Which of these is NOT a method for managing nutrient inflows?

The choice of constructing a dam on waterways represents a method that primarily focuses on modifying water flow and managing water levels rather than specifically addressing nutrient inflows. While dams can influence water quality and the transport of sediments and nutrients, they are not directly a nutrient management strategy. Instead, they often serve purposes such as flood control, hydroelectric power generation, or water supply.

In contrast, checking for hidden nutrient sources, leaving a buffer zone for fertilization, and avoiding the addition of fertilizers are all proactive approaches specifically aimed at managing the input of nutrients into aquatic systems. These practices directly target the reduction of excess nutrients, which can lead to problems such as algal blooms and water quality degradation. Therefore, constructing a dam does not fit within the framework of managing nutrient inflows as effectively as the other methods listed.