Groundbreaking begins Thursday morning on a multi-year, countywide program to provide sewer service to Miami-Dade residents with septic tank systems. Mayor Daniella Levine Cava says as sea-level rise increases, septic tanks begin to fail wreaking havoc for residents and the environment, especially Biscayne Bay. There are about 120-thousand septic tanks in the county, the project will begin with converting 9-thousand in the most flood-prone areas. State and federal funds will help cover the cost-projected to be more than 4-billion-dollars.