Analysis of Recreational Water Characteristics

Abstract

Users of natural recreational waters may be exposed to physical hazards and pathogens that are present in the environment. These pathogens may be natural or resulting from human activities, which in turn can be from point source and non-point source pollution. In Canada, recreational water quality monitoring generally falls under provincial and territorial jurisdictions. An environmental health monitoring program developed through this research attempts to characterize and communicate the physical and biological risks associated with recreational water use. Some items addressed during this research include: 1) Determination of the parameters correlated to water quality at beaches 2) Selection of beaches for further monitoring Within the current research and monitoring approaches, there are gaps in knowledge with respect to the factors that affect water quality at a recreational beach setting. While many research papers have considered time series data from one or two beaches, there remain questions with respect to which beaches should be selected for monitoring. Thus, the following hypothesis was formulated and tested. That the physical characteristics of a beach area are not correlated with water quality when considered in conjunction with environmental factors (null hypothesis). The hypothesis, which was rejected, is important as many jurisdictions only monitor a select number of beaches. Based on the results from testing and subsequently rejecting, the hypothesis, two models were developed. The first model attempts to explain the geometric mean of E. coli and includes such parameters of significance as turbidity and Secchi disc data, residential density, water temperature, pH, beach grooming, wind speed, stormwater runoff, parking facilities, presence of seaweed and algae, numbers of swimmers present, bird populations and whether or not pets are permitted at the beach area. The second model describes the probability of detecting E. coli and can be represented by the same parameters including turbidity (both average and maximum), water temperature, parking facilities, and presence of seaweed and algae. Parameters that differ in this model include conductivity, number of toilets, occurrence of rainfall in the previous 24-hours, and prevailing winds both parallel and onshore to the beach area. Based on these two models, a process for ranking beaches to select those that should be sampled in any given year was developed. The following criteria were applied for making those environmental monitoring and resource allocation decisions:  A significant residential density should surround the beach. In addition, the area surrounding the beach can drain to the beach area  The beach should be popular with swimmers. This could perhaps be measured by the number of toilets.  The beach should allow pets on the beach.  Waterfowl should frequent the beach area.  High amounts of seaweed and algae in the swimming area should be common. This could be due to blue-green algae blooms.  The beach should have a parking lot available for users.  Beaches in areas with more wind should be preferred  Beaches where the water temperature is typically higher should be preferred.