Overflow and microbiological contamination in surface and groundwaters in La Costa city (Canelones department, Uruguay)

In this paper the results of a geological risk study made during 2005 related to overflow and microbiological water contamination at Ciudad de la Costa City (Canelones department) are shown. This city has been showed a great urban growth for the last three decades. New hydrogeological studies looking forward the phreatic level and its bacteriological quality allow to know the level of the risk along 2005´s first semester. The top of the phreatic table in 40% of the studied area is below than 0.50 meter depth. The results of fourteen bacteriologic analyses in groundwater samples show extreme contamination values in faecal colliform, Pseudomona sp. and Aeruginosa content. Both surface drainage and beach water bacteriologic analyses did not show contamination values except those corresponding to Carrasco creek