CGN5930 Spring 2008, Environmental Hydrologyr

 

 

 

Frequency Analysis of Unsteady Flow

 

FEMA Flood Analysis Method

 

Home work:

 Using following data to do frequency analysis,

Note: T= (n+1)/m, n= total number of sample, m is the mth largest value, T is the return year.

 

1)Find 100-year flow value using linear regression

Example of Flow data

 

2)Analysis using Gumbel method to predict 100 year flow

  2-a) traditional method (textbook method) for parameter estimation

 

Reading : other method in determining Gumbel parameters

 L-moment method in parameter estimation (see

Recent Journal paper [1], [2] on using L-moment method in estimating parameters in Gumbel distribution

 

 

 

Unsteady flow data for HEC-RAS unsteady simulations

 

Course Review for Test #1:

 

1) Continuity equation, 2) Momentum equation.

  • What are the unknown variables that are solved in unsteady flow equations.
  • What types of unsteady flow boundary conditions can be handled

 

Part II. ¨CComputer-based test:

¡¤        Applications of HEC-RAS for unsteady flow problems

  • Focus on examples given in the class (Beaver Creek examples)
  • Test problems covers

1)      Specify unsteady boundary conditions, such as

Upstream time series of flow,

Down stream time series water elevation, etc

              2). View model out put to show flood area.

              3). Design/modify hydraulic design to reduce flood area.

               4) ability to create culvert section with deck, and design culvert.

            

       

2. Hydrodynamics reference book

 

hydrodynamics.pdf

 

3. HEC-RAS homepage

  free model package, documents of user manual and application examples

http://www.hec.usace.army.mil/software/hec-ras/

 

New features of HEC-RAS

hec-rasnewfeature.pdf

 

HEC-RAS theory :

hecraschap02.pdf

 

 

Examples:

  1. Simple unsteady flow: Beaver Cr ¨Cunsteady flow
  2. Simple unsteady flow: Beaver Cr ¨Cunsteady flow with culverts
  3. Detention pond (storage area): Beaver Cr ¨Cstorage area

 

-Class exercise: Create river geometry for HEC-RAS

       use data from above example 2, recreate river geometry

hec_create.xls

 

-Unsteady flow boundary conditions:

          upstream: flood hydrograph,

         downstream: water level variations ivan.xls

 

-hydraulic designs in HEC-RAS

 

 

 

 

 

GIS maps, layers:

 

FDOT

Welcome to the FDOT Planning Offices Web pages -- a site for statewide transportation planning in Florida.

http://www.dot.state.fl.us/planning/statistics/gis/default.htm

 

FDOT PROJECTS AT THE GEOPLAN CENTER

http://www.geoplan.ufl.edu/projects/fdot/fdotindex.html

 

Collins Software Houston Texas, 713-682-1556

Providing GIS Web Publishing solutions and GIS Database Migration software utilities

Web Mapping Software

http://www.collinssoftware.com/freegis_by_region.htm#United

 

County Resources

Land surveying and related links for Florida Counties

http://www.floridageomatics.com/common/county.html

 

Tallahassee-Leon County GIS is the Geographic Information Systems (GIS)

http://www.tlcgis.org/

 

NOAA data website

http://www.ngdc.noaa.gov/mgg/gdas/gd_designagrid.html

 

example: