Before a packed crowd at the Friends’ annual meeting on April 29, Adam Bosch, a spokesman for the New York City DEP and a natural storyteller, gave a fascinating overview of the city’s water supply, with an up-close look at a huge repair project now underway: tunneling, yet again, under the Hudson to create a bypass so that a leaky tunnel can be closed off. His vivid presentation offered many memorable images, especially of the giant space-age machines boring that tunnel.