Economic Linkages Between Coastal Wetlands and Water Quality:
   A Review of Value Estimates Reported in the Published Literature




               Richard F. Kazmierczak, Jr.
          Associate Professor of Environmental Economics
         Department of Agricultural E

                           -

    http://www.agecon.lsu.edu/faculty_staff/IntroFacPages/kazmierczak.htm




Natural Resource and Environment Committee             Staff Paper 2001 02
LSU Agricultural Economics & Agribusiness                   May 2001
        Economic Linkages Between Coastal Wetlands and Water Quality:
        A Review of Value Estimates Reported in the Published Literature

                     Richard F. Kazmierczak, Jr.
                 Louisiana State University Agricultural Center


                           Summary

     This manuscript summarizes a total of 12 peer-reviewed studies,1 published from 1981 to 2001,
reporting 28 separate estimates for the disaggregate2 value of water quality services provided by coastal
and non-coastal wetlands. Estimates ranged across three orders of magnitude and are highly dependent on
the specific geographic site providing the service, the type of water quality service provided, the
measurement technique, and whether locally derived benefits were calculated to extend across all existing
wetlands. Considering only coastal zone wetlands across all study categories, the value of water quality
services ranged from $2.85/acre/year to $5,673.80/acre/year, with a mean and median of $825.04/acre/year
and $210.93/acre/year, respectively.3, 4 The large difference between the mean and median value reflects
the non-normal distribution of the estimates, and in particular the influence of a few very high values.
Eliminating the most extreme outliers from the calculations generated mean and median values of
$323.05/acre/year and $178.64/acre/year, respectively. By comparison, reported estimates of willingness-
to-pay (WTP) values for wetland water quality services were relatively consistent across studies,5 ranging
from $41.71 to $101.81, with a mean and median of $66.59 and $63.19, respectively. The apparent
importance of geographic location, and the specific use demand, on water quality service value suggests
that this facet of coastal wetland benefits needs to be carefully examined within a spatially disaggregated
context.


                          Introduction

     Coastal wetlands are increasingly recognized as essential to natural systems and human activities
because of the environmental services that they provide. However, this recognition has not resulted in
capitalized economic value for landowners (Heimlich et al. 1998). Nonmarketed wetland benefits may be
important to society, but the lack of a market value for the services means that they are often de-

1
  To the author’s knowledge this represents all the peer-reviewed published studies that explicitly seek to value the
linkage between wetlands and water quality/purification services.
2
  From a theoretical economic perspective, the services provided by wetlands generally should not be disaggregated
and valued separately due to the potential for double counting and offsetting effects (see Pendleton and Shonkwiler
[2001] for a discussion of this in a different context). For example, the provision of water purification services may,
in many cases, simultaneously provide for increased habitat and species protection. Valuing each of these services
separately (when, in fact, they are inseparable) and summing will lead to overestimating total potential wetland
value.
3
  All values in year 2000 dollars (see Table 1).
4
  In a partial review of wetland valuation studies, Heimlich et al. (1998) calculated a much broader range on the per
acre value estimates, in part because they considered the provision of a number of different services besides water
quality, but also because they converted household and individual willingness-to-pay (WTP) values to per acre
values using various assumptions not necessarily contained in the original studies. The review presented in this
manuscript does not take this approach, and instead lists the WTP values separately (if not originally presented on a
per acre basis) for comparison purposes.
5
  Note that the WTP estimates were not, in general, estimated on a per acre basis, and thus should not be directly
compared with the per acre values estimated from non-WTP studies.
                               1
emphasized relative to physical loss or the private economic gains that can arise from conversion of
wetlands to other land uses (van Vuuren and Roy 1993). While the search for quantitative measures of
wetland values is challenging due to the diversity, socioeconomic context, and complex hydro-biological
functions of wetlands (Scodari 1990), informed policy requires that both market and nonmarket wetland
values be incorporated into the decision making process.

     One of the most important, but usually nonmarketed, services provided by coastal wetlands is
water quality control, and in particular the retention, removal, and transformation of nutrients. Numerous
studies have shown that natural and constructed wetlands can be effective tertiary processors of wastewater
effluent (Richardson and Davis 1987; Conner et al. 1989; Reed 1991; Kadlec and Knight 1996). Efficient
at removing excess nutrients and pollutants, wetlands and their environmental services may be especially
critical in coastal Louisiana and the Northern Gulf of Mexico for the mitigation of degraded water flowing
south through the state (Louisiana DEQ 1988; Doering et al. 1999). The value of this service comes in the
form of reduced costs of water purification, where the water is used in production and consumption, or
reduced contamination where the water continues to reside in the environment. As with most types of
pollution, however, the economic damages associated with water quality impairment, and thus the value of
the purification services performed by wetlands, are difficult to measure. Thus, the key economic issue is
to establish the value to water quality of an acre of coastal wetland preserved, restored, enhanced or
created.

     This report documents the current status of knowledge concerning the economic value of the water
quality services generated by coastal and other wetlands. In particular, studies that focus on valuing water
purification services as an unbundled product of wetland function are highlighted.6 A brief overview of
the theoretical economic linkages between wetland ecosystems and water quality is first presented, thus
providing a basic framework for understanding why specific variables and measurement methods are of
interest. Second, the common methods used to value the water quality services of wetlands are outlined,
along with their major advantages and disadvantages. This information can help the reader evaluate the
usefulness of any particular estimate. Next, the results of individual water quality service valuation studies
are presented and summarized. Lastly, the report concludes with a complete list of the literature cited.


               Relationship Between Wetlands and Water Quality

     Policymakers face complex, multi-objective trade-offs when attempting to develop strategies for
coastal restoration and protection.7 Implementation of any specific strategy will result in benefits and costs
that will, in general, be different than those experienced under alternative strategies. Economics can be
used to help inform policymakers about the relative benefits and cost of different strategies, but analysts
require information on (1) the relationship between anthropogenic activities and coastal wetland loss, (2)
the costs imposed on society from coastal wetland loss, and (3) the costs of taking action to prevent coastal
wetland loss. In the typical environmental management scenario, human activities are considered to be a
cause of degradation, and the management of these activities via regulation or the use of economic
instruments has the goal of reducing environmental impacts. Changing established human activities is
potentially costly, and the cost will vary by the specific type of activity and its interrelationship with the
environment. While some Louisiana coastal wetland loss can be attributed to traditional human industrial,
municipal, and agricultural activities, natural environmental processes on a regional, hemispheric, and

6
  A substantial part of the wetland valuation literature attempts to measure the theoretically correct multi-product
value of wetlands and not the individual service components. An overview of the results generated by these studies
is presented in the report (Table 2) for comparison to the single-product water quality value estimates.
7
  The following discussion was adapted from Keithly and Ward (2001).
                               2
global scale are also important. Complicating the identification of causal linkages and their importance to
water quality is the heterogeneity of existing wetlands. Some wetlands perform many functions, but some
may perform few or even none. In addition, many of the environmental services are generated
simultaneously in varying degrees by the same wetland function. From this perspective, water purification
and/or quality preservation services of wetlands can best be understood as part of an economic joint
product. This jointness-in-products creates difficulties in measuring the economic importance of specific
wetlands functions, and as a result the literature contains a limited number of empirical studies that isolate
the water quality costs (foregone benefits) imposed on society from wetland loss.

     Abstracting from the technical measurement difficulties, there are a number of general benefits
that accrue to society from its interaction with any large-scale ecosystem such as coastal wetlands (Pearce
and Turner 1990). Ecosystems supply both stock and flow resources that can be used as direct and indirect
inputs to production and consumption activities, thereby generating productivity and growth in the overall
economic system. While the resources can be either renewable or nonrenewable, goods and services
provided by Louisiana’s coastal wetlands (and their associated marine ecosystems) are generally
considered renewable resources.8 The provision of quality water via purification processes can be
considered one of these renewable resources, and it is tied to a second benefit, the ability of coastal
wetlands to assimilate wastes. As long as the waste flow into the ecosystem is below its assimilative
capacity, the ecosystem is able to turn the wastes into harmless and/or ecologically useful products. On a
regional scale, however, assimilation capacity is dependent of the amount and distribution of the ecosystem
in relationship to the waste sources. For Louisiana’s coastal wetlands, potential demands for water
purification are in part diffuse, but also highly concentrated in some areas (particular for municipal
wastewater treatment). Lastly, a benefit arises because ecosystems provide a source of utility that is
independent of its direct consumptive uses. This utility, derived through the biological and cultural
diversity of ecosystems, is generated by coastal wetlands through non-consumptive use activities (such as
viewing) and knowledge that the functioning ecosystem exists. Water quality is an integral component of
this last source of benefits from coastal Louisiana wetlands.

     Once the benefits of an ecosystem are identified, economic values need to be assigned to these
benefits. Having these assigned values allows policy makers to quantitatively assess the economic benefits
that society might gain from marginal improvements in the integrity of the ecosystem. Value is associated
with the amount that society (both current and future generations) would be willing to pay for the services
and attributes provided by the ecosystem if they were not provided free of charge. The greater the benefits
derived from the services provided by any particular ecosystem, the more that ecosystem is valued by
society. In general, the value of these services tends to be positively related with the integrity of the
ecosystem. Of course, any action taken to decrease the loss of Louisiana’s coastal wetlands, and thus
increase the welfare of society at large, comes with a cost. These costs must be weighed against the
benefits to determine, from the criteria of welfare economics, whether specific restoration or preservation
actions are warranted, and to what extent.




8
 While significant nonrenewable mineral extraction, and the related economic activity, takes place in coastal
Louisiana and the adjacent continental shelf, to a large extent its continued existence is not dependent on maintaining
the integrity of the coastal wetlands. The extraction industry’s cost structure may change if coastal wetlands are lost,
but not likely to the extent that they would become economically infeasible. Navigation and port activities, however,
are more likely to be negatively affected by the loss of coastal wetlands.
                              3
                        Valuation Methods

     The total economic value of a wetland area is the sum of the amount of money that all people who
benefit from the wetland area would be willing to pay to see it protected (Whitehead 1992). If this
definition of wetland value is to be empirically viable, individuals that benefit must (1) realize that they
benefit, (2) understand the full extent to which they benefit, and (3) be capable of placing a dollar value on
the level of their benefits, either through reference to market-based prices or some alternative, nonmarket
pricing system. Methods for valuing the stock of natural capital assets and service flows generated by
wetlands have been extensively discussed in both the published and unpublished literature.9 While
philosophical debate has occurred over the ability to empirically measure the full range of benefits that
flow from an environmental resource, economists generally agree that accurate measurement is possible if
valuation studies are carefully conducted (U.S. Department of Commerce 1993). In fact, review of past
nonmarket valuation studies suggests that previously perceived variability and unreliability in the estimated
values does not actually exist, particularly if one controls for the varying characteristics of the resources
being valued and the way in which the estimated values are presented (Carson et al. 1996). Thus,
published value estimates might be useful in analyzing the economic impact of Louisiana's coastal
wetlands as long as careful attention is given to the details of the study and the resources being valued.10

     Four theoretically plausible valuation methods have been used in the neoclassical economic
literature to place valid dollar values on wetland resources.11 These methods are the net factor income
(NFI) method, the contingent valuation method (CVM), the travel cost method (TCM), and the hedonic
price method (HPM). A fifth set of methods found in the literature, but not theoretically valid under
typical application, is the damage cost or replacement cost methods (DCM or RCM). All of these methods
are briefly described below. In addition, the non-neoclassical literature, as well as the biological literature,
often contains studies employing energy analysis methods (EAM), whereby the value of ecosystem assets
are directly related to their energy processing abilities.12 Shabman and Batie (1978) detailed the
fundamental problems and economic fallacies imbedded in this approach,13 and no further discussion of its
use is included in this report. The results from two studies employing EAM, however, are reported in
Table 2 in order to completely characterize the wetland valuation literature.

    The NFI method uses market prices to measure the additional profit earned by firms due to the
contribution of the wetlands to production activities, and it generates use values. Thus, the NFI method is
most appropriate when the wetland provides a service that leads to an increase in producer surplus, or the
9
  For excellent early overviews, see Greenley et al. (1982) and Amacher et al. (1989). Scodari (1990) provides a
thorough review of the advantages and disadvantages of various methods specifically within a wetland valuation
context, while Whitehead (1992) contains a lucid, if somewhat terse, review of the methods and the theory behind
them. More recent papers detailing established and newer methods include Feather et al. (1995), Apogee Research,
Inc. (1996), Mahan (1997), Bockstael (1998) and Pendleton and Shonkwiler (2001). For comprehensive reviews of
the theory and application of contingent valuation methods for nonmarket goods and services, see U.S. Department
of Commerce (1993) and Bishop et al. (1998).
10
  This type of detailed examination was beyond the time constraints of this study, but it should be seriously
considered for inclusion in future phases of a valuation project.
11
  The brief methods discussion borrows from Amacher et al. (1989), Whitehead (1992), and others.
12
  This approach, which first received widespread publicity and policy attention due to a study by Gosselink et al.
(1974), is based on the Odum and Odum (1972) contention that society's use of resources should maximize the net
energy production of the total environment (including its natural and developed components).
13
  The fundamental problem is that EAM fails to recognize the nature of the process by which economic values are
determined, and makes an "illegitimate marriage" of the principles of systems ecology with economic theory
(Shabman and Batie 1978). "This leads to estimates of marsh service value that are, at best, inaccurate. At worst,
these inaccurate estimates may capture the focus of policy debate, and hinder, rather than improve, the resource
management process for coastal wetlands."
                              4
economic gains attained by the users of the resource, because it exploits the relationship between the value
of the production activity and the wetland acreage. In the NFI method the physical relationship between
wetland areas and the economic activity is empirically estimated from data on the production activity. It is
then possible to identify the increase in producer surplus (economic gain) associated with the use of the
wetland resource.14 If the empirical estimates are obtained through statistical regression, then estimates of
the marginal value product (MVP) of the wetland resource can be generated. In this context, the MVP
provides a direct measure of the firm owner's willingness-to-pay to avoid wetland degradation.

     Producer surplus generated by the use of a wetland can also be estimated using the RCM. This
approach values the wetland=s service based on the price of the cheapest alternative way of obtaining that
service. For example, the value of a natural wetland in the treatment of wastewater might be estimated
using the cost of chemical, mechanical, or constructive alternatives. The use of RCMs needs to be
governed by three considerations (Shabman and Batie 1978): (1) the alternative considered should provide
the same services, (2) the alternative selected for cost comparison should be the least-cost alternative, and
(3) there should be substantial evidence that the service would be demanded by society if it were provided
by that least-cost alternative.15 Taken together, these condition differentiate RCM from the more general
class of DCMs, where the entire value of a marketable good or service is tied to the preservation of a
wetland resource, ignoring consumer and producer substitution possibilities. Even with restrictive
application, the RCM can only be considered to yield an upper bound on the true WTP for the wetland
service because the producer may not choose to actually use the alternative considered (Anderson and
Rockel 1991).

     The CVM is a survey approach that measures the total economic value of all wetland goods and
services by directly asking individuals about their WTP. The CVM establishes a hypothetical market by
providing information about wetland resources, specifying payment rules and vehicles, and posing
valuation questions. Answers to these questions can be used to directly measure WTP, and CVM may be
the only way to estimate many non-use values of environmental resources. But, in order for CVM to yield
valid economic measures, study participants must be both willing and able to reveal their values. Other
valuation approaches, such as TCM and HPM discussed below, depend on revealed preferences through
market transactions and other behavior. Statements from economic actors about how they would act under
hypothetical circumstances, as used in the CVM, are a very different measure and ultimately need to
assessed for validity (Bishop et al. 1998). A panel of experts organized by the National Oceanic and
Atmospheric Administration (NOAA) of the U.S. Department of Commerce, and co-chaired by Nobel
laureate economists Kenneth Arrow and Robert Solow, concluded that (1) there is too much positive
evidence to dismiss CVM and its usefulness in providing information about values, (2) CVM studies do
not automatically generate value information, but are highly dependent on the content validity of the
survey, and (3) CVM is an evolving market valuation technique (U.S. Department of Commerce 1993). In
the words of the panel (p. 4610), “CV studies convey useful information. We think it is fair to describe
such information as reliable by the standards that seem to be implicit in similar contexts, like market
analysis for new and innovative products and the assessment of other damages normally allowed in court
proceedings . . . . Thus, the Panel concludes that CV studies can produce estimates reliable enough to be a
starting point of a judicial process of damage assessment, including lost passive-use values.”
14
  In practice, it is often assumed that the demand for the good being produced by the water user is perfectly elastic,
and thus changing wetland services has no effect on consumer surplus.
15
  For example, suppose that 90 pounds of nitrogen could be removed from freshwater each year by an acre of
coastal marshland (as is typical for the Caernarvon freshwater diversion of the Mississippi River in Louisiana -- see
Mitsch et al. 1999, p. 88), at a cost savings of $100 per year (an entirely arbitrary value) when compared to the cost
of treatment plant removal. If the marsh acre does not actually receive the waste load, than no dollar benefits for
waste assimilation exist. Furthermore, to properly apply this approach the variable waste assimilation capacities of
different types of coastal marshland would need to be accounted for in the analysis.
                               5
     The TCM approach is often used to measure the recreational benefits of wetlands, but it is
generally applicable to valuing any nonmarket wetland good or service that individuals are willing to travel
to and use at the wetland site. The TCM method estimates the costs incurred traveling to visit and use the
site, with the concept being that the travel and time costs are measures of implicit market prices. The
estimated costs are then used to construct demand functions that use travel and time costs as independent
variables.16 Consumer surplus per recreation trip and year can then be approximated from the estimated
demand curve. The application of TCM assumes that (1) users have identical utility functions for the
activity, and thus will have identical demand functions, (2) users are indifferent between incurring costs as
user fees or travel costs, (3) weak complimentarity holds in that changes at competing sites do not affect
use at the site being valued, and (4) site use is not congested. Given these assumptions, TCMs cannot be
used to value nonmarket goods and services that either do not require the user to visit the site or that are
offsite products. Furthermore, TCM generally cannot account for multiple sites, visits to multiple sites on
the same trip, or the impact of small resource changes on user perceptions and travel patterns.

     The HPM has been used to measure the contribution of wetlands for flood control and the role of
wetland aesthetics in housing and property prices. Thus, HPMs attempt to tie wetland service value
directly to a market price (Freeman 1998). In a market at equilibrium, land values and land rents should be
a function of land characteristics, including the proximity to and services provided by wetlands. The
increment to the land or housing price arising from wetland services is a measure of the implicit price of
that service. There are three key assumptions required to apply HPM to estimate the wetland contribution
to land values. First, there must be data on a continuum of sites with varying wetland characteristics and
acreage. Second, purchasers and sellers of wetland parcels are assumed to have access to the same
information regarding the condition of the site and the nature and use of the wetland. Third, wetland
purchasers (or purchasers of property near wetlands) are assumed to have identical preferences for wetland
characteristics. The assumption of identical preferences makes estimation of demand curves possible when
data does not exist about individual preferences.

     The valuation method employed in any particular water quality study depends primarily on the
ability to quantitatively discern the biophysical linkages between characteristics of a particular wetland
area and the change in the quality of water as it moves through the area. In cases where this relationship is
well understood, NFI methods can be employed. In cases where the biophysical linkages are not well
described, but the demanded water quality can be defined, then RCM or CVM may be most appropriate
even in light of their limitations. No water quality service value studies were found that employed TCM or
HPM approaches. Of course, the choice of a particular measurement method is important and can have
implications for the estimated value of a wetland area. For example, in a meta-analysis of wetlands
valuation studies, Woodward and Wui (2000) discovered that NFI methods tended to generate lower
estimated values for wetlands than did RCM. This confirms the Anderson and Rockel (1991) observation
that RCM should generate an upper bound on actual value.


                     Review of Estimated Values

     Peer-reviewed literature estimates of the water quality service values generated by an acre of
wetland are presented in Table 1. Four different categories of studies were identified; Louisiana specific
studies, other U.S. studies, international studies, and studies that did not report their results on an area
basis (primarily CVM based WTP studies). In addition, peer-reviewed literature estimates of total service

16
  Other independent variables are also employed, including the theoretically requisite income and various potential
demand shifters, depending on the situation being modeled.
                            6
values generated by an acre of wetland were arranged by the same four categories and are presented in
Table 2. The overall service value estimates are potentially useful when evaluating a study, as individually
disaggregated service values should (obviously) never exceed total service value. In fact, individually
disaggregated service values, when summed across all service categories, also should not exceed total
value. In any event, the total values are included in the report to help the reader gain a broader
understanding of the information available in the valuation literature.

     Reported estimates for the value of Louisiana wetlands in the provision of water quality services
ranged from a low of $2.85/acre/year to a high of $5,673.80/acre/year, with a mean and median value of
$975.01/acre/year and $281.24/acre/year, respectively (Table 1).17, 18 Given that all the Louisiana-specific
studies used the same RCM approach, the disparity in valuation can be strictly linked to differing site
characteristics, the specific water quality service being demanded, and (in the case of the lowest estimated
value) whether localized benefits were calculated to extend across all existing wetlands in the coastal zone.
This latter approach substantial underestimates the potential water quality service value of wetlands near
municipalities and industries that might use them for tertiary treatment of wastewater, while at the same
time overestimating the water quality service value of wetlands not located near municipalities (and thus
likely to provide zero wastewater processing benefits). In a similar way, the water quality service value of
wetlands for industrial wastewater tertiary treatment in Louisiana might be extremely high at a specific
location (for example, the $5,673.80/acre/year for processing a potato chip plant's effluent), but the
benefits are restricted to a very small number of acres. The apparent importance of geographic location
and localized use demands on water quality services suggests that single estimate of this service value
should not be used in any kind of economy-wide analysis. Instead, efforts need to be made to identify, as
closely as possible, the spatial distribution of current, and possible potential, water quality service use
demands. This information would be very useful in prioritizing wetland restoration and preservation
activities, particular with respect to wastewater treatment services and associated joint-products of wetland
functions.

     Studies conducted for wetlands in other regions of the U.S. reported water quality service values
that ranged from $88.64/acre/year to $2,687.59/acre/year, with a mean and median value of
$513.99/acre/year and $165.24/acre/year, respectively (Table 1). These estimates fell within the range of
values reported specifically for Louisiana, although the mean and median values were substantially lower.
This occurred even though most of the other estimates were conducted for coastal wetlands in similar
climatic conditions.19 A limited number of international studies also reported water quality service values
well within the range of those reported for Louisiana, with estimates varying between $98.72/acre/year and
$1,963.68/acre/year (mean and median values of $720.57/acre/year and $99.31/acre/year, respectively).
The difference between the international studies and values for Louisiana might be expected, however,
given the differences in the types of wetlands being valued and their location. Considering only coastal
zone wetlands across all study categories (Louisiana, other U.S., and international), the value of water
quality services ranged from $2.85/acre/year to $5,673.80/acre/year, with a mean and median of
$825.04/acre/year and $210.93/acre/year, respectively. The large difference between the mean and median
value reflects the non-normal distribution of the aggregated estimates, and in particular the influence of a

17
  All values in year 2000 dollars.
18
  It should be emphasized that all of the reported Louisiana valuation studies were conducted by one set of authors
in a very specific time period. The importance of this information to understanding the value of water quality
services derived from Louisiana wetlands is not clear, although it is always preferable to have multiple, independent
studies on which to base inferences.
19
  The importance of climate, and its relationship to the maximum level of waste processing that can be obtained
from a given wetland, is intimately linked to the maximum value that can be expected from wetland water quality
services. This can be seen by noticing the relationship of site location and value in both Tables 1 and 2 (although,
given varying valuation measures, the relationship is not perfect).
                              7
few very high values. Eliminating the most extreme outliers from the calculations generated mean and
median values of $323.05/acre/year and $178.64/acre/year, respectively.

     For comparison purposes, reported estimates of willingness-to-pay (WTP) values for wetland
water quality services ranged from a low of $41.71 to $101.81, with a mean and median of $66.59 and
$63.19, respectively (Table 1). Two things are particularly interesting about these estimates. First, the
variability among the estimates is substantially lower than the estimates generated with other valuation
methods (primarily RCM). Given that RCM measures very site and use demand specific values for water
quality services, it appears that CVM approaches to valuing water quality services may be measuring a
generalized WTP that incorporates the probability of any given tract of wetland being used for water
purification. Alternatively, the CVM studies may be measuring a completely different water quality
service compared to the specific wastewater treatment services that were calculated in the RCM studies. In
particular, the values derived from the CVM studies may be related to a WTP for a generalized water
quality service that maintains the functioning of the larger coastal ecosystem. Whether the former, latter,
or some other explanation applies may only be determined by a detailed examination of the studies, their
methods, and especially their survey design.

     Given the widely varying estimates of water quality service values, and the apparent site and use
specific reasons for the variability, this facet of coastal wetland benefits needs to be carefully examined
within a spatially disaggregated context. Barring a spatially disaggregate study, a conservative approach to
incorporating coastal wetland water quality services into a generalized impact analysis might be to utilize
the WTP estimates found in the literature to calculate an annualized acreage value. The best way to
approach this would be to examine each reported study for information that would allow generalization of
the household WTP to actual land areas given user and nonuser populations. This approach was attempted
for a number of studies by Heimlich et al. (1998), but with somewhat limited success due to problems with
assumptions made by the authors. If such a detailed approach is not feasible, then it might be acceptable to
take advantage of the remarkable consistency of reported WTP values across all types of wetlands
(particularly in comparison to the non-WTP estimates) and their approximately normal distribution to
estimate a defensible “average” value for coastal wetland water quality services. For example, assuming
3.5 million acres of coastal wetlands in Louisiana,20 a coastal population of 2.05 million,21 and a mean
WTP of $66.59,22 the annualized value of water quality services for coastal Louisiana would be
approximately $39/acre/year.




20
  Source: Louisiana Coastal Restoration Web Site at http://www.lacoast.gov/wetlands/overview/justification.htm
21
  Source: NOAA at http://www.ocrm.nos.noaa.gov/czm/czmlouisiana.html
22
  The WTP studies reported water quality service values on a per individual and per household basis. This
calculation assumes the mean WTP can be applied to each individual, and that the individuals would be willing to
pay this amount on an annual basis. Note also that no coast-specific WTP studies were found in the literature.




                            8
Table 1. Published estimates of water quality service values provided by wetlands, 1981-2001.
                              Site               Discount                           Time             NPV        Annualized        Annualized
                Site            Size                 Rate                         Horizon     Base     Estimate       Value/Acre         Value/Acre
                                                                                                                   (yr 2000 $)a
 Study     Location    Type    Site Use   (acres)   Valuation Method       (%)                          (years)     Year    (base yr $)      (base yr $)


        ------------------------------------------------------------------------------------------- Louisiana Specific Studies -------------------------------------------------------------------------------------------
                                                                                                           2.16b
Farber 1996     Entire        Coastal     Tertiary         23.7    Cost savings (based on               3       93    1990      1,425,000                     2.85
          Louisiana      wetlands     municipal       million   Breaux et al. 1995)
          coast                 wastewater

Breaux et al.    Thibodaux,      forested     tertiary          570   cost saved vs conventional;             9       30    1990       448,000         76.50         100.79
1995        Louisiana      swamp      municipal              with chlorination
                             wastewater

Breaux et al.    Thibodaux,      forested     tertiary          570   cost saved vs conventional;             9       30    1990       504,000         86.07         113.40
1995        Louisiana      swamp      municipal              with ultraviolet
                             wastewater

Breaux et al.    Thibodaux,      forested     tertiary          570   cost saved vs conventional;             9       30    1990       800,000         136.61         179.99
1995        Louisiana      swamp/      municipal              ultraviolet vs conv. chlorinates
                     bottoms     wastewater

Breaux et al.    Thibodaux,      forested     tertiary          570   cost saved vs conventional;             9       30    1990      1,250,000         213.46         281.24
1995        Louisiana      swamp/      municipal              only conv. chlorinates
                     bottoms     wastewater

Breaux et al.    Thibodaux,      forested     tertiary          570   cost saved vs conventional;             9       30    1990      1,310,000         223.70         294.73
1995        Louisiana      swamp/      municipal              only conv. ultraviolet
                     bottoms     wastewater

Breaux et al.    Dulac,        coastal     tertiary         2860   cost savings for 15 plants -            9       25    1990     17,820,000         634.33         835.74
1995        Louisiana      wetland     seafood plant            lower bound (small plant)
                             wastewater             estimate

Breaux et al.    Dulac,        coastal     tertiary         2860   cost savings for 15 plants -            9       25    1990     27,560,000         981.04        1,292.54
1995        Louisiana      wetland     seafood plant            upper bound (large plant)
                             wastewater             estimate

Breaux et al.    Grammercy,      Hard-      tertiary chip        6.2   cost savings for one small             9       15    1990       215,220       4,306.44        5,673.80
1995        Louisiana      wood       plant                manufacturer
                     bottoms     wastewater




                                                             9
Table 1. Published estimates of water quality service values provided by wetlands, 1981-2001 -- continued.
                               Site               Discount    Time                                    NPV         Annualized        Annualized
                 Site            Size                 Rate  Horizon                            Base     Estimate       Value/Acre        Value/Acre
                                                                                                                   (yr 2000 $)a
 Study     Location    Type    Site Use   (acres)   Valuation Method       (%)   (years)                            Year    (base yr $)      (base yr $)

        --------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
Fritz et al.    Orlando,       Cypress     Tertiary        790.72   Cost savings over                  6        20    1976       265,659         29.29         88.64
1984        Florida        dome       municipal             conventional - with buffers
                              wastewater

Fritz et al.    Waldo, Florida    Wetland     Tertiary        65.49   Cost savings over                  6        20    1976        22,958         30.56         92.99
1984                            municipal             conventional - with buffers
                              wastewater

Fritz et al.    Orlando,       Cypress     Tertiary        790.72   Cost savings over                  6        20    1976       362,411         39.96         120.93
1984        Florida        stand      municipal             conventional - with buffers
                              wastewater

Fritz et al.    Waldo, Florida    Wetland     Tertiary        39.54   Cost savings over                  6        20    1976        22,958         50.62         153.19
1984                            municipal             conventional - no buffers
                              wastewater

Fritz et al.    Orlando,       Cypress     Tertiary        395.36   Cost savings over                  6        20    1976       265,659         58.58         177.28
1984        Florida        dome       municipal             conventional - no buffers
                              wastewater

Fritz et al.    Orlando,       Cypress     Tertiary        395.36   Cost savings over                  6        20    1976       362,412         79.92         241.87
1984        Florida        stand      municipal             conventional - no buffers
                              wastewater

Woodward      -----         Mixed      General          -----  Econometric meta-analysis of           -----      -----   1990          -----         417        549.41
and Wui 2001                        water quality           39 studies yielding per acre
                                               values; excludes WTP where                                            90% C.I. of
                                               per acre value was not                                              126 - 1,378
                                               generated

Thibodeau and    Charles River     Costal      Tertiary        8,535   Cost savings over                  6     Infinite    1978        16,960       1,017.60        2,687.59
Ostro 1981     Basin         wetlands     municipal             conventional
                              wastewater


         --------------------------------------------------------------------------------------------- International Studies ---------------------------------------------------------------------------------------------
                                                                                                         85.80 ecuc
Gren et al.     Danube        Mixed      Reduced         4.3 m   Non-WTP date derived from            -----      -----   1991          -----                   98.72
1995        floodplain               nitrogen and            Gren 1993, Elofsson 1993,
                              phosphorus             and Haskoning 1994

                                                             10
Table 1. Published estimates of water quality service values provided by wetlands, 1981-2001 -- continued.
                               Site               Discount    Time                                    NPV         Annualized       Annualized
                 Site            Size                 Rate  Horizon                             Base     Estimate       Value/Acre        Value/Acre
                                                                                                                   (yr 2000 $)a
 Study     Location    Type    Site Use   (acres)   Valuation Method       (%)   (years)                            Year    (base yr $)      (base yr $)

         --------------------------------------------------------------------------------------------- International Studies ---------------------------------------------------------------------------------------------
                                                                                                             94d
Gren 1999      Baltic Sea      All       Nitrogen sink       -----  Non-linear national cost             -----      -----   1998          -----                   99.31
          drainage basin    wetlands     for 50%               minimization under a
                              reduction              doubling of wetland acreage
                                                scenario

Costanza et al.   World wide      Coastal     Waste          815 m    Mixed aggregation of various           -----      -----   1994          -----        1,690        1963.68
1997                   wetlands     treatment        world   studies; little detail given
                                           wide   concerning specific studies


       ---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
                                                                                                           38.88 g        41.71g
Mathews 1999    Minnesota       River      Reduce           -----  WTP contingent valuation and           -----      -----   1997          -----
                              phosphorus             travel cost in a combined
                              loads by 40             model
                              percent

                                                                                                           38.59e g        42.35 g
Farber and     Pennsylvania     Streams     Quality          -----  Conjoint, random utility             -----      -----   1996          -----
Griner 2000                        increase -             model
                              moderate to
                              unpolluted

                                                                                                           37.61f g        57.01 g
Lant and      14 towns in      Riverine     Quality          -----  WTP contingent valuation             -----      -----   1987          -----
Roberts 1990    Iowa and       wetlands     increase -             adjusted for non-response bias
          Illinois along             poor to fair
          border

                                                                                                           55.46e g        60.87 g
Farber and     Pennsylvania     Streams     Quality          -----  Conjoint, random utility             -----      -----   1996          -----
Griner 2000                        increase -             model
                              severely to
                              moderately
                              polluted

                                                                                                           43.22f g        65.51 g
Lant and      14 towns in      Riverine     Quality          -----  WTP contingent valuation             -----      -----   1987          -----
Roberts 1990    Iowa and       wetlands     increase -             adjusted for non-response bias
          Illinois along             good to
          border                 excellent




                                                             11
Table 1. Published estimates of water quality service values provided by wetlands, 1981-2001 -- continued.
                               Site               Discount    Time                               NPV        Annualized      Annualized
                 Site            Size                 Rate  Horizon                        Base    Estimate      Value/Acre       Value/Acre
                                                                                                            (yr 2000 $)a
 Study     Location    Type    Site Use   (acres)   Valuation Method       (%)   (years)                       Year    (base yr $)     (base yr $)

       ---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
                                                                                                     47.16f g      71.49 g
Lant and      14 towns in     Riverine    Quality          -----  WTP contingent valuation           -----      -----   1987         -----
Roberts 1990    Iowa and       wetlands    increase -            adjusted for non-response bias
          Illinois along           fair to good
          border

                                                                                                     77.15 g       91.94 g
Stevens et al.   New England     Wetlands    Pollution         -----  WTP contingent valuation           -----      -----   1993         -----
1995                   in general   control              mail survey
                            combined
                            with flood
                            protection
                            and water
                            supply

                                                                                             92.76e g      101.81 g
Farber and     Pennsylvania     Streams  Quality        ----- Conjoint, random utility          -----      -----  1996         -----
Griner 2000                     increase -           model
                          severely to
                          unpolluted
 a
  Study values inflated to common year 2000 values using the Bureau of Labor Statistics (BLS) CPI Inflation Calculator, which bases yearly adjustments on the average consumer price index by year.
 b
  Author spread the cost savings across all projected wetland acres lost through 2083; insufficient data reported to calculate the cost savings just on acres lost that might be used in waste treatment.
 c
  Inflated to year 2000 using the BLS CPI Inflation Calculator and converted to U.S. dollars using the ratio 1.10ecu/$1.00
 d
  Value represent the simple average for 8 Baltic countries reported in Gren (1999). Germany, reported on in the article, was excluded from the simple average because of the extreme estimates
 ($1,778/acre/yr) resulting from a complex interaction with atmospheric deposition of nitrogen. The range of values is primarily due to different climatic conditions, and thus wetlands processing ability, in
 the different countries. See Gren (1999) for more details.
 e
  Authors estimate multiple user, nonuser, and combined models in both dichotomous and multiple choice formats; values reported represent the best statistical estimates for a combined user model.
 f
  Authors also examined the potential for strategic bidding and rejected the hypothesis based on distributional relationship of bids to respondent income.
 g
  Value is not reported on a per acre per year basis. In most cases, the value represents household willingness-to-pay for the service where the service/wetland quantity relationship is not defined.




                                                          12
Table 2. Published estimates of total service values provided by wetlands, 1975-2001.
                               Site                                    Discount      Time               NPV      Annualized        Annualized
                 Site             Size                                      Rate     Horizon     Base      Estimate     Value/Acre         Value/Acre
                                                                                                                    (yr 2000 $)a
 Study     Location     Type    Site Use   (acres)   Valuation Method                            (%)     (years)     Year     (base yr $)     (base yr $)

         ------------------------------------------------------------------------------------------- Louisiana Specific Studies -------------------------------------------------------------------------------------------
Costanza and     Terrebonne      Coastal     Summation       650,000    Simple summation of mixed            8.0     Infinite    1983        586.73         46.94         81.16
Farber 1987      Parish,       Louisiana    of                 method estimates of
           Louisiana               commercial             individual services
                              fishing,
                              trapping,
                              recreation,
                              and storm
                              protection

                                                                                                           194.32b
Costanza et al.    Louisiana      Coastal     Commercial         -----  Production function, revenue        8.0 , 3.0     Infinite    1983    2,429 - 8,977                    335.96
1989                    wetlands     fishing,              accounting, travel cost, and
                              trapping,              WTP contingent valuation
                              recreation,
                              and storm
                              protection

Costanza and     Terrebonne      Fresh      All services     650,000    Energy analysis based gross           8.0     Infinite    1983         6,400        512.00         885.20
Farber 1987,     Parish,       coastal                       primary productivity
Costanza et al.    Louisiana      wetlands                       conversion, net value lost
1989                                              when converting wetland to
                                                open water

Costanza and     Terrebonne      Saltwater    All services     650,000    Energy analysis based gross           8.0     Infinite    1983         6,700        536.00         926.70
Farber 1987      Parish,       coastal                       primary productivity
           Louisiana      wetlands                       conversion, net value lost
                                                when converting wetland to
                                                open water

Costanza and     Terrebonne      Brackish     All services     650,000    Energy analysis based gross           8.0     Infinite    1983        10,602        848.16        1,466.40
Farber 1987      Parish,       coastal                       primary productivity
           Louisiana      wetlands                       conversion, net value lost
                                                when converting wetland to
                                                open water




                                                             13
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                          Time             NPV         Annualized       Annualized
                 Site             Size                 Rate                        Horizon     Base     Estimate       Value/Acre        Value/Acre
                                                                                                                   (yr 2000 $)a
 Study     Location     Type    Site Use   (acres)   Valuation Method       (%)                         (years)     Year     (base yr $)      (base yr $)

        --------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
van Vuuren     Lake St. Clair,    Freshwate    Public and        741   Travel cost                    4.0        50    1985          4,435         83.55        133.71
and Roy 1993    Michigan &      r wetlands    club hunting,     undiked
          Canada                 angling,
                             trapping

Gupta and     Massachusetts     LLNN       Benefits of        -----  Average state acquisition price          7.0        30    1972           500          40         165
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)

van Vuuren     Lake St. Clair,    Freshwate    Public and       370.7   Travel cost                    4.0        50    1985          6,027        113.54        181.71
and Roy 1993    Michigan &      r wetlands    club hunting,      diked
          Canada                 angling,
                             trapping

van Vuuren     Lake St. Clair,    Freshwate    Public and        49.4   Travel cost                    4.0        50    1985          6,968        131.27        210.08
and Roy 1993    Michigan &      r wetlands    club hunting,      diked
          Canada                 angling,
                             trapping

Roberts and    Mud Lake,       Fresh      All services       -----  Cost savings, residual return          -----      -----   1995           -----         375        423.72
Leitch 1997    MN-SD         wetland                       to water utilities, contingent
                                               valuation

Gupta and     Massachusetts     HLNN       Benefits of        -----  Average state acquisition price          7.0        30    1972          1,400          113         466
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)

Gupta and     Massachusetts     LLNH       Benefits of        -----  Average state acquisition price          7.0        30    1972          1,700          137         564
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)

                                                            14
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                         Time             NPV         Annualized       Annualized
                 Site             Size                 Rate                        Horizon     Base     Estimate       Value/Acre        Value/Acre
                                                                                                                  (yr 2000 $)a
 Study     Location     Type    Site Use   (acres)   Valuation Method       (%)                        (years)     Year     (base yr $)      (base yr $)

       --------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
Gupta and     Massachusetts     MMNM       Benefits of        -----  Average state acquisition price          7.0        30    1972          3,000          242         997
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)

Gupta and     Massachusetts     LHNL       Benefits of        -----  Average state acquisition price          7.0        30    1972          4,100          330        1,359
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)

Gupta and     Massachusetts     HHNH       Benefits of        -----  Average state acquisition price          7.0        30    1972          6,000          484        1,994
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)

Gupta and     Massachusetts     LLLL       Benefits of        -----  Average state acquisition price          7.0        30    1972          6,400          519        2,138
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)

Gupta and     Massachusetts     HHLH       Benefits of        -----  Average state acquisition price          7.0        30    1972         11,700          943        3,885
Foster 1975               Wetland     wildlife,             scaled by habitat score
                             visual/cultura           (wildlife) or quality (visual
                             l, water              cultural), 1971 ACE study of
                             supply, and            Charles River (flood control),
                             flood control           1970 USGS study (supply)




                                                            15
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                           Time             NPV         Annualized       Annualized
                 Site             Size                 Rate                          Horizon     Base     Estimate       Value/Acre        Value/Acre
                                                                                                                    (yr 2000 $)a
 Study     Location     Type    Site Use   (acres)   Valuation Method       (%)                          (years)     Year     (base yr $)      (base yr $)


         --------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
Gupta and       Massachusetts     HHMH       Benefits of        -----  Average state acquisition price          7.0        30    1972         26,000         2,095        12,750
Foster 1975                 Wetland     wildlife,             scaled by habitat score
                               visual/cultura           (wildlife) or quality (visual
                               l, water              cultural), 1971 ACE study of
                               supply, and            Charles River (flood control),
                               flood control           1970 USGS study (supply)

Gupta and       Massachusetts     LLHL       Benefits of        -----  Average state acquisition price          7.0        30    1972         40,700         3,280        13,512
Foster 1975                 Wetland     wildlife,             scaled by habitat score
                               visual/cultura           (wildlife) or quality (visual
                               l, water              cultural), 1971 ACE study of
                               supply, and            Charles River (flood control),
                               flood control           1970 USGS study (supply)

Gupta and       Massachusetts     HHHH       Benefits of        -----  Average state acquisition price          7.0        30    1972         46,000         3,707        15,271
Foster 1975                 Wetland     wildlife,             scaled by habitat score
                               visual/cultura           (wildlife) or quality (visual
                               l, water              cultural), 1971 ACE study of
                               supply, and            Charles River (flood control),
                               flood control           1970 USGS study (supply)

Thibodeau and     Charles River     Costal      All services      8,535   Simple summation of mixed              6     Infinite    1978        171,772       10,306.32        27,220
Ostro 1981      Basin         wetlands                      method estimates of
                                                individual services


          --------------------------------------------------------------------------------------------- International Studies ---------------------------------------------------------------------------------------------
                                                                                                                       174.13c
Gren et al.      Danube        Mixed      All           4.3 m   Summation of individual           5.0 and     infinite    1991       3,027 ecu      151.35 ecu
1995         floodplain               ecosystem             service estimates                2.0                          to
                               services                                    percent                      7568 ecu
                                                                                                 per acre

Costanza et al.    World wide      Coastal     All services      815 m   Mixed aggregation of various           -----      -----   1994           -----        5,983        6,952
1997                    wetlands     and products       world   studies; little detail given
                                            wide   concerning specific studies




                                                              16
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                      Time            NPV        Annualized     Annualized
                 Site             Size                 Rate                    Horizon     Base     Estimate       Value/Acre      Value/Acre
                                                                                                           (yr 2000 $)a
 Study     Location     Type    Site Use   (acres)   Valuation Method       (%)                     (years)    Year    (base yr $)      (base yr $)

       ---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
                                                                                                     1,553de      1,851e
Sathirathai and  Thailand       Mangrove    Direct and     988      various                    -----      -----   1993          -----
Barbier 2001              wetland    indirect use
                            (timber,
                            fishing,
                            coastline
                            protection)

                                                                                                     20.77e      23.47e
Mullarkey and   Northwest      Fresh     Total value        110   WTP mail survey; respondent          -----      -----   1995          -----
Bishop 1999    Wisconsin      wetland    under high            certainty and scope test
                            certainty             included

                                                                                                     57.83e      65.34e
Mullarkey and   Northwest      Fresh     Total value        110   WTP mail survey; respondent          -----      -----   1995          -----
Bishop 1999    Wisconsin      wetland    under low             certainty and scope test
                            certainty             included

                                                                                                     67.80e      94.15e
Pate and      San Joaquin     General    Generalized      90,000   WTP mail survey of Oregon           -----      -----   1989          -----
Loomis 1997    Valley, CA      wetlands    to all uses            residents

                                                                                                      252e      100.79e
Loomis et al.   Nebraska       Platte     Wastewater      300,000   WTP mail survey                -----      -----   1998          -----
2000                  River     dilution,
                            water
                            purification,
                            erosion
                            control,
                            habitat, and
                            recreation

                                                                                                     114.29e      136.20e
Stevens et al.   New England     General    Recreation,        -----  WTP contingent valuation           -----      -----   1993          -----
1995                  wetlands    rare species,           mail survey
                            food
                            production,
                            flood
                            protection,
                            water supply
                            and pollution
                            control




                                                         17
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                      Time            NPV        Annualized     Annualized
                 Site             Size                 Rate                     Horizon     Base     Estimate       Value/Acre      Value/Acre
                                                                                                            (yr 2000 $)a
 Study     Location     Type    Site Use   (acres)   Valuation Method       (%)                     (years)    Year    (base yr $)      (base yr $)

       ---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
                                                                                                      99.75e      138.52e
Pate and      San Joaquin     General    Generalized      90,000   WTP mail survey of              -----      -----   1989          -----
Loomis 1997     Valley, CA      wetlands    to all uses            Washington residents

                                                                                                     196.01e      272.20e
Pate and      San Joaquin     General    Generalized      90,000   WTP mail survey of Nevada           -----      -----   1989          -----
Loomis 1997     Valley, CA      wetlands    to all uses            residents

                                                                                                     210.77e      292.70e
Pate and      San Joaquin     General    Generalized      90,000   WTP mail survey California          -----      -----   1989          -----
Loomis 1997     Valley, CA      wetlands    to all uses            residents outside the San
                                             Joaquin Valley

                                                                                                     215.55e      299.34e
Pate and      San Joaquin     General    Generalized      90,000   WTP mail survey of San            -----      -----   1989          -----
Loomis 1997     Valley, CA      wetlands    to all uses            Joaquin Valley residents

 a
   Study values inflated to common year 2000 values using the Bureau of Labor Statistics (BLS) CPI Inflation Calculator, which bases yearly adjustments on the average consumer price index by year.
 b
   Storm protection accounted for 79 percent ($153.20/acre/yr) of the total value.
 c
   Inflated to year 2000 using the BLS CPI Inflation Calculator and converted to U.S. dollars using the ratio 1.10 ecu/$1.00 U.S.
 d
   Value is strongly influenced by estimates for coastline protection, which account for 96% of the total.
 e
   Value is not reported on a per acre per year basis. In most cases, the value represents household willingness-to-pay for the service where the service/wetland quantity relationship is not defined.




                                                          18
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