Background
The Ohio Department of Natural Resources has been investigating various locations in Ohio and assessing scenarios in which the aquatic invasive species, Silver carp and Bighead carp ("Asian carp"), could possibly migrate into the Lake Erie Basin from the Ohio River Basin via natural and man-made waterways in Ohio. Investigations are underway to determine what, if any, natural waterways adjacent to the Lake Erie Basin-Ohio River Basin divide have the potential for the headwaters from each basin to develop a cross-connection during flooding events.
Two areas on Ohio's historic canal systems have been identified as possible connection points for Asian carp: the Miami and Erie Canal in the western part of the state and; the Ohio and Erie Canal in the eastern Ohio. However, these potential connection points are currently considered very low risk for the possibility of Asian carp migration from the Ohio River Basin to the Lake Erie Basin for two reasons: there are no established populations of Silver or Bighead carp in Ohio waterways and; the potential routes for northern migration from the Ohio River via natural tributaries poses several impediments because of dams and locks systems on these connecting tributaries. The following provides information about these two areas.
Miami and Erie Canal
When construction was completed around 1845, the Miami and Erie Canal provided a waterway from Lake Erie to the Ohio River by way of the Great Miami River. Since the canal was largely abandoned at the turn of the twentieth century, much of this canal was disconnected, de-watered or filled in, but a few sections of the canal still remain. Generally speaking, Ohio River Basin waters could flow into the Lake Erie Basin either through Grand Lake St. Marys or through a section of the canal still connected to the Great Miami River located in the Village of Minster in Shelby County.
Grand Lake St. Marys
Grand Lake St. Marys, having been used as a reservoir for the Miami and Erie canal, is still connected to portions of the canal within the Lake Erie Basin as well as to the Wabash River system which is in the Ohio River Basin. Portions of the Wabash River in Indiana are known to have established populations of Asian carp far downstream of the lake. The lake itself lies in the Ohio River basin immediately south and west of the Lake Erie Basin-Ohio River Basin divide.
The dam that creates the lake and its spillway are located on Beaver Creek at the west end of the lake. Beaver Creek flows into the Wabash River about 10 miles downstream of the dam. However, it's highly unlikely that Asian carp could migrate further up the Wabash River to even enter Beaver Creek. The reason for this is Roush Dam, a 90-foot flood control dam near Huntington, Indiana which has no fish passage structure, making it a complete barrier to fish movement further upstream on the Wabash River. Additionally, only Bighead carp, not Silver carp that are more prone to jumping, have been found at the foot of Roush Dam, first in 2005 and then again in 2008.
While it's highly improbable that Asian carp could naturally migrate past the Roush Dam near Huntington, Indiana, it may be important to better understand the nature of the connection between Grand Lake St. Marys and Beaver Creek. The height difference between the spillway and the toe area under normal conditions is about 13 feet. Currently, the Federal Emergency Management Agency's flood risk maps indicate the 100-yr-flood elevation for the Beaver Creek at the spillway is about 9 feet below the spillway crest. In addition, the map also shows that the water elevation in the lake at the 100-yr-flood is about 2.3 feet above the spillway crest. As a result, there would be a difference more than 11 feet difference between the Beaver Creek and the lake level during the 100-yr-flood. If a large storm event (much greater than the 100-year flood) were to cause Beaver Creek to rise 10 feet or more, Asian carp could potentially jump into the lake.
Waters from Grand Lake St. Marys flow into the canal (Lake Erie Basin) through a gate outlet structure located on the east end of the lake. Water can also flow from the lake through a gated and screened 20-inch pipe to supply water to a fish hatchery (Lake Erie Basin), which then discharges into the canal. Waters from this canal flow into the St. Marys River and the Auglaize River, tributaries to the Maumee River, which eventually flows into Lake Erie.
If Asian carp ever became established in Grand Lake St. Marys, the fish would have to maneuver through the gated outlet structure on the east end of the lake to enter into the canal system. The physical separation between the lake and canal consists of a highway embankment (State Route 364) about 50 feet wide and approximately 10 feet high. Only during an extreme flood event (much greater than a 100-year event) could the two waters connect.
Canal System in the Village of Minster
The Miami and Erie canal was filled in and cut off from the rest of the canal in the Village of Minster, but watered sections still remain that connect to the Great Miami River watershed to the south and to the St. Marys River and Auglaize River to the north. The embankment across the canal is located about 30 yards north of SR 119 that locates on the north side of Minster. The embankment is approximately 30 feet wide and 4 feet high. It would take an extreme storm event in order for flood water to overtop the embankment and cross-connect with the canal north of the embankment.
Asian carp could potentially migrate to this point by way of the Ohio River to the Indiana-Ohio state border, up through the Great Miami River, up through Loramie Creek, and then into the canal to Minster. Along this route there are approximately fourteen dams of varying sizes that have a strong likelihood of impeding upstream migration of Asian carp. And then only during an extreme flood event, could the carp make its way into the Lake Erie Basin section of the canal.
Ohio and Erie Canal
Completion of the Ohio and Erie Canal in 1832 provided a waterway from Lake Erie to the Ohio River (by way of the Muskingum River and the Scioto River). Connections between the two basins exist in the Akron area at a gated outlet structure from Long Lake (Portage Lakes System, Ohio River Basin), which can release water into a feeder canal that is connected to Summit Lake (Ohio River Basin). Water from Summit Lake flows through Lock 1 which has both a principal and an emergency weir as well as a gated outlet structure that allows water to flow into the Little Cuyahoga River, a tributary of the Cuyahoga River, which flows into Lake Erie.
The gated outlet structures (flood gates) for Long Lake are located on the Tuscarawas River at the northeast end of the lake. The height difference between the spillway and the toe of the spillway, under normal conditions, is about 5 feet. During flood events at the flood gates' location, the water in the Tuscarawas River can rise to where there is about a one-foot elevation difference between the Long Lake pool level and the river. Water flows into the feeder canal from Long Lake through the control of two feeder gates. If carp were ever to become established in Long Lake, individual specimens would have the potential of maneuvering through the two feeder gates into the feeder canal.
Additionally, downstream of the spillway, the feeder canal (that is connected to Summit Lake to the north) and the Tuscarawas River lie parallel to each other for about 8 miles. They are separated by about 300 feet of land at the narrowest location and a canal embankment about 5 feet high.
If Asian carp were ever to migrate into the feeder canal, either through the feeder gates at Long Lake or by an extreme flood event that creates a pathway between the river and the feeder canal, the carp could migrate north through Summit Lake to the uncontrolled weirs and gated outlet structure at Lock 1, which discharges into the Little Cuyahoga River.
However, in order to reach this potential connection point on the Ohio and Erie Canal, Asian carp would have to migrate far enough upstream on the Ohio River and then enter into the Muskingum River around the City of Marietta, Washington County. The Muskingum River merges with the Tuscarawas River, and eventually connects to Long Lake. Along this route there are approximately 10 low head dams and a lock system.
Historically, the Ohio and Erie Canal System utilized a Scioto River route which at one time began at the City of Portsmouth, Scioto County, the most southern of the canal system, but this route had been permanently filled in. In fact, State Routes 23 and 104 were mostly built by filling the old canal prism.
Summary
Since Asian carp have been reported in the Wabash River and are prevalent in the lower portions of the Ohio River, Ohio Department of Natural Resources is closely monitoring the potential connection points in Ohio. Additionally, Ohio Department of Natural Resources is continuing to investigate other potential connections along the basin divide internally as well as actively participating in the inter-basin transfer study being conducted by the United States Army Corps of Engineers. As new or additional information about potential connection points in Ohio is gathered, mitigation efforts will be developed, prioritized and acted upon according to the risk factor they pose.