The archaeological record varies with the fluvial style and sedimentation of a river, thus controlling the location, preservation, and recognition of archaeological sites. This project identifies archaeological site patterning and preservation along a fluvial system in Iowa that has been relatively stable since the last glaciation. The Upper Des Moines River in Iowa formed approximately 12,500 yr. cal BP as an englacial channel routing glacial meltwater south along the Des Moines Lobe. During the last glacial retreat, the channel incised forming what is now called the High Terrace (TH). Early post-glacial occupations in Iowa would have had access to this the high terrace and uplands. Thus, the Paleoindian and early to middle Archaic site distributions along the Upper Des Moines River are found in upland and upper terrace locations. The intermediate terrace (TI) formed between 4000 and 1000 yr. cal BP and represents the elevation of the river flood plain during this period. Late Archaic people had access to this surface as well as the TH and uplands. By 1000 yr. cal BP, the Upper Des Moines River had eroded down to bedrock and established a floodplain at the level of the lower terrace. Subsequent erosion produced the modern channel configuration with an established series of dated terraces (High Terrace (TH), Intermediate Terrace (TI), and Low Terrace (TL)). The Woodland period peoples would have had access to the current/modern fluvial landscape. To assess site locations strategies of populations that inhabited the Upper Des Moines River valley in the Holocene, 721 archaeological sites were examined and classified using site reports and artifacts as Paleoindian, Archaic, Woodland, Historic and Unknown. The sites were then mapped and associated with geomorphic features in the valley. As expected, Paleoindian sites and Early to Middle Archaic sites were all located on the upper terrace and uplands because the intermediate and lower terraces had not yet formed. Late Archaic people had access to the floodplain that formed intermediate terrace as well as the uplands and upper terrace. Woodland period sites occurred on high (upland and TH), intermediate (TI), and low (TL and floodplain) elevation landforms along the river. The study demonstrated there was a preference for burials/ceremonial sites being placed at higher elevations (TI and higher) and habitation sites being placed at lower elevations (TL and current floodplain) near the main river channel.

A Fremont site distribution model for the Grand Staircase-Escalante National Monument during the period A.D. 500—1050/1100 posits that the Fremont subsistence strategy (seasonal mobility with dependence on both agriculture and hunting/foraging) is reflected by a site pattern of low-investment, seasonal or short-term habitation sites and isolated storage facilities at "lowland" elevations, and high-investment, long-term residence sites at "upland" elevations (McFadden 1998, 2000). This research assesses the model to evaluate its general precision, looking particularly at its success in modeling site locations for long-term residential versus seasonal/short-term habitation sites. A database including more than 400 Fremont sites was created to evaluate the model. Data variables examined in this thesis included elevation, distance-to-water, and primary landform. Analysis of the elevation data demonstrates that the McFadden model does not fit the actual distribution of Fremont sites identified from survey. Further analysis also established that distance-to-water is not an effective variable in accurately modeling Fremont site patterning over this region. The association between functional site types and primary landforms, however, does appear to more accurately reflect site distribution as observed on the ground. Based on these results, a new model for Fremont site distribution in the upper Escalante River drainage is proposed.