A hydraulic study uses hydrology and stream characteristics to determine what?

A hydraulic study is integral in understanding the relationships between water flow, its volume, and the characteristics of the channels through which it moves. The primary purpose of such a study is to determine flood elevations, which represent the height of floodwaters at specific locations during a flood event. This aspect is crucial for planning, zoning, and designing floodplain management strategies.

Flood elevations are vital for various applications, including the implementation of building regulations, setting appropriate flood insurance rates, and helping communities prepare for flood events. By analyzing data on stream flow, rainfall, and terrain, hydraulic studies can provide detailed assessments of potential flood conditions, ultimately guiding safety measures and land use planning in flood-prone areas.

While the other options relate to significant aspects of floodplain management, they do not address the direct outcomes of hydraulic studies in the same way that flood elevations do. Flood zones involve the classification of land areas at risk, floodway maps indicate where floodwaters flow most actively, and elevated structures pertain to construction practices rather than the analytical findings of hydraulic assessments.