the effective integration of land and water management issues is hampered by the fact that although the province of venice has the administrative responsibility for residential and industrial development on much of the coast it does not control upstream land use which also affects water quality in the lagoon and in coastal waters and it does not control the main urban areas of the lagoon the responsibility of the municipalities in theory all plans are required to refer to the watershed plan but compliance with and interpretation of these plans is often weak sewage in the historic centre is untreated and flows directly into the lagoon which receives an organic and pathogen loading equivalent to a city of more than persons during the tourist season