Water Marks: Navigating the Challenges of Modern Marine Design

Boating with the Current: 
New Directions for Riverine Harbors and Inland Water Infrastructure

This year’s PIANC-Smart Rivers Conference was held in Pittsburgh, a city built at the convergence of three rivers. It was the perfect location for sessions and discussions centered on best practices in 21st century river transport and inland waterway design.

Pittsburgh’s historic development echoes that of many U.S. riverine cities: communities that grew through river-based commerce and industry, and have subsequently redeveloped their waterfronts for largely public and recreational uses. The Smart Rivers conference sessions identified a number of additional shifts that are likely to emerge in the years ahead. Interestingly, some of the key trends for inland waterways appear to be taking us back to the future.

Reinvestment in Water-Based Transport

Before the advent of rail lines and highways, rivers were the primary transportation corridors and the lifeblood of U.S. inland communities. The Mississippi River was and still remains an important artery of commerce. At its zenith, the Mississippi was the great interstate highway of the central U.S., ferrying passengers and goods up and down the river in ever-increasing numbers.

With the continued push to reduce global pollution, in particular greenhouse gases (GHG), it should be noted that waterborne transport is considered to be the greenest option. Waterway transport produces only a tenth of the GHG produced by roadway transport and a quarter less than rail transport.  Additionally, trucks can only carry a fraction of the load of a single barge, which has major cost as well as GHG implications. By all accounts, water transport is a cheaper form of commercial transportation. Freight transported on rivers also has the added benefit of keeping trucks off of congested roadways.

Given that a reduction in transportation costs is necessary to be competitive in a global market, more countries will likely be moving toward inland waterway transport. River transport can be unpredictable.  Strong currents, obstructions, extreme weather and varying water levels pose great hazards to navigation and delays to shipments. However, the transportation opportunities are significant, especially when coupled with improved infrastructure and channel maintenance.

While the U.S. is among the largest users of inland waterways for transport, they are far behind Europe, which has one of the most advanced waterway systems in the world. Rivers much smaller than the Mississippi have been engineered to remove navigation variability through riverbank stabilization and sustainable channel sedimentation control. The construction of numerous canal connections allows smaller, ocean-going steamers to sail directly into the center of the continent.

In addition to commercial transport, river cruises are gaining popularity, particularly along the Mississippi and St. Lawrence, resulting in cities vying for docking terminals to generate new tourism revenue streams. Cities are recognizing what a valuable tourism development resource a river can be. The trend toward more tourist-oriented, destination boating facilities will also manifest itself on rivers, with increased investment in vessel launches and transient docking facilities.

With a renewed tourism and recreational interest in our waterways, and a likely future increase in commercial traffic on our rivers, the federal government and local communities will be more focused on repairing antiquated infrastructure, as well as improving channel maintenance and the overall health of the river.

The U.S. waterway system has historically relied heavily on the U.S. Army Corps of Engineers to perform dredging and infrastructure activities. Waterways have suffered due to delays in dredging cycles from unpredictable federal funding. With funding for the Corps likely to become more uneven and unpredictable, even with the current administration’s stated emphasis on infrastructure, these services may shift to private companies, fueling a growth in these waterway and marina-serving markets.

One problem many waterways will likely encounter is increased conflicts and pressures from the mix of commercial and recreational users. Recreational boating is typically allowed within industrial waterways, making increased presence on the water a potential safety hazard. Additionally, increased barge traffic results in more frequent boat wake, which will have an impact on both erodible river shoreline and floating infrastructure.

Designing with the River

Riverine communities in the U.S. that have historically barricaded themselves against the hazards of rising waters and flooding are now finding their way back to the river with resilient waterfront designs. This increase in living shoreline and green infrastructure approaches is likely to continue, as waterways become more naturalized and less channelized: in many ways, more like they used to be.

While Europe has responded with a more structured approach to river maintenance, initiatives to protect the natural areas and wetlands along the rivers have gained favor in the U.S. Studies suggest that wetlands not only offer habitat opportunities but also act as a sponge for flood waters, protecting communities from some of the devastating effects of severe weather. Many experts observed that the recent hurricane flooding impacts in Houston were exacerbated by a significant loss of wetlands to development over the past two decades.

The current Dutch initiative “Room for the River” utilizes a wide range of adaptive channel and levee design approaches, integrated with low-lying natural open space areas to give flood waters a place to go. The Noordwaard project in the Netherlands presented during the PIANC conference provides an outstanding example of this approach. The presentation abstract summarizes the benefits to both upstream and downstream communities:

Historically, engineers have taken defensive action against rising waters of the rivers, building levees and dikes which limited, and in some cases, restricted access to the water. As upstream development continued to reclaim floodplains and constrict the river, communities downstream were left in a perilous position forcing them to continuously increase the height of the protective structures, cutting them off further from the river. The new model is smarter and greener. Communities and engineers have learned to work with the river and allow for temporary inundation of low-lying lands. These low-lying lands can still be used for a variety of purposes but are designed to be resilient following a flood event. This creates a more natural, yet engineered solution to the unavoidable event of higher water levels.

It is important to note that many rivers extend beyond the borders of any one state, which will require a more holistic, multijurisdictional approach to river channel management and flood resilience moving forward. But increased riverine traffic and connectivity have huge implications for the recreational boating industry, which could find itself in the midst of an inland waterway renaissance.

Margaret Boshek is a civil and coastal engineer with SmithGroupJJR’s Waterfront Practice. She can be contacted at Margaret.Boshek@smithgroupjjr.com.