Editing Velletri (section)

==Physical geography==

===Territory===
The territory of Velletri stretches between two distinct areas. The northern part is situated on the southern foothills of the [[Colli Albani]] range and was geologically formed about 150,000 years ago, after the collapse of the Volcano Laziale (caldera). On the other hand, the southern boundary forms around [[Pontine Marshes]], whose reclamation started at the time of [[Pope Pius VI]] and was accomplished during the regime of [[Benito Mussolini]].

According to the classification given by the Geological Survey of Italy,<ref>''Carta Geologica d'Italia'', foglio 150 (Roma), edizione 1967</ref>  much of the territory consists of ground-type LPS, or [[paleosols]], the rest is mainly composed of soils lp, lapilli, argillificate, Mafic, and [[leucite]] analcimizzata.  
[[File:Monte Artemisio - colli Albani.jpg|right|thumb|250px|Mount Artemisio overshadows Velletri]]

The [[Seismic classification]] of Velletri's territory is Zone 2 (medium-high seismicity).<ref>Anche secondo le categorie sismiche stabilite dal D.M. LL.PP. 1984 e la successiva ordinanza P.C.M. n° 3274 20 marzo 2003 Velletri era in zona sismica 2. Sono nella stessa zone sismica tutti i Colli Albani.</ref>

===Hydrography===
The territory of Velletri collects water run off from many streams.  These streams, most of them torrential in character or small in scale, are known as ''[[:wikt:fosso|fossi]]''.  Main ''fossi'' include: 
*''Fosso Minella'' at the edge of the municipal area to [[Genzano di Roma]], near the Velletri ''[[frazione]]'' of Sant'Eurosia. This stream originates from Monte Spina, elevation {{convert|731|m|ft}} above sea level, in the territory of [[Nemi]], with the name of Acqua Lucia.  It is named after the Minella bridge on State Road 7, Via Appia Nuova and originates at {{convert|405|m|ft}} above sea level, at the foot of Colle degli Olmi.  Minella also runs parallel to the  fosso delle Tre Armi, which then connects to it.
*''Fossa Sant'Eurosia'', originating from Colle degli Olmi; it goes through the village of the same name, located at {{convert|238|m|ft}} above sea level.
*''Fossa Paganica'', which originates from springs on Colle Caldaro (467 m), and on Colle Tondo (596 m).
*''Fosso di Ponte Veloce'', which arises from Colle Tondo, on Maschio dell'Artemisio (812 m) and in the Faccialone forest (615 m).  This watercourse near Villa Borgia, superseded the old town of Velletri, changes name to Fossa Farina near the iron bridge of the Roma-Velletri railway.
*''Fossa Anatolia'': originating from Colle Bello (600 m), it flows at the foot of old town Velletri, until it joins the Fossa Farina.

Other water sources include the ''Acqua de Ferrari'', at {{convert|650|m|ft|abbr=off}}, underlying Monte de Ferrari ({{convert|886|m|ft|abbr=off}} above sea level) at [[Rocca di Papa]], from which is  part of the municipal water supply.<ref name="ReferenceA">''Carta Geologica d'Italia'', edizione 1967</ref>

===Topography===
The old town's altitude is substantially uniform from  the elevation of Piazza Giuseppe Garibaldi at 339 m [[Above mean sea level|above sea level]], the square of the Trivium at {{convert|332|m|0|abbr=off}}  above sea level, and Napoletana at {{convert|329|m|0|abbr=off}} above sea level.  The area west of the walled city is a bit higher at San Lorenzo reaching {{convert|372|m|0|abbr=on}} [[Above mean sea level|above sea level]].  The remainder of the territory to the south and west is basically flat except for small hills that do not exceed {{convert|300|m|0|abbr=on}} above sea level.<ref name="ReferenceA"/>

===Climate===
The climate of Velletri is mild, due to the [[Tyrrhenian Sea]] not being far, and to the protection offered by the [[Alban Hills]] and Mount Artemisio in the north. The climate is very rainy, with an annual average of {{convert|1400|to|1500|mm|0|abbr=on}} precipitation, making it the rainiest city of Lazio and one of the most rainy cities in Italy.  Humid currents from the southwest facing the Mont Artemisio condense all the rain on Velletri, leaving clouds restricted to the northern side of the [[Colli Albani]].  It snows rarely.<ref>Ad ogni modo, fuori dai periodi fissati non è consentito usare per più di sei ore giornaliere gli impianti di riscaldamento</ref>
*[[Climate classification]]: Zone D, 1544 GR / G
*[[Turbulent diffusion#Atmospheric diffusion and pollutants|Atmospheric Diffusivity]]: average