Can a farmer add a small addition onto his farmhouse in the floodway without an engineer's review?

When considering whether a farmer can add a small addition onto his farmhouse in the floodway without an engineer's review, the focus is on the concept of the "conveyance shadow." This term refers to the area behind a structure, like a farmhouse, where floodwaters are somewhat impeded by the structure itself. In some floodplain management frameworks, minor additions that are located within this shadow may not significantly affect the movement of floodwaters and could be permissible without a formal engineered review.

It's important to note that floodway regulations are designed to minimize the risk of flooding by preventing structures from obstructing flood flows and increasing flood levels. Therefore, if an addition is situated in a location that does not impede the flow or is deemed safe under local floodplain management regulations, it could be allowed without requiring engineering approval.

In contrast, the other options do not align with the specific regulatory framework regarding floodways. An engineer's approval is typically required for more substantial modifications that could impact flood risk or management, and temporary structures usually also fall under scrutiny to ensure they do not pose a flood risk. Additionally, adding a structure below the base flood elevation still requires careful consideration of potential flooding impacts and would not satisfy the floodway regulations without proper evaluation.