Aging Infrastructure and Ecosystem Restoration

As a result of recent infrastructure failures, particularly the tragic failure of the Interstate-35 bridge in Minnesota, the US Senate passed the National Infrastructure Improvement Act (NIIA), which would create the National Commission on the Infrastructure of the USA. The commission’s broad mandate would be to assess the nation’s infrastructure and its ability to meet current and future demands.  Such policy development coincides with ongoing efforts to manage and restore degraded ecosystems.  This provocative intersection of aging infrastructure and environmental degradation provide unprecedented and largely unappreciated opportunities for ecosystem restoration.

Convergence of Phenomena

The United States is at an unusual juncture of three growing phenomena.  First is the widespread decay of infrastructure.  The 20th century saw rapid growth in population, the economy, and infrastructure (see chart).  Many structures have been in place for 50 years or more, and increasing portion of national infrastructure is now approaching or exceeding it’s originally intended design life and will require over $1.6 trillion to reach acceptable levels of safety and function (1).

The second phenomenon is the degradation of the environment and loss of associated ecosystem services (2).  Substantial ecological degradation can be attributed, at least in party, to infrastructure expansion.  Roads increase sediment erosion, fragment habitat, and facilitate the spread of invasive species (3).  Dams and levees restrict fish migration and have drastically altered river flow regimes (4).  Offshore platforms discharge waste, release atmospheric pollution, and compete with commercial fishing (5). 

Third is the burgeoning of ecosystem restoration as both a science and an industry (6).  To date, restoration has often been limited in scale, and its effectiveness is frequently unclear (7).  Nevertheless, there is growing demand, political will, and funding for restoring degraded ecosystems (7, 8).

Restoration via Decommissioning

Decommissioning can take several forms, including full removal, partial removal of key components, or abandonment.  Publicly versus privately owned infrastructure may differ in decommissioning procedures and ability, but all are subject to the National Environmental Policy Act and equivalent state laws, although these laws generally do not facilitate ecological restoration.

On rivers, dam decommissioning is increasingly common, whereas levee decommissioning is rare.  Of the 79,000 dams in the United States, 3500 have been rates as unsafe, collectively in need of $30 billion for rehabilitation, repair, or removal (1).  Levee inventories are less clear, but estimates exceed 25,000 km (9), many with unknown structural integrity (10).  To date, 600 dams have been removed, primarily for safety and economic reasons.  Dam removal is followed by rapid recovery of invertebrate, fish, and riparian vegetation communities (11).  Levee decommissioning, often abandoning breached levees, reduces economic demands of levee reconstruction while improving floodplain habitat and water quality (12).

Of the 6 million km of roads in the United State, 885,000 km are on public lands maintained by federal land agencies, a portion of which are rarely used (13).  The U.S. Forest Service (USFS), with 250,000 km of roads over 50 years old, estimated its maintenance backlog at $10 billion for 26% of system roads (13).  The USFS decommissioned 7900 km of roads between 2002 and 2005 and has identified almost 300,000 km for possible decommissioning over the next 40 years (14).  Decommissioning decreases economic liabilities but is also an important tool for restoring forest ecosystems (13).

In U.S. federal waters, there are 3900 offshore oil and gas platforms, primarily in the Gulf of Mexico (GOM), about one-third of which are idle (15).  Federal policies require that platforms be removed within 1 year of lease expiration, and 2700 platforms have been removed.  Removed platforms have been primarily shallow-water platforms and mostly disposed of onshore (15).  Costs and environment impacts of removing deep water platforms are substantial.

Full platform removal has drawbacks, including environmental impacts and loss of the potential ecological values of the structure as an artificial reef (16).  Research shows that platforms facilitate the expansion of coral populations in the GOM (17) and act as refuges for juvenile fish, increasing fish production off the coast of California (18).  Rigs-to-Reefs Programs allow reuse of decommissioned structures as artificial reefs.  Through 2004, 190 retired platforms were dedicated for fisheries enhancement, which reduced decommissioning costs and led to $20 million in industry donations to state environmental management trust funds (15).

Department of Defense (DOD) facilities pose an unusual challenge and opportunity.  Of the 257 million ha of federal lands in the United State, 10 million ha belong to the DOD (19).  Access restrictions have made military bases some of the richest ecological reserves of any of the nation’s public lands (19).  Through the Base Realignment and Closure (BRAC) program, 400 military sites were closed or reclassified between 1988 and 2002.  To date, management of 21 bases on 445,000 ha has been transferred from the DOD to the U.S. Fish and Wildlife Service to become National Wildlife Refuges (e.g., Jefferson Proving Ground became Big Oaks National Wildlife Refuge).

Perhaps the largest combination of infrastructure management and ecosystem restoration is the Comprehensive Everglades Restoration Project (CERP), an effort to restore the 2.3 million-ha watershed and its ecosystem (8).  Hydrology in the Everglades is manipulated through hundreds of control gates, thousands of kilometers of levees, 2900 km of canals, and dozens of pump stations, which largely continue to function well.  The CERP is based on infrastructure modification and partial removal to move the ecosystem to a more natural and sustainable configuration through a 40-year, $20 billion project.

Policy Directions and Exit Strategies

Infrastructure policy should do more than fund projects; it should set national priorities and initiatives.  The National Commission on Infrastructure would set such strategic priorities and consider infrastructure financing, rehabilitation, and maintenance.  Rehabilitation under the NIIA includes considering removal of infrastructure that is deteriorated or no longer useful.  When infrastructure has been decommissioned, ecological restoration has been a side benefit.  Prioritizing decommissioning sites based on a combination of ecological, economic, and safety concerns can benefit multiple stakeholders, possibly reducing overall decommissioning costs (15).

Infrastructure decommissioning is likely to occur during discrete windows of opportunity.  These may be policy-related (e.g., expiration of a dam license), natural (e.g., flooding), or through deliberate legislation (e.g., CERP).  However, political will for such expenditures is difficult to maintain, particularly during political transitions (20).  A less broadly applied funding mechanism is the use of market-like principles in which infrastructure decommissioning is used to generate credits to offset environmental impacts elsewhere (see figure above).

The greatest lesson from current aging infrastructure is the need for exit strategies, which vary greatly among infrastructure types.  Policies for decommissioning dams are surprisingly rare and vague (11), whereas policies for decommissioning offshore platforms are unambiguous (15).  Because the costs of decommissioning and cleanup for infrastructure can be substantial, more explicit policies should require provisions for decommissioning as part of infrastructure license or lease terms, perhaps similar to that for offshore facilities, where bonding requirements are specified and based on the estimated cost of full removal.

Any infrastructure policy approach must confront the national conundrum of pressing infrastructure problems and continuing environmental degradation.  Specifically, a National Commission on Infrastructure should squarely face decommissioning as a viable option, and the environmental benefits gained through such decommissioning should be assessed as definable benefits and leveraged when possible and practicable.

From Science Magazine, VOL 319, January 18, 2008

Martin W. Doyle,1* Emily H. Stanley,2 David G. Havlick,3 Mark J. Kaiser,4 George Steinbach,5 William L. Graf,6 Gerald E. Galloway,7 J. Adam Riggsbee8