany, whose name derives from the small lake (estany in the Catalan language) that existed in its municipality, is located on the northern slopes of the Moianès Highlands (at 870 m a.s.l.) in the province of Barcelona (Catalonia) in the northeast of Spain (Figure 1).

Figure 1

Situation of the village, and dried zone.

Figure 1

Situation of the village, and dried zone.

This village is concentrated around the Monastery of Santa Maria de l'Estany, founded by the Augustinian Order in the year 1080. This monastery has a great historical, cultural and artistic heritage with its spectacular Romanesque cloister. The monastery was an important religious and political centre in the Middle Ages (Pladevall & Vigué 1978).

THE ESTANY

The village of L'Estany is situated in a small endorheic basin of 1.1 km2 in the Oligocene – marshy hydrogeological area (209 Artes sheet of the Hydrogeological Areas Map of Catalonia), consisting of a series of geological marl – detritic materials over a bedrock of sandstone. The central part of the valley is an endorheic basin collecting stormwater runoff and groundwater, leading to the ancient lake or wetland over a maximum area of 7.6 ha (Figure 2).

Figure 2

General view of L'Estany valley.

Figure 2

General view of L'Estany valley.

The area occupied by the lake (L'Estany) is included in the inventory of wetlands in Catalonia (code 08000707). In the northern part of L'Estany, there was a watershed dividing line that when the lake overflowed allowed the water to pass under a medieval bridge (El Pontarró: the big bridge) pertaining to another catchment.

L'Estany is situated in an endorheic basin, filled by the sediments contributed by runoff and lacustrine vegetation. In a recent study of the geological evolution basin with exploratory boring (Beuter and Blasco SLP 2015), geological profiles of the bed sediments have been identified and the presence of up to four lacustrine levels was deduced, the last being the level before the drainage works started (Figures 3 and 4).

Figure 3

The lake before the drainage (Beuter and Blasco SLP 2015).

Figure 3

The lake before the drainage (Beuter and Blasco SLP 2015).

Figure 4

Geological profile NNE – SSW (modified from Beuter and Blasco SLP 2015).

Figure 4

Geological profile NNE – SSW (modified from Beuter and Blasco SLP 2015).

REASONS AND AIMS OF THE DESICCATION OF L'ESTANY

Since Hippocrates in the 4th century (B.C.) associated fevers with marshes or swampy areas and the ‘bad air’ from those, society has been aware of the environmental influence on public health of stagnant water areas. The ancient Greeks recognized four types of fevers associated with quiet waters and their vapours (Rusell 1943). Some of the earliest civilizations identified the existence of this relationship, without knowing its mechanism or process of transmission of related illnesses.

Until the 19th century, the transmission of the diseases via mosquitoes, whose reproduction habitats were precisely those flooded areas, was not identified.

Throughout history and up to the 18th century, there are many references to the mentioned relationship as well as of the beneficial effect that desiccation produced on public health (Alberola 1983). In theory, the reason for the desiccation was the belief that stagnant water is unhealthy for the population and the aim is that with the elimination of these waters, the population will be healthy. Since the 17th–18th centuries, the increase of population and the need to produce more food added a very important economic component to the objective of desiccating: to obtain new fertile land for agriculture.

FEVERS AND SWAMPY AREAS

One of the most influential papers in the 18th century – called the century of fevers (Peset 1977) – was the ‘On the Noxious Effluvia of Marshes’ (Lancisi 1717). In this publication, Lancisi describes five epidemics of malaria, expresses his belief that the disease is conveyed by the bites of insects, and he writes ‘The remedy, I have rightly decided, was adequate drainage, which I have repeatedly urged the authorities on’. He also makes reference to the fact that in 1611 Pope Paul the Fifth had carried out drainage work on Lake Gandolpho Turnus to restore the health of the population.

Expansion of fevers (malaria) in Spain and the Mediterranean area was widespread given its geographical and climatic conditions and the presence of wetlands, marshes and endorheic lake basins as well as the expansion of rice paddies (Castejón 2015) (Figure 5). There is abundant literature on disease outbreaks in areas of Catalonia (Empordà, Maresme and Ebro river delta) and the Spanish East as Murcia, Valencia and Alicante. For instance, the epidemic of 1,637 in Cartagena, in which doctors claimed that the cause of the fever episodes was the stagnant waters of the Almarjal lagoon, was followed by completely draining and drying out the lagoon (Soler 1970). However, the drainage was not definitive as the lagoon filled up in times of heavy rains. This is something that we also believe happened in L'Estany until its definitive drying with the construction of ‘La Mina’.

Figure 5

Incidence of malaria in Spain in the 18th and 19th centuries according to the number of reported outbreaks and the proximity between the affected areas (Castejón 2015).

Figure 5

Incidence of malaria in Spain in the 18th and 19th centuries according to the number of reported outbreaks and the proximity between the affected areas (Castejón 2015).

DRAINAGE WORKS

While references to the existence of drainage canals can be dated to the years 1323–1324, it is not until the 16th century that documentary evidence can be found about the works to dry L'Estany.

The drainage, not completed until the 18th century, was carried out in various phases. It is believed that due to the shallow depth of L'Estany and according to the rainfall, the amount of surface flooded has been changing as well as the stagnant water areas.

Two stages are considered as major works, as follows.

First stage 16th century

In February 1554, the Abbot of the monastery of Santa Maria, Carles de Cardona, signed a contract with the master builder Johan de Borde to enlarge two existing channels. One ran from the Pontarró (North) to the centre of the west side of L'Estany and the other was secondary and a tributary of the first, which is thought to be the present ‘rec de les Nogueres’.

The expansion of the channels consisted of increasing its depth by 8 ‘pams’ (hand spans) (1.56 m) and its width by 6 ‘pams’ (1.17 m).

The contract included two clauses. (a) The excavated lands had to be disposed of away from the channels and (b) at the north, where it was thought to be rocky and hard materials were to be found, the excavation must be carried out according to the criteria of a monk of the monastery acting as Inspector of Works.

The work was carried out in five and a half months. Once finished, a new contract for the maintenance and cleaning of the channels was signed.

The success of the works to drain L'Estany was not complete as perhaps over time channels were clogged, losing their ability to drain.

Second stage 18th century

In October 1732, as in 1554, the authority of the monastery (in this case one of the five Royal dignitaries of the country), Dr Ferran Macià, along with the master builder Josep Morató, inspected L'Estany in order to decide on the necessary plan of action for its emptying and drainage. In theory, it was recommended to deepen by 8 pams (1.56 m) the main drain over a length of 90 ‘canes’ (140 m), located on rocky terrain (the northern part of L'Estany).

After different vicissitudes, including the necessity of financing the works, and the fact that the health situation in the area had deteriorated, the five Royal dignitaries, in March 1734, requested that the ‘Capítol de Vic’ (the religious authority at the cathedral of Vic, nowadays in the Barcelona province, Catalonia) who collected the taxes of the population, make a contribution to the works to be carried out. In the request, the serious health situation of the population was outlined. The increase of the surface of L'Estany, due to the lack of slope and capacity of the existing channels, was the cause of the corruption of the flooded and stagnant waters. These produced malignant vapours, and the Royal dignitaries believed that this was the cause of the epidemics that the population suffered annually. The request also indicated that there would be a plan of action carried out by a team of experts to ensure drying of the lake, and that this would increase the area of agricultural land.

In April 1734, the five Royal dignitaries signed a contract for the recovery works of the existing channels to the master builders Josep Pascual and Marià Terricabres, writing in the contract the characteristics of the deepening works from the northern mouth of the canal (output) where the rocky area is located (Table 1).

Table 1

Technical details contained in the contract for the recovery of the L'Estany canals and mine

ExcavationCoating
Walls of dry stone
Coverage
Central vault arch with dry stone
Interior gauge
Length 392 m Width 0.58 m Width 0.58 m Central height 2.14 m 
Depth 1.96 m Height 1.56 m   Width 17 m 
Width 2.35 m       
ExcavationCoating
Walls of dry stone
Coverage
Central vault arch with dry stone
Interior gauge
Length 392 m Width 0.58 m Width 0.58 m Central height 2.14 m 
Depth 1.96 m Height 1.56 m   Width 17 m 
Width 2.35 m       

THE DRAINAGE SYSTEM

The drainage network of L'Estany is formed by a mine and two canals dug in the ground: ‘rec del Mig’ and ‘rec de les Nogueres’ (Mid and Walnut Trees canals) that pour their waters to the beginning and the middle part of the mine. The water that circulates through the mine outflows to a stream into the basin of the river Llobregat (Figure 6).

Figure 6

Drainage system of the L'Estany area.

Figure 6

Drainage system of the L'Estany area.

L'Estany mine

The mine or gallery is the most important hydraulic work in the area, being declared a Cultural Property of Local interest in 2009. From 1999, seeing its state of abandonment, the municipal architects initiated actions and projects in order to rehabilitate the mine. The recovery works finished in 2010.

The mine runs from its southern entrance in the central part of the valley to the outlet in its northern part (Figure 7). It has three mouths: a southern entrance, a middle path entrance (the waters of the ‘Rec de les Nogueres’) and the outlet mouth in the north. Along the route there are several ventilation and maintenance wells. At present, some of the wells are sealed.

Figure 7

Features of L'Estany mine.

Figure 7

Features of L'Estany mine.

The mine was built with dry stone without mortar, a laborious work that involved great skill and required the direction of a specialist as the master builder. The dry stone technique was widely used in the entire area of the Spanish Mediterranean for different works such as walls of terraces, farm stalls, ice wells and so on.

The mine, gallery or hydraulic conduit, was built after deepening and enlarging the main drainage channel, which had existed since the middle of the 16th century. With the increase in its depth, it was possible to fully drain the lake.

The mine was built into this main drain. After its construction, the space over the mine was filled with stones and layers of earth. In this way, the problem of bank stability was avoided and it was also possible to recover the continuity of the space over the drain and use it for agricultural purposes.

Figure 8 shows an outline of the longitudinal profile of the mine with two types of sections:

  • Section A: This has a length of 35 m, and a variable width between 0.60 and 1.20 m. The walls of dry stone have a thickness between 0.30 and 0.58 m. This A section is covered with flat stones of large dimensions and earth as indicated.

  • Section B (see also Figure 9): This has a length of 390 m, and a width of 1.17 m. The walls of dry stone have a thickness between 0.30 and 0.58 m. This section B is covered by a central vault arch and has a height in the centre of 2.14 m. There is also earth over the structure.

Figure 8

Longitudinal section of the mine (modified from Morros & Puigferrat 2010).

Figure 8

Longitudinal section of the mine (modified from Morros & Puigferrat 2010).

Figure 9

Interior view and section of the mine (section B).

Figure 9

Interior view and section of the mine (section B).

All the ground floor of the mine is paved with stones.

The mine has an average gradient of 0.85% with a drop between the inlet and outlet of 3.61 m.

The ventilation and maintenance wells have a square shape of 1.5 × 1.5 m and walls of dry stone.

EVOLUTION OF THE DRAINAGE

Once L'Estany dried up completely, the operation of the drains and mine was limited to the periods of intense and prolonged rainfall, but if the mine and drains had not been kept clean and free of materials from landslides, flooded areas might appear as it did in the spring (Easter) of 1969 (Figure 10).

Figure 10

Area flooded after heavy rains in Easter 1969. Source:http://www.viulestany.cat.

Figure 10

Area flooded after heavy rains in Easter 1969. Source:http://www.viulestany.cat.

DISCUSSION AND CONCLUSIONS

The history of L'Estany drying up reflects the evolution of the relationship between a population and its environment according to the existing knowledge at the time and its technical and economic capacities.

Since the discovery that stagnant waters were not healthy for the population, the ability and means to drain L'Estany increased over the years. This ability reached its peak with the construction of the gallery, dewatering the lake and at the same time obtaining land for agriculture. Thus it allowed the development of an urban nucleus around the religious centre of the monastery.

Now the health, economic and social situation of the area does not depend on the environmental sanitation and agriculture as it did three centuries ago. The monastery, even without its socio-political power of former times is at present an important religious, cultural and artistic focus and a tourism attraction.

The recent restoration of the gallery prevents eventual flooding of the lake plain. The enhancement of this hydraulic work of the 18th century is a claim of the population and increases the attraction for tourism alongside the monastery.

The possible recovery of part of the former lake area is no longer considered a health risk, but as another environmental attraction to strengthen tourism. Because of this, the Catalan Water Authority has prepared a first draft for the recovery of the lake.

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