The reason Evansville is so easily shaped is because of the underlying bedrock. Under the glacial sediments and alluvial deposits from the Ohio River are 300-million-year-old rock layers from the Pennsylvanian age. The first layer consists of sandstone, the second layer is limestone, and there is also a mix of shale and coal within these rocks.
These materials are considered to be relatively soft, meaning they are easily eroded by agents like wind and water, which will effortlessly shape the land, contributing to the hills and valleys we see today. This also allows the Ohio River to cut back land by eroding the banks and then depositing the eroded materials to create areas like point bars.
Although the glaciers didn't exactly reach Evansville, there are still long-lasting effects that the multiple glaciation periods had on the city's topography. The Illinoian glaciation period, which was around 132,000 years ago, was the glacier that reached the furthest, just north of Evansville. The Wisconsin glaciation was the most recent ice age, adding onto what the Illinoian ice age created. This period was about 100,000 to 75,000 years ago, and when these ice sheets started to recede 18,000 years ago, they deposited many tons of silt-sized particles that are easily blown by wind called loess. This material is a heavy contributor to Evansville's hills.
When glaciers start to melt, the meltwater that gets released can build up enough pressure to erode solid bedrock into new channels, which is how the Ohio River was created. During this process, the meltwater is also transporting even more sediment to form outwash plains and moraines. The river channel was most likely created during the Illinoian ice age, and then refined later by the Wisconsin ice age.
Loess is sediment primarily composed of silt-sized grains that is known to be extremely rich in minerals and nutrients, and the entire state of Indiana is completely blanketed in it. In some parts of Evansville, the loess layer is over 200 feet thick. If you've ever heard of Indiana being a part of "America's Breadbasket" or the "Corn Belt", you should know that loess is a major contributor to why we have those titles.
It is incredibly rich in nutrients needed for plant life, like potassium, calcium and phosphorus, because of the minerals that the glaciers erode, including quartz, feldspars and calcite. It also has a high porosity while staying soft, which creates a soil with high water retention that allows roots to easily push through.