What function does a curtain drain serve?

A curtain drain primarily functions to collect and redirect groundwater flow. This drainage system is typically installed in areas where high groundwater levels can interfere with the functionality of onsite wastewater systems or create conditions that may lead to issues such as soil saturation. By redirecting groundwater, a curtain drain helps to maintain a suitable environment for its proper drainage and treatment capabilities.

Regarding the other choices, while aesthetic appeal may be a consideration in landscape design (which would not be the primary function of a curtain drain), enhancing soil absorption capabilities directly relates to the characteristics of the soil and does not pertain to the specific role of a curtain drain. Additionally, a curtain drain does not serve as a primary wastewater treatment unit; instead, it is designed to manage groundwater flow, supporting the overall effectiveness of onsite wastewater systems by preventing flow that could disrupt treatment processes.