Evaluation of Dormant Season Evapotranspiration
Water use during the dormant season is often considered to be insignificant in terms of the total water balance. Evapotranspiration was measured over three fields with different crop covers...
Potential-Scour Assessments at 130 Bridges in Iowa
A total of 130 highway bridges in Iowa were assessed for potential scour using a potential-scour index developed by the U.S. Geological Survey for a bridge-scour study in western Tennessee....
Heuristic Knowledge-base Approach to Runoff Estimation in Midwestern States Using a SCS Curve Number Method
The applications of the Knowledge-Based engineering has emerged as a potential technique for incorporating human expertise and some degree of intelligent judgment into decision-supporting...
Frequency of the 1993 Flood in the Upper Mississippi River Basin
The frequency of the 1993 flood in the upper Mississippi River Basin is characterized by applying Bulletin 17B and L-moment methods to 111 unregulated watersheds in the basin. The analysis...
Contraction Scour at a Bridge over the Iowa River
Flooding of the Iowa River during July and August 1993 caused extensive contraction scour at the State Highway 99 bridge over the Iowa River at Wapello, Iowa. At least 3.3 m of piling...
Reconstruction of Concentration Boundary Condition for Unsteady Pesticide Transport Modeling
A one-dimensional unsteady contaminant transport model which used an unsteady hydraulic field was used to model pesticides (metolachlor, metribuzin) in the Iowa River/Coralville Reservoir....
Impacts of the 1993 Flood on the Mississippi River in Illinois
The 1993 flood has now been recognized as one of the greatest floods on the Mississippi and Missouri Rivers. Its geographical extent included portions of Iowa, Missouri, Illinois, Wisconsin,...
Historical Trends in Flood Discharges on the Upper Mississippi River
Long-term streamgage records in the Upper Mississippi River Basin were analyzed using a Kendall Tau-b analysis to determine trends in flooding and average flows. Over the 130 years of...
Spreadsheet Pavement Management Systems for Local Roads
Changes in administration and funding levels at the local government level are continuing to illustrate the need for information systems to aid the county engineer or public works director....
Saylorville Spillway: Emergency to Service Spillway
The spillway for Saylorville Lake located on the Des Moines River, 12 miles north of the city of Des Moines, Iowa, a large metropolitan, was designed as an emergency spillway. Due to subsequent...
Scour at a Bridge Over the Weldon River, Iowa
Contraction scour at the State Highway 2 bridge over the Weldon River in south-central Iowa was caused by a flood of record proportions on September 14 and 15, 1992. The peak discharge...
A Decision Support System for Water Quality Modeling
A prototype Decision Support System (DSS) has been developed to evaluate the environmental and economic consequences of alternative farming practices. This system was developed to help...
Reliability-Based Design for Feeeze-Thaw Concrete
Observation of pavements in Iowa shows results from the test for freezing and thawing of concrete, ASTM C-666, is not always consistent with field performance. Similar concrete made with...
Source of Atrazine and Desethylatrazine in a River, During Base Flow
A budget of atrazine and desethylatrazine loads was computed for a 116-kilometer reach of the Cedar River in Iowa to determine where these compounds enter the river during base-flow conditions....
Impact of Farming Systems on Water Quality in Iowa
Increased detection of nitrate and pesticides in surface and ground water has prompted concern about the impact of farming systems on water quality. A number of studies have been incorporated...
Long-Term Effects of Tillage and Crop Rotation on the Leaching of Nitrate and Pesticides to Shallow Groundwater
Contamination of groundwater by nitrate-nitrogen (NO3-N) and pesticides is a serious problem and concern in Iowa. The extent of contamination can...
Modeling Nitrogen Movement Through Loess Soils
This study evaluates the ability of the Root Zone Water Quality Model (RZWQM) to track the movement and fate of nitrate (NO3--N)...
Submerged Vane Projects for Bank Stabilization and Sedimentation Management
Submerged vanes are small flow training devices placed in a stream to eliminate or create secondary currents to direct sediment in a controlled fashion. In recent years submerged vanes...
Flexible Pipe Design Revisited
An overwhelming soil factor in the Iowa formula and random deformations at installation affords soil a prominent role in flexible pipe; this, together with a maximal deflection rule make...
Influence of Tillage on Hydrology in Western Iowa
USDA Agricultural Research Service has operated four field-sized watersheds in the deep loess soils of western Iowa since 1964. Throughout this time, two watersheds were cropped to corn...
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