Joining an unlikely coalition of construction executives, union officials and conservationists, a group of local municipal officials and state lawmakers gathered yesterday at Hommocks Conservation area in Mamaroneck to focus attention on the critically needed clean water infrastructure projects in Mamaroneck, New Rochelle and surrounding communities. "Projects discussed not only included needed upgrades to wastewater and drinking water facilities, but the very underground infrastructure of pipes and culverts that are currently crumbling beneath our feet," said Nancy Seligson, Supervisor of the Town of Mamaroneck.