the consumer surplus is zero if a user chooses notto participate in an activity ie stays at home it is negative if the experience is taken away eg contamination closes a swimming beach and it is positive if the experience is undertaken in some form the consumer surplus value from a recreation experience may change overtime the quality of the site may be altered improvements will increase surplus while a deterioration will decrease it external factors may influence the experience increased congestion for bikers or lack of snow for crosscountry skiers may decrease surplus and user preferences may evolve new activities may introduce new opportunities to capture a surplus this important and oftentimes overlooked input affects the overall value of a recreation site