After calculating this consumer surplus for each cant6n, the results are summed across all cantons yielding an annual consumer surplus estimate of USD 97 500 and USD 116 200, respectively. Assuming the real value of this recreational flow remains the same over time and using a real interest rate of 4%, the present value of domestic recreation at this site is between USD 2.4 and USD 2.9 million . Given that there are about 3000 Costa Rican visitors per year, the site is worth about USD 35 per domestic visit