Watershed Conservation Plan - Destination Erie

Lake Erie, whose watershed includes the study area for this planning document (see below), has the
smallest volume of any of the Great Lakes, measuring about 484 km 3 (116 mi 3 ) and covering an area of about
25,700 km 2 (9,922 mi 2 ) or about 10.5% of the Great Lakes water surface. The land area that drains into Lake
Erie, herein defined as its watershed, covers about 78,000 km 2 (30,115 mi 2 ) or about 15% of the entire Great
Lakes watershed's land drainage area. Lake Erie is also clearly the shallowest of the Great Lakes, with a
maximum depth of 64 m (210 ft) and a mean depth of 19 m (62 ft) or roughly a quarter of the mean depth of
79.2 m (239.1 ft) for all five Great Lakes.
Because of its relatively small size, Lake Erie is considered by the EPA to have suffered the greatest
exposure to the effects of urbanization and agriculture (United States Environmental Protection Agency
[EPA] 2005). Specifically, the watershed's generally fertile—and, hence, intensively farmed—soils contribute
very large amounts of agricultural runoff (i.e., nonpoint source water pollution, including herbicides,
fungicides, insecticides, as well as the nitrate and phosphate components of fertilizers and animal wastes) to
the lake itself. The impacts from agriculture—combined with the industrial, commercial, and municipal
impacts from the Lake Erie basin's 17 metropolitan areas with populations over 50,000—have led to alarming
levels of pollution, habitat loss, and infiltration by exotic plant and animal species, to name just a few of the
more prominent problems.
Although Lake Erie covers about 26,000 km 2 (10,000 mi 2 ), its average depth is only about 19 m (62 ft),
making it the shallowest of the five Great Lakes. Due to its small size, the lake warms rapidly in the spring
and summer, frequently freezes over in winter, and has the shortest retention time (2.6 years) of any of the
Great Lakes. Lake Erie's western basin, comprising about one-fifth of the lake's surface, is very shallow with
an mean depth of 7.4 m (24 ft) and a maximum depth of 19 m (62 ft) (USEPA 2005).
2.2 The Natural State of the Pennsylvania Lake Erie Watershed
2.2.1 Location and Description
Pennsylvania's Lake Erie watershed is located in northwestern Pennsylvania on the southern shore of
Lake Erie between Ohio on the west and New York State on the east (Figure 2.2). The watershed extends a
minimum of 9.8 km (6.1 mi) and a maximum of 40.2 km (25 mi) south of Lake Erie, encompassing portions
of two counties and either portions or the full extent of 33 municipalities and townships (Figure 2.3). The land
drainage area of Pennsylvania's Lake Erie watershed (hereafter referred to as the study area) covers ca. 1,315
km 2 (508 mi 2 ), or about 1.7% and 0.2% of the total land drainage areas of the Lake Erie watershed and Great
Lakes basin, respectively. The study area is composed 19 major subwatersheds (which are listed and
described in Table 2.1), 66 discrete subwatersheds, 39 named streams, and 1,338 discrete mapped stream
segments. The largest of the study area's major subwatershed are situated in its western reaches. The mean
elevation of Lake Erie is 174.3 m (572 ft) above mean sea level (msl).
2.2.2 Physiography
The study area is roughly bisected by portions of two physiographic provinces, the Eastern Lake section
of the Central Lowland physiographic province in the north and the Glaciated Pittsburgh Plateau section of
the Appalachian Plateaus physiographic province in the south (Figure 2.4). The former is a relatively narrow,
southwest-northeast-trending zone that covers ca. 567.2 km 2 (219 mi 2 ) and roughly follows the southern shore
of Lake Erie, widening slightly as it trends west. The latter is a similarly southwest-northeast-trending zone
that covers ca. 747 km 2 (288.7 mi 2 ); it is composed of rolling land that is of notably higher elevation than the
coastal lowland. A transitional, narrow strip of sometimes steeply sloping land called the Escarpment Slope
marks the division between the two provinces.
The Eastern Lake section borders the lake and extends south for a distance of 3.2–16.4 km (2–5 mi). Its
elevation starts slightly above the lake level and extends upland to ca. 245 m (800 ft) above msl. This lake
plain terminates along the lake edge as a cliff that rises locally in excess of 24.5 m (80 ft) above lake level,
the highest portions being near the town of North East (in the eastern portion of the study area) and northwest
of Girard (in the western portion of the study area). The cliff face exposes glacial drift (mostly till) over most
of its length, and bedrock at its base in many areas (Tomikel and Shepps 1967).
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