Flash flood prediction l.jpg
This presentation is the property of its rightful owner.
Sponsored Links
1 / 22

Flash Flood Prediction PowerPoint PPT Presentation


  • 184 Views
  • Updated On :
  • Presentation posted in: General

Flash Flood Prediction. James McDonald 4/29/08. Introduction - Relevance. 90% of all national disasters are weather and flood related Central Texas – “Flash Flood Alley” Project Goal – To compare flash flood prediction on multiple scales (NWS, LCRA, City of Austin).

Download Presentation

Flash Flood Prediction

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Flash flood prediction l.jpg

Flash Flood Prediction

James McDonald 4/29/08


Introduction relevance l.jpg

Introduction - Relevance

  • 90% of all national disasters are weather and flood related

  • Central Texas – “Flash Flood Alley”

  • Project Goal – To compare flash flood prediction on multiple scales (NWS, LCRA, City of Austin)


Agencies the main players l.jpg

Agencies – The main players

  • NWS – ultimately responsible for issuing flood warning

  • LCRA – manages flood releases from the Highland Lakes

  • City of Austin – flood monitoring and emergency management


Nws west gulf river forecasting center l.jpg

NWS – West Gulf River Forecasting Center

  • 1 of 13 NWS River Forecasting Centers

  • Also includes in house Meteorological forecasting


Nws river forecast procedure l.jpg

NWS River Forecast Procedure


Nexrad radar l.jpg

NexRAD Radar

  • 4 km x 4 km grid cell

  • Rain gages across state used to calibrate radar

  • Radar - mean areal precipitation (per hour)


Sub basins l.jpg

Sub-basins

  • Delineated by USGS streamgage

  • Total QPF (Quantitative Precip. Forecast)

    • 6 hr. UH time step

    • Stage height by USGS rating curve


Nwsrfs nws river forecast system l.jpg

NWSRFS - (NWS River Forecast System)

  • Similar to HEC-HMS (good for design)

  • NWSRFS – good for real time flood forecasting

  • Sacramento Soil Moisture Accounting Method (SAC-SMA)

    • Able to adjust soil moisture to tweak model


Human adjustment l.jpg

Human Adjustment


Distributive modeling l.jpg

Distributive Modeling

  • The Future

  • Finer rainfall distribution instead of mean areal across entire sub-basin

  • Rainfall variation - GIS


Lcra lower colorado river authority l.jpg

LCRA - Lower Colorado River Authority


The forecast spreadsheet early 1980 s l.jpg

The Forecast Spreadsheet – early 1980’s

  • Inputs:

    • Colorado River Forecast @ San Saba

    • Time-lagged tributary hydrographs

    • WSEL of Lake Buchanan & Lake Travis

    • Reservoir releases


The spreadsheet forecasting l.jpg

The Spreadsheet - Forecasting


Catchment forecast system cfs l.jpg

Catchment Forecast System (CFS)

  • Post 1997 flood

  • Integrates HEC programs:

    • PRECIP

    • HEC1

    • UNET


Hydromet hydrometeorological data acquisition system l.jpg

Hydromet: Hydrometeorological Data Acquisition System


Hec s corps water management system cwms l.jpg

HEC’s Corps Water Management System (CWMS)

  • Integrates the following models:

    • HEC-HMS, Hydrologic Modeling System

      • 289 sub-basins

      • 205 routing reaches

      • 18,340 mi^2

    • HEC-ResSim, Reservoir Evaluation System Simulation

      • 7 reservoirs

    • HEC-RAS, River Analysis System

      • 864 cross-sections

      • 347 river miles


History of austin flooding l.jpg

History of Austin flooding

November 15, 2001: 8” of rain in 6 hr. (reported up to 15”)

October 17, 1998: 31 deaths

7,000 people evacuated from homes

Property damages ~ $1 billion

454 Austin homes damaged

December 20, 1991: 200 homes in Travis and Bastrop counties were completely under water

May 24, 1981: 13 drowned, $36 million in damages, Shoal Creek 90 gpm -> 6 million gpm


City of austin am i flooding now l.jpg

City of Austin – Am I flooding now?

  • Flood Early Warning System

  • Emergency Operations Center


Austin watersheds time is not our friend l.jpg

Austin Watersheds – Time is not our friend

  • 7,000 homes in Austin floodplain

  • Tc range 30min. – 6 hr.

  • Lowering arm – low water crossing – marginal success

  • 20 roads close with 5-yr storm


Flood early warning system l.jpg

Flood Early Warning System

  • Components include:

    • ~40 creek and lake gauges

    • ~80 rain gauges

    • Automated data transfer every 15 minutes to the National Weather Service

    • High Hazard Dam Action Plan


Conclusions final comparisons l.jpg

Conclusions – Final Comparisons


Special thanks to l.jpg

Special thanks to:

  • Mike Shultz, National Weather Service, Ft. Worth, TX

  • Matt Ables & Melinda Luna, LCRA

  • Susan Janek, City of Austin, FEWS

    Questions?


  • Login