Final answer:
The minimum grade for culverts is around 0.5% to 1% to ensure effective water drainage. This pertains to the elevation and total relief for determining culvert placement.
Step-by-step explanation:
The minimum grade for culverts, except in very flat terrain, is critical to ensuring proper drainage and preventing water pooling and potential road damage. Culverts should be installed with a slight gradient to allow for water to flow naturally through them. Although the specific minimum grade can depend on local regulations and the design of the drainage system, a common minimum grade is often around 0.5% to 1%. This helps to maintain the flow of water even during low flow conditions and prevents sediment from building up inside the culvert, which can lead to blockages.
In the context of the student's question regarding elevation and relief, 'f' asks about the elevation of the lowest point along a line, which could be relevant when determining the proper placement of a culvert. The 'g' part of the question is asking for the total relief, which refers to the difference in elevation between the highest and lowest points along the line of the cross-section. This information is essential when calculating the slope or grade of the ground where the culvert will be installed, to ensure that the culvert's minimum grade requirement is met for effective water drainage.