Wetlands Ecosystem Services Value in Constructed Wetlands: The Case of the George W. Shannon Wetlands Water Reuse Project

Aims: To determine the value of constructed wetlands for water reuse projects.
Study Design: Replacement/Avoided cost modeling and benefit transfer.
Place and Duration of Study: George W. Shannon Wetlands, Texas.
Methodology: Two approaches are compared, replacement costs and willingness-to-pay (WTP) for wetlands. Replacement costs of the constructed a wetland is based on engineering estimates and modeling. Replacements costs are compared to benefit transfer of WTP from previously estimated meta-analysis functions.
Results: The replacement cost of the constructed wetlands is estimated to be $1,688/acre/year. Using three previously published meta-analysis transfer functions, mean WTP are $843, $999, and $1,169 / acre / year. Estimated 95% confidence interval is $95 to $7,435 / acre / year.
Conclusions: The estimated values indicate constructed wetlands have value to society. The confidence interval clearly indicates the uncertainty associated with valuing ecosystem services and goods. Confidence intervals or sensitivity analysis is clearly warranted in valuing ecosystem services and goods. The three transfer functions are within 20% of each other. As expected, the replacement cost value is higher than the transfer functions and may represent an upper bound.