D01 copertina_R_OK C August 20-28,2004 Florence -Italy

Field Trip Guide Book - D01 Associate Leader:I.P. Martini Leader: A.Costantini 32 GEOLOGICAL CONGRESS Volume n°3-fromD01toP13 FOUNTAINS AQUEDUCT) ANDMONUMENTAL BOTTINI (UNDERGROUND HILLTOP TOWNANDITS HISTORY OFAMEDIEVAL URBAN GEOLOGY, ART AND SIENA (CENTRALITALY): During-Congress nd INTERNATIONAL D01 21-05-2004, 14:55:18 The scientific content of this guide is under the total responsibility of the Authors

Published by: APAT – Italian Agency for the Environmental Protection and Technical Services - Via Vitaliano Brancati, 48 - 00144 Roma - Italy

Series Editors: Luca Guerrieri, Irene Rischia and Leonello Serva (APAT, Roma)

English Desk-copy Editors: Paul Mazza (Università di Firenze), Jessica Ann Thonn (Università di Firenze), Nathalie Marléne Adams (Università di Firenze), Miriam Friedman (Università di Firenze), Kate Eadie (Freelance indipendent professional)

Field Trip Committee: Leonello Serva (APAT, Roma), Alessandro Michetti (Università dell’Insubria, Como), Giulio Pavia (Università di Torino), Raffaele Pignone (Servizio Geologico Regione Emilia-Romagna, Bologna) and Riccardo Polino (CNR, Torino)

Acknowledgments: The 32nd IGC Organizing Committee is grateful to Roberto Pompili and Elisa Brustia (APAT, Roma) for their collaboration in editing.

Graphic project: Full snc - Firenze

Layout and press: Lito Terrazzi srl - Firenze

D01 copertina_R_OK D 21-05-2004, 14:57:00 Volume n° 3 - from D01 to P13

32nd INTERNATIONAL GEOLOGICAL CONGRESS

SIENA (CENTRAL ITALY): URBAN GEOLOGY, ART AND HISTORY OF A MEDIEVAL HILLTOP TOWN AND ITS BOTTINI (UNDERGROUND AQUEDUCT) AND MONUMENTAL FOUNTAINS

AUTHORS: A. Costantini (Università di Siena - Italy) I.P. Martini (University of Guelph, ON, Canada)

Florence - Italy August 20-28, 2004

During Congress D01

D01_R_OK A 21-05-2004, 15:01:10 Front Cover: The Virgin Mary protects Siena during the earthquakes of 1466-67. Detail of a painted wooden cover of a Bicherna – the medieval, annual, account registry. (Archivio di Stato di Siena, tavoletta di Biccherna n. 34: Francesco di Giorgio Martini e fi duciario, “La Vergine protegge Siena in tempo di terremoti”, anno 1467. Autorizzazione n°540 del 10/9/ 2003 su concessione del Ministero per i beni e le attività culturali. The illustration is 54 x 41 cm in size.)

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SIENA (CENTRAL ITALY): URBAN GEOLOGY, ART AND HISTORY OF A MEDIEVAL HILLTOP TOWN AND ITS BOTTINI (UNDERGROUND AQUEDUCT)

AND MONUMENTAL FOUNTAINS D01

Leader: A. Costantini Associate Leader: I.P. Martini

Introduction two years. Good information can be obtained from Siena is located on a hilltop of porous, shoreface, the Diana Association (http://www.comune.siena.it/ Pliocene sandstone. It became an important town in diana) that also provides alternative underground and medieval times (1100-1400 AD) because it was on surface trips. Useful references are: Douglas (1902, a major route for pilgrims travelling from France to 2000) and Hook (1979) for the history of Siena; Rome the Via Francigena. It suffered from an absence Bargagli Petrucci, F. (1992), Balestracci et al. (1993), of readily available water because no large river fl ows and Serino (1998) for the Bottini; a virtual tour of part nearby. It was also involved in continuous fi ghts with of Bottino Maestro di Fonte Gaia is being prepared as neighbouring Florence and the territory was not rea- an Italian and English CD-ROM by the Laboratorio dily defendable. The solution for the medieval town di Ricerca e Progettazione Siena città dell’Acqua was to build an underground aqueduct consisting of a (Comune di Siena); http://faculty.washington.edu/ 25 km-long network of tunnels, called Bottini, which kucher/diana/english/biblio.htm for a bibliography collected water from hills to the northwest and brou- of water in Siena; http://www.neogeo.unisi.it/e_geo/ ght it to public fountains (fonti). The underground home.htm for maps of area; http://www.sienaol.it for aqueduct was used for drinking water until the early city and surrounding maps and other information; 1920s. It is now being refurbished to provide water http://www.comune.siena.it is the official site of the for general use and particularly for watering gardens Municipality of Siena. and city parks. The objectives of the fi eld trip are to examine the Regional historic-geologic setting geomorphology and geology to determine the main Like any other town, the development of Siena has characteristics of the aquifer (shore sandstones and been conditioned by the geomorphologic and geolo- conglomerates), aquifuge (offshore and lagoonal gic characteristics of its territory. The town is located silty clays), and water potential of the area; to con- in a Neogene basin (Siena Basin) (Fig. 1; Bossio et sider the historical-sociological conditions that led al., 1998) of the inner part of the Northern Apennines, to the construction of the underground aqueduct; to on hills of Pliocene sandstones and conglomerates marvel at some of the engineering and architectural underlain by silty clays. The Siena Basin is a 20 km constructions of the aqueduct itself and at the monu- wide and 40 km long trough parallel to the trend of mental fountains; and, fi nally, to savor, albeit briefl y, the Apennines chain. The sediments of the Siena area the enchanting atmosphere, architecture and cuisine derived from both the Chianti to the north and the of Siena, one of the best preserved medieval towns of Montagnola Senese to the west. The fi rst source is Tuscany, in both its buildings and way of life,. demonstrated by cobbles found in the Bottini under The trip includes surface views but also one 1.5 hour- the town, of quartzo-feldspathic sandstone of the long stop in narrow tunnels utilizing portable artifi cial Macigno formation that crops out in the Chianti area. lights. This is a rare – for most people, unique – op- Siena is bounded on three sides by deeply dissected portunity to visit the Bottini. However, the latter stop hill fl anks, and on one side by topographically irre- is unsuitable for persons not comfortable in narrow, gular highlands underlain by Pliocene deposits and closed spaces. An alternative surface activity has been pre-Neogene substrate rocks (Fig. 2). No major river scheduled for them. For those visiting the Bottini, fl ows nearby, and the few seasonal streams run in fi eld or running shoes and a light pullover or fi eld- deep valleys, making it impossible for the Sienese to jacket with long sleeves are recommended. Similarly, bring water to the city by gravity. During early times a powerful fl ashlight is suggested to take pictures (Etruscan, Roman and early medieval times) suffi cient underground. The surface stops will not require any water existed for small settlements. However, starting special equipment except for a hat against the sun. in the 1100s, Siena grew and reached a population of D01 to P13 n° 3 - from Volume Permission and a guide (bottinere = person working more than 60,000 inhabitants over an area of 2 km2 at in the Bottini) from the Municipality of Siena are its apex, in the early part of the XIV century. The thri- required to visit any part of the Bottini, but they are ving city needed water – a lot of it. Bringing it from rarely, if ever, obtained other than for the occasional the distant hilly fl anks of the basin by gravity would school field trip. This is done to avoid deterioration have required construction of subaerial aqueducts, of the fragile underground environment. In any case, which would have been very expensive and perhaps requests to enter the Bottini need to be made well in diffi cult to defend against enemies. So it was decided advance because there are waiting lists of more than that water would have to be sought in the immediate

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Volume n° 3 - from D01 to P13 D01 - D01 Leader: A.Costantini called because theweaklycementedsandstone(locally The constructionofsuchanaqueductwasfeasible readily defendableundergroundaqueduct. public fountainsinsidethewalledcitythroughamore vicinity ofthetown,andcollectedtransportedto added toaugmenttheagingMt. Amiata aqueduct Siena). Duringthe1960s,waters fromtheLuco Well were 1900s gettingwater fromMt. Amiata (about60kmfrom A modernaqueductwas built duringtheearlypartof Figure 1-Schematic geologicalmapoftheSienaBasin. are composedofthefollowingfacies. upward sequencescanberecognized(Fig.3).They The occurrenceofatleastfourmajorshoaling- exposed inthetunnelwallsandonsurfaceoutcrops. 70 mofthecoarser-graineddepositsarefairlywell deposits, andunderlainbyoffshoresiltyclays.About interlayered withimpermeablelagoonalfi bioturbated shorefacesandstonesandconglomerates, vertical walls.Theaquifersarelower-middlePliocene and thickshells,shows contains abundantmarinemacrofossilswithboththin local small-scalecross-laminations.Thissandstone silty, fi deposit (Terzuoli,1997). plant fragments.Itisinterpretedasadistaloffshore macrofossils withthinshells,andsparsefi Bluish-gray sandy,siltyclaywithabundantmarine 4 ne-grained sandstone,weakly cemented,with tufo ) canbereadilyexcavatedandmaintains Facies 2 Ophiomorpha : Gray,argillaceous, ne-grained ne-grained Facies 1 bioturba- : 10 cmlong bioturbations by (up to2cm)pebbles,andrareclayclasts.Itshows (mostly ostraeeandpectinids),fewisolatedsmall massive. Itcontainsabundantmarineshellfragments 3: preted torepresentaproximaloffshoresetting. layers bioturbatedby is locallyinterlayeredwiththin(upto5cm)clay tions andoccasionalverticalburrows.Thesandstone an uppershorefacesetting. sandstone. Thisfaciesisinterpretedtohaveformedin Macaronichnus segregatis,Conichnus glomerates. Bioturbationsby most frequentlyfragmented,arefoundinthecon- present. Shellfossils,someencrustedonpebbles, upward inthesuccession.Plane-andcross-bedsare pebbly fi nated smallpebblesandsomecutswithsandy, cm thick.Thesandstonelayerscontainfewdissemi- thick lensingbeds,andconglomerateinlayers2-15 of medium-grained,yellowsandstonein10-40cm be alowershorefacedeposit. possibly burrows 0.5-1cmindiameterandupto15long, thick (upto6m)sandyconglomerates( up, bytheoffshorefacies( The lowersequenceischaracterized,fromthebottom subaerial toshallow-watersettings. facies isthoughttorecordabeachfacerangingfrom present andarebioturbatedby approximately 2moccur.Lensesofsandstoneare layers. Amalgamated,conglomeraticunitsofupto frequently separatedintofairlywellsorted,lenticular rical. Imbricationoffl and thecoarser-grainedonesgenerallyaresub-sphe- fi from smallpebblestocobbles,allwellrounded.The occasionally withopenframework.Theclastsvary conglomerate, withvariousamountsofsandymatrix, ve superimpositionof The overlyingsequencesarecomposedbyarepetiti- fi indicating arapid,relativesealevelriseandslower capped bysequencesrefl major changefromoffshoretoshoresettings.Thisis overall regression.Thelowermostsequenceshowsa of thenorthernpartSienaBasinrepresentan local thinlignitelayersoccuraswell.Thedeposits and Natica crofauna andmacrofossilssuchas fossiliferous siltsandclayswithbrackishwatermi- third sequences(Fig.3),mostlycharacterizedby lagoonal faciesarewelldevelopedatthetopof ner-grained clasts tendentiallyhaveadiskshape, lling oftheaccumulation-space socreated.Among Yellow,fi lls. Theconglomeratelayersshow thickening

of Skolithos . Marlstones,medium-grainedsandstone; ), Terebellina ne-grainedsandstone,weaklycemented, Ophiomorpha, Thalassinoides . Thissandstoneisconsideredto at clastsoccurs.Theare Planolites. Facies 3,4,and5 ectingfl , Rosselia Facies 5: Facies 1,2 Ophiomorpha, Skolitos Facies 4: Macaronichnus uctuationsgenerally This faciesisinter- Cardium, Ceritium , andsub-vertical Clast-supported occurinthe ) overlainby Interlayering . Additional Facies 5 21-05-2004, 15:01:40 Facies . This (up to ). , SIENA (CENTRAL ITALY): URBAN GEOLOGY, ART AND HISTORY OF A MEDIEVAL HILLTOP TOWN AND ITS BOTTINI (UNDERGROUND AQUEDUCT)

AND MONUMENTAL FOUNTAINS D01

these times that innovations were fi rst established in Sie- na, such as a fi re brigade to combat one of the scourges of medieval times. Siena developed rapidly because of two major factors. First, besides being great traders in distant foreign markets, the people of Siena became bankers to the Pope and various religious prelates, and, second, the town was located on one of the major routes for pilgrims going to Figure 2 - Old print depicting medieval Siena built on Rome: a branch of the Via Francigena. Indeed the a hill bounded on three sides by steep slopes. Fortresses pilgrims who had followed for some time the easier protected the town to the north (foreground) where the town had expanded along a hillcrest. Eventually the town valley-bottom roads, switched to the hilly route when was conquered in the mid 1500s from this vulnerable the lowlands became paludifi ed and infested with ma- side. (The original print is in the Biblioteca Comunale di laria-carrying mosquitoes. Siena was located on the Siena). hilly route. Furthermore, Siena ensured protection and safety to the travellers while in its territory, as well other hypotheses, it is interesting to speculate that as good accommodations, trading and banking – the some of these high-frequency fl uctuations may be town had also struck its own valuable silver coin. partly associated with eustatic movements driven With wealth, the population and industries grew, and by Antarctic glaciers that developed at that time. the need for water increased. As a result, the Bottini The basal contact between the offshore clays and were constructed. Not everything was fi ne though. the shore sandstones and conglomerates determines First, Siena, like most other medieval towns, was the elevation of the principal groundwater table. The dealt a terrible blow by the plague (peste) that deci- impermeable caps of the various sequences and some mated its population in 1348: one out of three people thin, intercalated, very fi ne-grained deposits establish died. Siena was never able to recover from that loss. the existence of secondary hanging water tables. The Second, economic and political antagonism emerged whole system has basin-centered (southwestward) with neighbouring .Florence. The people of Florence polarity; that is, the bed dip, and groundwater and eventually replaced those of Siena as bankers to the surface fl ows are all in the same direction. Therefore, Pope, and they struck a new golden coin (fi orino), the steep fl anks of the deeply-incised valleys boun- more valuable and sought after than the silver one of ding Siena intercept the groundwater fl ow, and major Siena. After several intricate historical events, even- springs occur at the base, with secondary springs at tually the two towns found themselves in opposite higher elevations. This overall simple groundwater camps: the ghibellina (Ghibelline) Siena allied with setting is complicated by numerous normal faults that France, and the guelfa (Guelph) Florence allied with cut and displace the various aquifer-aquifuge contacts Spain. After several wars, King Charles V of Spain to various altitudes. The early fountains were built conquered Siena in 1555 and gave it to Florence. Sie- near the springs, particularly the largest, lowermost na was never again an independent entity. ones, such as at Fontebranda (also called Fonte Bran- da), and their fl ow was enhanced by digging tunnels (an early version of the Bottini) following the aquifer- Field itinerary D01 to P13 n° 3 - from Volume ~Km (time) Notes aquifuge contact. 0 (8.00 hr) Fortezza da Basso. The Medici family Archeological investigations have established that built this in 1534. Florence is located at the southea- Siena was fi rst an Etruscan site, and later a small stern edge of the intermontane, Pliocene-Pleistocene Roman colony (Sena Julia). Siena was an important Firenze-Pistoia Basin. It is crossed by the Arno River town during medieval times; it became one of the that has experienced several large fl oods throughout fi rst free comuni (city states), and fl ourished during the ages, the latest most-damaging one occurring in the XII-XIV centuries when it reached its maximum 1966. territorial extension and political power. It is during - Follow the Viali di Circonvalazione to Porta Roma-

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Volume n° 3 - from D01 to P13 D01 - D01 Leader: A.Costantini 929 AC.Becauseofthisroute,aswellitsmoney villages alongtheViaFrancigenastartingfrom ments indicatingthatithadbeenoneofthemedieval scans (III-IIcenturyBC).Therearehistoricaldocu- The S.Gimignanositewasfi rstoccupiedbytheEtru- 31 FrontalviewofS.Gimignanointheforeground. merates, sandstonesandclaysofNeogenebasins. substrate) andoftheLigurides,Plioceneconglo- unit (atectono-stratigraphicofthepre-Neogene the routenoteOligo-MioceneturbiditesofTuscan 7 Startofthehighway(superstrada)forSiena.Along tigraphic unitofthepre-Neogenesubstrate). carbonate turbiditesoftheLigurides(atectono-stra- southern edgeoftheFlorence-PistoiaBasin,on Benedictine Cicestensismonks.Itislocatedonthe Originally ithousedCertosinimonks,recentlythe 5 CertosadelGalluzzo(Florence)wasbuiltin1342. na andtakethehighway(superstrada)toSiena. column Paleoenvironment interpretationisindicatedontheright exposed onthewalls oftheBottinivisitedduringstop4. B. Enlargedportionsofthetwo topmost sequences in thewestern partofthecityarea(afterTerzuoli, 1997); Four coarsening-upward sequences(I-IV)recognized Figure 3-GeneralizedstratigraphyoftheSienaarea: A. 6 near theMontalbucciorestaurant(Back-covermap). 71 Stopatasuitablelookoutalongtheroad,at/or upper Pliocenesandstone(shorefacefacies). to Montalbuccio.Alongtheroadnoteexposuresof sort ofaU-turn)andthenturnright,takingtheroad Past thegasstationsturnleftandgoalongroad(a Marco, rathercontinuestraighttothegasstations. turnarounds. AttheintersectiondonotclimbtoS. signs toPortaS.Marcothoughthefi rst andsecond 69 Siena:Takethe“SienaOvest”exitandfollow 63 Basciano.StartoftheSienaBasin. (MTR). background, whichispartoftheMid-TuscanyRidge see theMontagnolaSeneseRidgetosouthin Miocene brecciasandcarbonates.Itispossibleto - ContinueonthesuperstradatowardSienacrossing square towers. destroyed byFlorencein1244.Thewallshave14 the reconstructionof1260-1270afterwallswere battles andrebuildingsofthewalls,latestbeing its territoryagainstFlorence.Itsufferedvarious the road.ItwasbuiltbySienain1203toprotect 57 Monteriggionicastleisvisibletothesouthof is famousworldwide. Italy. Theglassindustryisstillveryactive:itscrystal it developedoneofthefirst printingestablishmentsin paper industries.InthesecondhalfofXVcentury during theXIVcenturybecauseofwool,glassand medieval times(XIIcentury).Itbecameprosperous settlement thatbecameafreecommuneduring 49 ColleVald’Elsa.AncientEtruscanandRoman 41 Poggibonsi. part oftheRepublicFlorencein1351. were symbolsofpower,which15areleft.Itbecame At itseconomicapexthetownhad75towers,which ching itsmaximumprosperityduringtheXIIcentury. Eastern communitiesfl ourished, thetowngrew,rea- fron production)withseveralEuropeanandMiddle lending, andcommercialactivities(includingsaf- they evendreamtaboutandsoughtamythicalriver centuries, despitederisionlikethatleveledbyDante, wells andundergroundaqueducts(Bottini).Formany searched forwaternearthetownthroughnumerous optimized useofwhattheyhave.Theyalsodoggedly the inhabitantshavelearnedwaterconservationand of alargesupplywater.SincetheXIXcentury glomerates. Thisisoneofthereasonsforlack southeast, underlainbyporoussandstonesandcon- highest pointtothenorthwestandlowest Siena islocatedonamorphologicalhigh,withits and historyoftheSienaarea; (9.30 hr)Montalbuccio-Introduction;geology Stop 1: coffee break . 21-05-2004, 15:01:45 SIENA (CENTRAL ITALY): URBAN GEOLOGY, ART AND HISTORY OF A MEDIEVAL HILLTOP TOWN AND ITS BOTTINI (UNDERGROUND AQUEDUCT)

AND MONUMENTAL FOUNTAINS D01

– la Diana – fl owing under the town. Starting in the other tunnels. early part of the XX century, modern technology has The Bottini are 25 km long (Fig. 4). They consist allowed the use of distant water supplies, from Mt. of several local Bottini that bring water to special Amiata fi rst, and then from wells from other parts of fountains such as Fontenuova, Fontanella and Fonte the Siena Basin later (Pozzo del Luco = Luco well). di Pescaia, and two principal (maestri) ones. The two The high Torre del Mangia (city-hall tower), the principal Bottini are the older, 7500m-long Bottino Campanile del Duomo (cathedral bell tower), and bell Maestro di Fontebranda, and the newer, 15,700m- towers of several other churches dominate the city long Bottino Maestro di Fonte Gaia. Each one gets skyline. During medieval times, each large palace had water from smaller tributary Bottini (influenti) like its own high tower for security reasons, but mostly as the one visible at Uopini. Originally the main Bottini a status symbol, as indicated in old prints and even were built to bring water only to public fountains; in the painting of the Effetti del Buon Governo by then later, starting in the early 1500s, secondary Ambrogio Lorenzetti. Only one of these towers, the tunnels were built to bring water also to wells of Mignanelli tower, can now be seen towering on the private homes (that is, to clients called utenze) and skyline; the others were cut down to the height of the institutions, such as convents and monasteries. The palaces. Walking around town, however, you can re- main Bottini system was built between the latter cognize the old towers because a very porous Triassic years of the XII century and 1460. Prior to that limestone (Calcare cavernoso; in Siena called also smaller excavations may have existed to enhance pietra da torre) was used for their construction, whe- the output of local fountains. Uopini is one of the reas bricks were used for most other constructions. water-source areas for the Bottini. It is located in the The following stops of the trip are designed to show: northern part of the Siena Basin where sand and clay major geomorphologic and geological features of the were deposited during the early and middle Pliocene. area (most stops), a water-source area of the Bottini Sandstones form the hill where the village of Uopini is (stop 2), the underground aqueduct (stop 4), various located (Fig. 5). They are underlain by, and have thin types of fountains (stops 5, 11), and architectural fea- interlayers of, silty clays, providing for a main water tures of the town (most stops). table at the base and suspended water tables higher in - Continue northward on the same road. To the right the hill. These are, and most likely were in the past, (NW) note Mt. Maggio composed of the Calcare ca- revealed by small springs. Furthermore, the layers dip vernoso (the rock type used in the construction of the to the south, toward Siena, and it is along this flank towers of Siena). Mt. Maggio marks the northwestern of the hill that the maximum recharge area occurs, edge of the Siena Basin. The Chianti highlands are and the groundwater flow is downdip. Appropriately visible in the foreground to the north. this is the flank the medieval people selected to build 71.5 T-intersection. Turn right toward the Cassia the influenti tunnels to intercept the highest, largest Road (SS 2). On the right view a modern suburb of water source (the highest aquifuge overlain by the Siena. topmost thickest sandstone). Here the tunnels are 73.3 Intersection, continue toward the Cassia (SS 2). small (narrow and low), just high enough for a person 75.4 Junction with the Cassia (SS 2); turn right (E) to walk in a crouched position. Openings (chimneys onto the Cassia (SS2) toward Siena. – smiragli) to the surface were dug at regular intervals 77.0 Intersection; turn left (NNW) toward Uopini, to verify the direction of and to aerate the tunnels, to exiting off the Cassia (SS2). remove material from them, and to provide workers 77.2 Intersection: continue toward the Badesse (do with access to tools and food. Three smiragli are not enter the village of Uopini). still visible on the hillslope below Uopini. To ensure 75.5 Stop just before the 3-way road junction. integrity of the tunnels and therefore good-quality water, the surface of this locality as well as of areas

Stop 2: all along the route of the Bottini was protected, and D01 to P13 n° 3 - from Volume (10.15 hr) Uopini - Introduction to the Bottini; no plant or crop cultivation was allowed, to prevent a water-source area. roots penetrating the roof of the tunnels. This land The term Bottini is used in Siena to refer to the tun- could not be used for grazing either, or for any other nels of the underground aqueducts that bring water to activity. Furthermore, the Bottini were kept clean and the public fountains. Other underground excavations the flow unimpeded by special workers (bottinieri), to exist under the town and they are referred to as cavitá, ensure good potable water. It is said that King Charles some originally used as dwellings, now either aban- V of Spain visited the Bottini (at the time strategic for doned or used for storage, wine cellars and the like. water supply and potential passageways for enemies The sewers of Siena consist of large pipes that follow and conspirators) and stated that Siena was “better”

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Volume n° 3 - from D01 to P13 D01 - D01 Leader: A.Costantini or, anotherversion,“ “Siena lapartemigliore that hesaidsomethinglike(translatedintoItalian): the Kingwasnotrecorded.ThepeopleofSienastate outside. TheexactoriginalSpanishphraseutteredby (or “prettier”accordingtoanotherversion)insidethan the term readily-defendable thanthetownoutside,orheused referring eithertothefactthatBottiniweremore the Bottiniandstatedanything,mostlikelyhewas dentro chefuori” this door). is, “Sienaopensitsheartwidetoyou”(…widerthan apre uncuorepiùgrande”(…diquestaporta);that Latin script“CormagistibiSenapandit”(“Sienati 81.8 PortaCamolliafamousalsoforthesculpted lowing the“centro”sign. 81.6 AntiportodiCamollia;continuestraightfol- (fl at)sideofSiena. one ofthefortifi cations builtonthemorevulnerable Emanuale IItowardAntiportodiCamollia.Thiswas 80.8 ContinuestraightaheadenteringVialeVittorio along thecrestofhill. centro”. TheroadfollowstheoldFrancigenaroute 79.2 Roadturnabout:followindicationsto“Siena onto theCassia(SS2)towardSiena. 78.6 IntersectionwiththeCassia(SS2);turnleft(E) is, towardSiena. - RetraceyourroutebacktotheCassia(SS2)that Bottini) thanabove,asitreallywas! the medievaltownwascleanerunderneath(in 8 lindo orperhaps . IfindeedtheSpanishKingvisited Siena épiúbella (better) limpio cel’haaldisotto” toindicatethat (prettier )

secondary Bottini(utenze).Thepathofthemaingorellois of Castelvecchio,locatedbehindtheDuomo; highest, andthefi of theoriginalthreehilltopsSienawasbuilton.The black- (ophiolite)striatedDuomoislocatedonone built onasteephillslope.Thewhite-(marble)and ristic partsofSiena,withitsancientmedievalhouses This stopallowsaviewofonethemostcharacte- across avalley. (10.45 hr)S.Domenico-Cityscape;causeway Stop 3: 83.4 Stopatsuitablelookout. Florence. the 1555defeatofSienabyMedici,rulers Domenico. TheFortezzaMediceawasbuiltsoonafter onto VialedeiMilleheadingtowardthechurchofS. road alongthewallsofFortezzaMedicea,andturn Biagio diMontLuc,thenViaArmandoDiaz,the - Turnrightalongthemedievalwalls.FollowVia modifi shapes; thesmallrectangularchannel inthefl continous delivery ofwater totheutenze(arrows =fl gorello (openchannel) carryingthewater; C.Different direction). (Rectangleontheupperrightoffi the requiredslopefor regularwater fl intersections between gorelloofmainBottinoand positioning ofthegorelloinBottini,tomaintain medieval town atislargest,andpathsofthevarious Figure 4-MapanddiagramsoftheBottini: A. The ed ordammedtoensurelocaldeeperfl Bottini (maestro~mainones);B. Various tunnel indicates thelocationsofFigure 5andStop2). rst tobeoccupied,hilltopwasthat ow; D. Mapsof ow and thus oor isthe 21-05-2004, 15:01:50 gure ow ow SIENA (CENTRAL ITALY): URBAN GEOLOGY, ART AND HISTORY OF A MEDIEVAL HILLTOP TOWN AND ITS BOTTINI (UNDERGROUND AQUEDUCT)

AND MONUMENTAL FOUNTAINS D01

other hilltop is that of the Castellare (an old, par- tially- preserved castle), near the Piazza del Campo (Back-cover map). Farther to the east, note the Torre del Mangia of the Town Hall, and even farther to the east, the only remaining massive, high, private tower (the tower of the Mignanelli family) in Siena. Ambro- gio Lorenzetti depicted this tower at the center of his painting the “Effetti del Buon Governo”. The church of S. Domenico and the Duomo were both affected by the earthquake of 1798: the bell tower of S. Domenico was damaged and two of the six marble columns of the Duomo were broken. This earthquake was asso- ciated with one of the closely spaced, normal faults that cross the town from NW to SE. The deep, steep valley separating S. Domenico from the area of the Duomo is typical of the southern part of Siena. These valleys conditioned the lifestyle of Siena, in terms of both the roadways and the location of the fountains. Fontebranda is located at the bottom of the valley, about 30 m below the observation point at stop 3. It was a very inconvenient location to get water from, and the many industries that developed there (mainly wool, cloth, and slaughterhouses) were constricted by the limited space available. In several instances the head portion of the valleys has been separated off and brought to good use. A case in point is the building of a causeway (completed in 1920) with dump fi ll between S. Domenico and the Figure 5 - Uopini area: A. Schematic geological map Fortezza Medicea. This allowed for faster communi- with trace of the Bottino and location of the smiragli; cation (Viale dei Mille) and the creation of a sunken B. Schematic cross-section with location of the Bottino space nowadays used for car parking and a sports intercepting the groundwater fl ow of the largest topmost fi eld. aquifer. Note optimum position of Bottino in respect to - Coffee break. surface morphology and dip of the strata. - From this point on, follow the route indicated on the back-cover map. to the tunnels had to be made at the meeting points. - [Next full stop will be in a ~ 800-m-long tunnel star- No particular rock bed was followed for the Bottino ting at Fontegiusta (also referred to as Fonte Giusta). Maestro di Fonte Gaia. When hard concretions (hi- People uneasy in tight, underground places are advi- ghly cemented sandstone blocks) were encountered, sed to go directly to Stop 4b]. which made the excavation diffi cult, the tunnels were reduced from an average width of 80 cm and a height Stop 4: of 1.80 m to the minimum necessary for a person (11.15 hr) Bottino Maestro di Fonte Gaia from to go through. The tunnels were built differently at Fontegiusta to Fonte Gaia (Piazza del Campo). different times and places, as is shown by roofs with Construction of the Bottini was done by hand at va- hut, barrel, square, and arc shapes (Fig. 4B). Starting

rious depths (2 to 30 m) below the surface to maintain in the early 1500s, secondary tunnels were built by D01 to P13 n° 3 - from Volume the 2‰ gradient necessary for water to fl ow smoothly. private citizens and institutions in order to get water Specialized miners (guerchi) did the work. They used from the main Bottini. The secondary tunnels varied simple tools (picks, shovels, and the like). Due to the in size greatly, depending on the wealth of the people narrow passages, only one man at a time could work involved. at the tunnel face. To accelerate construction of the The main Bottini were slanted to be lined with bricks. newer Bottino Maestro di Fonte Gaia, two crews were It was a valiant and costly enterprise that was never utilized in various segments, one working from the executed, mainly because of the economic crisis fountain side backward, and the other on the opposite that followed the decimation of the population by side. Alignment errors were made, and adjustment the 1348 plague. Only those parts of the Bottini that

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Volume n° 3 - from D01 to P13 D01 - D01 Leader: A.Costantini to 2mdeep)decantationpools( to thisend.Large(~50mlong,~4wide,andup and theBottiniclean,severalotherthingsweredone water tothetown.Besideskeepingsurfaceground to ensureaconstantsupplyofgood,clean,drinkable tunnels ( settling ofsedimentsintroducedfromthecollector it enteredthewalledcity.Thesepoolsallowed along theBottinoMestrodiFonteGaiajustbefore days on. ized users,pilferageofwaterwascommonfromearly from theirwellswithbuckets.Besidestheseauthor- livered totheirwells.Theclientsthenretrievedwater they wereallowed;thatis,fortheamountofwaterde- charged accordingtothenumberandsizeof clients, exceptsomereligiousinstitutions,were was placedatthestartofsecondarytunnel.All clients, aplatewithholes( 4D). Tomeasuretheamountofwaterprovidedto ering waterspeed,andincreasingdepth(Fig. gorello by partiallydammingitwithabrick,orforcingthe water fl the secondarytunnelsandtoclientwells( gradient (Fig.4C).Toensureconstantwatersupplyto the fl places, itwasconstructedhigherormuchdeeperthan er, occasionallyonthesideoffl water. The ( A small(15cmwide,25deep),openchannel the chimneywalls. smiragli are stillvisibleontheroofofBottinileadingto traces oftheropesusedtolowerandraisematerial and indepthdownto30mbelowthesurface.The from squaretocircular,insize2.53meters, almost-regular intervals.The Smiragli features. cks andtheyprovideagoodviewofthegeological More than65%oftheBottiniarenotcoveredbybri- overlying palaceswerereinforcedwithbrickcovers. or requiredextrasupportbecauseoftheweight were indangerofslumping,hadwaterinfi water throughprecipitationofCaCO as wellreductionofthecalciumcontenthard Precipitation ofCaCO before thewaterwasdistributedtopartsofcity. smaller poolswerebuilt,alsonearthecenteroftown, called regularly, usuallyevery50-60years.Thisworkis The calciteplaquesthatdevelopedhadtoberemoved gorelli 10 gorello oor ofthetunnelstomaintainproperslope , eventuallyimpedingtheregularfl sgrumatura ow inthemain tomeander,hencereducingitsgradient,low- ) wascutinthefl . Goodgeologicalsectionsareexposedalong (chimneys)werebuiltalongtheBottiniat infl uenti

Until theearly1900s,greatcarewastaken gorello ) afterunusuallyheavyrainstorms, , anditwas,stillis,donewith wasexcavatedusuallyatthecent- 3 oor oftheBottinitocarry gorello occurred alsoallalongthe dadi smiragli ) ofvariousdiameters wasdeepenedeither galazzoni oor, butinother varyinshape 3 . Similarbut ow of water. ) werebuilt utenze ltrations, ), the dadi

tunnels identifi ed indescendingordertowardFon- (The numbers(suchas#68)refertosecondary ( the methodsofdistributingwatertopublicfountains niques ofundergroundaqueducts,andtoestablish Siena area,toobservetheancientconstructiontech- to analyzeinsomedetailshorefacedepositsofthe The objectivesofthisundergroundwalkingtourare: the fullrestorationofthisimportantwatersystem. assistance andvolunteerworkisneededtocomplete as theEuropeanCommunity.Muchmorefi Bank, aswellbyinternationalorganizationssuch such astheTownofSienaandMontedeiPaschi other activitieshasbeenprovidedbylocalinstitutions, help forrefurbishingtheBottiniandfountains usually organizedbytheDianaAssociation.Financial short fi can beglimpsedbyparticipatinginsomespecial, fragile environment,partoftheundergroundworld and toafewschoolgroupsperyearsafeguardthe Although visitstotheBottiniarelimitedafewsites have beenproducedaboutthemandthefountains. pictures; inadditionvideos,CD-ROMS,andwebsites books havebeenpublished,somewithnumerous Shows havebeendoneontheBottini,andseveral ancient monumentalfountains(FontediPescaia). being setupinabuildingconstructedoveroneofthe purposes. AWaterMuseum(Museodell’Acqua)is re-evaluation ofthiscomplexwatersystemfortourist buried havebeenrefurbished.Allthishasalsoledtoa that hadfallenintodisuseand/orbecomepartially foundations. Furthermore,manysurfacefountains slumping, henceanevaluationofthestability associated withthepresenceoffaultsandpotential other things,theyprovideanevaluationofurbanrisk Siena. Thesestudiesareimportantbecause,among of theundergroundexposuresbyUniversity has permitteddetailedgeologicalstudiestobemade the undergroundaqueductfornon-potableuses,and This hasallowedthere-utilizationofwaterfrom dumped materialfrommany has startedcleaningthevarioustunnelsandremoving the helpofvolunteersfromDianaAssociation, entrances totheBottinifromprivatehomesand,with The MunicipalityofSienahasgatedoffthemany underground featuresofSienahavebeenrefurbished. In thelasttwodecades,Bottiniandother cave-like formations(Balestraccietal.,1993). Bottini thatcalciteprecipitationhasproducedsurreal, dammed toserveasreservoirs.Itisalongthese even duringdryperiods,someBottiniwerepartially Furthermore, toensurereasonablewatersupply niches dugintheBottiniwallsortransportedoutside. special irontools.Theremovedplaqueswerestoredin fonti ) andtoprivatewells. eld tripstoeasy-to-reach, near-surfacesites, smiragli andwells. 21-05-2004, 15:01:54 nancial

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te Gaia. The distance in meters (m) is from Fonte sandy wall of the tunnel. Note that CaCO3 encrusts Gaia.) the surface of the sand below the conglomerate, indi- - Access to the underground aqueduct (Bottino) is cating that water is percolating from the base of the through the Fontegiusta entrance. After descending conglomerate itself. a steep staircase, a short tunnel leads to the Bottino # 59-58 Conglomerate with poorly-sorted clasts; Maestro di Fonte Gaia. among them there is a large angular clast of Macigno - Note a few pencil-like stalactites, small encrusting sandstone. This indicates that this material was deri- stalagmites, and some cave formations along walls. ved from the NW, from the Chianti area, the nearest # 68 (~ 780 m) Via di Camollia 31– secondary tunnel outcrop of the Macigno sandstone. to a private well (client, utenza). # 56-55 Change in direction, width and height of #67 Small niches excavated on the walls for sacred Bottino. Secondary tunnels (utenze). images and for oil lamps. It was common practice for # 55-54 Thin interlayers of small pebble conglome- the miners to bring along such images and/or scratch rate alternating with sandstone; cross-laminations. crosses on the walls, as protection against under- # 53 Coarse-pebble conglomerate interlayer in san- ground evils. Observe the exposure of sandstone and dstone. thin, lensing conglomerate interlayers. Concretions # 52-53 Shell concentration exposed on the roof of the (tightly cemented CaCO3 sandstone pods) occur con- tunnel (Cardium). sistently at the lower contact of the conglomerates. # 51 Secondary tunnel (utenza) apparently dug or en- Conglomerates have round, sub-spherical pebbles, larged with a slightly different technique or tool. and are poorly sorted and not well structured. # 49 Modern gate, and tubes possibly from the mid- # 66 (~730 m) Note a cross scratched on the wall, 1900s and a niche in the wall fi lled with pieces of calcite that # 48-46 Smiraglio del Cavallerizzo (located were routinely (about every 50-60 years) removed between Piazza Gramsci and Piazza G. Matteotti). (sgrumatura) from the water channel (gorello) to free The tunnel here is at a depth of about 18 m. Note in- up water fl ow. The thickness of the CaCO3 pieces is cisions on the roof of the Bottino made by ropes used about 4.5 cm, suggesting a rate of CaCO3 precipita- to lift material to and from the tunnel. Conglomeratic tion of about 7.5 mm per year. Exposure of sandstone layer well exposed. Ophiomorpha burrows. with few isolated small pebbles and thin conglomera- # 45 Horizontal- and cross-laminations in sandstone, tic lensing layers; note dark gray algal growth on the some marked by granules and very small pebbles. lower parts of the sandy walls. ~ # 43 (~ 400 m) Narrow excavation on the right wall, # 65 (~713 m) Small dam along the main gorello to and round hole on the left wall of the tunnel. These raise the water level to allow continuous supply to indicate that a door or wooden barrier was placed at secondary, private gorello (utenza). Enlargement of this point, locked with a sliding piece of wood. the Bottino with a bench over a conglomeratic and ~ 382 m Normal fault striking N140o and dipping concretionary layer (diffi cult to excavate). These en- to the east at 60o. The fault face shows slickensides largements usually occurred when two crews working with striae and steps indicating direction of rock mo- in opposite directions met, and errors in alignment of vement. Nearby there is a slight enlargement of the the tunnels had occurred. The direction of advance- Bottino indicating a meeting of two crews working in ment of the two crews can be surmised from the ar- opposite directions and a slight error in alignment of cuate excavation marks (concave toward the miner). the tunnels. Note water dripping (stillicidio) from the roof of the #41 Cross-laminations in sandstone, and thin con- tunnel. In the past it was wrongly believed that this glomerate layers. Nice nameplate (targa) of a client would be a sizable source of water. (utenza) designed in 1866 and refurbished recently # 64 Square-shaped smiraglio about 20 m deep. (2002). Three-dimensional exposure of conglomera-

# 61 Three-dimensional view of conglomeratic tic channel fi ll. D01 to P13 n° 3 - from Volume layers. # 41-40 Part of a large conglomeratic layer (chan- # 60 Niche fi lled with pieces of CaCO3 removed from nel). This conglomerate shows canalization at the the gorello. Small brick arches have been built to sup- base. Its top, however, is considered to be the original port the roof. Note roots from the roof and fresh air bedding surface (So), and therefore it indicates the entering the Bottini. This tunnel is shallow here below dip of the strata. Reworked fossil shells are present in the Lizza (square of La Lizza) where there are trees. the conglomerate. Such a contamination would not have been permitted # 39 Nameplate (targa) of a convent (Convento when the Bottini were used for drinking water. delle Cappuccine) indicating that some religious # 59 (600 m) Thin conglomeratic layer halfway up the institutions were exempt from fees (senza tassa) for

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Volume n° 3 - from D01 to P13 D01 - D01 Leader: A.Costantini client thatcommissionedthedigging. cious. Thisdependedinpartonthewealthof very narroworlow,tohighandrelativelyspa- private tunnelsdiffergreatlyfromeachother, # 21Verynarrowsecondarytunnel.Thesecondary, as beachfacedeposits(Terzuoli,1997). rates seenonsurfaceoutcropshavebeeninterpreted observed onacursoryinspection.Similarconglome- fi ll structuresoccurthroughout.Nofossilshavebeen planar toslightly-erodedboundaries.Thincut-and- The layerslensoutatthescaleofoutcrop,with with agreateramountofsandymatrixthanothers. sub-spherical, thesmallerpebblesdisk-shaped),some well sortedclasts(allrounded;thecoarserones vary inclastsizefromlayertolayer,eachwithfairly merates. Theconglomeratesarewellstructured;they ristic ofthissiteisthedevelopmentthickconglo- of ViadeiRossi.Theprincipalgeologicalcharacte- -(OPTIONAL): Deviationintothesecondarytunnel fossiliferous layersmaybetempestites. dissolved) withhighlybioturbatedsandstones.The fossiliferous layers(theshellsareforthemostpart si). Noticeonnearbywallsthealternationofhighly # 22Dadi(flow regulators)attheutenza(ViadeiRos- outline. of thetunnelonroof,markedbyrustyweathered Note largeOphiomorphaburrowonoppositeside Bookstore islocatedalongViaBanchidiSopra. below thepalaceandtowerswhereFeltrinelli # 24Utenzawithwell.Thisislocatedapproximately on leftwall. # 25Largeoystershellinsandyconglomeraticlayer meratic lenses. # 26Afewfossilsinsandstoneandsomethinconglo- fl oor. gorello coveredbybrickstoprovideafl at, walking tch forlowceilings!).Inthesecondarytunnel,note straight onthemainBottinotowardFonteGaia.(Wa- # 30(~225m)ViadellaSapienzajunction:continue the mostphotogenicpointsforthisfeature(Fig.6). 33-31 Severalmeandersofthegorello.Thisisone slumping. Someisolatedconcretions.Afewtarghe.# ~ 280m(near#36)Abrickwallwasbuilttoavoid (clients, utenze). to thesidechannelsandwell(pozzi)ofmansions ter levelandensurethattherewasaaconstantsupply down andthusdeepenthewaterfl ow toraisethewa- # 36Tightmeanderingofthegorello,builttoslow occur isolatedwithinthesandstone. conglomeratic interlayers.Somesmallpebbles # 38(~324m)Thickrocksuccessionwithfeworno roof ofthetunnel. # 39-38(~335m)Conglomeraticlayerreachesthe the waterused. 12 (grate onthefloor ofthecourtyard)locatedinbui- # 6Well(Pozzodelfi oraio): itcorrespondstoawell layers insandstone. #8 Three-dimensionalviewofthinconglomerate # 9Conglomeratelayerinsandstone. sub-spherical clastsincoarse-grainedsandstone. # 10Thinconglomeraticlayerswithwell-rounded, # 12Isolatedlargelensoffl at-pebbleconglomerate. tion. other layershaveabundantMacharonicusbioturba- ~ 95Sandstonelayersparallel-andcross-laminated; eastward 70o. of atleast2m.ItsorientationisN155oanditdips walls androofoftheBottino.Thefaulthasathrow ~ 102mWell-defi ned normalfaultvisibleonboth clients. side tomaintaintherequiredslopewellsof of thesecondarytunnel,butitisbuilthigheronone that thegorelloisnotplacedatcenterfl oor # 15Severalplates(targhe),oftwomaintypes.Note advancing fromoppositedirections in alignmentofthetunnelsdugbytwodifferentcrews # 19EnlargementintheBottino,possiblyduetoerror (note largePecten)conglomeraticlayer. # 20Verylowsecondarytunnel.Thin,fossiliferous Figure 6-Meanderingpathofagorellotolocallyslow down anddeepenwater fl distribution tointersectinggorelliofutenze(clients). ow toensureconstantwater 21-05-2004, 15:01:58 SIENA (CENTRAL ITALY): URBAN GEOLOGY, ART AND HISTORY OF A MEDIEVAL HILLTOP TOWN AND ITS BOTTINI (UNDERGROUND AQUEDUCT)

AND MONUMENTAL FOUNTAINS D01

lding in front of the Nannini Café in Via dei Banchi di Sopra, now occupied by a fl ower shop. # 2 Artifi cial pool (vasca di decantazione) constructed for settling of residual particulate matter before di- recting the water to clients in the Piazza Indipendenza area (Back-cover map). #1 Old suspended Bottino and gorello leading the waters to the original site of Fonte Gaia (slightly displaced from the present fountain). - Cross iron-gate and enter a man-made cavity dug into shoreface sandstone. This is one of about 500 cavities in underground Siena. Note conglomerate on the roof. - Continue to the next room that contains instruments still used by the bottinieri for the sgrumatura of the Bottini. - Climb a short staircase to exit onto Piazza del Campo. Stop 4b: (11.15hr) An alternative to stop 4 of the Bottini is to walk to the Piazza del Campo. Besides admiring the palaces around this square, people can visit the Museum of the Palazzo Pubblico Figure 7 - Palazzo Pubblico and Torre del Mangia.. Note (Town Hall) and climb the Torre del Mangia for a ma- stratifi cation of different bricks used during construction. gnifi cent view of the city and countryside (Fig. 7). The valley. This wall is now located under the Town Hall. museum contains several famous art pieces, among The ground was smoothed out and eventually covered them the Maestá by Simone Martini in the room of by bricks disposed in a fi shtail fashion. Piazza del the Mappamondo, and the fresco (wall painting) of Campo is one of the most famous town squares of the Effetti del Buon Governo by Ambrogio Lorenzetti Italy, because of its beauty and because a bareback in the Sala dei Nove (room of the nine governing of- horse race - the Palio - is run there twice a year in July fi cials). The latter gives the opportunity to compare and August. and contrast the Siena of the early 1300s with the one Fonte Gaia is located at the apex of the square in of today visible through the palace windows. It is also front of the Town Hall. Jacopo della Quercia, one of worth climbing to the back terrace of the palace whe- Siena’s most important sculptors, built the fountain re the elected offi cials during the Government of the from 1409 to 1419. The present-day fountain is a Nine could spend their free time: these offi cials were copy made by Tito Sarocchi in 1868. The original not allowed to ever leave the Town Hall for the dura- artwork is located in the museum of Santa Maria tion of their six-month tenure. From this terrace there della Scala. When the new images were put in place, is a splendid view of one of the valleys (Valdimonte) the fountain was also moved by 15 m to be exactly of Siena inside the town walls, and of the surrounding at the top-center of the square. This is a monumental countryside. Note the resemblance between the pre- fountain, but in medieval times it had practical uses as sent view and the one depicted in the Effetti del Buon well. When the square was used as a market, entrails Governo fresco. of killed animals were washed at the fountain, and

the water was available for various other uses as D01 to P13 n° 3 - from Volume Stop 5: well. Fonte Gaia never delivered as much water as (12.45 hr) Piazza del Campo; Fonte Gaia. wanted or needed. It nevertheless represented a great Piazza del Campo is the center of life in Siena. It has achievement of bringing water to the center of town, a shell-like shape derived from its being the apex of where no nearby spring was available. one of the valleys of Siena - Valdimonte. Until the Siena, the town without water, has constructed XI century, this area was located outside the old town some of the most beautiful fountain complexes in walls. New town walls enclosed it during the fi rst Italy. There are various types of public fountains: half of the XII century. To avoid erosion, a retaining monumental fountains, the fountains of the contrade wall was built in 1194 separating out the apex of the

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Volume n° 3 - from D01 to P13 D01 - D01 building againstearthquakes Figure 9- Arches in Via dellaGalluzzabuilt toprotectold Leader: A.Costantini to thelegendthatSienawasfoundedbyfugitive aqueduct. Theyallhavetheheadofawolf,inhomage Simple publicfountainswerebuiltforthenew1900s becomes alife-longadherentofthatneighbourhood. ritual inthecontrada,andfromthatdayonperson are whereeverynewbornisbaptizedwithapagan nine areextremelyimportanttolifeinSiena.They for eachofthe17contradetown.Thesefonta- called fontanine(=smallfountains),havebeenbuilt Bottino MaestrodiFonteGaia.Otherfountains, The latterfontiwere,andstillare,suppliedbythe of thecitizens,notbecausegeologicalconditions. were insteadbuiltinsidethetownwallsforbenefi some wereoutsidethetownwalls.Morerecentfonti not onlydiffi of theolderfontioftenwasthattheirlocation close toasuspendedwatertable.Thedisadvantage Fonte Becci,whichislocatedonthetopofahill,but a suspendedwatertable.Anotheroldfonteisthatof Pescaia ataslightlyhigherelevationassociatedwith valleys nearthemajoraquifer-aquifugehorizon,and and Ovile,whicharelocatedinthelowerpartof fonti ofSienaarethoseFontebranda,LaVetrice systems usedinvariousways(seestop11).Theoldest = fountains.Themonumentalfountainswerecomplex constructions, knowninSienaasfontinotjustfontane in valleybottoms,whichlaterbecamemonumental probably simpleconstructionsaroundnaturalsprings newer 1900saqueducts.Theolder,originaloneswere (neighbourhoods), andthepublicfountainsof 14 cult toreachbutalsodefend,because t who wereraisedbyashe-wolf. sons ofRemus(themythicalco-founderRome) Museum ofModernArtislocated. mini or,asitiscalledtoday,ofthePapesse,where located; and,totheright,notePalazzoPiccolo- the world-famousAcademiaMusicaleChigianais as, totheleft,Chigi-Saracini(1300AC)where Calcare cavernoso.Notevariousoldpalacessuch Duomo. Observethevariousoldtowersbuiltwith - TurnleftontoViadiCittàandwalkuptowardthe at theCostarella. entrance tothesquare).ThestartofPalioraceis reach ViadiCittàthroughtheCostarella(wide-road - walls. Pubblico andofavalley(Valdimonte)insidethetown cent viewscanbeenjoyedofthebackPalazzo Square behindtheTownHall,fromwheremagnifi Have lunchatarestaurant,possiblyintheMarket (13.30 hr)Lunch. Stop 6: Climb thetowerfora360 Caterina Piccolomini,sisterofPopePioII,builtit. This palace(1460-1495AC)issocalledbecause (15.30hr)(OPTIONAL)PalazzoPiccolomini. Stop 7: del Duomo. - TurnrightintoViadelCapitanoandwalktoPiazza Aquila (theEagleneighborhood). In thissquarenotethefontaninaofcontrada - ContinuealongViadiCittàuptoPiazzaPostierla. fi and, inparticularoftheolderquartersenclosedby rst citywalls. AfterlunchcrossPiazzadelCampoupwardto Piazza S.Giovanni. Thisconglomerateisinterpretedasa Figure 8-Conglomerateexposedonabuilding wall in o panoramic viewofthecity, beach deposit. 21-05-2004, 15:02:02 - SIENA (CENTRAL ITALY): URBAN GEOLOGY, ART AND HISTORY OF A MEDIEVAL HILLTOP TOWN AND ITS BOTTINI (UNDERGROUND AQUEDUCT)

AND MONUMENTAL FOUNTAINS D01

Stop 8: - Continue to the bottom of the slope and turn left (16.15 hr) Piazza del Duomo. (WSW) onto Via S. Caterina. On the right notice the The Duomo of Siena is a magnifi cent Gothic house and church of S. Caterina. monument built between 1229 and 1290. Only a brief, cursory visit can be made. Of particular importance Stop 11: are the walls with typical white (marble) and black (17.30 hr) Fontebranda. (ophiolite) stripes, the vast, albeit dark, Gothic Fontebranda is one of the oldest and most famous interior, and the main altar (pulpito) by Nicola Pisano. monumental fountains of Siena, mentioned by Dante In front of the Duomo there is the museum of Santa in the Divine Comedy: Maria della Scala, one of the many medieval pilgrim- “MA S’IO VEDESSI QUI L’ANIMA TRISTA hospices along the Via Francigena. It was a hospital DI GUIDO O D’ALESSANDRO, O DI LOR FRATE from medieval times until recently. It now contains a PER FONTE BRANDA NON DAREI LA VISTA.” museum and, in its basement, good examples of dug (Inf. XXX 76-78) (If I saw here the sad souls of cavities and a deep well, called il Rotone, from the big Guido or Alessandro, or of their brother, I wouldn’t wooden wheel used to lift the buckets of water. give up the sight of them even for Fonte Branda) To build the Duomo, the top of the hill was leveled The location has a natural spring because of its ideal down to a conglomeratic layer that provided good position near the contact between the main aquifer of foundations. A new, grandiose cathedral (Duomo the area and the underlying, thick, impermeable silty Nuovo) was under construction between 1321-1339. clays. This water has been used since antiquity, pos- The old cathedral (the present Duomo) would have sibly since pre-historic times, certainly by Etruscans been used as the transept of the new nave constructed and later by Romans, as indicated by a 394 AC do- at 90 degrees from it. The project was aborted because cument. The early medieval fountain was located at of the 1348 plague, as well as because of the instability a slightly higher elevation than the present one. The of the ground - a fault runs along the area. This fault present fountain was built in 1193. It was a complex was responsible for earth movements during the 1798 structure, much of which still exists, albeit somewhat Siena earthquake (intensity 7-8 on the Mercalli scale). changed through the ages. The original constructions A few columns, fi ve arches and the incomplete facade and their uses can be found in old prints (Fig. 10). (called facciatone = grande facciata = large facade) is The water from the Bottini fl owed into pools placed all that remains standing of the Duomo Nuovo. in a cascade fashion The fi rst pool was for drinking - Walk to the NE corner of the square and descend the water for people, the second for drinking water for steep marble staircase at the side of the Baptistery, to animals, the third for washing clothes, and the fourth Piazza San Giovanni. for washing and freshening-up animals, an important activity in ancient times. The water that drained from Stop 9: the pools was used for various artisan activities, such (17.00 hr) Piazza San Giovanni - Baptistery and as washing wool and slaughtered animal remains, as conglomeratic layer. well as tanning hides. Eventually the waters were The Gothic Baptistery was built in 1317 in a quarry canalized and used to drive mills, before being discar- from where sand and gravel was mined for the con- ded. They were too polluted to pour onto the various struction of the Duomo. On the wall of a nearby hou- gardens and fi elds (orti), as was done for other similar se, to the east, note a conglomeratic deposit showing fountains. Indeed, the Fontebranda area was at those clasts of various sizes, well sorted, with slightly times the industrial part of town: a busy, foul-smel- inclined layers. This conglomerate is interpreted as a ling place, as written complaints indicate. Although beach deposit (Fig. 8; Terzuoli, 1997). Fontebranda was one of the best fountains, it never - From the NE corner of Piazza San Giovanni walk provided enough water to satisfy the demand. Much north into the narrow Via di Diacceto.

work was done to improve its outfl ow. The 7500m- D01 to P13 n° 3 - from Volume long Bottino Maestro di Fontebranda, eventually Stop 10: completed by 1460, was constructed by progressively (17.15 hr) Lookout (belvedere). digging farther away from the fountain, trying to open Brief photographic stop to view the church of S. Do- as much of the lower part of the aquifer as possible. menico and, at valley bottom, the house and church of This Bottino is entirely located deep under the nor- S. Caterina and Fontebranda . thern part of the town of Siena. - Continue for ~ 40 m and then turn left (NW) down Recently, since the late 1900s, the Fontebranda area into Via della Galluzza. Notice arcs built to reduce has been renovated and turned into a tourist site. damages by earthquakes (Fig. 9). Shops, restaurants, coffee houses, and offi ces have

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Volume n° 3 - from D01 to P13 D01 - D01 Leader: A.Costantini ~ 160(20.00hr)Florence,FortezzadaBasso. - ReturntoFlorence structure. now beingcanalizedaroundthefoundationsof water interferedwiththeconstruction.Suchis of Siena’smainaquifer.Accordingly,muchground- This undergroundparkinglotwasbuiltatthebase (18.30 hr)Fontebrandaparkinglot. Stop 12: ous 1798earthquake. the traceofnormalfaultresponsibleforruin- Farther upalongthepathitispossibletoobservealso conglomerates ofgravellybeaches(Terzuoli,1997). are interpretedasshorefacedeposits,overlainby again intoasecondconglomerate.Thesandstones another bioturbatedsandstonelayergradingupward a conglomeraticunit.Thelatterissharplyoverlainby morpha at Fontebrandashowalower,bioturbated(by Maestro ofFonteGaia(stop4).Therocksexposed the sequencesthatwereexaminedinsideBottino rock sequencesoftheSienaarea.Theseunderlay cient pathprovideseasyaccesstothelowertwo on theverticalslopesbelowS.Domenico.Anan- A goodrockexposureisavailableatFontebranda to thevalleybottom. to transportpeoplefromthehigherpartoftowndown the ancienttownwalls,andelevatorsarebeingbuilt ge undergroundparkinglothasbeenbuiltjustoutside been builtonthesiteofoldslaughterhouses,alar- were obtainiedfromtheArchiviodiStatoSiena, Useful informationandpermissiontopublishfi Acknowledgments 16 ) sandstonegradingbyalternationupwardinto Ophio- gures Antonella ManciniandBarbaraTerrosi. Universita’ diSiena.(InItalian). del Bacinodell’Alberta(Canada).TesidiDottorato, del BacinodiSiena(Italia),B)Idepositid’estuario marginali: A)Lesabbieconglomeratichecostiere stratigrafi Terzuoli, A.(1997).Sedimentologia,ichnologiae Editrice, Siena.(InItalian). immagini dellacittàedellesuefonti.NuovaImagine Serino, V.(ed.)(1998).Sienael’acqua,Storia Italian). in theprivatecollectionofEttorePellegrini).(In Francesco RossiStampatore,Siena(volumeisnow della CittàdiSienaausode’forestieri.Bonettiper Pecci, G.A.(1761),Ristrettodellecosepiùnotabili London. Hook, J.(1979),Siena.ACityanditsHistory. Siena (InItalian). litica esocialedellarepublicadiSiena.BettiEditrice, Douglas, L.(2000;originaledition1926).Storiapo- Douglas, R.L.(1902),AHistoryofSiena.London. moria SocietàGeologicaItaliana,52,513-525. western sideoftheNorthernApennines(Italy).Me- Neogene-Quaternary sedimentaryevolutioninthe Bossio, A.,Costantini,Foresi,L.M.,etal.(1998). Periccioli, Siena.(InItalianandLatin). dalle originifi Le FontidiSienaeiloroacquedotti.Notestoriche Bargagli Petrucci,F.(1992;previousprintsin1974). (In Italian). Bottini medievalidiSiena.EdizioniALSABA, Balestracci, D.,Lamberini,D.andCivai,M.(1993).I References a dialtarisoluzioneinambienti marini no alMDLV.Twovolumes,Edizioni to I.P.M.Diagramsweredrawnby Council (NSERCGrantNo.A7371) Science andEngineeringResearch di SienatoA.C.,andbytheNatural Fondi perlaRicercadell’Universita’ this projectwereinpartprovidedby per ilTurismodiSiena.Fundsfor Ettore Pellegrini,andtheAgenzia Biblioteca ComunalediSiena,Dr. (guazzatoio) (fromPecci, 1761,p.154). and freshening-upwork-animals clothes, and,tothefarleft(H),washing animals (abbeveratoio), washing for humans(I),drinkingwater for for, fromrighttoleft,drinkingwater Pools (I,H)atFontebranda were San Domenicoconvent at topofhill. Fontebranda andtheChurch ofthe Figure 10-Oldprintshowing 21-05-2004, 15:02:07 Back Cover: road map of the Siena area with stop locations

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