Herbert Hoover National Historic Site - Environmental Factors

Herbert Hoover National Historic Site by National Parks Service

Pioneers crossing Iowa found this land among the most difficult portions of their passage. Iowa's groundwater based hydrology resulted in a myriad of sloughs that stopped wagon wheels, as they penetrated the saturated soil to the hubs. Development of the land resulted in the loss of these wetlands in eastern Iowa. Small creeks cut into the soils where linear wetlands once stored rainwater and refreshed the ground water. This change in hydrology has impacted water quality and quantity.

Temperatures range broadly over the annum with -28oF and 108oF representing the extremes. The average growing season extends over 183 days from April through September. Average precipitation is 36 inches a year with about 60% occurring during the growing season. These extremes in temperature and moderate rainfall allow for lush growth of the prairie. Fire also maintains the prairie and savannas in Iowa by excluding shrubs and small trees.