US Army Corps of Engineers
Great Lakes and Ohio River Division

Huntington District

Navigation Studies

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2012 Low-Water and Mississippi River Lock 27 Closure

The "2012 Low-Water and Mississippi River Lock 27 Closure" event study examines carrier, shipper, US Coast Guard, US Army Corps of Engineers responses to the extended low-water conditions due to the drought of 2012. Private sector responses were elicited with a survey of 175 shippers and interviews with ten waterway carriers and cost impacts estimated from their survey responses. USCG personnel with the Lower Mississippi Sector and Upper Mississippi Sector provided data on groundings and tow restrictions. Operations personnel with the Corps provided descriptions of actions taken in response to the low water and estimates of the cost of keeping the channel open.

Shale Gas Final Report

The emergence and rapid growth of the shale gas industry in the Northeastern U.S. raises questions regarding Great Lakes and inland waterways system transportation demand, and on U.S. Army Corps of Engineers responsibilities for those systems. The hydraulic fracturing process (fracking), when applied to Marcellus and Utica formation shale, produces natural gas in large quantities and at low prices. Fracking has created an entirely new industry since 2007, and that industry is still developing rapidly. This report looks at the development of shale gas in the Great Lakes and Ohio River basins and this development's implications for use of inland waterways (specifically the Ohio River System and the Great Lakes)."

Port and Waterway Modernization: Inland Waterways and Export Opportunities

Inland Waterways and Export Opportunities-FINAL 2013-1-03

Near continuous evolution of the global ocean-going fleet to ever larger vessels - an evolution of particular relevance to the Western Hemisphere with the scheduled opening of an expanded Panama Canal in 2014 – provided the impetus for Congress to direct the U.S. Army Corps of Engineers (USACE), Institute for Water Resources (IWR), to examine the preparedness of U.S. ports and waterways for 21st Century world trade. The results of this examination were presented in IWR's U.S. Port and Inland Waterways Modernization: Preparing for Post-Panamax Vessels, dated June 2012. The USACE Planning Center of Expertise for Inland Navigation (PCXIN) was given the opportunity to report on how promised ocean freight rate reductions from an expanded Canal might affect inland waterways and U.S. export opportunities. The PCXIN's findings are reported in Inland Waterways and Export Opportunities. This report supports IWR's Port and Waterway report, specifically by examining the ability of the inland waterway system to support and enhance export opportunities, relying upon readily available sources and recent evaluations of major inland systems conducted by the U.S. Army Corps of Engineers.

Port and Waterway Modernization: Overland Transportation Profile and Trade Affecting Inland Waterways

FINAL Tioga 060812 Waterways Outlook Report

This report was prepared by the Tioga Group for the USACE Planning Center of Expertise for Inland Navigation as part of their examination of opportunities for enhanced exports via inland waterways. The specific impetus for this examination is the near

future opening of new and larger locks on the Panama Canal - an occasion widely expected to alter U.S. imports and export patterns. The first issue addressed is the existing roles and export market shares of the waterways ports, and the modal splits between rail and barge. The analysis draws from statistics gathered by Customs and Border Protection (CBP) and maintained by the Census Bureau, and statistics gathered by USACE and maintained at the Navigation Data Center. The research team supplemented the statistics with other data sources and port contacts. The specific focus of this analysis is the potential impacts on exports via U.S. inland waterways and waterway ports. The waterway export points of interest in this analysis are: The Mobile Customs District, and the Tennessee-Tombigbee Waterway export port of Mobile. The New Orleans Customs District, and the Lower Mississippi export ports of Baton Rouge, New Orleans, Plaquemines, and the nearby port of Lake Charles. The Portland Customs District, and the Columbia-Snake export ports of Kalama, Longview, Portland, and Vancouver (WA).

Waukegan Harbor CDP ITR—2003
Lower Mongahela Update ITR—2002
A Life Cycle Component Model was developed to calculate expected costs given engineering reliability data. A specialized equilibrium model was developed to estimate rate-savings-eroded-diverted costs and determine base equilibrium waterway traffic. Given the base equilibrium waterway traffic and the varied alternate mode responses / costs, the WAM was modified to divert traffic and accumulate transportation cost statistics for simulation of scheduled and unscheduled closures of various durations. Waterway closure induced traffic impacts were also estimated. The normal O&M costs, base transportation costs, helperboat costs (if any), construction costs (if any), incremental maintenance closure costs, incremental unscheduled closure costs and the expert elicitation AAR costs are combined to generate the total costs associated with a particular scenario. Externality costs were also estimated as part of this study, though these costs were not used in project justification. The final feasibility report was completed April 2002. The efforts resulted in WRDA 2003 funding for constructing a 600' x 110' replacement lock
The review examined the feasibility of undertaking any capital improvements to the Great Lakes navigation system. The review identified factors and trends that affect the character of the existing system and projected future commodity flows and the external factors that affect them. Factors investigated included evolving transportation technologies, inter-modal linkages, characteristics of the Great Lakes fleet, changes affecting demand sectors, lock, channel and harbor capital improvements and related purposes. The reconnaissance level study, completed in June of 2002, documented what improvements may be warranted for further investigation in a follow-on feasibility study.
Computer Model Development (2001-2002) The GLLAST is a modified version of the International Joint Commission (IJC) model which was developed and used as part of the Levels Reference Study: Great Lakes - St. Lawrence River Basin. It uses several input files to calculate the time required to transport a given amount of commodities in a given fleet of boats for a given set of monthly average water levels and a given set of port/connecting channel depths. Calculations are made on a movement-by-movement basis. This way the monthly variations in lake levels and the boats' seasonal load line limits are included in the analysis. The GLLAST model has the ability to provide a detailed look at how port and connecting channel depths interplay with the Great Lakes fleet and water levels. The model was applied in the Great Lakes Navigation System Review, Recon. Report.
Modal Impacts-Great Lakes—2001
The Navigation Planning Center modified the deep draft simulation model to evaluate the economic impacts of further development and navigation improvements within Port Everglades Harbor. The deep draft version of the Waterway Analysis Model (WAM) was modified to simulate the interaction of dock area performance (loading and unloading rates, and turning basin times), vessel sizes, channel dimensions (width, depth, and bendway characteristics) and tidal flows for the various alternatives being considered by the Jacksonville District. The modified WAM also used on-the-fly animation to help show the problem areas which impede current or future operations. The animation shows a map of the harbor with key features such as, docks, channels, turning basins and one-way reaches. Icons and displays show tidal cycles and their effects on the harbor, as well as the usage of the harbor by vessels of different sizes. The economic impacts were limited to the measurement of vessel transit costs.
Kanawha River System Study—2000-2003
The Myers/Greenup feasibility report, an interim report from the Ohio River Mainstem study, ORMSS uses a regional systems approach to address the investments needed to provide an efficient navigation system on the Ohio River Mainstem. The economic system analysis using the Tow Cost/Equilibrium (TC/EQ) examined alternative investment strategies across 20 existing lock sites and across time. The TC/EQ model was used along with the Life Cycle Lock Model to estimate the expected costs of closures (repair and navigation industry delays) and resulting system transportation savings under alternative maintenance regimes. Both models were also used to estimate system savings for alternative non-structural and with-project condition investments. Extension of the small, auxiliary chambers from 600' in length to 1200' in length was authorized at both projects in WRDA 2000.
The Navigation Planning Center developed a deep draft simulation model that was used to evaluate the economic impacts of further development within Charleston Harbor. The deep draft version of the Waterway Analysis Model (WAM) was modified to simulate the interaction of dock area performance (loading and unloading rates, and turning basin times), vessel sizes, channel dimensions (width, depth, and bendway characteristics) and tidal flows for the various alternatives being considered by the Charleston District. The modified WAM also used on-the-fly animation to help show the problem areas which impede current or future operations. The animation shows a map of the harbor with key features such as, docks, channels, turning basins and one-way reaches. Icons and displays show tidal cycles and their effects on the harbor, as well as the usage of the harbor by vessels of different sizes. The economic impacts were limited to the measurement of vessel transit costs.
Commodity, State, Project & Congressional Profiles—1999-2003
Modal Impacts - Ohio River Basin—1999-2000
Indiana Harbor ITR—1999
WAM Shallow Draft Users Manual—1999
Through ORNIM the Center began to utilize newer database management techniques, integrate the linkages between the various models, include engineering reliability of lock components, integrate environmental analysis and analyze the multitude of investment permutations at all projects simultaneously under a variety of future traffic forecast scenarios, This required upgrading LRD's models into the Ohio River Navigation Investment Model (ORNIM).
Chicago Harbor Lock is located at the mouth of the Chicago River in downtown Chicago, Illinois adjacent to the Navy Pier, a major tourist and entertainment attraction. A risk and reliability analysis was performed using a spreadsheet model (Component Replacement Optimization Worksheet) designed specifically for this study. Probabilities and consequences of major component failures were estimated using engineering reliability analysis and probabilities for time of year were estimated using Monte Carlo simulation. These analyses formed the basis for estimating the expected economic consequences to recreation boaters, the barge industry and, most importantly, the commercial lock-tour industry of the alternative maintenance strategies. As a result of this analysis, it was recommended that the lock undergo major rehabilitation. The Rehabilitation Evaluation Report for the Chicago Harbor Lock was completed in July 1999 and approved by HQUSACE in September 1999.
Lower CU and TN Rivers Traffic Mgt Study—1997-98
The original 1986 authorization was a conditional authorization and an LRR was needed for the required Chief's report. Draft LRR was completed December 1999 and final LRR completed October 2000. Per HQUSACE policy compliance review assessment, a revised final LRR was completed April 2002. Construction cost changes necessitated a third final LRR which was completed November 2002. Fourth, final LRR was completed in fall of 2003. Benefits for lock replacement are founded on avoidance of accident related closures. As such, the analysis is highly dependant upon simulation analysis of probabilistic events with probabilistic consequences over an uncertain future. The analysis incorporates forecast scenario uncertainty and all analysis statistics are reported in probabilistic terms (e.g. BCR distribution).
London L/D Rehab—1997
Marmet L/D PED Update—1996
The Detroit District has requested that the Navigation Planning Center perform an economic update for the replacement of a lock at Sault Ste. Marie, Michigan. The Navigation Planning Center is preparing a benefit update as part of the Detroit District's Limited Reevaluation report for a replacement lock at Sault Ste. Marie. Adapting the Navigation Planning Center's simulation model, the Waterways Analysis Model, to a Great Lakes facility like the Soo Locks is a major component of the benefit estimating process. This work is currently underway.
Kentucky Lock Limited Reevalutaion Report—1995
The primary study purpose is to develop the best plan for maintaining a reliable navigation system on the mainstem of the Ohio River. Specifically, the study will evaluate maintenance, major maintenance, major rehabilitation and new construction investment needs for 19 navigation locks and dams, and will identify the optimum plan for meeting those needs. The ORMSS will produce a System Investment Plan (SIP). Earlier in the study, two site specific lock facilities were identified where initiation of construction is warranted prior to 2020. Feasibility level documentation and full NEPA analysis were produced for these 'near-term' sites; J.T. Myers and Greenup Locks and Dam. These projects were authorized by the Water Resource Development Act (WRDA) 2000. Follow-on feasibility level of detail study reports with NEPA analysis will be required for all other projects indicated within the study planning horizon by the Ohio River Mainstem System Investment Plan (SIP). The SIP will include a timetable and cost estimates for future anticipated navigation investments along the Ohio River Mainstem through the year 2060, including both large-scale investments and small-scale navigation improvements. The report document will include the culmination of the various plan formulation, economic, engineering, and environmental study analyses using such tools and techniques as structural reliability modeling, water transportation economic modeling, and environmental modeling.
Uniontown (Myers) L/D Feasibility—1993-1994
McAlpine L/D PED Update—1994
Lower Mon PED Update—1994
ORS Lock Capacities Update—1994
Kentucky L/D LRR—1993
This is the second of three interim studies conducted on the Kanawha River. Like Winfield, Marmet has dual 56' x 360' lock chambers which are obsolete given today's modern inland fleet. Marmet also has structural condition problems which will require major rehabilitation of the existing chambers if another 50-years of use is required. This study was the first study in LRD to incorporate engineering reliability and required development of simulation models to quantify expected cost of failure consequences. The project was authorized for construction by the WRDA 96; construction began in 2002 and is scheduled for completion in 2007.
Green River Phase I Feasibility—1993
Commodity traffic data and annual dredging costs were utilized to determine the economic feasibility of continued maintenance dredging along the lower 2.6 miles of the Elk River. Benefits attributable to maintenance dredging are the terminalling cost savings enjoyed by commercial users of the Elk River when compared to costs associated with using terminals along the Kanawha River.
This study analyzed capacity problems, approach problems, and structural condition problems of L/D's 2, 3, and 4. The navigation system analysis included development of traffic demand forecasts, lock capacities, vessel fleets, transportation rates, and navigation benefits for each alternative. Major capacity analysis challenges included developing fleet forecasts for existing and proposed facilities and evaluation of the capacity and economic impacts of lock closures during new construction, major maintenance, rehabilitation, and periodic maintenance. In addition, several modernization alternatives, including the tentatively selected plan, involved reduction in the number of projects through pool raises. The proposed modernization plan which includes a new dam at L/D 2, elimination of L/D 3 and new locks at L/D 4, was authorized in the Water Resources Development Act of 1992. Construction began in 1995 and is currently scheduled for completion in 2009. The modernized L/D 2 will be named Braddock L/D and the new L/D 4 will be renamed Charleroi L/D.
This study utilized commodity traffic data and annual dredging costs to determine the economic feasibility of continued maintenance dredging along the lower 8.6 miles of the Big Sandy River. Benefits attributable to maintenance dredging are the transportation rate savings enjoyed by commercial users of the lower Big Sandy when compared to a competing, additional line-haul transportation cost associated with using terminals along the Ohio River.
Upper Ohio Progress Report—1991
By means of the Barkley Canal, Kentucky Lock on the lower Tennessee River and Barkley Lock on the lower Cumberland River provide alternate routes for entering and exiting the upper Tennessee and upper Cumberland Rivers. This study addressed congestion and capacity problems associated with both locks as well as channel capacities in ten narrow, tight bend ways of the lower Cumberland River. The dual traffic options offered by this two-lock subsystem necessitated the development of a sophisticated computer model to properly measure the traffic split between the two projects and the corresponding lock performances. Traffic demand forecasts, lock capacities, vessel fleets, transportation rates, and navigation benefits were developed for each. Noteworthy advances in capacity analysis were achieved within the context of these studies. First, the Waterway Analysis Model (WAM) was successfully applied to the ten lower Cumberland bend ways. This model application permitted detailed simulation of vessel operations. The results of these efforts were integrated for subsequent estimates of lock capacity and delay. The addition of a new 110' x 1200' lock at Kentucky Lock and Dam was authorized by the Water Resource Development Act (WRDA) of 1996. Construction began in 1998 and is scheduled for completion in 2007.
The LRD Navigation Planning Center completed benefit estimates for Georgetown Harbor on the Atlantic Coast of South Carolina. This study examined the savings to shippers that are expected to accrue from continuing maintenance dredging of the project. The major components of the study included identifying existing and potential traffic, identification of alternative ports and modes of transportation for delivery of commodities, estimates of transportation costs for the water and non-water alternatives, and benefit analysis.
Lock Maintenance Closure Study—1990

Benefit Re-Evaluation for the Olmsted (Illinois and Kentucky) Locks and Dam (1990)

Periodic updates of project benefits and costs are required by ER 1105-2-100. Project costs used in this document were an update from the Olmsted L&D General Design Memorandum (GDM) Supplement. Updated project benefits were based on a more recent set of traffic demand forecasts, transportation rates, and lock capacity and delay relationships, all of which were used in making new economic model runs for the recommended plan. Detailed comparisons were made between the original and updated benefits, traffic demands, and transportation rates. This updated analysis indicates that the recommended plan is feasible.

This study utilized the Waterway Analysis Model (WAM) to predict delays for tows using the existing locks during construction of the new lock at Winfield. It also evaluated various traffic plans and identified the plan which would maximize tonnage throughout.
Green River Navigation Recon—1990
Using analytical techniques, this study evaluated optimum locking policies during closure of the main chambers. The use of helper boats and the best tow queuing policy were evaluated.
Under the auspices of the Directorate of Civil Works, Headquarters, U.S. Army Corps of Engineers, this study had the objective of identifying and prioritizing investment needs within the entire U.S. inland waterway system. Investment need and prioritization criteria are economic. Investments were prioritized to maximize system net benefits subject to the availability of funds from the Inland Waterways Trust and General Funds. Systems economic analysis was used to achieve this optimization. The LRD Navigation Planning Center has provided and will continue to provide key support in establishing traffic demands, lock capacities, navigation operating characteristics, and modeling. The results of this research will be used by Headquarters and the Inland Waterways User Board to establish the navigation investment program of the Corps.
This study was concerned with potential navigation improvements on the Kentucky River. As a part of this study, the Navigation Center was required to review and update commodity traffic and benefit analysis that had been completed under contract. The study required a supplemental market survey and commodity resource analysis as well as a partial system analysis for the two and three lock navigation systems that were under consideration.
Drought Impact Study—1989
This paper provided an initial assessment of the feasibility of improving the Cooper-Santee waterway. Limited field investigations and interviews of potential users were conducted to identify potential future movements and associated tonnage ranges. Movements were subjected to rate analysis and screened to establish a probable traffic base. Preliminary benefits to this traffic were estimated as the rate savings over other modes of transportation. A special feature of this study was evaluation of the economic viability of container on barge service.
The LRD Navigation Planning Center Chief served on a study advisory board for the formulation and evaluation of a new lock on the entrance channel to the McClellan-Kerr (Arkansas River) Waterway. Over the last several decades, the water surface profile within this reach of the waterway has declined restricting drafts and imposed costly dredging burdens. The Little Rock District proposes to cost-effectively remedy this threat to reliable navigation by installation of a lock to ensure navigable water depths with reduced dredging. The LRD Center has also provided technical support to the Little Rock District for formulation and evaluation.
The Navigation Planning Center developed a deep draft simulation model that was used to evaluate the economic impacts of further development within Charleston Harbor. The deep draft version of the Waterway Analysis Model (WAM) was modified to simulate the interaction of dock area performance (loading and unloading rates, and turning basin times), vessel sizes, channel dimensions (width, depth, and bendway characteristics) and tidal flows for the various alternatives being considered by the Charleston District. The modified WAM also used on-the-fly animation to help show the problem areas which impede current or future operations. The animation shows a map of the harbor with key features such as, docks, channels, turning basins and one-way reaches. Icons and displays show tidal cycles and their effects on the harbor, as well as the usage of the harbor by vessels of different sizes. The economic impacts were limited to the measurement of vessel transit costs.
Upper Tennessee River Recon—1988-1991
McAlpine Locks and Dam is a complex project located in metropolitan Louisville, Kentucky. The project includes 110' x 600' and 110' x 1200' locks in the Portland Canal and a large navigation dam with hydroelectric generating facilities. The study examined capacity and delay problems, lock condition problems, and navigation complexities associated with the canal and several bridges, as well as an inefficient and obsolete auxiliary chamber. Significantly, new ground was broken in evaluating operations and capacity for this study. A new capacity simulation model was built and applied to incorporate navigation restrictions in the Portland Canal, particularly those associated with channel operations, safety and bridge openings. Based on these economic and capacity analyses, Congress authorized replacement of the existing 110' x 600' lock with a new 110' x 1200' chamber in the Water Resources Development Act of 1990 and construction started in 1996, with completion scheduled for 2006.
Wabash River Navigation Recon—1987
This study examined lock congestion and capacity problems associated with severely undersized locks at Winfield L/D on the Kanawha River, WV, currently the nation's busiest inland navigation facility in terms of lockages. High utilization and delays at Winfield result from two primary factors: high economic demand for the movement of commodities and obsolescence of the twin 56' x 360' locks for a modern inland fleet dominated by jumbo class and larger barges. Because these larger barges each require a separate lockage, tows must be broken into numerous "cuts" for service. Innovative fleet forecasting techniques were required to achieve capacity evaluations that fully reflected the expected growth in use of larger barges as well as the anticipated acceleration in the adoption of such barges with new larger locks. These lock capacity and delay studies along with traffic forecasts and economic modeling formed the basis for a complete benefit/cost analysis for the modernization of this project. Modernization was authorized in the Water Resources Development Act of 1986 (PL99-662) and a new 110' x 800' lock was completed in November 1997.
Locks and Dams No. 52 and 53 (Olmsted L/D) Feasibility—1985
This report explains the development of traffic demand forecasts for the Ohio River System. The forecasts are based on movements occurring in 1980, detailed field interviews with waterway users, extensive industry and market studies and regional economic forecasts available from other government and private sector entities. Traffic demand forecasts are basic data inputs to models of the Ohio River Navigation System. The 1985 forecasts were actually the second generation of traffic projections made for the entire Ohio system. The first set of system wide forecasts were included in the Gallipolis Locks and Dam study.
This report documents the estimation of water and overland mode transportation rates for all movements using the Ohio River Navigation System. The study included a statistical sampling of movements for which actual rates were collected, analysis of these rates, and the use of standard regression techniques to estimate transportation rates for movements not included in the sample. The rates estimated in this study are the basis for estimating navigation system benefits as well as incremental benefits for proposed investments in the system.
The Locks and Dams 7 & 8 study provided the vehicle for additional improvements to techniques for evaluating navigation operations and waterway capacity. The study evaluated replacement of the small single chamber lock facilities at both projects. Challenges associated with both maintenance and fleet analyses were met through innovative adaptation of existing capacity and economic models. Models applied to the study included the Tow Cost Model (TCM), a fleet sizing and costing program, the Waterway Analysis Model (WAM), a traffic simulation model, and the Marginal Economic Analysis Model (MEA), to measure the incremental system benefits and impacts of alternative plans. Based in part on evaluations from these studies, lock improvements were authorized in the Water Resources Development Act of 1986. Grays Landing Lock and Dam replaced L/D 7 in 1993 and Point Marion Lock replaced Lock 8 in 1993.
This study developed the Corps' first comprehensive systems analysis supporting Congressional authorization of a major inland navigation project, Gallipolis Locks and Dam on the Ohio River. State-of-the-art efforts included development of computer models, databases and analytical techniques to evaluate capacity and operational constraints posed by obsolete locks. The study also produced a complete cost/benefit analysis and economic optimization for a wide range of alternative plans. In addition to supporting the authorization of new, larger locks, this milestone study provided major refinement and enhancement of capacity analysis techniques still in use today. The new 110' x 600' and 110' x 1200' locks in a canal were opened in January1993.
Undertaken for the Institute for Water Resources, this research effort exposed the compatibility of available economic systems models: the Tow Cost Model and General Equilibrium Model. Extensive runs of the two models together with comparison of outputs from both were used to establish consistency.
The LRD Navigation Planning Center has been collecting waterborne commerce data from barge and towing companies headquartered in the Ohio River Basin since 1985. In this effort the Center supports the Corps' Waterborne Commerce Statistics Center (WCSC), which has nationwide responsibility for the collection, coding and publication of waterborne commerce data. Currently, 125 Ohio River Basin companies accounting for 307 million tons of waterway traffic report their inland waterway moves to the Center. Beginning in 2003, the Center began collecting data from U.S. vessel operators operating on the Great Lakes. There are approximately 50 Great Lakes companies moving bulk commodities such as iron ore, coal and aggregates and another 40 or so companies operating excursion, sightseeing and car ferry trips. The total tonnage for the Great Lakes cargo operators is almost 110 million tons. This effort is funded by WCSC in New Orleans, which is a division of the Navigation Data Center at Fort Belvoir.
This report documented the Tow Cost Model (TCM) as enhanced and applied within the LRD Navigation Planning Center. The TCM is a waterway system transportation cost model. While similar to a barge costing model, it differs in that all movements using the system are contained within the model. Therefore, delay estimates computed and costed within the model, can be made to reflect total current or expected future use of the system.

The Corps of Engineers, over many years, has pursued continual refinement in the development of the waterway traffic forecasts used in project economic analyses. The multi-scenario spatial utility steam coal forecasting described in this paper, which is based on the work of Hill & Associates, Inc. (H&A), represents a substantial refinement over previous forecasting efforts.

H&A prepares 20-year steam coal forecasts based on the interaction of two major linear programming models, the National Power Model (NPM) and the Utility Fuel Economics Model (UFEM). The NPM is a utility industry model that dispatches all electric generating plants in the U.S. (both coal and non-coal), producing forecasts of generation by fuel type within a context of transmission and environmental constraints. The UFEM makes use of highly-detailed coal supply data (for approximately 98 coal types) to allocate fuels among plants and units. These two models developed forecasts of coal demand, by type of coal, for electric generation, which were then “mapped” to the waterway.

H&A prepared separate forecast scenarios based on three alternative environmental regulatory futures. The first of these represents a continuation of existing law, which in this case is the National Ambient Air Quality Standards. This scenario is referred to as the NAQ scenario. The second H&A scenario (referred to as the BUS scenario) reflects implementation of the administration’s Clear Skies Initiative. The final H&A scenario is implementation of the Clear Skies Initiative without the proposal’s severe mercury restrictions. This scenario is referred to as the BNH scenario.