Rilevanza idrogeologica delle tessiture epicarsiche e delle forme carsiche dell'Alta Murgia (Puglia)

The aim of the present study is to examine the influence of the epikarstic textures and karstic forms and their hydrogeological relevance on terms of the hydrogeological balance in a semiarid area,the Alta Murgia region (Apulia, Southern Italy). The Alta Murgia is a Cretaceous limestones plateau characterized by a typical karstic landscape, and constitutes the main recharge area of the Murgia karstic aquifer due to the elevation, climatic conditions, surface karstic textures and morphology. The morphological features of the karstic plateau are defined by the density of surface arstic forms. Karst surface shows natural distribution of modest deposits of terra rossa and regolith on the bottom of the morphologic depressions, outlining a primordial hydrographical network often convergent in dolines or endorheic basins. Epikarstic textures and arstic forms play a dominant role in the surface and subsurface hydrology. Field and laboratory surveys have been carried out to define the hydraulic and physical characterization of the epikarstic textures at field scale and their importance on the flowing threshold. The hydraulic behaviour of surface textures allowed to assess the infiltration capacity in order to perform a refined analysis of the saturation process and the runoff subsequent the attainment of the ponding time. Analyses at a larger scale demonstrate that infiltration and runoff phenomena are largely influenced by infiltration coefficients of the epikarstic textures, defined by physical and hydraulic textures parameters, and show the important function of geomorphological karstic forms on the water balance. In presence of karstic forms such as endorheic basins, olines and polje, the runoff do not discharge out, but converges towards hydrographic network and flows into these depressions and infiltrates. The results point out that the epikarstic textures and karst morphology of the Alta Murgia, mainly act on the surface, subsurface and groundwater recharge, especially because vegetation, soils features, distribution of the different textures and their infiltration coefficients, control the hydrological processes, such as actual evapotranspiration, water storage, infiltration and runoff amounts. INGLESE