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Cost Analysis

Costs of Restoration - Benefits of Restoration - Overview of Benefit-Cost Analysis

The Costs of Environmental Restoration Projects

Salt Marshes | Seagrass | Fish Runs | Factors Affecting Restoration Project Costs

Wakefield Fish Ladder on the Saugatucket River in South Kingstown.
Fish pass structure at Gilbert Stuart birthplace in Saunderstowne.
Courtesy: NOAA

How much does it cost to fix a car? The answer to that question depends on several things: what kind of car it is, what is wrong with it, and where you take it to get it worked on, to name a few. The cost of restoring a degraded habitat is much the same, depending, for example, on the type of habitat, the manner in which it has been damaged, and how completely you want to restore it (King and Bohlen 1995).

The bottom line is, there is no way to know for sure how much a restoration project will cost without looking closely at the conditions of the site, the legal requirements, the nature and magnitude of monitoring requirements, and a wide range of other technical, scientific, and engineering considerations. Having said that, recent studies do provide a starting point for estimating the cost of a restoration project. They also help to identify factors that can drive up the cost of a project.

Salt Marshes
The cost of salt marsh restoration is highly variable. Economies of scale may exist, but differing site conditions and restoration methods can result in vastly different costs for projects that appear to be similar. A recent study of environmental restoration in New England indicates that it costs, on average, about $16,000 to restore an acre of salt marsh, with planning, construction, and monitoring accounting for about 10, 75, and 15 percent of total restoration costs, respectively. However, of the eleven salt marsh restoration projects considered in the study, only one had costs that fell within 25 percent of this average. Overall, costs ranged from about $900 to almost $90,000 per acre (Louis Berger and Associates 1997; price levels adjusted to reflect 2001 dollars).

Some examples taken from this study will help to illustrate this variability.

  • A low-relief berm restricted tidal flushing and freshwater drainage, creating conditions in 14 acres of marsh that encouraged the spread of phragmites. Volunteer labor was used to breach the berm in a project that cost less than $2,000 per acre, including planning and monitoring.

  • Ten feet of fill material was excavated from four acres of land in Stratham, New Hampshire. Over the next year, the site was revegetated with bulrush, salt hay grass, and cattails. This project cost almost $90,000 per acre, with post-construction monitoring accounting for more than a quarter of the total cost.

  • In Massachusetts, 20 acres of salt marsh had converted to a freshwater wetland when the natural hydrology was altered by the construction of seawalls, street drainage systems, and one-way tide gates. Restoring these 20 acres to a salt marsh ecosystem required the installation of automated tide gates, the plugging of selected culverts, and the construction of about 500 feet of dike to allow tidal flushing without flooding the homes that abut the marsh. The total cost of this project, which also included revegetation and the modification of outfall structures to prevent blockage by silt deposition, was about $20,000 per acre.

  • Another project in New Hampshire was undertaken to restore four acres of salt marsh. This salt marsh changed to a freshwater wetland when the natural hydrology was altered by the installation of a tidal gate and an undersized culvert on a farm driveway. The tidal gate was removed and a larger culvert was installed at a total project cost of $6,000 per acre.

In general, projects that consisted solely of restoring natural hydrology tended to cost much less than those that required extensive excavation, revegetation, or both.

It costs about $45,000 to restore an acre of seagrass if you count only the cost of collecting, preparing, and planting the seagrass plugs (Fonseca et al. 2001; price levels reflect 2001 dollars). However, the total cost of a seagrass restoration project can be more than five times that amount, or about $245,000 per acre. By far, the greatest single cost of restoring seagrass is the cost of monitoring the project after its completion. Monitoring projects to ensure that the plants survive and reproduce is important, but it is labor-intensive and must be conducted over a number of years. Some activities that are unique to seagrass restoration account for significant project costs. Costs associated with site selection and mapping, including ground truthing, are generally higher for seagrass restoration projects than for other restoration projects. Monitoring costs are generally higher, too. Some activities that are common to all restoration projects, such as permitting, National Environmental Policy Act (NEPA) compliance, and contractor profit, also account for a significant part of the total project cost.

There are good reasons why it can be so costly to monitor the success of seagrass restoration projects. Because the habitats are underwater, the mobilization costs can be significant, especially when diving is a necessary component of the monitoring. When restoration projects are the result of litigation, detailed monitoring may be required to ensure that the conditions specified in the settlement are met.

Fish Runs
There are two ways to restore a blocked fish run: remove the obstacle or make a way for the fish to pass over or around it. When a dam blocks a fish run, one obvious way to restore the stream is to remove the dam (Connecticut River Watershed Council, Inc. 2000). When this is not possible or desirable, artificial fishways can be constructed to help fish pass over the dam or other obstruction.

The cost of removing dams varies greatly. A 1999 report presenting case studies for more than 30 dam removal projects throughout the United States shows that some small dams can be removed for under $10,000. However, the removal of a large dam can cost more than $1 million–sometimes a lot more (Friends of the Earth et al. 1999; price levels reflect 2001 dollars and do not include the costs of permits, easements, design, or monitoring). About half of the dam removal projects that were evaluated cost less than $100,000. In general, costs vary with the height and width of the dam, but project-specific factors, such as structure type, sediments, water rights, easements, and the need for monitoring can greatly impact the total cost.

The cost of constructing an artificial fishway is proportional to the height of the dam or other obstruction. Two commonly used fishways are steeppass and denil fishways. The type of fishway that is used depends on the height of the dam, the size of the river, and the characteristics of the target species. Steeppass fishways can be used for dams up to 12 feet in height . They are the least expensive fishways, costing about $10,000 for every vertical foot of dam height . If the dam height exceeds eight or nine feet, a resting pool should be added, which costs another $5,000. Denil fishways are similar in design to steeppass fishways, but can be used for moderately large dams. A denil fishway costs about $20,000 for every vertical foot for dams up to six feet in height. For higher dams, denil fishways cost about $25,000 to $30,000 for every vertical foot (Connecticut River Watershed Council, Inc. 2000; cost levels are indicative of 2001 price levels).

Factors Affecting Restoration Project Costs
There are three major phases to implementing an environmental restoration project–planning, construction, and post-construction monitoring–and in each of these phases there are activities that can significantly increase project costs.

Factors that Can Increase the Cost of the Planning Phase

  • NEPA compliance
  • permitting
  • feasibility studies
  • sediment testing
  • dam safety analysis
  • mapping and ground-truthing (especially with seagrass restoration)
  • acquisition of lands, easements, rights-of-way
  • finding and assessing compensatory sites

Factors that Can Increase the Cost of the Construction Phase

  • construction of roads or other access
  • characteristics of materials to be excavated
  • means of excavation
  • presence of contaminated materials (special handling and disposal requirements)
  • how far excavated materials must be hauled
  • volume of traffic on affected roadways (especially for culvert repair or replacement)
  • revegetation
  • restoration of lands damaged by construction
  • control of phragmites or other invasive plants
  • aesthetic or other considerations at historical sites
  • replacement plantings to compensate for those lost from initial effort

Post-Construction Monitoring
The need for monitoring the performance of a project can greatly increase its cost, and this can vary greatly by project type. Monitoring may also be a legal requirement on some projects to assure that the conditions of the permits have been met.

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Connecticut River Watershed Council, Inc. 2000. Providing fish passage around dams in the Northeast: a fishway for your stream. The Connecticut River Watershed Council, Inc., Easthampton, Massachusetts. Visit http://www.ctriver.org/ to order copies of this publication.

Fonseca, M.S., W.J. Kenworthy, B.E. Julius, S. Shutler, S. Fluke. 2001. Handbook of Ecological Restoration, Chapter 7: Seagrasses. Cambridge University Press, Cambridge.

Friends of the Earth, American Rivers, Trout Unlimited. 1999. Dam Removal Success Stories: Restoring Rivers Through Selective Removal of Dams that Don't Make Sense. Visit http://www.americanrivers.org/damremovaltoolkit/ssoverview.htm to download a PDF file of this publication.

King, D.M. and C.C. Bohlen. 1995. The cost of wetland creation and restoration. Technical Report DOE/MT/92006-9 (DE95000174). U.S. Department of Energy, Washington, D.C.

Louis Berger and Associates. 1997. Costs for wetland creation and restoration projects in the glaciated Northeast. U.S. Environmental Protection Agency, Region 1, Boston, Massachusetts.

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