Abstract The 2005 removal of the 3.6-m-high Munroe Falls Dam from the middle Cuyahoga River, Ohio, provided an opportunity to assess dam removal channel-evolution models and to anticipate impacts from additional dam removals on the Cuyahoga River. Preremoval geomorphic and sedimentologic conditions were characterized. Monitoring of the river response to dam removal has continued for 5 yr. The dam removal lowered base level and increased flow velocity upstream of the former dam site. Postremoval, the initial channel response was rapid incision to the predam substrate, followed by rapid lateral erosion of the exposed impoundment fill. Four to nine months after removal, dewatering and vegetation of the exposed impoundment fill greatly reduced the rate of lateral erosion. For 2.5 yr post -removal, sandy bar forms were present upstream of the former dam, and sand was transported under all flow conditions of the year. Subsequently, the bed has become armored with gravel. Downstream of the former dam site, the channel aggraded with sand, causing flow to occupy meander bend chutes that had formerly only been active during high flow. A sandy deltaic feature has accumulated 3.3 km downstream in the impoundment created by the Le Fever Dam. The impacts of the Munroe Falls Dam removal are generally well described by published channel-evolution models with minor exceptions due to local geology and hydrology. The similarities between the Munroe Falls and Le Fever Dam impoundments suggest that this study can aid in understanding the impacts of the possible future removal of the Le Fever Dam.

The Bradtville drift, the Canning till, and their correlatives in southwestern Ontario have been previously thought to be early Wisconsinan in age. Here another alternative is offered, whereby the Bradtville drift is assigned to the Illinoian stage, the lowermost Member A of the overlying Tyrconnell Formation to the late Sangamonian; Eowisconsinan, or the earliest part of early Wisconsinan, and its Member B to the early Wisconsinan substage. The age of the Canning till is still unknown. Member A of the Tyrconnell Formation is an accretion gley that formed about 20 m below the present level of Lake Erie, thus requiring a low outlet for the Erie basin. At that time, the Erie basin was drained probably by the buried Erigan channel, which extends about 50 m below the present level of Lake Erie. Member B of the Tyrconnell Formation is varved glaciolacustrine silt and clay, the deposition of which required a rise of lake level above the present one. This rise could have been caused by the Ontario lobe overriding the Niagara peninsula, possibly as far as Gowanda, New York; however, the ice margin remained in the eastern part of Lake Erie. The above hypothesis is supported by available lithologic and paleoecologic data from the region adjoining the north-central and eastern part of Lake Erie, but supporting numerical age determinations beyond the range of radiocarbon dating are still lacking.

Abstract The New York bluffs of Lake Erie, which stretch northeastward 100 km from the Pennsylvania border, and those of Lake Ontario, which extend eastward 212 km from the Niagara River along the south shore of the lake, expose one of the most continuous sets of glacial drift in the northeast. The Erie bluffs are predominantly Devonian shale. However, the shale is mantled by sandy-silt till remarkable for its lateral uniformity in texture, but with distinct “down-ice” trends in lithologic properties relating to the regional bedrock or glacial reworking. Proglacial lacustrine silt, clay, and sand, deposited in 90 to 50 m of water in glacial Lakes Whittlesey and Warren between 13.5 and 12 ka, overlie the till. The bluffs of Lake Ontario are cut only sparingly in Ordovician red sandstone and shale and expose three major lithostratigraphic units. A lower red or pink sandy-till sheet is overlain by widespread gray and red glaciolacusrrine silt and clay. These fines provide major input to a younger, sillier, purplish-gray or gray till marked by both massive basal facies and upper subaqueous-flow or basal melt-out diamicton. A blanketing glaciolacustrine sequence occurring in the lower, nondrumlin areas is largely related to glacial Lake Iroquois. Locally, proglacial sands, lenses of flow till, or stone concentrations indicate a short readvance during lake formation. The two major tills of the Lake Ontario bluffs correlate with a similar sequence in adjacent Ontario, Canada. These, in turn, are tied to the Halton Till of the Port Huron advance. The lower till sheet of the United States Erie shore is related to a preceding advance, which is tentatively identified as the Lake Escarpment glaciation, and the Wentworth Till of nearby Canada.