Predicting Trigger Level for Ice Jam Flooding of the lower Mohawk River using LiDAR and GIS
Abstract
Ice jams are an annual occurrence along the Mohawk River in upstate New York. The jams commonly result in significant flooding especially when the progress of the ice is impeded by obstructions to the channel and flood plain. To minimize flooding hazards it is critical to know the trigger level of flooding so that we can better understand chronic jam points and simulate flooding events as jams occur as the lower Mohawk. A better understanding of jamming and trigger points may facilitate measures to reduce flooding and avoid the costly damage associated with these hazards. To determine the flood trigger level for one segment of the lower Mohawk we used Air-LiDAR elevation data to construct a digital elevation model to simulate a flooding event. The water flood simulation using a LiDAR elevation model allows accurate water level measurements for determining trigger levels of ice dam flooding. The study area comprises three sections of the lower Mohawk River from the (Before location) to the (After location), which are constrained by lock stations centered at the New York State Canal System Lock 9 (E9 Lock) and the B&M Rail Bridge at the Schenectady International (SI) Plant. This area is notorious for ice jams including one that resulted in a major flooding event on January 25th, 2010 which resulted in flood levels at 74.4 m in the upper portion of the second section of the study area (Lock 9) and at 73.4 m in the lower portion (SI plant). Minimum and maximum elevation levels were found to determine the values at which up stream water builds up and when flooding occurs. From these values, we are able to predict the flooding as the ice jam builds up and breaks as it progresses downstream. Similar methodology is applied to find the trigger points for flooding along other sections of the Mohawk River constrained by lock stations, and it may provide critical knowledge as to how to better manage the hazard of flooding due to ice jams.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H21F1185F
- Keywords:
-
- 1855 HYDROLOGY / Remote sensing