Techniques for estimating dollar impacts from marine recreational activity

"To improve the economic analyses in our assessments, I set out to select a method to derive dollar values from recreational participation indicators and changes in these indicators due to environmental events. I selected the "unit-day value method" because I thought it was the most efficient means to assess impacts at the direct level of expenditure. Using the method, I multiplied the unit-day values (in dollars) by recreational participation indicators (in usage units) for specified time periods and present the resulting dollar figures as the direct impact. I then applied the method in two test cases involving San Francisco Bay park attendance data for 1985."