What is the significance of a cutoff trench in embankment construction?

The significance of a cutoff trench in embankment construction primarily lies in its role in controlling water seepage. A cutoff trench is designed to intercept and redirect subsurface water flow, which is crucial in preventing water from seeping through the embankment. By doing so, the trench helps to maintain the structural integrity of the embankment, as uncontrolled seepage can lead to erosion, weakening, or even failure of the embankment over time. This is especially important in areas where the embankment is subject to water pressure from behind it, as the trench acts as a barrier to minimize the potential for soil saturation and instability.

The design and placement of a cutoff trench are critical in ensuring that the embankment remains stable and functional, effectively protecting the area behind it from potential flooding or collapse due to excessive water accumulation. Therefore, the correct answer underscores the fundamental purpose of the cutoff trench within the context of stormwater management and embankment performance, highlighting its importance in maintaining proper drainage and structural stability.