Fresh water springs are unique natural resources that are contained within public lands across the United States. Natural resource management on public lands generates many interesting policy issues as the competing goals of conservation, recreational opportunity provision, and revenue generation often clash. As demand for recreational cave diving sites increases, this article provides natural resource site managers with the first statistical estimate of divers' willingness to pay (WTP) to dive cave and cavern systems. Using a contingent valuation model (CVM) and correcting for hypothetical bias, we find that divers' median WTP for cave diving opportunities at the site of interest is between $52 and $83 per dive. Model results also provide weak evidence of diver sensitivity with respect to scope, as individuals are willing to pay more for dives that are judged to be higher in quality. A unique natural resource in the state of Florida is the number and size of fresh water springs. The Florida Geological Survey has inventoried more than 700 springs, of which 33 are considered first magnitude, or those that have an average flow of 100 cubic feet per second (2.83 cubic meters per second) or more. The concentration of springs in Florida is not duplicated anywhere else on the earth. The Florida Department of Environmental Protection (DEP) has the management responsibility for Florida's public lands and the Division of Recreation and Parks (DRP) manages a system of 160 state parks that combine to put 700,000 acres scattered throughout the state under public management (Florida DEP 2009). Approximately 70% of Florida's parks are related in some way to a natural spring. Natural resource management on public lands generates many interesting policy issues. The competing goals of conservation, recreational opportunity provision, and revenue generation often clash. In recent times, as Florida public sector budgets have shrunk, natural resource managers have begun to search for revenue generation alternatives. This situation is especially true in Florida, and recently the DRP increased entrance fees for state parks. For federal funding purposes, states are required to publish recreation plans every five years. The most recent plan for Florida was produced by the Florida DEP in 2007. Chapter 5 of the plan addresses "outdoor demand and need," and it is stated that "Since outdoor recreation resources and facilities are generally felt to be 'free' goods and services, 'demand,' as an economic concept, does not lend itself to practical application" (Florida DEP 2009). This article takes a first step towards providing a mechanism for practical application of demand measurement for a resource with public good elements. Because springs are an important natural resource in Florida and a key element in many state parks, a spring-based state park was selected for the contingent valuation demand modeling that follows. In doing so, we provide the first estimate of individuals' WTP for SCUBA diving at U.S. fresh water cavern and ca...