Morfologia carsica e fenomeni di alluvionamento nel salento leccese sud-orientale
Abstract
It
Le piogge che interessano il Salento (circa 700 mm/anno) non danno luogo ad un’idrografia superficiale evidente per la diffusa presenza di rocce permeabili e la debole inclinazione delle superfici. Le acque di ruscellamento, di breve percorso, s’infiltrano nel sottosuolo in corrispondenza di punti assorbenti presenti sul fondo di depressioni tettoniche e/o carsiche.Molti centri abitati sono sorti in queste depressioni per la reperibilità d’acqua a poca profondità e per le condizioni favorevoli all’agricoltura. Le depressioni, però, sono episodicamente alluvionate nel corso di eventi meteorici intensi. Nonostante le opere di sistemazione idraulica degli ultimi 50 anni, la situazione appare peggiorata.L’urbanizzazione di aree sempre più estese ha aumentato il volume delle acque di ruscellamento e sconvolto le naturali direzioni di deflusso, estendendo le aree soggette al rischio d’alluvionamento.
En
The Salento Peninsula is characterized by annual average rainfall of about 700 mm.Rainfalls cluster in autumnal months, reaching the highest values in south-eastern area, whereas the lowest ones are recorded in western and middle-northern sectors. In spite of copious rains, Salento landscape is marked by a poorly developed drainage pattern due to the occurrence of karstified and jointed rocks and slightly inclined flat surfaces. In fact, surface waters rapidly infiltrate underground in correspondence of karstic sinkholes. In particular, the Salento south-eastern sector is characterized by the presence of numerous depressions whose genesis can be related to tectonic and karst processes. These depressions, lengthened from NO to SE, developed on Miocene and Plio-Pleistocene unities and show their bottom covered by clayey-sandy colluvial deposits, which sometimes disguise and partly obstruct the main sinking points. Many villages are placed at the bottom of these depressions because of phreatic waters presence at small depth and favourable conditions for agriculture. Unfortunately, these areas are prone to flooding during the most intense meteoric events, as during the downpour of the 6-7 October of 1957, which caused 12 southeastern Salento villages to be flooded. Despite the hydraulic works built during the last 50 years, the situation appears worsened. The urbanization of wide surfaces of the territory has determined the significative increase of surface waters and the changing of the natural flow directions increasing the areas affected by flooding.
Le piogge che interessano il Salento (circa 700 mm/anno) non danno luogo ad un’idrografia superficiale evidente per la diffusa presenza di rocce permeabili e la debole inclinazione delle superfici. Le acque di ruscellamento, di breve percorso, s’infiltrano nel sottosuolo in corrispondenza di punti assorbenti presenti sul fondo di depressioni tettoniche e/o carsiche.Molti centri abitati sono sorti in queste depressioni per la reperibilità d’acqua a poca profondità e per le condizioni favorevoli all’agricoltura. Le depressioni, però, sono episodicamente alluvionate nel corso di eventi meteorici intensi. Nonostante le opere di sistemazione idraulica degli ultimi 50 anni, la situazione appare peggiorata.L’urbanizzazione di aree sempre più estese ha aumentato il volume delle acque di ruscellamento e sconvolto le naturali direzioni di deflusso, estendendo le aree soggette al rischio d’alluvionamento.
En
The Salento Peninsula is characterized by annual average rainfall of about 700 mm.Rainfalls cluster in autumnal months, reaching the highest values in south-eastern area, whereas the lowest ones are recorded in western and middle-northern sectors. In spite of copious rains, Salento landscape is marked by a poorly developed drainage pattern due to the occurrence of karstified and jointed rocks and slightly inclined flat surfaces. In fact, surface waters rapidly infiltrate underground in correspondence of karstic sinkholes. In particular, the Salento south-eastern sector is characterized by the presence of numerous depressions whose genesis can be related to tectonic and karst processes. These depressions, lengthened from NO to SE, developed on Miocene and Plio-Pleistocene unities and show their bottom covered by clayey-sandy colluvial deposits, which sometimes disguise and partly obstruct the main sinking points. Many villages are placed at the bottom of these depressions because of phreatic waters presence at small depth and favourable conditions for agriculture. Unfortunately, these areas are prone to flooding during the most intense meteoric events, as during the downpour of the 6-7 October of 1957, which caused 12 southeastern Salento villages to be flooded. Despite the hydraulic works built during the last 50 years, the situation appears worsened. The urbanization of wide surfaces of the territory has determined the significative increase of surface waters and the changing of the natural flow directions increasing the areas affected by flooding.
DOI Code:
10.1285/i15910725v26supp113
Full Text: PDF
