Cherry Creek Reservoir has periodic blue-green algae blooms and high chlorophyll-α concentrations. The conditions that cause these algae blooms are complex; therefore, CCBWQA uses two models to help make management decisions: one for the Reservoir and one for the Watershed. A method to link the two models was completed in 2020 and was implemented in 2024 by Hydros Consulting.

CCBWQA uses the two models to better understand how watershed and in-Reservoir processes interact and affect water quality. The models help CCBWQA ask "what if" questions that can be used to identify and prioritize actions to improve water quality in the Reservoir.

While no major new modeling scenarios were developed during the past year, efforts focused on evaluating and communicating the results of the linked watershed–reservoir simulations. Collectively, the modeling indicates that even under scenarios incorporating watershed controls and reasonable reductions in external nutrient loading, internal nutrient loading from reservoir sediments remains a significant driver of in-reservoir water quality conditions.

These findings reinforce that continued watershed management is important, but that in-reservoir management strategies to address internal loading will likely be necessary to achieve long-term water quality objectives and beneficial use protection.