Evaluation of the Iowa Department of Transportation's Compensatory Wetland Mitgation Program, August 30, 2004

The purpose of this investigation was to evaluate the Compensatory Wetland Mitigation Program at the Iowa Department of Transportation (DOT) in terms of regulatory compliance. Specific objectives included: 1) Determining if study sites meet the definition of a jurisdictional wetland. 2) Determining the degree of compliance with requirements specified in Clean Water Act Section 404 permits. A total of 24 study sites, in four age classes were randomly selected from over 80 sites currently managed by the Iowa DOT. Wetland boundaries were delineated in the field and mitigation compliance was determined by comparing the delineated wetland acreage at each study site to the total wetland acreage requirements specified in individual CWA Section 404 permits. Of the 24 sites evaluated in this study, 58 percent meet or exceed Section 404 permit requirements. Net gain ranged from 0.19 acre to 27.2 acres. Net loss ranged from 0.2 acre to 14.6 acres. The Denver Bypass 1 site was the worst performer, with zero acres of wetland present on the site and the Akron Wetland Mitigation Site was the best performer with slightly more than 27 acres over the permit requirement. Five of the 10 under-performing sites are more than five years post construction, two are five years post construction, one is three years post construction and the remaining two are one year post construction. Of the sites that meet or exceed permit requirements, approximately 93 percent are five years or less post construction and approximately 43 percent are only one year old. Only one of the 14 successful sites is more than five years old. Using Section 404 permit acreage requirements as the criteria for measuring success, 58 percent of the wetland mitigation sites investigated as part of this study are successful. Using net gain/loss as the measure of success, the Compensatory Wetland Mitigation Program has been successful in creating/restoring nearly 44 acres of wetland over what was required by permits.

Iowa Department of Corrections Iowa State Penitentiary Final Operational and Architectural Program

The planning effort for ISP began in 2006 when the IDOC retained the Durrant/PBA team of architects and planners to review the Iowa correctional system. The team conducted two studies in the following two years, the first being the April 2007 Iowa Department of Corrections Systemic Master Plan. Both studies addressed myriad aspects of the correctional system including treatment and re-entry needs and programs, security and training, and staffing.

Development of Asphalt Dynamic Modulus Master Curve Using Falling Weight Deflectometer Measurements, TR-659

The asphalt concrete (AC) dynamic modulus (|E*|) is a key design parameter in mechanistic-based pavement design methodologies such as the American Association of State Highway and Transportation Officials (AASHTO) MEPDG/Pavement-ME Design. The objective of this feasibility study was to develop frameworks for predicting the AC |E*| master curve from falling weight deflectometer (FWD) deflection-time history data collected by the Iowa Department of Transportation (Iowa DOT). A neural networks (NN) methodology was developed based on a synthetically generated viscoelastic forward solutions database to predict AC relaxation modulus (E(t)) master curve coefficients from FWD deflection-time history data. According to the theory of viscoelasticity, if AC relaxation modulus, E(t), is known, |E*| can be calculated (and vice versa) through numerical inter-conversion procedures. Several case studies focusing on full-depth AC pavements were conducted to isolate potential backcalculation issues that are only related to the modulus master curve of the AC layer. For the proof-of-concept demonstration, a comprehensive full-depth AC analysis was carried out through 10,000 batch simulations using a viscoelastic forward analysis program. Anomalies were detected in the comprehensive raw synthetic database and were eliminated through imposition of certain constraints involving the sigmoid master curve coefficients. The surrogate forward modeling results showed that NNs are able to predict deflection-time histories from E(t) master curve coefficients and other layer properties very well. The NN inverse modeling results demonstrated the potential of NNs to backcalculate the E(t) master curve coefficients from single-drop FWD deflection-time history data, although the current prediction accuracies are not sufficient to recommend these models for practical implementation. Considering the complex nature of the problem investigated with many uncertainties involved, including the possible presence of dynamics during FWD testing (related to the presence and depth of stiff layer, inertial and wave propagation effects, etc.), the limitations of current FWD technology (integration errors, truncation issues, etc.), and the need for a rapid and simplified approach for routine implementation, future research recommendations have been provided making a strong case for an expanded research study.

Evaluation of the Iowa Department of Transportation's Compensatory Wetland Mitigation Program, TR-500, 2004

The purpose of this investigation was to evaluate the Compensatory Wetland Mitigation Program at the Iowa Department of Transportation (DOT) in terms of regulatory compliance. Specific objectives included: 1) Determining if study sites meet the definition of a jurisdictional wetland. 2) Determining the degree of compliance with requirements specified in Clean Water Act Section 404 permits. A total of 24 study sites, in four age classes were randomly selected from over 80 sites currently managed by the Iowa DOT. Wetland boundaries were delineated in the field and mitigation compliance was determined by comparing the delineated wetland acreage at each study site to the total wetland acreage requirements specified in individual CWA Section 404 permits. Of the 24 sites evaluated in this study, 58 percent meet or exceed Section 404 permit requirements. Net gain ranged from 0.19 acre to 27.2 acres. Net loss ranged from 0.2 acre to 14.6 acres. The Denver Bypass 1 site was the worst performer, with zero acres of wetland present on the site and the Akron Wetland Mitigation Site was the best performer with slightly more than 27 acres over the permit requirement. Five of the 10 under-performing sites are more than five years post construction, two are five years post construction, one is three years post construction and the remaining two are one year post construction. Of the sites that meet or exceed permit requirements, approximately 93 percent are five years or less post construction and approximately 43 percent are only one year old. Only one of the 14 successful sites is more than five years old. Using Section 404 permit acreage requirements as the criteria for measuring success, 58 percent of the wetland mitigation sites investigated as part of this study are successful. Using net gain/loss as the measure of success, the Compensatory Wetland Mitigation Program has been successful in creating/restoring nearly 44 acres of wetland over what was required by permits.