Evaluating watershed health in Costa Rican national parks and protected areas

Although the biodiversity of Costa Rican national parks, forests, and wetlands has been extensively surveyed, there has not been a watershed assessment that reflects their baseline water quality. Undoubtedly, the influx of 3.1 million visitors annually can lead to deterioration. Additionally, the country’s movement toward 100% carbon neutral energy means reliance on capturing water for the production of hydroelectricity. The missing hydrologic data set is of immediate concern, as watershed health predicts total ecosystem health. This field-based project measures eight parameters (pH, temperature, fecal coliform, dissolved oxygen, biochemical oxygen demand, nitrates, total phosphates, turbidity) needed to assign a watershed quality index (WQI) value at nine national parks or protected areas. Overall, the WQI for the systems surveyed reflect good water quality. Results compared with US Environmental Protection Agency (EPA) and World Health Organization (WHO) drinking water standards indicate limited levels of contamination at most sites, with elevated signatures of nitrates, phosphates, turbidity, and/or fecal coliforms at few. The parks selected include coastal lowlands and central highlands; they also experience diverse tourist activities, degrees of use, and forest type that are challenges when managing land sustainably.