Economic and Health Risk Trade-Offs of Swim Closures at a Lake Michigan Beach

Abstract

This paper presents a framework for analyzing the economic, health, and recreation implications of swim closures related to high fecal indicator bacteria (FIB) levels. The framework utilizes benefit transfer policy analysis to provide a practical procedure for estimating the effectiveness of recreational water quality policies. Evaluation criteria include the rates of intended and unintended management outcomes, whether the chosen protocols generate closures with positive net economic benefits to swimmers, and the number of predicted illnesses the policy is able to prevent. We demonstrate the framework through a case study of a Lake Michigan freshwater beach using existing water quality and visitor data from 1998 to 2001. We find that a typical closure causes a net economic loss among would-be swimmers totaling $1274-37 030/ day, depending on the value assumptions used. Unnecessary closures, caused by high indicator variability and a 24-h time delay between when samples are taken and the management decision can be made, occurred on 14 (12%) out of 118 monitored summer days. Days with high FIB levels when the swim area is open are also common but do relatively little economic harm in comparison. Also, even if the closure policy could be implemented daily and perfectly without error, only about 42% of predicted illnesses would be avoided. These conclusions were sensitive to the relative values and risk preferences that swimmers have for recreation access and avoiding health effects, suggesting a need for further study of the impacts of recreational water quality policies on individuals.

Direct healthcare costs of selected diseases primarily or partially transmitted by water

“…For illness associated with recreational water, the popularity of swimming implies a large population of exposed people and a high potential economic cost of illness or beach closure. Dwight et al estimated that nearly 75 000 excess cases of illness were due to water pollution at just two beaches in Orange County, California [19], while an economic analysis of closures at a single Lake Michigan beach found a net economic loss of $1274-37 030 per day (depending on the method used to assign values for health and recreation costs) [20].…”

Estimating the economic benefits of regional ocean observing systems

“…On site sampling, off site laboratory analysis, and a reliance on fecal indicator bacteria instead of human pathogens result in two principle types of errors associated with water quality monitoring (Rabinovici et al 2004): 1) Type I errors in which beaches are closed even though water quality parameters are within a 19 For 9 closure days, we did not have attendance data. In these cases we used figures from the prior year or a nearby beach.…”

“…(These increased closures would result in a loss of recreational values. Rabinovici et al, 2004, argue that even appropriate closures result in recreational value losses that may exceed gains in public health values.) We focus only on the gains in public health values that could result from a reduction in Type II compliance errors.…”

“…For the purposes of analysis, we group the policy errors associated with the shortcomings of the current protocol for monitoring and reporting water quality data into two types of errors in the execution of beach closure policy (we follow the example of Rabinovici et al 2004). First, in some the current protocol causes beaches to be closed when these beaches are, in fact, in compliance with water quality standards; we refer to these types of errors as Type I errors and note that these errors largely impact the recreational value of beaches.…”

Regional Public Health Cost Estimates of Contaminated Coastal Waters: A Case Study of Gastroenteritis at Southern California Beaches

“…Several previous studies address the potential economic impacts of swimming-related illnesses. Rabinovici et al (6) and Hou et al (7) focused on the economic and policy implications of varying beach closure and advisory policies at Lake Michigan and Huntington Beach, CA, respectively. Dwight et al (8) estimated the per case medical costs associated with illnesses at two beaches in southern California and used this to make estimates of public health costs at two Orange County beaches.…”