Abstract:
Snake Creek Embankment is located 8 miles northeast of Riverdale, North Dakota and forms a large subimpoundment
(Lake Audubon) to the Garrison Reservoir. The embankment supports a major highway,
power transmission line, and railroad. The Bureau of Reclamation owns and operates a pumping plant to
maintain the water level in Lake Audubon for the diversion of water from Garrison Reservoir to the eastern
side of North Dakota, but the Lake is also heavily for wildlife conservation and recreation purposes. The
embankment was constructed by the US Army Corps of Engineers (USACE) in conjunction with Garrison
Dam and extends over 2-1/2 miles and rises as much as 85 feet above the valley floor. The project is
situated on complex glacial geology associated with terminal moraines. A severe drought between 2001-
2008 resulted in the decline of Garrison reservoir to unprecedented low levels, creating adverse
underseepage conditions that required timely mitigation to avoid potential adverse impacts to the structural
integrity of the embankment.

Speaker:
• David Sobczyk, P.E. is currently the Operations Project Manager for the USACE Missouri River Project
Office. From 2002-2015, Mr. Sobczyk worked as a Geotechnical Engineer in USACE and served as the
Omaha District Dam Safety Program Manager where he was heavily involved in various designs &
evaluations for the 28 high hazard Dams within the Omaha District, including the 6 massive dams that
comprise the Missouri River main stem system. Dave graduated from the University of Nebraska – Lincoln
with a degree in Civil Engineering in 1993, and worked as a geotechnical/materials engineer in private
consulting prior to joining USACE in 2002. Dave is married to his wife of 25 years, Jolene, and has four
children (Sam, Bailee, Makena, and Sonny).

• Ryan Leigh, P.E. is a Dam Safety Engineer within the recently formed Dam Safety Production Center in
USACE Omaha District. Ryan began his flood-fighting career as an intern for Kiewit during the 2011
Missouri River flood, helping manage flood risks at Omaha’s Eppley Airfield. After completing degrees in
civil and geotechnical engineering at the University of Illinois, he moved to Omaha to work for the US
Army Corps of Engineers. With the Corps he has enjoyed dam and levee safety work, which includes
inspection, design, construction, and flood-fighting from Omaha to Colorado and the US Virgin Islands.
Ryan and his wife Katie enjoy gardening and taking care of their pet dog Schefield.