Agenda - Parks and Recreation Commission - 04/08/2021

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that reside there. This section discusses how these forces have impacted the present day composition of natural communities and the landscape in Rivers' Bend Park. Natural History Bedrock Geology and Glacial Landscapes "The majority of the region is mantled by debris left by glaciers and glacial rivers; beneath this, the bedrock that is closest to the surface in Ramsey is of the Cambrian System, which is some 500-600 million years old." This includes Cambrian and Ordovician dolomite, sandstone, and shale.' "The topography of the area was most heavily influenced by the last period of glaciation which ended in east -central Minnesota about 10,000 years ago. During this event, glaciers sculpted the landscape and left behind a variety of deposits, including drift/till and outwash composed of sand and gravel, and windblown deposits of very fine sands. During the last glaciation, the Superior Lobe ice sheet advanced into the region from the east, and finally retreated about 20,000 years ago. With each advance and retreat, the melting ice sheet deposited immense piles of sand and gravel along its margins, and massive rivers of glacial meltwater carried additional sand and sediment across the area. These riverine, or fluvial, deposits cover much of the city and resulted in the Anoka Sand Plain. Direct glacial modification of the landscape, such as the deposition of till and moraine, and the influence of periglacial processes such as outwash, have formed the vast majority of the landforms in this region. Most of the deposited materials associated directly with glaciers, such as till and moraine are unsorted. These consist of mixed materials, which range in size from clay and fine sand to large boulders. Overall, the materials deposited in the City tend to form well - drained to very well -drained landscapes with sands and gravels common."4 Specifically, the majority of Rivers' Bend Park's soils are sandy in nature. Vegetation at the Time of Settlement According to the original land survey notes (compiled in Minnesota between 1850's and 1900's), the presettlement vegetation of [Rivers' Bend Park] was an area of riverbottom or floodplain forest along the Rum River surrounded mostly by oak openings and barrens, but also bordering prairie to the southeast. Original species included elm, ash, cottonwood, boxelder, silver maple, willow, aspen, and hackberry.4'$ Influence of Humans on the Landscape Ideas about the history of Native Americans and their influence on the local landscape are still evolving. Native Americans have probably inhabited and hunted in the area for over 10,000 years. The impacts of Native Americans on the land were caused by their use of a wide variety of plants and animals for food, altering vegetation patterns for cultivation and by setting fire to broad expanses of landscape. Native Americans (and European fur traders) used fire to hunt game; create desired habitat; clear the landscape for travel, communication and defense; and obtain firewood. While some fires in the region would have occurred naturally, the activities of Native Americans undoubtedly accounted for the vast majority of fires. Prairies, savannas, and oak forests are fire -dependent plant communities, and would most likely not have been present in the Twin Cities Area at the time of European settlement without these fires.4 4