Queens Botanical Garden is located in a dip that is lower than the surrounding streets. Most of the garden is atop landfill, which in turn covers the former Kissena Creek. As a result, water tends to flow downward from nearby areas toward the garden, and sinkholes previously tended to form inside the Queens Botanical Garden. Because of these qualities, "The New York Times" called the site, "hydrologically speaking ... a drainage ditch". The 2001 master plan called for redesigning the garden around the dip, and included five "systems" with a total of 27 water features. As part of the master plan, a "cleansing biotope" was built across the northern side of the Queens Botanical Garden.