Monday, May 16, 2022

Agnes’s Impact on the Northern Tier of Pennsylvania

Recent weather conditions in the South-Central Region of Pennsylvania were reminiscent of the seemingly endless rain of Tropical Storm Agnes, but Agnes was a steady deluge that swelled streams and rivers over their banks. The difference is obvious in that we experienced approximately 4 inches of rain this past weekend as opposed to 12, 14 and upwards of 19 inches from Agnes.  As we continue our series of blogs focused on the impact on cultural resources due to flooding from the storm, our area of focus this week is North Central PA and the Southern tier of New York around Chemung and Elmira, NY. 

Major River Basins, Tioga River Valley circled

Tioga County is in the Glaciated High Plateau, Glaciated Low Plateau and Deep Valleys Sections of the Appalachian Plateau Province. These physiographic landforms are characterized by eroded hills and generally narrow, steep sided valleys.  The major streams are the Cowanesque and Tioga Rivers that form the major waterways of the Chemung and the Susquehanna’s North Branch drainage. Pennsylvanian, Mississippian, and Devonian rocks constitute the geological makeup of Tioga County and originally these rocks were a part of the vast sea sediments that formed some 290-405 million years ago. 

The Cowanesque River is a major west-east drainage in northern Tioga County. It is a tributary of the Tioga River, which flows north to join the Chemung in New York state. The Chemung then curves to flow south to join the North Branch of the Susquehanna River. The Cowanesque River basin lies in both Pennsylvania and New York, draining an area of 772 km^ (298 mi^). The headwaters of the Cowanesque River are in the Allegheny High Plateau section located west of Tioga County, in north central Potter County. From there, the river flows approximately 61 km (38 mi) east to join the north-flowing Tioga River at Lawrenceville.

This environment creates an ideal setting for flood waters to inundate the small streams and tributaries that feed these larger waterways, leading to major flooding in the region during increased precipitation. Spring ice jams, snow thaws and heavy thunderstorms had contributed to previous catastrophic storms in 1889, 1935 and 1946 to name a few. The Army Corp of Engineers authorized the construction of a flood control project to in July 1958 to alleviate flooding. However, construction did not begin until after Agnes struck her heavy blow.  

 Location of Project Area (Goodwin 1990)

In preparation for construction, several surveys were initiated by the National Park Service and the Army Corp. to review the potential impact on cultural resources.  The project involved the construction of two dams, the Tioga-Hammond Lake, and the Cowanesque Dam- see map above. Archaeological surveys by Dr. Jacob Gruber of Temple University recorded new sites and revisited sites previously surveyed by John Witthoft of the Pennsylvania Historical Commission (now the PHMC). Impact areas were identified and plans for recovery or preservation of these resources were developed. The small village of Nelson, including the Presbyterian Church and cemetery, was moved to higher ground above the Cowanesque Flood plain.  Prior to the move, local residents were surveyed for their opinion on relocating and their oral histories documented. Today, the village is perched on a hillside overlooking the dam. 

Beecher's Island Presbyterian Church, Nelson. PA-SHPO, PHMC, PA-SHARE

Archaeological sites recorded through these efforts were scant. In fact, Gruber reported that the flooding in 1946 had obliterated any evidence of precontact human occupation in the Tioga River Valley or in the adjacent Crooked Creek Valley. “I must conclude, therefore, that these areas were not subject to prehistoric settlement.”  Although John Witthoft had recorded a site (36TI0001) at the confluence of the Tioga River and Crooked Cree. Local collectors were also aware of the site and shared their collections with Dr. Gruber. Gruber noted the presence of soapstone (steatite), bannerstone, and many points (projectile points), but did not consider this as significant information.  

Onondaga chert points (36TI0001). The State Museum of Pennsylvania

Late Woodland Pottery (36TI0001). The State Museum of Pennsylvania

Dr. Gruber’s survey identified potential sites in the Cowanesque Valley, the Antonio site(36TI0030) received preliminary salvage archaeology during the summers of 1966 and 1967 by Temple students as reported by Daniel Crozier. The site was assigned to the Early Woodland to Late Woodland culture periods based on ceramics, stone tools and projectile points recovered. Storage pits were identified, a hearth feature and an undetermined activity area. Crozier recommended the Army Corp. purchase the site in 1973 to allow for extensive archaeology, unfortunately no additional archaeology was undertaken at this site.  

Stone Tools - net sinker, bipitted processing stones(36TI0001). The State Museum of Pennsylvania

The construction of the dams and subsequent expansion of the capacity of the Cowanesque Dam led to the discovery of additional sites and an opportunity to expand our knowledge of the region.  Of the six sites recorded, three of the buried floodplain sites (36Ti33, 36Ti34, and 36Ti37), appeared capable of documenting the transition from the hunting-gathering late Middle Woodland to the horticultural early Late Woodland and were identified for further investigation. 
Archaeological reports for north central Pennsylvania report precontact traditions as evolutionary and typologically comparable to the Archaic and Woodland cultural periods. The periods represented by the components at these sites, which date ca. A.D. 160 (second prehistoric component at 36Ti34) to ca. A.D. 1200 (36Ti37), span a time of important cultural change in eastern North America corresponding to the appearance of maize horticulture in the Northeast. The shift from a somewhat mobile, hunting-gathering oriented late Middle Woodland peoples to maize using, more sedentary early Late Woodland peoples is a major culture change and an interesting research topic for archaeologists. Data from these floodplain sites were thought to be relevant to questions about the development of horticulture as an activity associated with spring fishing camps, thus suggesting an explanation for why maize horticulture spread so quickly among otherwise non-horticultural, forest dwelling peoples. 

Archaeologists recovered ceramics, tree-nut remains and a fragment of a maize cob. Nuts identified included hickory, oak acorn, and hazelnut.  Seeds identified were chenopodium, seed of tick-clover {Desmodium spp.), a wild legume (Fabaceae) cotyledon fragment, a possible ash samara kernel, a hawthorn {Crataegus spp.) nutlet fragment. Among these, it is possible that only the hawthorn nutlet represents a food remain. Unfortunately, poor preservation of bone limited the recovery of dietary remains to those recovered through floatation. Calcined bone fragments were too small to identify. Plowing activities had disturbed features and mixed the artifacts associated with them across the landscape (Goodwin 1990). 

Excavations at 36Ti34 also exposed the remains of a burned log cabin, dated between A.D. 1790 to 1830. The historic component was represented by the charred, virtually intact floor of the cabin, several pit and trough features, and by a large and varied array of historic artifacts. 

The impact of Tropical Storm Agnes on communities in the Cowanesque and Tioga River Valley was catastrophic, but the damage there paled in comparison to the havoc incurred when the waters of the Tioga River merged with the Chemung near Corning, New York.  We will continue our series on Agnes in a few weeks when we trace the impact of the Chemung River as it flows back into Pennsylvania in Bradford County. 

The Army Corp of Engineers estimates that these flood control projects, the Cowanesque and Tioga-Hammond Lakes, the potential for downstream flooding and related damages will be significantly reduced.  It is estimated that, the two projects would have prevented an estimated $360 million in damage during Tropical Storm Agnes. Of this total, Cowanesque Lake alone would have prevented about $142.8 million in damage along the Cowanesque, Tioga, Chemung, and Susquehanna Rivers between Lawrenceville and Sunbury (all values given in 1972 dollars and for 1972 conditions).

The impact of flooding and soil erosion continues to harm archaeological sites and identifying their location and providing protection to these cultural resources is important in preserving our past for future generations. Please support these efforts and record known archaeological sites in the Pennsylvania Historical and Museum Commissions reporting system, PA-SHARE.  


Crozier, Daniel A.
1972   Preliminary Archaeological Salvage Operations in a Portion of the Cowanesque Dam Flood Control Project: The Antonio Site 36Ti30. Report submitted to U.S. Department of Interior, National Park Service, Northeast Region.

Gruber, J.W.
1965     An Archaeological Survey of Some Dam Areas in Berks, Carbon, Tioga, and Centre Counties, Pennsylvania. Report submitted to the U.S. Department of interior, National Park Service, Northeast Region.

Gruber, J.W.
1966     An Archaeological Survey at Certain Reservoir Areas in Pennsylvania. Report  submitted to the U.S. Department of Interior, National Park Service, Northeast Region.

Hay, C.A., C. Stevenson
1984    Phase III Archeological Data Recovery From 36Ti33, 36Ti34, And 36Ti37,   Cowanesque Lake Reformulation Project, Tioga County, Pennsylvania.
Baltimore: U.S. Army Corps of Engineers, Baltimore District.

Neumann, Thomas W. , Neal H. Lopinot, Leslie D. McFaden, R. Christopher Goodwin, and Jennifer Cohen
1990    PHASE III Archeological Data Recovery From 36Ti33, 36Ti34, And 36Ti37,    Cowanesque Lake Reformulation Project, Tioga County, Pennsylvania. 
Baltimore: U.S. Army Corps of Engineers, Baltimore District.

For more information, visit or the Hall of Anthropology and Archaeology at The State Museum of Pennsylvania .

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