Effects of urban development on the flood-flow characteristics of the Walnut Creek Basin, Des Moines Metropolitan area, Iowa,1978.

This report deals with the probable impact of urban development on the magnitude and frequency of flooding in the lower reach of the Walnut Creek Basin.

Consolidated Plan for Housing and Community Development: Annual Performance Report, 2007

This document is the State of Iowa's Annual Performance Report (APR) for the period beginning January 1, 2006 and ending December 31, 2006 (Program Year 2006). This report is intended to fulfill the U.S. Department of Housing and Urban Development (HUD) requirements that require the state to annually review and report the progress made in carrying out its Consolidated Plan for Housing and Community Development. This report, and the supplemental documentation included with it, replaces several year end reports submitted individually in the past.

Constructability in the Bridge Design Process, HR-320, 1991

In the United States many bridge structures have been designed without consideration for their unique construction problems. Many problems could have been avoided if construction knowledge and experience was utilized in the design process. A systematic process is needed to create and capture construction knowledge for use in the design process. This study was conducted to develop a system to capture construction considerations from field people and incorporate it into a knowledge-base for use by the bridge designers. This report presents the results of this study. As a part of this study a microcomputer-based constructability system has been developed. The system is a user-friendly microcomputer database which codifies construction knowledge, provides easy access to specifications, and provides simple design computation checks for the designer. A structure for the final database was developed and used in the prototype system. A process for collecting, developing and maintaining the database is presented and explained. The study involved a constructability survey, interviews with designers and constructors, and visits to construction sites to collect constuctability concepts. The report describes the development of the constructability system and addresses the future needs for the Iowa Department of Transportation to make the system operational. A user's manual for the system is included along with the report.

Roadway Design Standards for Rural and Suburban Subdivisions Final Report, June 2007

In Iowa, there are currently no uniform design standards for rural and suburban subdivision development roadways. Without uniform design standards, many counties are unable to provide adequate guidance for public facilities, particularly roadways, to be constructed as part of a rural subdivision development. If a developer is not required to install appropriate public improvements or does not do so properly, significant liability and maintenance expenses can be expected, along with the potential for major project costs to correct the situation. Not having uniform design standards for rural and suburban subdivision development improvements in Iowa creates situations where there is potential for inconsistency and confusion. Differences in the way development standards are applied also create incentives or disincentives for developers to initiate subdivision platting in a particular county. With the wide range of standards or lack of standards for local roads in development areas, it is critical that some level of uniformity is created to address equity in development across jurisdictional lines. The standards must be effective in addressing the problem, but they must not be so excessive as to curtail development activities within a local jurisdiction. In order to address the concerns, cities and counties have to work together to identify where growth is going to be focused. Within that long-term growth area, the roadways should be constructed to urban standards to provide an easier transition to traditional urban facilities as the area is developed. Developments outside of the designated growth area should utilize a rural cross section since it is less likely to have concentrated urban development. The developers should be required to develop roadways that are designed for a minimum life of 40 years, and the county should accept dedication of the roadway and be responsible for its maintenance.

Insights into the Design and Characteristics of the Sedimentation Process at Multi-Barrel Culverts in Iowa, TR-596, 2010

The present study is an integral part of a broader study focused on the design and implementation of self-cleaning culverts, i.e., configurations that prevent the formation of sediment deposits after culvert construction or cleaning. Sediment deposition at culverts is influenced by many factors, including the size and characteristics of material of which the channel is composed, the hydraulic characteristics generated under different hydrology events, the culvert geometry design, channel transition design, and the vegetation around the channel. The multitude of combinations produced by this set of variables makes the investigation of practical situations a complex undertaking. In addition to the considerations above, the field and analytical observations have revealed flow complexities affecting the flow and sediment transport through culverts that further increase the dimensions of the investigation. The flow complexities investigated in this study entail: flow non-uniformity in the areas of transition to and from the culvert, flow unsteadiness due to the flood wave propagation through the channel, and the asynchronous correlation between the flow and sediment hydrographs resulting from storm events. To date, the literature contains no systematic studies on sediment transport through multi-box culverts or investigations on the adverse effects of sediment deposition at culverts. Moreover, there is limited knowledge about the non-uniform, unsteady sediment transport in channels of variable geometry. Furthermore, there are few readily useable (inexpensive and practical) numerical models that can reliably simulate flow and sediment transport in such complex situations. Given the current state of knowledge, the main goal of the present study is to investigate the above flow complexities in order to provide the needed insights for a series of ongoing culvert studies. The research was phased so that field observations were conducted first to understand the culvert behavior in Iowa landscape. Modeling through complementary hydraulic model and numerical experiments was subsequently carried out to gain the practical knowledge for the development of the self-cleaning culvert designs.

06017-009 Saylor Creek Watershed Final Report

With the Saylor Creek Watershed Improvement Project, Iowa Heartland RC&D and other area stakeholders have an opportunity to display how "best management practices" (BMPs) can reduce storm water runoff and improve the quality of that runoff in an urban setting. Conservation design is a uew approach to storm water management that addresses the negative impacts of storm water runoff and turns them into a positive. The master plan for the Prairie Trail development surrounding the watershed project will incorporate bioretention cells, bioswales, buffer strips, rain gardens, as well as native plant landscaping to slow storm water runoff and naturally clean sediment out of the water before it reaches Saylor Creek. In addition to conservation design elements, the project will utilize storm water detention ponds and creek bed restoration to develop a complete storm water "treatment train" system within Prairie Trail. The extensive use of conservation storm water management for Prairie Trail is unique for urban development in Iowa.