Discharge measurement with salt dilution method in irrigation canals: direct sampling and geophysical controls

An important starting point for designing management improvements, particularly in irrigation areas, is to record the baseline state of the water resources, including the amount of discharge from canals. In this respect discharge measurements by means of the salt dilution method is a traditional and well-documented technique. However, this methodology can be strongly influenced by the natural streaming characteristics of the canal (e.g. laminar vs. turbulent flow) and accurate precautions must be considered in the choice of both the measuring section and the length of the measuring reach of the canal which can affect the plume shape. The knowledge of plume distribution in the measuring cross-section is of primary importance for a correct location of sampling points aimed in obtaining a reliable measurement. To obtain this, geophysical imaging of an NaCl plume from a slug-injection salt dilution test has been performed within this paper by means of cross-flow fast electric resistivity tomography (FERT) in a real case history. Direct sampling of the same plume has been also performed with a multisampling optimization technique to obtain an average value over the measuring section by means of contemporarily sampling water in nine points. Results show that a correct visualization of the passage of the salt plume is possible by means of geophysical controls and that this can potentially help in the correct location of sampling points

Residual sludge from dimension stones: characterisation for their exploitation in civil and environmental applications

Abstract Residual sludge coming from dimension stones working plants represents a problem for Stone Industries (cost connected to their landfilling); sludge as such can be used for environmental restoration of derelict land or in cement plants, according to Italian regulation. However it is also possible to think about their systematic treatment for the production of Secondary Raw Materials or "New Products". To individuate possible different applications a geotechnical characterization was conducted on sludge as such and on different mixes. In detail the possibility of using them as products for dumps waterproofing and for land rehabilitation and reclamation is discussed