Which of the following practices can help reduce eutrophication?

The practice of implementing rainwater harvesting systems is effective in reducing eutrophication because it allows for the collection and storage of rainwater, which can then be used for irrigation and other purposes instead of relying on fertilizers. When rainwater is harvested and used properly, it can reduce the amount of surface runoff that carries excess nutrients, particularly nitrogen and phosphorus, into nearby water bodies. This runoff is often a significant contributor to eutrophication, where nutrient-rich waters lead to algal blooms that deplete oxygen and harm aquatic life. By capturing rainwater, we can minimize the runoff that enters streams, rivers, and lakes, thereby helping to mitigate the conditions that lead to eutrophication.

In contrast, using more fertilizers on gardens can exacerbate eutrophication, as excess fertilizers can wash into waterways and contribute to nutrient overload. Clearing native vegetation along waterways can destabilize the ecosystem, further allowing nutrients to enter lakes and rivers without any natural filtering. Lastly, increasing industrial runoff would introduce additional pollutants and nutrients into aquatic systems, which is contrary to the goal of reducing eutrophication. Thus, the implementation of rainwater harvesting systems stands out as a sustainable practice to help combat this environmental issue.