Village the stream cuts through the Alps region (a steep sided valley cut through the Onondaga Escarpment) and experiences a drop in temperature as ground water influx increases. Dissolved oxygen levels increase moving northward while pH levels remain constant. This section is indicative of a typical limestone-based freestone stream. Watershed Overall, the Nine Mile Creek watershed covers and includes portions of ten towns within Onondaga County and two towns in Cortland County. Nine Mile Creek is the major tributary of Onondaga Lake, comprising almost 50% of the catchment area of the Lake. Geology The contemporary landscape of central New York is primarily a result of glacial activity between one million and ten thousand years ago. The last glacier to recede (starting about 19,000 years ago and leaving New York entirely approximately 11,000 years ago) deposited the Valley Heads Moraine, a prominent geological feature that separates the St. Lawrence watershed from the Susquehanna watershed. Before the deposition of the Valley Heads Moraine, glaciers had deepened the many north-south oriented valleys that characterize the region. These valleys originally were streams that flowed to the south. The moraine formed a series of lakes in the valleys. Drainage was still to the south over the moraine until the glacier retreated far enough to the north to allow escape of the waters along the southern edge of the glacier. At an elevation of about 900 feet, the glacial lakes filling the finger lakes valleys joined to form an interlocking system of lakes to the west (glacial Lake Warren ). At first Lake Warren continued to drain to the west, but as the ice retreated west of Rome, New York, flow shifted to the east into the Mohawk-Hudson River system. As the ice continued to retreat, a series of east-west channels were cut by the easterly flowing glacial meltwater. According to Fairchild, the westernmost of these was the gully that runs from near Mud Pond about 4 miles north-northeast of Skaneateles and 4 miles north-northwest of Marcellus and empties into Nine Mile Creek 2 miles south of the Village of Marcellus. The water was impounded in the Otisco Valley (glacial Lake Marcellus), and the delta formed where debris carried by this meltwater stream was deposited as it entered the lake can be easily seen on topographic maps. The meltwater soon continued draining to the east, carving the channel now known as Pumpkin Hollow that leads east