TRB Publications Index

Design, Construction, and Monitoring Practices for Aquatic Organism Passage

Sat, 03 May 2025 16:36:17 GMT

Aquatic organism passage (AOP) water crossing design is an evolving field at the nexus of the built environment and natural world. When successful, AOP water crossings provide sustainable transportation infrastructure and environmental benefits via a connected habitat for fish and other aquatic organisms. The objective of this synthesis is to document current state department of transportation (DOT) practices related to the design, construction, and monitoring of AOP water crossing structures. Information for this study was gathered through a literature review, a survey of state DOTs, and follow-up interviews with selected DOTs. Case examples of five state DOTs provide additional information on AOP practices.

Estimation of High-Frequency Auditory Masking in Beluga Whales by Commercial Vessels in Cook Inlet, Alaska

Wed, 29 Jun 2022 10:59:39 GMT

Industrial development in Cook Inlet, Alaska, has raised concerns about the decline of the resident beluga whale (Delphinapterus leucas) population over the past decades. Anthropogenic noise sources, such as commercial vessels, can cause auditory masking of cetacean vocalizations used in communication, navigation, and foraging. This study includes a source-level spectrum of a containership, positioned in Cook Inlet within the primary shipping channel, and audiograms obtained from a live, stranded beluga calf in Cook Inlet, in sound transmission loss modeling. The model uses a hybrid parabolic equation/raytracing solution to determine underwater sound pressure levels. Whereas the communication band of belugas can be fully masked by ambient noise and underwater radiated noise from a containership positioned at 5,000?m, the echolocation band (for navigation) is only partially masked at shorter ranges (=2,500?m). Increased multipath reflections from the propagation of underwater noise in the upslope direction contributes significantly to the attenuation of high frequencies and minimizes masking in the echolocation band of the beluga whale. To assess the complex task of auditory masking, critical ratios were used to determine the difference between the energy of a pure tone and the noise in the masking band. A successful strategy to reduce underwater radiated noise must consider the interactions and contributions of mitigation measures that have already been shown to be effective. The technical and economic profitability of these measures will largely depend on the design, operating parameters, and mandatory requirements for a particular vessel.

Improving Road Stream Crossings for Storm Resiliency and Aquatic Organism Passage: Pennsylvania Case Study

Tue, 03 Mar 2020 16:02:56 GMT

Pennsylvania is home to more than 86,000 mi of streams and rivers, second in the United States only to Alaska. With over 120,000 mi of nonfederal public roads, 75,000 mi of which are owned by 2,500 local municipalities, Pennsylvania has an extensive network of stream culverts and bridges owned and maintained by a wide variety of entities. Unfortunately, a large percentage of these stream crossings, especially in rural areas, are inadequately sized for the streams they attempt to convey. Undersized crossings pose a host of problems for both the road and stream including channel erosion, road erosion, gravel aggradation, blockage of aquatic organism passage, road flooding, and even loss of structure. Pennsylvania’s Dirt, Gravel, and Low-Volume Road Maintenance Program (Program), administered through the Pennsylvania State Conservation Commission, provides $28 million annually in funding to local municipalities to implement environmental improvements on unpaved and low-volume (<500 average daily traffic) paved roads. Starting with a funding increase in 2014, the Program has increased its focus on stream crossing replacements, now funding about 100 annually. This report summarizes the efforts of the Program from 2014 to 2018 to focus funding on road–stream crossing replacements that provide an environmental benefit, and to ensure new crossings are adequately sized and installed properly. The experiences and lessons learned in Pennsylvania can benefit other entities as concerns about both aquatic organism passage and flood resilience in a changing climate gain traction across the United States and beyond.

Marine Transportation and the Environment: Trends and Issues

Mon, 05 Mar 2018 11:34:00 GMT

This article explores the environmental impacts of commercial marine transportation and emerging technologies and regulatory frameworks that can mitigate the effects of fleet operations. Topics covered include (1) Air pollution including controlling sulfur and using alternative fuels and liquefied natural gas to aid in meeting air quality concerns; (2) Changing trade routes including the impact of the possible melting of the Arctic ice cap, possible new shipping routes, expected traffic, and the need to protect biodiversity in new areas; (3) Vessel discharges and wastewater treatment options; and (4) Underwater sound and impact on aquatic life.

A DEM Study of Penetrating in Granular Materials with Changing Shape

Tue, 07 Mar 2017 10:25:07 GMT

The Atlantic razor clam (Ensis directus) possesses an exceptional penetration performance via the periodical expansion/contraction motion of its body during burrowing. In essence, the burrowing process is a soil-penetrator interaction problem where the penetrator has a time-varying shape. The mechanism is very similar to that of the pressuremeter test used in geotechnical site characterization, but different in that such an expansion/contraction process is a dynamic one with relatively high frequency. Although various experimental and analytical researches have been conducted to explore the burrowing mechanism, the understanding on the interaction between a shape-changing structure, such as as a clam, and the surrounding soil is far from complete. This paper provides insights into the cyclic burrowing process in uniform non-cohesive dry granular sands from Discrete Element Method (DEM) modeling. While it is not attempted to explore the burrowing mechanics with realistic burrower geometry and kinematics, a simplified 2D model is developed to study the key feature of the burrowing behavior of the razor clam: dynamic interaction between soil and a circular penetrator with a radius changing in a sinusoidal fashion. Different expanding/contracting frequencies are considered in order to explore their effects on penetration resistance. Various stages of the penetration process including initial movement, progressive expansion and contraction are captured. Results show that the cyclic expansion/contraction has significant effects on penetration resistance and consuming penetrating energy. Patterns of soil displacement and contact force chain are investigated to shed light on the underlying mechanism. To further the exploration of burrowing efficiency, these results are also compared with the data from static penetration simulation. It is found out that there exists a unique critical expansion/contraction frequency, under which the penetration energy consumption is lowest.

Evaluation of Waste Concrete Road Materials for Use in Oyster Aquaculture

Mon, 24 Feb 2014 08:42:47 GMT

The Maryland State Highway Administration (SHA) intends to increase the use of recycled materials and to use products in an environmentally responsible manner. As roads and bridges are resurfaced, old concrete is removed and is usually discarded. It would be in the best interest of SHA, in support of its sustainability initiatives, that these materials be recycled and repurposed for alternative uses. One such potential use is to condition portions of the Chesapeake Bay bottom to support spat-on-shell aquaculture projects. For recycled concrete aggregate (RCA) to be used within the aquatic setting of the Chesapeake Bay, its chemical behavior under saturated conditions must be understood to avoid potential adverse impacts to the bay's aquatic ecosystem. The primary objective of this study was to determine the suitability of recycled concrete as conditioning material for on-bottom oyster aquaculture in the Chesapeake Bay. The results of this project showed that using RCA as a base material for oyster reefs did not adversely affect oyster spat growth and survival, or the surrounding environment. There was no statistical difference between shell and RCA on the growth, survivorship, average length, or recruitment of young oysters. Initial pH was slightly higher for the RCA than the oyster shell control, but pH stabilized to around 7.6 to 7.8 for all treatments after seven days. Based on the findings of this study, the recommendation is to initiate a second phase study that places RCA on test plots in the Chesapeake Bay to validate the laboratory tests in-situ.

Stream Simulation for Aquatic Organism Passage at Road–Stream Crossings

Wed, 27 Jul 2011 13:42:22 GMT

Historically, road–stream crossing structures were designed on the basis of the hydraulic capacity of the structure for a specific design flood without consideration of aquatic species or the swimming and jumping abilities of a single target fish species and life stage during its migration, and ignored the movement needs of other adult fish, juvenile fish, and aquatic organisms occupying the stream. Hydraulic designs typically constrict the channel, create flow hydraulics and channel conditions that are markedly dissimilar from those in the natural channel, and impede the movement of most other nontarget fish and aquatic organisms along the stream corridor. The stream simulation approach for designing road–stream crossing structures was recently adopted by the U.S. Department of Agriculture Forest Service as a pragmatic and sustainable long-term solution to maintain passage for all aquatic organisms at all life stages at road–stream crossings while meeting vehicle transportation objectives. This study shows how the stream simulation design process integrates fluvial geomorphology concepts with engineering principles to design a natural and dynamic channel through the road–stream crossing structure. The premise of stream simulation is that the creation of channel dimensions and characteristics similar to those in the adjacent natural channel will enable fish and other aquatic organisms to experience no greater difficulty moving through the structure than if there were no crossing. Stream simulation channels are designed to adjust laterally and vertically to a wide range of floods and sediment or wood inputs without compromising the movement needs of fish and other aquatic organisms or the hydraulic capacity of the structure.

Alternative Aircraft Anti-Icing Formulations with Reduced Aquatic Toxicity and Biochemical Oxygen Demand

Mon, 30 Aug 2010 16:40:11 GMT

The current research was conducted to identify alternative aircraft and pavement deicer and anti-icer formulations with improved environmental characteristics compared to currently used commercial products (2007). The environmental characteristics of primary concern are the biochemical oxygen demand (BOD) and aquatic toxicity of the fully formulated products. This current report presents the results of the second phase of the research, wherein candidate alternative components were evaluated and mixtures were built up through a progressive series of performance and environmental testing and down-selecting. At the direction of the research panel, the research objectives in this phase were the development of a Type IV aircraft anti-icing fluid formulation with reduced toxicity compared to commercially available products, and identification of an additive for solid pavement deicers to reduce caking. Section 1 of the report contains background information. Section 2 presents a summary of the rationale for the selection of alternative candidate aircraft and runway deicing/anti-icing components evaluated in the test program. A summary of the test plan used to evaluate the alternative components is presented in Section 3. The test program was divided into two parts: Tier 1 and Tier 2. Details of the Tier 1 experimental results are presented in Section 4 and the Tier 2 results in Section 5, including a summary of the aquatic toxicity results for the final Type IV formulation. Degradation pathways for the deicing components are detailed in Section 6. Conclusions of the study are presented in Section 7, and suggested future research topics are provided in Section 8.

Alternative Aircraft and Pavement Deicers and Anti-Icing Formulations with Improved Environmental Characteristics

Fri, 23 Apr 2010 15:56:28 GMT

Airport Cooperative Research Program (ACRP) Project 02-01, "Alternative Aircraft and Airfield Deicing and Anti-Icing Formulations with Reduced Aquatic Toxicity and Biochemical Oxygen Demand," was conducted to examine the potential to develop aircraft and airfield deicing and anti-icing formulations with lower aquatic toxicity and reduced biochemical oxygen demand (BOD). Such products could reduce infrastructure costs to airports, provide aircraft operators and airports with greater operational latitude in deicing and anti-icing operations, and improve the overall reliability of the air transportation system. This Research Results Digest summarizes the key results, findings, and conclusions of ACRP Project 02-01. An extensive library of policy documents, patent literature, professional literature, project reports, and other data was compiled and reviewed as well as a collection of deicer manufacturer literature. Toxicity tests were conducted, BOD and chemical oxygen demand were characterized in deicer formulations, and alternative deicer formulations with reduced toxicity and BOD that would be operationally and commercially viable were identified.

Using Three-Dimensional Hydrodynamic Modeling and Fish Swimming Energetics to Assess Culverts as Potential Physical Barriers to Upstream Fish Movement

Fri, 17 Apr 2009 09:56:56 GMT

Fish passage through culverts is an important consideration in road and stream crossing design. Although no comprehensive inventory of culverts on fish-bearing streams in the United States is available, there are an estimated 1.4 million stream-road crossings. The most common physical characteristics that create barriers to upstream fish passage include excessive water velocity, insufficient water depth and large outlet drop heights. Over the past decade, interest in the effect of culvert barriers on aquatic systems has grown; accordingly, various passage assessment techniques have been used to determine whether a structure is a barrier and under what flow conditions. Recent research has shown that determining the barrier status of a culvert is not trivial, and that different methods are often not congruent in their classification of barriers. The purpose of this research was to test the use of 3-D hydrodynamic modeling to assess potential culvert barriers to upstream fish movement. The approach quantified the 3-D velocity field within the culvert barrel using computational fluid dynamics. A range of potential paths through the culvert were identified using an algorithm that estimates energy paths, and passage along the paths was assessed by combining the swim speed-fatigue time relationship with the 3-D velocity field. Results from the 3-D approach were compared to an approach that used the 1-D velocity field to estimate passability. Comparisons between estimated passage and measured passage showed the 3-D method more accurately indicated the barrier status of the structure compared to the 1-D method.

Aircraft Deicing and Airfield Anti-Icing Formulations: Aquatic Toxicity and Biochemical Oxygen Demand

Tue, 14 Apr 2009 11:42:54 GMT

This document is an interim report on a project that is exploring the environmental characteristics of aircraft and pavement deicers and anti-icers. The focus is primarily on biochemical oxygen demand (BOD) and aquatic toxicity of formulated products and individual chemical components of formulations. This report includes a background of issues leading to this research, objectives of this document, and a description of the efforts and findings of this research.

Beneficial Use of Lime Sludge for Soil Stabilization

Thu, 19 Feb 2009 14:43:34 GMT

Water plants annually produce significant amount of lime sludge during water purification procedures. They are typically stored in lagoons and disposed as solid waste. This presents a significant economic burden to daily operations. This study investigates a sustainable development strategy from beneficial utilization of this material. An experimental program is implemented to address the technical issues related to the application of this material in the construction of soil embankment, where lime is commonly used as soil stabilizers. Specific topics investigated include: the effects of dry versus wet mix procedures on lime introduction to soils, procedures for determining the optimal content of lime sludge, and the long term durability under freeze-thaw cycles. This pilot study will help to implement a sustainable strategy to utilize lime sludge for routine construction activities.

Geomorphic, Aquatic, and Engineering Design Considerations for Low-Water Crossings

Thu, 07 Jun 2007 10:20:30 GMT

A wide variety of low-water stream crossings have been built on low-volume roads across the United States over the past 50 years with the primary objectives of traffic access and cost savings. They are generally a rigid structure in a dynamic stream system, so most have worked to varying degrees from a road use standpoint. Many have required maintenance, repairs, or design modifications to function as they exist today. In addition, most structures have caused problems with regard to stream sediment transport, promoting upstream aggradation or downstream scour and creating barriers or limitations to the passage of aquatic organisms. Three fundamental types of fords both maintain good stream function and provide for traffic use: simple at-grade fords, low-water bridges, and vented fords with a large waterway opening area, preferably with a natural stream channel bottom. Each has a large waterway open area that does not constrict most flow. Ideally the width is at least equal to that of the natural bankfull channel. This paper discusses the problems observed and the requirements for a ford to meet stream function needs, pass sediment appropriately, provide for the passage of fish and other aquatic organisms, and meet engineering design needs. Some fords are designed specifically to function in extreme dynamic conditions, such as in debris torrent or alluvial fan channels, in desert or other “flashy” hydrologic regimes, or where debris jams and overbank flooding are frequent. Fitting the structure to the site requires experience and sound geomorphic, hydraulic, and engineering design. The task should be undertaken with an interdisciplinary team approach.

Watershed Sediment Reduction

Thu, 07 Jun 2007 10:20:29 GMT

Unpaved roads are a significant source of sediments that degrade aquatic habitats. During the 1990s, counties in northwestern California faced road maintenance challenges as they were required to reduce sediment produced by their facilities and operations in order to comply with new regulations implementing provisions of the U.S. Endangered Species Act and Clean Water Act. In 1997, five counties in the region joined forces to address this problem, particularly with respect to anadromous fish. Together they obtained grant funding to study the effect of their activities on salmonid populations, develop mitigations, and undertake improvements. This paper reviews the sediment reduction treatments and implementation strategies employed by Mendocino County at two case study sites. Both are on resource roads 14 to 20 ft wide experiencing typical summer volumes of fewer than 50 vehicles per day and annual rainfall exceeding 40 in. An erosion inventory identified these road sections as being significant sediment contributors within their respective watersheds. The sediment reduction projects were completed between August and October 2002 with the use of low-impact-to-hydrology designs modified to comply with AASHTO guidelines. Where these features could not be accommodated, standard best management practices for gravel roads were employed. Compared with adjacent, untreated sections of road, both project sites performed well during exceptionally wet winters. Maintenance requirements have been significantly reduced, and sediment delivery is estimated to be down 84% at one site. Grant funding made these projects cost-effective for the county, but more economical alternatives are suggested for locally funded projects.

Past and Present Landscapes and Plant Cover of the Kimmes-Tobin Mitigated Wetlands, Foxboro, Douglas County, Wisconsin

Fri, 06 Apr 2007 08:15:39 GMT

The Kimmes-Tobin Wetlands were created from 470 acres of farmland in 1993, to replace wetlands lost through construction for US 53, Wisconsin 35 and 13. Botanical monitoring of aquatic vegetation for the Wisconsin DOT began in 1994 and was completed in 1998. A total 111 taxa were found for all sites during the study. The actual delineated wetland within the sites is dominated by 12 plant species and the final wetland delineation acreage was 171 acres on the 470 acre property. The site relies on surface drainage and rainfall over substrate with a low infiltration rate. In December 1997, scrub shrub, wet meadow, shallow marsh, deep marsh and aquatic bed species all were present and mapped. Three plant species tend to dominate the approximately three foot transition between standing water and the construction berm: Typha latifolia, Scirpus cyperinus, and Phalaris arundinaceae. Utilizing prevalence indices and weighted averages Davidson, principal investigator, stated that the 12 cells were mature wetlands and they were accepted by the Wisconsin DNR. In 2000, ownership of the Kimmes-Tobin Wetlands was transferred from the Wisconsin DOT to the University of Wisconsin Superior Foundation and the Foundation manages these wetlands and is responsible for the long term stability of these wetlands, now called the McQuarrie Wetlands. In the fall of 2004 Dr. Davidson, Dr. Bajjali and Dr. Balcer began offering formal instruction of inter-disciplinary studies in the wetland.