Research on Scotia lake presented at Mohawk Watershed Symposium
Collins Lake in Scotia could hold the key to predicting future floods along the Mohawk River according to one professor.
Presentations were abundant during the daylong Mohawk Watershed Symposium at Union College in the Olin Center on Friday, March 18, but outside the auditorium there were various posters set up and one addressed studying core samples from Collins Lake, taken in 2000, which led to the discovery of a pattern of flooding in the area. Kaitlin Clark and Donald Rodbell from the Geology Department at Union College presented the research.
This is a very unusual lake sitting right on the floodplain of the Mohawk River, said Rodbell. `It is really one of the only lakes that’s got any antiquity that is right on the floodplain.`
The drainage basin of the Collins Lake is almost the same size as the lake, but sediment has accumulated in at high rate over the last 1,000 years. Within core samples from the lake, said Rodbell, there were massive, organic rich sediment. Due to the type of organic sediment found in samples, Rodbell believes density-driven undercurrents left the sediments during flooding.
`It provides a really good archive of Mohawk River flooding,` said Rodbell.
Core samples were approximately 7 metes long, which did go back around 1,000 years, said Rodbell, which allowed an extensive recording of flooding in the Mohawk to be studied. He pointed to the several light, whiter layers of the core samples and said each of the lighter portions represented a period of flooding,
`This is the longest time series that has probably ever been generated for the Mohawk for high discharge events,` said Rodbell. `Peaks that exceed the red line here suggest that the sediments is actually coming out of the Schoharie Valley and out of the Catskills, so we are trying to actually partition which of the sub basins of the Mohawk the sediment is coming out of.`
He added there are identifying characteristics of sediments from different locations to help determine where they are coming from, such as the `red beds` from the Catskills.
He said the core sample segments believed to be cause by flooding match up with region hurricane records.
`When we compare it with New England hurricane record we can see that a lot of these peaks line up either with New England or Mid-Atlantic hurricane coming up the coast and saturating up the Catskills,` said Rodbell.
Another area he said he needs to investigate are how ice jam records, which start around 1840, match up with the core samples to see if it matches up similarly to the hurricane records.
`Between ice jams and hurricanes, those are the things that tend to drive the Mohawk to flood,` said Rodbell. `We are trying to get a sense of the pulsing of flooding events and what they might be tied to.`
He said the ultimate goal is to be able to predict future flooding occurrences.
`If we can look back in time and understand what drives flooding in the last several centuries then we can turn it around and look forward and say what the long-term weather predictions like and what kind of weather patterns might get setup.`
The Mohawk River actually cut itself off at least 1,000 years ago to form the lake, said Rodbell, with the original lake actually being much smaller. What used to be a marshland to the east ended up adding to the lake.
`It is just a freak of nature that produced a basin there that then would only get sediment when the river flooded,` said Rodbell.
Since 1994 he had been exploring this study with college students for projects and assignments. Over time, he said, it becomes more and more clear what potential the lake could have for flooding study.“
