Massachusetts is blessed with relatively abundant precipitation (an average of 45 inches each year) leading many residents to the erroneous belief that there’s plenty of “surplus” water available for human consumption at any time and for any purpose. Russ Cohen of the Mass. Department of Ecological Restoration clues us in to why our water resources can at times be insufficient to support our aquatic ecosystem, how human activities – both historically and today – adversely affected our river and stream systems, and what potential solutions are available to mitigate these impacts.  This event on Monday, March 21, the March meeting of The Garden Club of the Back Bay, is co-sponsored by the Arnold Arboretum of Harvard University, the Boston Junior League Garden Club, the New England Wild Flower Society, and the Wellesley College Friends of Horticulture.  Garden Club members will receive a written notice of this meeting, along with car pool information to the Wellesley College Botanic Garden, where the event will take place.  The meeting, however, is also open to the public for a small fee ($10 if a member of the Arnold Arboretum, NEWFS or WCFH, $15 if a non-member). Registration may be accomplished at http://www.wellesley.edu/WCFH.