LAKE AND WETLAND CHANGES PRE AND POST I-90 CONSTRUCTION: AN ASSESSMENT OF THE EVOLUTION OF JUNIUS PONDS, NY FROM 1938 TO 2019

Pond and wetland water levels are critical for maintaining rich ecosystems, but they are commonly dissected by roadways that disrupt water flow and connectivity. The Junius Ponds Unique Area, NY, consists of fens and four ponds nested in kame deposits which support rare plant and animal species. The ecosystem relies on the stability of the wetlands and ponds to sustain habitat. I-90 and SR 318 dissect the system. Here, we construct a series of maps based on airphotos, satellite images and modern observations to investigate and quantify changes in pond and wetland drainage patterns and extent from 1938 to 2019. We pair this with down looking and side scan sonar imagery to establish a detailed bathymetry and map the transition from shore to deeper water enabling an assessment of the surfaces flooded by higher water levels. We examine water level changes pre and post I-90 construction. Preconstruction, the pond system relied on a large marsh filled drainage that drained Lowery Pond into Newton Pond. In 1957 I-90 was constructed in between the two ponds. During construction, two culverts were set which locked drainage pathways in place. Since this time, water levels in Lowery Pond immediately upstream of I-90 have varied but have generally been rising through time, causing the pond to expand shrinking wetland habitat. In 1938 Lowery Pond’s extent was 6100 m², post construction in 1963 the pond contracted to 5960 m², and 56 years later in 2019 Lowery Pond is at its largest extent 7130 m². These changes seem to be largely due to gradual infilling of culvert flow pathways and episodic beaver activity. Our mapping efforts are helping with Junius Ponds management and its future restoration. Our work serves as a model for understanding the evolution and management of this and many similar systems.