Hydraulic analysis refers to the determination of what happens to a water surface elevation within a waterway during certain storm events. These storm events could include the 2-year, 10-year, 25-year, 50-year, and 100-year storms.
A hydraulic analysis allows you to see how a waterway could affect a property during certain rainfall events. This is also the part of a floodplain analysis that involves the actual determination of the water level elevation for a floodplain boundary.
How Hydraulic Analysis Is Different From Hydrologic Analysis
A hydraulic analysis is used to determine the water levels within a waterway. A hydrologic analysis on the other hand involves the determination of the drainage areas, characteristics, and runoff flow rates of the land draining to the waterway being studied. The results of the hydrologic analysis would be required for the hydraulic analysis.
Some Factors Involved With a Hydraulic Analysis
The main factor involved with a hydraulic analysis is the hydrologic analysis. An accurate hydrologic analysis is required for a hydraulic analysis to generate results that are reliable for use in a civil engineering project.
Related: What Is Hydrology in Civil Engineering?
Some other factors include the slope of the waterway, the ground cover of the waterway, and any structural obstructions within the waterway such as parts of roads and bridges.
Something else that might also have to be considered is what is immediately downstream of the waterway being studied such as a confluence with another waterway.
The Steps Involved With a Hydraulic Analysis
The following are the four main steps involved with a hydraulic analysis.
1) Determine what section of waterway to analyze.
2) Prepare the hydrologic analysis to determine runoff flow rates.
3) Determine cross section data of the section of waterway to be analyzed.
4) Calculate the water level elevations at various parts of the waterway.
Where to Find Hydraulic Analysis Information
Hydraulic analysis information for a major waterway that involves floodplain boundaries delineated by FEMA (Federal Emergency Management Agency) can usually be obtained directly from FEMA.
Information for minor waterways that have been studied can probably be obtained by the civil engineer who did the analysis. You should be able to find contact information for this engineer on an existing conditions plan or a land development plan that contains the waterway.
A Hydraulic Analysis Could Be a Major Part of a New Land Development
A hydraulic analysis can be especially important as part of a new land development project that involves a waterway. This analysis allows for the design engineer to determine the impact of an existing waterway on your proposed development and to figure out how to design any proposed waterway crossing accordingly.
