HAB a Good Summer!: Integrated Site Improvements to Address Algal Blooms at a Major Recreation Lake

Christina Hughes, PE, CFM, ENV SP, Project Manager, Ramboll

Harmful Algal Blooms (HABs) occur when aquatic conditions are optimal for algal growth, produce toxins that are harmful to humans and aquatic species, and are often triggered by warm temperatures and increased nutrient loads from human activity. Reactionary approaches can offer temporary solutions, but holistic site planning helps identify the full range of water quality impacts to provide a more sustainable solution. A case study at Harriman State Park in New York shows how integrated planning can be applied across a watershed area to more efficiently design facility improvements to benefit water quality.

Lake Welch Beach at Harriman State Park, a significant recreational resource for the New York City metropolitan area, was closed for almost the entire 2022 peak season due to multiple persistent HABs. The lake is currently the discharge point for treated wastewater effluent and non-point source storm water runoff resulting in high nutrient loading. To prevent future beach closures and address nutrient concentrations, New York State Office of Parks, Recreation, and Historical Preservation (OPRHP) has initiated a multi-phased approach to understand the root cause of HAB outbreaks, develop a comprehensive lake nutrient budget, and implement direct treatment and site infrastructure solutions to address water quality.

During a 1-year monitoring period, OPRHP implemented several immediate treatment methods for the peak 2023 season that resulted in no beach closures. The project also consists of improving park infrastructure to provide enhanced water quality inputs into the lake, including WWTP upgrades, effluent relocation, green infrastructure, and wetland rehabilitation. This presentation will discuss the integrated approach to site improvements as well as considerations for short- and long-term aquatic health for lake management, using the Lake Welch site as a case study.

Author Bio

Christina Hughes is a project manager and the Mid-Atlantic Climate Adaptation Lead at Ramboll in Arlington, VA with a focus on flood resilience and blue-green infrastructure. She has ten years of experience in the field of water resources engineering and currently serves as project manager for the Lake Welch Water Quality Improvements project at Harriman State Park in New York.