Italy’s salty Po Delta hurting businesses

PORTO TOLLE, Italy — Drought and unusually hot weather have raised the salinity in Italy’s largest delta, where the mighty Po River feeds into the Adriatic Sea south of Venice, and it’s killing rice fields along with the shellfish that are a key ingredient in one of Italy’s culinary specialties: spaghetti with clams.

At least one-third of the stock of prized double-valve clams raised in the Po Delta have died off. Plants along the banks of the Po River are wilting as they drink in water from increasingly salty aquifers and secondary waterways have dried up, shrinking amphibians and birds’ wetland homes.

“It is evident that there is an entire system with an ecology that will have permanent problems,’’ said Giancarlo Mantovani, director of Po River Basin Authority. The ecosystem includes the Po Delta Park, which along with neighboring lands in Veneto form a reserve recognized by UNESCO for its biodiversity.

The amount of water entering the delta from the Po River is at an all-time low, hitting just 3,350 cubic feet a second, last month, due to drought conditions caused by a lack of wintertime snowpack and spring and summer rains. That is one-tenth of annual averages. It has been nearly two months since farmers have been able to tap the river water for agriculture.

The impact may be even more lasting, as saltwater is leaching inland distances never before recorded, and seeping into aquifers, underground layers of rock that can hold water.

And while deltas are by definition an area of exchange between fresh and salt water, the movement is becoming more and more one-directional: Inland penetration of saltwater has increased from just over a mile, in the 1960s and six miles, in the 1980s, to an astounding 24 miles, this year.

“The territory around the Po is three meters below sea level, therefore there is a continual flow of saline water that is going into the aquifers,’’ Mantovani said. “We are therefore not only creating an agricultural problem, a human problem, but also an environmental problem. ... This is a perfect storm.”