Archaeological Research Reveals Past Clarity of the Little Miami River
Posted On: 03/09/2018 - 11:16am, Posted By: Bob Genheimer, Curator of Archaeology
Since 2008, the Cincinnati Museum Center has conducted a summer field school at an archaeological site in Hamilton County, Ohio. The location, known as the Hahn Site, rests on a glacial outwash terrace east of Newtown in the Little Miami Valley. Recovered cultural artifacts and radiocarbon dating demonstrate that the site supported prehistoric villages during portions of the Middle (ca. AD 1300-1400) and Late Fort Ancient (ca. AD 1400-1650 periods.
Excavations of trash-filled storage pits at the site have found large amounts of flint, ceramics, animal bones, and freshwater mussel shells or bivalves. The latter are the remains of animals collected from the nearby Little Miami River and consumed by village inhabitants. The mussel shells constitute approximately 10% of the total site debris by count and by weight.
This mussel horizon at Feature 37 contained nearly 3000 bivalves identifiable to the species level.
While mussel shells are ubiquitous throughout Hahn site deposits, occasionally, large numbers are recovered from single deposits representing a unique harvesting episode. Such was the case at a pair of Late Fort Ancient pit features (Features 37 and 159) where thousands of paired valves were exposed (Figures 1 and 2). Through use of the museum’s extensive comparative mussel collection (Figure 3), a total of 26 species were identified from the two pits. The range in size (very small to very large) of the harvested specimens indicates that little selection was undertaken at the river collecting locales. Interestingly, because 65% of the identified 9,582 shells belong to species known to be sensitive to river turbidity and sedimentation, the Little Miami is thought to have carried little silt during the Late Fort Ancient period. The clarity of the stream continued into the eighteenth century when French explorers described the Little Miami as a river with colorless water.
The margins of a large mussel horizon are visible in this profile view of Feature 159.
Historical records show that an increase in the Little Miami River’s silt load began in the nineteenth century due to agriculture, gravel mining, and construction activities in its watershed. Today, erosion silt continues to be a major habitat feature of the river. The effects of the siltation are evident in recent (1990-91 and 2006-07) bivalve sampling of the river. Only 14 mussel species (dead or alive) are presently confirmed for the lower portion of the stream. Of particular interest, today, only a mere 2% of the mussels living within 2.5 miles of the Hahn Site belong to species sensitive to turbidity and sedimentation. In effect, the vast majority of species that had been discarded into the pit features some 400 to 500 years ago have been extirpated from the stream. Only the adoption of effective soil erosion control methods will allow the return of the native mussel fauna to the Little Miami River.
Portion of comparative bivalve collection in the Zoology Department.
But, while the Little Miami River may have been a much cleaner stream during the 14th through 17th centuries, it does not mean that Native Americans did not impact mussel populations. Mussels are not particularly high in food energy, and hence large numbers were collected to maximize the relatively minor quantities of soft tissue available in an individual bivalve. As a result, continued harvesting of mussels at the same locations may have overtaxed the bivalve populations, and may have resulted in periods of decline or unsuitably low numbers during the end of the prehistoric period.
For more detailed information on the bivalve identifications from the Hahn, click here.