2017 Spencer Comprehensive Land Use Plan

Spencer, Iowa  2017  Comprehensive Plan

is covered with later glacial deposits from an early Wisconsin glacial advance. The entire region was then subjected to vigorous erosion activity that accompanied the later advance of the Wisconsin ice sheet. As a result, features of a freshly glaciated landscape were lost as a well- established branching network of streams formed over the entire region. The deeper thickness of the loess mantle, the overall elevation of the land surface, and the present precipitation and vegetation distinguish the Northwest Iowa Plains from the state’s other landforms.” The Des Moines Lobe Landform “Has a landscape that is gently rolling with abundant moraines, shallow wetland basins or potholes, and a few relatively deep natural lakes. This landform still retains the imprints of recent glacial occupation. Loess is entirely absent. The most prominent landform patterns left by the Wisconsin glacier on the Des Moines Lobe are the end moraines. The Des Moines Lobe is part of the Prairie Pothole Region that extends north and west into western Minnesota, eastern North and South Dakota, and the Canadian Prairie Provinces. Most of the potholes have been drained with ditching and underground tile lines to make way for agriculture. Agriculture was also responsible for greatly increasing the rate at which streams and drainage patterns developed in this geologically young landform.”

Figure 5 -

Landform Regions Map of Iowa

SOILS Soil conditions determine several important land use decisions when planning for future growth and development. Where community and economic growth occurs on a balanced and fragile ecosystem, the types of soils and their suitability or lack thereof to development becomes of significant importance. Factors such as building suitability, percolation rate, productivity, and slope are all important in determining future growth patterns. These factors all have various effects on placement of utilities, recreation areas, transportation networks, sewer treatment facilities, residential development, industrial development, commercial development, and agricultural usage.

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NW Iowa Planning & Development