The Effects of Headcut and Knickpoint Propagation on Bridges in Iowa, October 2008

Headcuts (known also as primary knickpoints) and knickpoints (known also as secondary knickpoints) have been found to contribute to the accelerated riverbed degradation problem in the midwestern United States. Step-changes that occur at the head of channel networks are referred to as headcuts, and those that occur within the confines of channel banks are referred to as knickpoints. The formation of headcuts and knickpoints and their upstream migration have been linked to the over-steepening of stream reaches when the flow plunges to the bed and creates a plunge pool. Secondary flow currents and seepage are believed to be some other parameters contributing to the formation and evolution of headcuts and knickpoints. Ongoing research suggests that headcuts and knickpoints, where they form and migrate, may account for 60% (or more) of the bed erosion in the streams. Based on preliminary observations, there is a strong indication that headcuts and knickpoints can also have a greater influence on flow thalweg alignment (line of deepest flow) for small rivers. A shift in thalweg toward a riverbank or embankment is usually a prime factor contributing to riverbank erosion and scour.

Quarterly Census of Employment and Wages, Preliminary County Data, Second Quarter, 2004

Second Quarterly County information for Census of Employment & Wage, County

Quarterly Census of Employment and Wages, Preliminary Statewide Data, Second Quarter, 2004

Second Quarterly County information for Census of Employment & Wage, Statewide

Technology Transfer of As-Built and Preliminary Surveys Using GPS, Soft Photogrammetry, and Video Logging, 2002

This research involved two studies: one to determine the local geoid to obtain mean sea level elevation from a global positioning system (GPS) to an accuracy of ±2 cm, and the other to determine the location of roadside features such as mile posts and stop signs for safety studies, geographic information systems (GIS), and maintenance applications, from video imageries collected by a van traveling at traffic speed.

The Long-Run Impact of Corn-Based Ethanol on the Grain, Oilseed, and Livestock Sectors: A Preliminary Assessment, November 2006

The ongoing growth of corn-based ethanol production raises some fundamental questions about what impact continued growth will have on U.S. and world agriculture. Estimates of the long-run potential for ethanol production can be made by calculating the corn price at which the incentive to expand ethanol production disappears. Under current ethanol tax policy, if the prices of crude oil, natural gas, and distillers grains stay at current levels, then the break-even corn price is $4.05 per bushel. A multi-commodity, multi country system of integrated commodity models is used to estimate the impacts if we ever get to $4.05 corn. At this price, corn-based ethanol production would reach 31.5 billion gallons per year, or about 20% of projected U.S. fuel consumption in 2015. Supporting this level of production would require 95.6 million acres of corn to be planted. Total corn production would be approximately 15.6 billion bushels, compared to 11.0 billion bushels today. Most of the additional corn acres come from reduced soybean acreage. Wheat markets would adjust to fulfill increased demand for feed wheat. Corn exports and production of pork and poultry would all be reduced in response to higher corn prices and increased utilization of corn by ethanol plants. These results should not be viewed as a prediction of what will eventually materialize. Rather, they indicate a logical end point to the current incentives to invest in corn-based ethanol plants.

Status of Young Women in the Juvenile Justice System Preliminary Data, 2007

Young women involved in the juvenile justice system present with characteristics and experiences that differentiate them from their male counterparts. As such, the juvenile justice system in Iowa must consider these factors if it is to effectively and efficiently impact recidivism and rehabilitation.

Iowa Preliminary Monthly Weather Summary, July 2009

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau. Iowa Secretary of Agriculture Bill Northey today commented on the Iowa Crops and Weather report released by the USDA National Agricultural Statistical Service.

Iowa Preliminary County Precipitation Estimates, July 2009

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau.

Iowa Preliminary County Precipitation Estimates, July 2009

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, April 19, 2011; With Addendums

Weekly letting report.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, May 17, 2011; With Addendums

Weekly letting report.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, June 21, 2011; With Addendums

Weekly letting report.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, July 19, 2011; With Addendums

Weekly letting report.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, August 16, 2011; With Addendums

Weekly letting report.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, September 20, 2011; With Addendums

Weekly letting report.