Inland Navigation: Environmental Sustainability

This chapter provides an overview of the ecosystem sustainability procedures currently used for United States inland waterways. It presents environmental considerations for construction, operation, and restoration of waterways in the continental United States. Navigable waterways in the United States include both coastal (tidal) and inland waterways used in the past, present, or potentially in the future, to move people or commodities. Environmental sustainability of waterways is being pursued by the United States and many other nations. All work on and in the federal waterways in the United States is controlled by Congress. Consideration of environmental impacts is an essential element in the design of any project, including navigation projects. Port navigation facilities are funded and built by federal agencies (such as the US Navy), by state and local governments, and by private concerns.

The earliest navigation projects were designed and constructed with minimal regard for depletion or destruction of natural resources. Projects were often of too modest a scale for large environmental impacts, and science was inadequate to define any but the most catastrophic effects. The US Army Corps of Engineers has established a set of environmental operating principles to ensure that its mission includes totally integrated sustainable environmental practices. These principles must be implemented through Corps’ regulations and manuals in order to become embedded in practice and achieve a standing comparable to economic issues. In addition to laws, regulations, and policies, the principles of sustainable development have now been incorporated into codes of ethics. ASCE, with the American Public Works Association (APWA) and the American Council of Engineering Companies (ACEC), has established the Envision infrastructure sustainability rating system within a new Institute for Sustainable Infrastructure for horizontal infrastructure service systems.

The inland waterway system in the United States consists of about 25,000 mi of inland waterways. The inland waterways were originally used by Native Americans for trade. In 1910, Congress passed the Rivers and Harbors Act, which authorized construction of a series of locks and dams to provide a 9 ft navigation depth on the Ohio River. This chapter presents a chronology of Navigation Development Activities on the Upper Mississippi River and Illinois Waterways. The Columbia-Snake Rivers developed a high lift lock-and-dam system with hydropower features between 1938 and 1975. Since the 1880s, a Trinity River barge canal was envisioned between Trinity Bay, near Houston and Dallas, Texas. The Trinity River navigation project was restarted in the 1960s, after Congress approved navigation by barges in 1965. Future work on the inland waterways in the United States will include replacement of current system components and potential construction of new waterways.

The inland waterway system of the United States is dominated by the Mississippi River and its tributaries. This chapter presents a physical/environmental description of some of the major US waterways. The Upper Mississippi, Ohio, and Columbia systems are characterized by relatively low sediment loads, stable channels, and lock-and-dam type improvements. The Missouri and Middle and Lower Mississippi Rivers are alluvial rivers transporting large quantities of fine sediment. Water quality is generally excellent compared to other major waterways; however, nitrogen supersaturation impacts on anadromous fish are a prime concern. The Red River Waterway provides a 200 ft wide ×9 ft deep channel for barge traffic from the Mississippi River to Shreveport, Louisiana. The Great Lakes/St. Lawrence Seaway is the most extensive shipping channel and lock system in North America. The navigation system is 2,038 nautical miles long and extends from the Atlantic Ocean to Duluth, Minnesota.

Waterways have always been used for water supply for cities and, in many cases, waterborne transportation. The federal objective of water and related land resources planning is to contribute to national economic development (NED) consistent with protecting the nation’s environment, in accordance with national environmental statutes, applicable executive orders, and other federal planning requirements. This chapter presents a brief description of major legislation related to environmental protection. Civil works (US Army Corps of Engineers’) studies and projects should be in compliance with all applicable federal environmental statutes and regulations and with applicable state laws and regulations where the federal government has clearly waived sovereign immunity. The Corps of Engineers incorporated ecosystem restoration as one of the environmental missions within the Civil Works program in response to the increasing national emphasis on environmental restoration and preservation.

A navigation project evolves from a conceptual plan to a rehabilitation or abandonment at the end of its life cycle. The various phases of the life cycle are: planning, design, construction, operation and maintenance, and rehabilitation and restoration of impacted habitat. The planning phase of a navigation project includes the determination of economic benefit, environmental impacts, the cost of alternatives, and the recommended plan. The design phase starts with the development of an overall project design that is more detailed than the recommended plan in the feasibility report. This design and cost estimate includes any structures, channel dredging, bank protection, relocations, and environmental features. The project is often accomplished by several contractors with coordination and adherence to plans and specifications by an independent construction management team. The objective of ecosystem restoration is to restore degraded ecosystem structure, function, and dynamic processes to a less degraded, more natural condition.

With the passage and implementation of the National Environmental Policy Act of 1969, environmental impact assessments of water resource projects under the US Army Corps of Engineers and other federal agencies assumed a greater level of importance. An environmental impact statement (EIS) is needed when a project is expected to have a significant impact on the existing ecosystem. Following an agreement with resource agencies, the EIS is forwarded to the US Fish and Wildlife Service for concurrence. The approved EIS is included with a report that recommends construction and forwarded to Congress for authorization. Cumulative effects analysis recognizes that the most serious environmental impacts may result from the combination of individually minor effects of multiple actions over time, rather than the direct or indirect effects of a particular action. An environmental assessment (EA) is used when there are no significant impacts expected from a recommended action for a navigation project.

This chapter provides information on hydraulics and sedimentation processes common to inland waterways to provide background information for environmental situations. Natural inland waterways include most rivers and lakes where water is already available, even if not always at a depth necessary for navigation. Canals are often constructed by excavation to extend or connect natural waterways. The US-Canadian Great Lakes are the prime example of natural waterways consisting of water impounded by natural geographic features and connected by rivers. Hydrology, weather, and climate are described in statistical terms when used in waterway studies. Sedimentation processes—the erosion, transport, deposition, and consolidation of sediment—driven by wind and flowing water cause significant issues in inland waterways. Sediment eroded from hills and mountains deposits when the ground slope flattens out, creating delta splays.

Dredging in the inland waterways is performed primarily with hydraulic pipeline equipment or mechanically by cable-suspended buckets. Dredging removes sediment from recent deposits in a navigational waterway (maintenance) or from a long-time natural state to create new navigation access. The dredging project is a function of site conditions, dredged material type and quantity, equipment availability, operations, and logistics for the discharge of dredged sediment. Special-purpose dredging systems have been developed during the last few years to pump dredged material slurry with high solids content and/or to minimize the resuspension of sediments. A long-term management strategy (LTMS), dredged material management plan (DMMP), or dredged material management strategy (DMMS) describes a plan for managing sediment removed during maintenance dredging. Although management of typical navigational dredged material allows for few design specifications, these specifications can be critical in managing the impacts and engineering for benefits, such as ecological function or flood protection.

The use of notches in spur dikes, longitudinal dikes, L-head dikes, and closure dikes is an excellent method for creating varying habitats for fish, birds, and other wildlife. At the same time, dike notches appear to have little to no impact on the efficiency of these types of river training structures to maintain a safe and efficient navigation channel. Other innovative river training structures, such as chevron dikes and hard points, have also shown positive environmental impacts without significantly affecting the navigation channel. One type of river training structure that has been used by the US Army Corps of Engineers for about the last 20 years is bendway weirs. When providing environmental enhancements and modifications to the design of either new or existing river training structures, certain aspects of the details to be included in the design need to be addressed.

Maintaining environmental equilibrium on waterways with locks and dams requires provisions for allowing fish migration both upstream and downstream. On rivers with fish species that migrate between freshwater and saltwater and back to freshwater, special features are required at locks and dams to maintain their survival. Initially fish ladders were provided for upstream migration of adult salmon and downstream juvenile salmon migration was over spillways or through powerhouses. The juvenile fish bypass systems in place at the lower Columbia and Snake River dams guide fish away from turbines by means of submerged screens positioned in front of the turbines. A bypass channel is an option for fish passage around a river obstruction that would prevent migration. Fishing regulations and restrictions are another method to manage fisheries in inland waterways.

Any environmental mitigation or restoration will need to address the loss of habitat for migrating birds and provide suitable replacement land to support the sustainable waterfowl population. Wildlife management plans and enforcement are needed to ensure the reproduction habitat requirements are met for the target species. Most new or restoration projects include land acquisition to mitigate for land lost to a waterway created reservoir. The three major technology areas of aquatic plant control that might be used in shallow draft channels are biological, chemical, and mechanical controls (or some combination of two or more of these methods). In 1966, the National Historic Preservation Act sought to protect, restore, and maintain historical and archaeological resources affected by federal projects. This legislation created a federal-state partnership to identify districts, sites, objects, buildings, and structures significant in American history, archaeology, and culture.

This chapter presents some examples of environmentally sustainable practices that are provided to give more detail of discussions given in the text. The examples are Red River Waterway, Upper Mississippi River, Lock 27 Mississippi, Bonneville Dam 2nd Powerhouse, Columbia River Deepening Project, Great Lakes, Lower Mississippi River, Willamette River, and Lower Mississippi Restoration. An Environmental Impact Statement (EIS) for the Red River waters was produced in September 1983. This EIS was needed to address the June 1980, Congress authorized establishment of the Tensas National Refuge. The analysis and understanding of cumulative effects acting on the Upper Mississippi River ecosystem presented an important context for developing ecosystem restoration alternatives. The Great Lakes navigation system is a 2,400 mi long deep water network of dredged channels, locks, and open water lake segments. The system extends from Duluth, Minnesota, to the Atlantic Ocean.