A new wave of upgrades at City Park’s Duck Lake is reinvigorating the oft-troubled, 5-acre site, including water filtration to fight rampant summer algae, new nesting structures to combat the bird poop that is weakening trees, and a long-overdue public art project that will transform the lake’s northeast border. “Since the pandemic, it’s been rediscovered,” said Georgia Garnsey, president of City Park Friends and Neighbors, a registered neighborhood organization.