Few cities are as beautiful as Ithaca. At the southern tip of Cayuga Lake, it is built around the waterfalls of Fall Creek, with centrepiece Ithaca Falls tumbling 150ft over a chiselled rockface.

Hydrilla is an invasive aquatic plant that threatens lakes, rivers and streams. It grows rapidly to form choking green mats in water up to 30 feet deep, making boating, swimming or fishing in those ...