For effective drainage in grading, what is typically required?

Effective drainage in grading is typically achieved through sloped surfaces. When surfaces are sloped, they facilitate the flow of water away from structures and prevent water accumulation in low areas. This is crucial because standing water can lead to soil erosion, instability, and foundation issues for buildings.

The slope allows gravity to assist in directing water toward designated drainage areas, which can include ditches, storm drains, or natural waterways. Proper grading with adequate slopes ensures that the soil remains stable and able to support any structures placed on top, reducing the risk of erosion and other water-related issues.

While flat surfaces might seem like an option for certain applications, they do not promote effective drainage and can lead to pooling water. High compaction is important for soil stability but does not directly impact drainage; instead, it helps maintain the integrity of the soil. A rocky substrate might allow for some water permeability, but it does not specifically address the need for directed drainage as effectively as sloped surfaces do.