Where does a raindrop go when it falls on the ground? It depends on where you live – more specifically, in which watershed. A watershed is an area of land in which all water drains to a common outlet, or a larger body of water such as a river or lake. Each drop of rain that falls within the watershed ends up in the same place. Try this simulation based on USGS data to find out where a raindrop will go after it hits the ground in your backyard.

In Ithaca, which is part of the Cayuga Lake Watershed, rainwater flows into Cayuga Lake and eventually makes its way to the Great Lakes. Water from surrounding areas mainly enters the lake at the south end and flows out to the north through the Seneca River, or the Cayuga-Seneca Canal. About half of the land in the watershed is used for farming, while 7% is developed. Natural areas make up the remainder of the land. Rain that falls within the watershed passes across the landscape on its way to Cayuga Lake.

As water flows across forests and fields and freeways, it picks up sediment and pollutants in its path and carries them to the lake. Eroded soil from farms and construction sites harms aquatic organisms by clouding the water. Soil also carries pollutants, including fertilizer from lawns and agricultural fields, that can end up in Cayuga Lake. An excess of nutrients in the lake can cause eutrophication or harmful algal blooms (HABs). The problems caused by runoff are made worse by impervious surfaces such as parking lots and roadways. These surfaces funnel stormwater into rivers and lakes without allowing it to drain into the ground.

It’s vitally important for our watershed, and any watershed for that matter, to be healthy. After rain water falls to earth, it should be able to pass through the soil and waterways without picking up pollutants and carrying them onward where plants, animals and humans might end up absorbing them.

You can help monitor Cayuga Lake’s health by joining us for a Lake Monitoring Cruise. On board, you might examine plankton under a microscope or sample sediment from under the lake. After you disembark from the MV Teal, you can continue to serve as a steward for Cayuga Lake and/or the watershed in which you live. Check out these Lake Friendly Living tips from our friends at the Cayuga Lake Watershed Network to learn how!