United States Army Corps Of Engineers Research Articles

Review paper on applications of the HEC-RAS model for flooding, agriculture, and water quality simulation

ABSTRACT The Hydrologic Engineering Center (HEC) of the United States Army Corps of Engineers (USACE) has developed the HEC-River Analysis System (RAS) hydraulic channel flow model as part of its portfolio of hydrologic and hydraulic modeling tools. HEC-RAS is a new version with capabilities to model flooding, modeling for agriculture production computations for water quality, and many more related to hydraulic modeling. The analysis components of the HEC-RAS system include one-dimensional steady flow water surface profile computations, one-dimensional and or two-dimensional unsteady flow simulation, one-dimensional and two-dimensional computations of quasi-unsteady or fully unsteady flow movable boundary sediment transport, and one-dimensional water quality analysis. The main objective of this paper is to review the use of HEC-RAS on flooding, agriculture, and water quality. The three primary components of the data input are plan data, geometry data, and flow data. Three of these scenarios applied to HEC-RAS and were proven by previous reviewers.

Re-examining Geospatial Online Participatory Tools for Environmental Planning.

Geospatial online participatory tools, or geo-OPTs, are increasingly used worldwide for engaging the public in planning. Yet, despite growth in the adoption and use of geo-OPTs, and the growing scholarship to accompany it, our understanding of their ability to support public participation in environmental planning is still underdeveloped. In this paper, we investigate the application of a geo-OPT by the United States Army Corps of Engineers (USACE), a leading water management agency in the United States, in three contextually and geographically diverse cases. Through a combination of document analysis, interviews, and participant observation, we examine the processes and dynamics associated with the development and use of the geo-OPT Crowdsource Reporter. Our findings highlight the importance of managing geo-OPTs not in isolation or as a panacea but rather as part of a broader planning process that recognizes the complexity and significance of communication in geo-OPT processes. Although it may be tempting and seemingly simple to create and launch these online tools, our research reveals how a lack of intention early on may lead to underuse or misapplication of the tool. More significantly, real damage can be done, like increased public frustration and alienation, resulting in breakdown in communications or even worsening public relations for federal agencies.

Machine learning motivated data imputation of storm data used in coastal hazard assessments

In the Coastal Hazards System's (CHS) Probabilistic Coastal Hazard Analysis (PCHA) framework developed by the United States Army Corps of Engineers (USACE), historical records of tropical cyclone parameters have been used as data sources for statistical analysis, including fitting marginal distributions and measuring correlations between storm parameters. One limitation of the available historical databases is that observations of central pressure and radius of maximum winds are not available for a large number of storms. This may adversely affect the results of statistical analyses used to develop hazard curves. This study uses machine learning techniques to develop a data imputation method to “fill in” missing storm parameter records in historical datasets used for Joint Probability Method (JPM)-based coastal hazard analysis such as the USACE's CHS-PCHA. Specifically, Gaussian process regression (GPR) and artificial neural network (ANN) models are investigated as candidate machine learning-derived data imputation models, and the performance of different model parameterizations is assessed. Candidate imputation models are compared against existing statistical relationships. The effect of the data imputation process on statistical analyses (marginal distributions and correlation measures) is also evaluated for a series of example coastal reference locations.

Planning and design of three USACE New York District projects

The United States Army Corps of Engineers (USACE) New York District (NYD) has had a tremendous impact on an approximately $6 billion comprehensive coastal storm risk management program in the last 10 years since Hurricane Sandy caused significant damage in the New York (NY) and New Jersey (NJ) area. There was 2013- 2014 emergency repair and restoration to existing beach nourishment and navigation projects, but also USACE NYD accomplished the planning and design for multiple coastal storm risk management projects in the NY and NJ area. Of those projects, specific coastal risk reduction features are described for the Sea Bright to Manasquan, NJ; East Rockaway Inlet to Rockaway Inlet, NY; and Montauk Point Lighthouse Stabilization, NY. The planning and design for these projects exemplifies resilience principles and planned adaptability to withstand the challenges of the dynamic coastal environment. The USACE NYD is faced with numerous challenges such as environmental restrictions, politics, real estate, sea level change, etc.; the magnitude of coastal planning, design and construction that has occurred over these past 10 years for the NYD studies and projects demonstrates the fortitude of collaboration combined with current and innovative engineering principles.

Stakeholder collaboration in the forecast-informed reservoir operations (FIRO) pilot project at Lake Mendocino, California

PurposeWater is a critical and contentious resource in California, hence any changes in reservoir management requires coordination among many basin stakeholders. The Forecast-Informed Reservoir Operations (FIRO) pilot project at Lake Mendocino, California explored the viability of using weather forecasts to alter the operations of a United States Army Corps of Engineers (USACE) reservoir. The pilot project demonstrated FIRO's ability to improve water supply reliability, but also revealed the key role of a collaborative Steering Committee. Because Lake Mendocino's Viability Assessment did not explore the features of the Steering Committee, this study aims to examine the relationships and interactions between Steering Committee members that supported FIRO's implementation at Lake Mendocino.Design/methodology/approachThe project identified 17 key project participants who spoke at a FIRO workshop or emerged through chain-referrals. Using semi-structured interviews with these participants, the project examined the dynamics of human interactions that enabled the successful multi-institutional and multi-criteria innovation as analyzed through text-coding.FindingsThe results reveal the importance for FIRO Steering Committee members to understand the limitations and constraints of stakeholder counterparts at other organizations, the importance of building and safeguarding relationships, and the role of trust and belonging between members. The lessons learned suggest several interventions to support successful group collaboration dynamics for future FIRO projects.Originality/valueThis study identifies features of the Steering Committee that contributed to FIRO's success by supporting collaborative negotiations of infrastructure operations within a multi-institutional and multi-criteria context.

Evaluation of weather-productivity models of construction labour for tropics

PurposeWeather is one of the main factors affecting labour productivity. Existing weather-productivity models focussed on hot and cold climates paying less attention to the tropics. Many tropical countries are expected to be the most areas affected by accelerated climate change and global warming, which may have a severe impact on labour health and productivity. The purpose of this paper is to assess whether the existing models can be used to predict labour productivity based on weather conditions in the tropics.Design/methodology/approachFive models are identified from the literature for evaluation. Using real labour productivity data of a high-rise building project in Malaysia, the actual productivity rate was compared with predicted productivity rates generated using the five models. The predicted productivity rates were generated using weather variables collected from an adjusting weather station to the project.FindingsCompared with other models evaluated in this paper, the United States Army Corps of Engineers (USACE) was found to be the best model to predict productivity based on the case study data. However, the result shows only a 57% accuracy level of the USACE model indicating the need to develop a new model for the tropics for more accurate prediction.Originality/valueThe result of this study is perhaps the first to apply meteorological variables to predict productivity rates and validate them using actual productivity data in the tropics. This study is the first step to developing a more accurate productivity model, which will be useful for project planning and more accurate productivity rate estimation.

Energy and emissions effects of airtightness for six non-residential buildings in Canada with comparison to contemporary limits and assumptions

Building air leakage is often a significant contributor to the energy consumption of a building and is difficult to characterize. Unlike the thermal performance of building envelope components, the high variability of airtightness of building assemblies and their interfaces makes air leakage of buildings difficult to predict. This publication describes the process and results for identifying leakage rates and locations within six non-residential buildings using airtightness testing, specifically six commercial buildings. Infrared (IR) scanning was used to visualize locations of air leakage in the building envelope. The energy and emissions effects from the measured performance were quantified and compared to the assumption in the relevant Canadian building code.The air leakage rates for all buildings tested in this work were less than the ASHRAE 90.1 standard limit of 2.0 L·s−1 m−2 @ 75 Pa, while three were less than the Air Barrier Association of America (ABAA)/United States Army Corps of Engineers (USACE) standard limit of 1.25 L·s−1 m−2 @ 75 Pa, and two were less than the National Energy Code of Canada for Buildings (NECB) assumption of 1.5 L·s−1 m−2 @ 75 Pa (a different area normalization is used for the NECB). The effects of airtightness on energy use intensity and annual operational emissions were quantified and found to be substantial and varied. The incremental energy use intensity ranged from a reduction of 47 kWh/m2ᐧyear to an addition of 64 kWh/m2ᐧyear.The most common location of leakage is between connections of building assemblies, especially the roof wall connection, and building components, particularly doorways, as well as at various envelope penetrations, such as for pipes and ventilation inlets/exhausts. The process of testing was documented and showed that the use of currently-available commercial equipment enables tests for typical small to medium-sized commercial/non-residential buildings to be completed efficiently. The results showed there is notable variation in airtightness levels between buildings and there are opportunities for improvement.

Southwest Pass Sedimentation and Dredging Data Analysis

Abstract The United States Army Corps of Engineers (USACE) maintains the Mississippi River, Baton Rouge, Louisiana, to the Gulf of Mexico Project as part of its Navigation mission to enable safe, r...

Flood mitigation data analytics and decision support framework: Iowa Middle Cedar Watershed case study

Flooding is one of the most frequent natural disasters, causing billions of dollars in damage and threatening vulnerable communities worldwide. Although the impact of flooding can never be diminished, minimizing future losses is possible by taking structural or non-structural mitigation actions. Mitigation applications are often costly practices. However, they can be more feasible for long-term planning and protection. On the other hand, selecting a feasible option requires a comprehensive analysis of potential risk and damages and comparing the costs and benefits of different mitigation types. This paper presents a web-based decision support framework called Mitigation and Damage Assessment System (MiDAS) that analyzes flood risk impacts and mitigation strategies at the community and property-level with the goal of informing communities on the consequences of flooding and mitigation alternatives and encouraging them to participate in the community rating system. The framework utilizes regulatory flood inundation maps, damage functions, property information, scenario-based climate projections, and mitigation inputs and guidelines from the Federal Emergency Management Agency (FEMA) and the United States Army Corps of Engineers (USACE). It will help users select the appropriate flood mitigation measures based on various characteristics (e.g., foundation type, occupancy, square footage) and provide cost estimates for implementing measures. The system also provides a decision tree algorithm for analyzing and representing the mitigation decision by reviewing existing guidelines (e.g., FEMA, USACE). We analyzed the community-level mitigation for three major cities in Eastern Iowa (Cedar Falls, Cedar Rapids, and Waterloo) and found certain measures (e.g., wet/dry floodproofing) are cost-effective for community-level mitigation. Implementation of mitigation measures can reduce the property's vulnerability and improve the response to a flooding event.

Vulnerability curves for masonry buildings affected by hyperconcentrated flows as natural disaster risk management tools for the quantification of material damage

The damage assessment caused by floods, earthquakes, hurricanes among others phenomenons in the world are analyzed with methodologies such as “Vulnerability curves”. In Peru, disasters caused by hyperconcentrated flows are alarming due to a climatic variability such as the “El Niño Costero” phenomenon. Therefore, this research has developed vulnerability curves for 1 and 2-story confined masonry buildings in Urb. San Idelfonso, Ica - Peru; linking the variables: flow depth, associated with the event produced by heavy rains at the top of the “Quebrada Cansas” caused by the “El Niño Costero” phenomenon in 2017, and the percentage of the damage based on the methodology of the United States Army Corps of Engineers (USACE), whose formula is the repair value and total building value. The monetary amounts and items of the buildings are obtained from the RM 415-2017-VIVIENDA of the Ministry of Housing, Construction and Sanitation of Peru. The process consisted of hydrological modeling in HEC-HMS, hydraulic modeling in FLO-2D, damage percentage estimate and vulnerability curves production. Finally, the vulnerability curves for hyperconcentrated flows were contrasted with similar studies regarding curves for flooding and debris flow. The results of the investigation showed that the “El Niño Costero” phenomenon in 2017 had an economic impact of at least 1.3 million soles in Urb. San Idelfonso. In addition, at least 24 buildings had a complete damage and 21 buildings an extensive damage.

A Multi-Reservoir Study of the Impact of Uncertainty in Pool Evaporation Estimates on Water-Availability Models

Quantifying evaporative loss from reservoirs plays a critical role in sound water-availability management plans and in reservoir management. Various methods are used to quantify reservoir evaporation; however, each method carries a degree of uncertainty that propagates to model predictions of available water within a reservoir or a reservoir network. Herein, we explore the impact of uncertainty in reservoir evaporation on model outputs of historical and future water availability throughout the five major reservoirs in the Savannah River Basin in South Carolina, USA, using four different evaporation methods. Variability in the total available water is evaluated using the United States Army Corps of Engineers (USACE) 2006 Drought Contingency Plan hydrologic model of the Savannah River Basin, which incorporates recent water-management plans and reservoir controls. Results indicate that, during droughts, reservoir evaporation plays a large role in water-availability predictions, and uncertainty in evaporative losses produces significant uncertainty in modeled water availability for extreme events. For example, the return period for an event in which the availability of water in Lake Hartwell was reduced to 50% of full pool capacity varied from 38.2 years to 53.4 years, depending on the choice of evaporation parameterization. This is a variation of 40% in the return period, depending on the choice of evaporation method.

Cumberland River Resource Stewardship and Protection: Managing the Cumberland River and the Land Between the Lakes Landscapes

Cumberland River formed on Cumberland Plateau by confluence of the Poor and Clover forks in Harlan county, Kentucky and loops south through northern Tennessee. It joints the Ohio River at Smithland, Kentucky. The Cumberland River is 1107 km long and has a drainage area of 46,830 km2. The Cumberland crosses a highland bench in Cumberland Plateau and flows in a gorge between 90 - 120 m cliffs. The Cumberland Falls is 20.7 m high. The river enters the central limestone basin of Tennessee, turning north, crosses the plain of western Kentucky to Ohio River at Smithland, Kentucky and at one point it is less than 3 km from Tennessee River. The Cumberland River had a long history of transporting furs, canoes, guns, armies, settlers, coal products and manufactured goods in the 1700s and 1800s. Three separate forks (Martin’s Fork, Clover Fork, and Poor Fork) flow out of the Appalachian Mountains in southeast Kentucky near the Virginia border to form the headwaters of the Cumberland River near Harlan, Kentucky. Steamboat traffic on the Cumberland River increased substantially in the 1800s as expanding coal fields, stone quarries and Tennessee produce began to be shipped throughout the region. The Cumberland River was surveyed during this period and between 1832 and 1838 Congress appropriated $155,000 for improving commercial navigation. With this infusion of money the United States Army Corps of Engineers (USACE) could clear the river of snags and build wing dams to deepen the channel. A 1060 km Cumberland River regional trail system, similar to the Tennessee River regional trail system under development, is needed to promote recreational tourism and increase use of the Cumberland River and basin. The primary objectives are: 1) to document how the landscape and geological resources of the Cumberland River have contributed to the successful water resource and economic development of a historic region in North America, 2) to identify future risks to the natural and environmental resources, 3) create a regional trail system with community access points and 4) create generations of people who care about the environmental stewardship and protection of the river and landscape resources.

A comparison study between CFD analysis and PIV technique for velocity distribution over the Standard Ogee crested spillways

A comprehensive study was performed to compare flow rate, mean velocity, vertical velocity distribution, and locations where the maximum velocity, dm, occurs on standard Ogee-crested spillways using experimental and numerical models. Five different models were constructed from rigid foam according to the specifications of the United States Army Corps of Engineers (USACE). The velocity of the flow was recorded along the downstream curve of the model for all models with different non-dimensional head ratios H/Hd of 0.50, 1.00, and 1.33. Particle Image Velocimetry (PIV) was used to measure the flow velocities. Velocity distributions were obtained by analyzing a series of captured images using Matlab codes. A commercially available Computational Fluid Dynamics (CFD) software package, Flow-3D, was used for modelling the experimental model setups. Flow-3D analyzes the Reynolds-averaged Navier-Stokes equations and is widely verified for use in the field of spillway flow analysis. The maximum difference between numerical and experimental results in mean velocity values that do not exceed 6.2% for all values of head ratios. The interpolated values of recorded maximum velocity by the PIV technique are smaller than those values numerically computed. In the lower dm locations, the percent difference between these regions reaches -8.65%; the upper locations are 2.87%. The vertical location (dm) drops to the lower location when the upstream head increases, and the distance from the spillway axis decreases linearly.

Storm Surge Barrier Protection in an Era of Accelerating Sea-Level Rise: Quantifying Closure Frequency, Duration and Trapped River Flooding

Gated storm surge barriers are being studied by the United States Army Corps of Engineers (USACE) for coastal storm risk management for the New York City metropolitan area. Surge barrier gates are only closed when storm tides exceeding a specific “trigger” water level might occur in a storm. Gate closure frequency and duration both strongly influence the physical and environmental effects on enclosed estuaries. In this paper, we use historical observations to represent future storm tide hazard, and we superimpose local relative sea-level rise (SLR) to study the potential future changes to closure frequency and duration. We account for the effects of forecast uncertainty on closures, using a relationship between past storm surge and forecast uncertainty from an operational ensemble forecast system. A concern during a storm surge is that closed gates will trap river streamflow and could cause a new problem with trapped river water flooding. Similarly, we evaluate this possibility using historical data to represent river flood hazard, complemented by hydrodynamic model simulations to capture how waters rise when a hypothetical barrier is closed. The results show that SLR causes an exponential increase of the gate closure frequency, a lengthening of the closure duration, and a rising probability of trapped river water flooding. The USACE has proposed to prevent these SLR-driven increases by periodically raising the trigger water level (e.g., to match a prescribed storm return period). However, this alternative management approach for dealing with SLR requires waterfront seawalls to be raised at a high, and ongoing, additional future expense. For seawalls, costs and benefits will likely need to be weighed on a neighborhood-by-neighborhood basis, and in some cases retreat or other non-structural options may be preferable.

Integrating Reservoir Operations and Flood Modeling with HEC-RAS 2D

Current free to use models developed by the United States Army Corps of Engineers (USACE) perform unique functions (e.g., hydrology, hydraulics, reservoir operations, and flood impact analysis) that are widely used in numerous studies and applications. These models are commonly set up in a framework that is limited to point source connections, which is problematic in regions with flat topography and complex hydrodynamics. The separate models need to be integrally linked and jointly considered for accurate risk communication and decision-making, especially during major storm events. Recently, Hurricane Harvey (2017) exposed the shortcomings of the existing framework in West Harris County, TX, where an insufficient understanding of potential flood risk and impacts contributed to the extensive flood damages sustained in the region. This work illustrates the possibility of using a single hydraulic model, HEC-RAS 2D, to perform all hydrologic, hydraulic, and reservoir operations modeling necessary for accurate flood impact assessments. Implications of this study include a simplification of the entire flood impact analysis, which could help future flood risk communication and emergency planning.

A Phase I Cultural Resources Survey of the Orbit Pipeline Project Jefferson, Liberty, and Chambers Counties, Texas

A Phase I Cultural Resources Survey of the Orbit Pipeline Project Jefferson, Liberty, and Chambers Counties, Texas

An Intensive Cultural Resources Investigation for the Redbud Pump Station Transmission Water Line Project Collin County, Texas

The City of McKinney (City) is proposing to construct and maintain 2.2 kilometers (km; 1.4 miles [mi]) of 42- inch (in) water transmission line for the Redbud Pump Station Transmission Water Line Project (Project) located within the City of McKinney, in west-central Collin County, Texas (Appendix A, Figure 1). On behalf of the City, BGE, Inc. (BGE) conducted an intensive pedestrian survey augmented by shovel testing of the Project. Because the proposed project is being contracted by the City of McKinney, a political subdivision of the state of Texas, the project sponsor is required under the Texas Antiquities Code and the Texas Natural Resources Code Chapter 26 ‘Rules of Practice and Procedure for the Antiquities Code of Texas’ to obtain a Texas Antiquities Permit to perform cultural resources investigations to assess whether cultural resources are present that may rise to the level of significance of State Antiquities Landmark (SAL) status. The Texas Historical Commission (THC) has assigned Antiquities Permit number 8763 to the Project. Furthermore, project construction designs minimize impacts to Waters of the United States (WOTUS) crossed by the project, not meeting the minimum threshhold established under Section 404 of the Clean Water Act (CWA) for the requirement of a Pre-Construction Notification (PCN) to the United States Army Corps of Engineers (USACE).

Hydraulic Modeling and Evaluation Equations for the Incipient Motion of Sandbags for Levee Breach Closure Operations

Open channel levees are used extensively in hydraulic and environmental engineering applications to protect the surrounding area from inundation. However, levees may fail to produce an unsteady flow that is inherently three dimensional. Such a failure may lead to a destructive change in morphology of the river channel and valley. To avoid such a situation arising, hydraulic laboratory modeling was performed on an open channel levee breach model capturing velocity, in x, y and z plans, at selected locations in the breach. Sandbags of various shapes and sizes are tested for incipient motion by the breach flow. We found that a prism sandbag has a better hydrodynamic characteristic and more stability than spherical bags with the same weight. Experimental results are then used to evaluate existing empirical equations and to develop more accurate equations for predicting critical flow velocity at the initial stage of sandbag motion. Results showed the superior predictions a few of the equations could be considered with an uncertainty range of ±10%. These equations explained the initial failed attempts of the United States Army Corps of Engineers (USACE) for breach closure of the case study, and confirmed the experimental results are simulating the case study of breach closure.

Flood risk management with HEC-WAT and the FRA compute option

United States Army Corps of Engineers (USACE) policy states that USACE will analyze water resources projects, including flood risk management projects, using a risk framework that incorporates watershed, systems and life-cycle approaches. However, software to directly support these requirements has not been available. The current software sed within USACE to perform these types of analyses, HEC-FDA (Flood Damage Reduction Analysis), has a number of limitations. For this reason and others, USACE’s Hydrologic Engineering Center (CEIWR-HEC) developed the Watershed Analysis Tool (HEC-WAT). HECWAT was initially developed to assist USACE personnel conduct water resources studies of complex riverine systems with an integrated, comprehensive and systems based approach. However, since USACE also requires a life-cycle analysis, CEIWR-HEC added capability through the Flood Risk Analysis (FRA) compute option that allows risk analysis computations while incorporating a life-cycle approach. HEC-WAT/FRA includes systems and life-cycle approaches, event-based sampling, parameter sampling, and the ability to do scenario and alternative analyses. Applications of the FRA compute include levee certification studies, dam and levee safety studies, and planning and design studies. This paper will introduce HEC-WAT/FRA, describe scientific advancements included within it and provide applications to demonstrate how it will advance USACE modeling approaches.

Lifecycle Problems in Consequence Estimation

The United States Army Corps of Engineers (USACE) guidance documents require economists and planners to meet a very high standard when evaluating consequences resulting from flood events. The guidance documents require analysts to evaluate how government action changes the consequences over time, in addition to evaluating how government inaction changes consequences over time as well. Corps guidance (Engineering Regulation 1105-2-100, Section 2-3.c.4 and Engineering Regulation 1105-2-100, Section 2-3.b respectively) require the evaluation of direct and indirect economic impacts, life risk impacts, and agricultural impacts for both current conditions and future most likely conditions across a range of alternatives. Evaluating the potential for impacts from flooding across time, and how time impacts their existence or vulnerability, is considered a “lifecycle approach”. Little to no guidance is available on the process of calculating this “lifecycle approach” regarding changes in the value and number of assets within the floodplain over time. Performing a lifecycle analysis of a project over durations from 30 to 100 years, depending on the project purpose, requires evaluation of the changes in human behavior caused by changes in the floodplain such as reconstruction of structures, maintenance of structures, construction of new structures, population growth, and what type of structures are being built within the study area. This type of evaluation is not fully supported by most of the software programs utilized for flood risk management in the planning context. This paper is intended to describe pros and cons of economic lifecycle evaluation techniques to address the needs stated by policy, and tools that are being developed to support this analysis.