In 2023, Boulder Reservoir managers identified a new non-native invasive weed species, the Eurasian Water Milfoil (EWM) that was beginning to get established in the reservoir. This fast-growing species has become an increasing problem for both recreation and use of the reservoir as a water supply. The city was encouraged to consider using chemical treatments to kill the weed. 

After extensive consultation with the NbS team who manages the city’s Integrated Pest Management policy, the Utilities and Parks department chose to develop a non-chemical control strategy focusing on a unique manual removal approach and utilization of the significant volumes of plant materials removed in a high-quality compost production strategy. This approach has the added benefit of providing a use for the significant volumes of goose droppings the Parks department has to collect in order to try and protect water quality.  

The city’s NbS team played a critical role in both providing a detailed assessment of the risks and benefits of the chemical treatment option and subsequently assisted in conducting the initial scoping and feasibility assessment of the compost-based approach.