Environmental Engineering Reference
In-Depth Information
an access gallery to the underground Fuente santa spring,
la Palma, spain
c. soler
Dirección General de Aguas del Gobierno de Canarias, Spain
aBsTRacT: This paper presents the work done to recovey the historical Fuente santa spring, well
known at Middle age due to its miraculous medical effects. The spring was buried by san antonio volcano
eruption in 1677, with debris, cinders and lava flows. a gallery was recently excavated under extreme and
difficult natural conditions, a total lack of stability with granular materials involved. The direction of the
axis of the gallery was initially unkown.
1
inTRoDUcTion
The most complex excavation confronted by the
local administration of the canary island refers to
a hydraulic work was a 200-m long recovery gallery
on the so-called Fuente santa (“holly Fountain”)
spring. This problem was not related to the creep
of the excavated material but rather a total lack of
stability in a gallery that was intended to be driven
through a pile of debris representing a 150-m high
overburden.
The Fuente santa used to be a thermal spring
emerging at sea level and at the foot of a coastal
The water sprang forth among the boulders of a
beach adjacent to the cliff and was impounded by
two tidal ponds that because of their different degree
of mixing with sea water evidenced various tem-
peratures; the closest source to the point of blowing
and therefore the hottest one, was named after san
lorenzo and the closest to the sea, to san Blas.
Figure 1. Profile of the ground with the Fuente santa
spring. it can be observed that thermal waters emerged at
the foot of the cliff in a coastal plateau constituted by a
boulder beach.
the
per capita
income of the islanders so as to be in
Bonanza and prosperity lasted the whole 16th
century and most part of the 17th century. During
those times the Fuente santa was visited by pres-
tigious personalities such as Pedro de Mendoza
y luján, alvar núñez cabeza de Vaca, Gaspar
Frutuoso and fray Juan de abreu Galindo.
The fame of the spring crossed the ocean
and barrels of the precious water were sailed
to america. it was believed that it healed skin
diseases, rheumatism, arthrosis, elephantiasis,
leprosy and syphilis, generating a health-related
tourism in the island. But when richness flowed in
abundance, when it was thought that health was
not a concern to la Palma inhabitants and when
holiness lied immersed in those pools at the south-
ernmost tip of this island, suddenly … everything
came to an abrupt end. on saturday november 13
2
hisToRY
The cliff is topped by a plateau with a certain slope
that reached elevation 500. it is known as
Cuesta
de Cansado
, (“weary uphill”), an appropriate
name to describe the “smoothness” of the surface.
such plain used to have fertile land where country
houses, orchards, a town and a hermitage once
were found. crops of potatoes, mallow, vegetables
and fruits provided enough resources to its inhabit-
ants and they even supplied food for large number
of pilgrims. They came from all christian countries
at that time from europe and the american con-
tinent arrived to enjoy miraculous cures. Prestige
acquired by the spring was such that visitors raised
