Bedrock Geologic Map of Iowa, 1998

Geologic map of Iowa in 1998

Bedrock Aquifers of Iowa, 2004

Bedrock Aquifers of Iowa in 2004

Healthy Iowans 2010 Mid-Course Revision, July 2005

In the past century, public health has been credited with adding 25 years to life expectancy by contributing to the decline in illness and injury. Progress has been made, for example, in smoking reduction, infectious disease, and motor vehicle and workplace injuries. Besides its focus on traditional concerns such as clean water and safe food, public health is adapting to meet emerging health problems. Particular troublesome are health threats to youth: teenage pregnancies, violence, substance abuse, sexually transmitted diseases, and other conditions associated with high-risk behaviors. These threats add to burgeoning health care costs. A conservative estimate of $69 billion in medical spending could be averted through the impact of public health strategies aimed at heart disease, stroke, fatal and nonfatal occupational injuries, motor vehicle-related injuries, low birth weight, and violence. These strategies require the collaboration of many groups in the public and private sectors. Collaboration is the bedrock of public health and Healthy Iowans planning. At the core of Healthy Iowans 2000 and its successor, Healthy Iowans 2010, is the idea that all Iowans benefit when stakeholders decide on disease prevention and health promotion strategies and agree to work together on them. These strategies can improve the quality of life and hold down health care costs. The payoff for health promotion and disease prevention is not immediate, but it has long-lasting benefits. The Iowa plan is a companion to the national plan, Healthy People 2010. An initiative to improve the health of Americans, the national plan is the driving force for federal resource allocation for disease prevention and health promotion. The state plan is used in the same way. Both plans have received broad support from Republican and Democratic administrations. Community planners are using the state plan to help assess health needs and craft health improvement plans. Healthy Iowans 2010 was written at an unusual point in history – a new decade, a new century, a new millennium. The introduction was optimistic. “The 21st century,” it says, “promises to add life as well as years through improved health habits coupled with medical advances. Scientists have suggested that if these changes occur, the definition of adulthood will also change. An extraordinary number of people will live fuller, more active lives beyond that expected in the late 20th century.” At the same time, the country has spawned a new generation of health hazards. According to Dr. William Dietz of the Centers for Disease Control and Prevention (CDC), it has replaced “the diseases of deficiency with diseases of excess” (Newsweek, August 2, 1999). New threats, such as childhood overweight, can reverse progress made in the last century. This demands concerted action.

RAGBRAI Learn about the Land; Day 3, July 2008

Although during much of its geologic history Iowa was part of an interior sea, today what we see on the land surface has been heavily influenced by recent glaciation. Everything from Iowa soils, rivers, lakes, and hills has been influenced by glaciation. Most of Iowa’s bedrock is hidden beneath a thick mantle of deposits from the Cenozoic (i.e., new life) Era, spanning the last 65 million years. Geologists have divided the Cenozoic Era into two periods. These are the Tertiary (1.8-65 million years ago) and Quaternary Periods (recent to 1.8 million years ago). Most geologic records in Iowa are from the Quaternary period, and include glacial till and loess.

Regional Approach to Landslide Interpretation and Repair, TR-430, 2001

The objective of this report is to provide Iowa county engineers and highway maintenance personnel with procedures that will allow them to efficiently and effectively interpret and repair or avoid landslides. The research provides an overview of basic slope stability analyses that can be used to diagnose the cause and effect associated with a slope failure. Field evidence for identifying active or potential slope stability problems is outlined. A survey of county engineers provided data for presenting a slope stability risk map for the state of Iowa. Areas of high risk are along the western border and southeastern portion of the state. These regions contain deep to moderately deep loess. The central portion of the state is a low risk area where the surficial soils are glacial till or thin loess over till. In this region, the landslides appear to occur predominately in backslopes along deeply incised major rivers, such as the Des Moines River, or in foreslopes. The south-central portion of the state is an area of medium risk where failures are associated with steep backslopes and improperly compacted foreslopes. Soil shear strength data compiled from the Iowa DOT and consulting engineers files are correlated with geologic parent materials and mean values of shear strength parameters and unit weights were computed for glacial till, friable loess, plastic loess and local alluvium. Statistical tests demonstrate that friction angles and unit weights differ significantly but in some cases effective stress cohesion intercept and undrained shear strength data do not. Moreover, effective stress cohesion intercept and undrained shear strength data show a high degree of variability. The shear strength and unit weight data are used in slope stability analyses for both drained and undrained conditions to generate curves that can be used for a preliminary evaluation of the relative stability of slopes within the four materials. Reconnaissance trips to over fifty active and repaired landslides in Iowa suggest that, in general, landslides in Iowa are relatively shallow [i.e., failure surfaces less than 6 ft (2 m) deep] and are either translational or shallow rational. Two foreslope and two backslope failure case histories provide additional insights into slope stability problems and repair in Iowa. These include the observation that embankment soils compacted to less than 95% relative density show a marked strength decrease from soils at or above that density. Foreslopes constructed of soils derived from shale exhibit loss of strength as a result of weathering. In some situations, multiple causes of instability can be discerned from back analyses with the slope stability program XSTABL. In areas where the stratigraphy consists of loess over till or till over bedrock, the geologic contracts act as surfaces of groundwater accumulation that contribute to slope instability.