David Ramirez, P.E. David Ramirez, P.E. Senior Hydrologist Senior Hydrologist Lower Mississippi River Forecast Center Lower Mississippi River Forecast Center Slidell, LA Slidell, LA l-Time Operation of HEC-RAS at l-Time Operation of HEC-RAS at r Mississippi River Forecast Ce r Mississippi River Forecast Ce USACE/NWS/USGS USACE/NWS/USGS Annual Tri-Agency Coordination Meeting Annual Tri-Agency Coordination Meeting Oct. 30 – 31, 2007 Oct. 30 – 31, 2007
Transcript
David Ramirez, P.E.David Ramirez, P.E.Senior HydrologistSenior Hydrologist
Lower Mississippi River Forecast Center Slidell, LALower Mississippi River Forecast Center Slidell, LA
Real-Time Operation of HEC-RAS at the Real-Time Operation of HEC-RAS at the Lower Mississippi River Forecast CenterLower Mississippi River Forecast Center
• Used for locations where hydrologic Used for locations where hydrologic techniques do not work as welltechniques do not work as well– Storm surge and other tidal effectsStorm surge and other tidal effects– Areas affected by backwaterAreas affected by backwater– Levee breachesLevee breaches– Off-channel storage areasOff-channel storage areas– Lateral inputs/diversionsLateral inputs/diversions– Dam breaksDam breaks
LMRFC Hydraulic LMRFC Hydraulic ModelingModeling
• Hydrologic ModelingHydrologic Modeling– Continuity equation and relationship Continuity equation and relationship
between storage in the reach and between storage in the reach and discharge at the outlet.discharge at the outlet.
• Hydraulic ModelingHydraulic Modeling– Continuity equation and the momentum Continuity equation and the momentum
equation. equation. – Unsteady flow routing is more physically Unsteady flow routing is more physically
based and is applicable to wider range based and is applicable to wider range of applications.of applications.
Hydraulic vs. Hydrologic Hydraulic vs. Hydrologic ModelingModeling
• Large number of existing models available Large number of existing models available from other agencies, state, and local from other agencies, state, and local governments.governments.
• Data format is compatible with many other Data format is compatible with many other software packages. software packages.
• Excellent technical support, training and Excellent technical support, training and user documentationuser documentation
• Modeling software is continuing to be Modeling software is continuing to be developed by HECdeveloped by HEC
Why HEC-RAS?Why HEC-RAS?
Hydrologic Engineering Center Hydrologic Engineering Center River Analysis SystemRiver Analysis System
(HEC-RAS)(HEC-RAS)
• One-dimensional model.One-dimensional model.
• Current capabilities:Current capabilities:– Subcritical & Supercritical flowSubcritical & Supercritical flow– Mixed regime (transcritical flow)Mixed regime (transcritical flow)– Hydraulic structures, e.g. culverts, bridges, Hydraulic structures, e.g. culverts, bridges,
weirs, etc. weirs, etc. – Unsteady flow analysisUnsteady flow analysis– Mobile Boundary Hydraulics (sediment Mobile Boundary Hydraulics (sediment
transport)transport)– Water Quality ModelingWater Quality Modeling
Data Requirements for a Data Requirements for a Hydraulic ModelHydraulic Model
• Upstream and downstream boundary Upstream and downstream boundary conditions (flow, stage, rating curves, conditions (flow, stage, rating curves, normal depth)normal depth)
HEC Geo-RASHEC Geo-RAS
• New model development can use GISNew model development can use GIS• Geo-referenced hydraulic models can be Geo-referenced hydraulic models can be
developed using a digital terrain model developed using a digital terrain model created with ESRI’s ARCGIS. created with ESRI’s ARCGIS.
• Using a DTM for model geometry requires Using a DTM for model geometry requires less surveyed cross sectional information. less surveyed cross sectional information. (Saves time and money!)(Saves time and money!)
• Geo-referenced hydraulic models can Geo-referenced hydraulic models can produce inundation mapsproduce inundation maps
HEC-RASHEC-RAS
Standard Hydraulic Geometry
Standard Hydraulic Geometry
TIN Processing
TIN Processing
WSE @ Cross SectionsHEC-RAS HEC-2 Cross
Sections
Hydrographic Survey
Inundated Area
Intersect Continuous WS with Land (terrain-based interpolation)
ARC/INFO
& ArcView
River Hydraulics ModelTopographic
Survey
Floodplain & Channel
TIN
Cross Sections
Extraction
FLOODPLAIN MAP
HEC Geo-RASHEC Geo-RAS
Incorporating HEC-RAS intoIncorporating HEC-RAS into LMRFC Operations LMRFC Operations
NWSRFSNWSRFSHydrologicHydrologic
ModelModel
Standard Standard Hydrologic Hydrologic Exchange Exchange
Format Format (SHEF)(SHEF)
HEC-DSSHEC-DSS(dss utilities)(dss utilities)
DSS-Vue (Python)DSS-Vue (Python)Updated HEC-RASUpdated HEC-RASFlow and Plan filesFlow and Plan files
HEC-RAS HEC-RAS Model RunModel Run
(PC)(PC)
DSS-Vue DSS-Vue (Python)(Python)
Writes TS Writes TS back to NWSRFSback to NWSRFS
Data FlowData Flow
NWS ForecastNWS Forecast
Pearl River ModelsPearl River Models
Upstream boundary:Upstream boundary:
Discharge from Ross Barnett Dam,Discharge from Ross Barnett Dam,
Jackson, MSJackson, MS
Lateral inflows:Lateral inflows:
JHMM6 - Hanging Moss CreekJHMM6 - Hanging Moss Creek
DLAM6 - Strong River at D’LoDLAM6 - Strong River at D’Lo
OVWM6 – Whitesand Creek at OVWM6 – Whitesand Creek at OakvaleOakvale
Local flows:Local flows:
JACM6, ROCM6, MTCM6 and CLMM6JACM6, ROCM6, MTCM6 and CLMM6
FLDWAV – levee option does not FLDWAV – levee option does not work in OFS, used “cave-in-bank” work in OFS, used “cave-in-bank” method to account for storage method to account for storage area represented in HEC area represented in HEC geometry.geometry.
This area is in coastal LA is very flat, This area is in coastal LA is very flat, tidally influenced and subject to storm surge.tidally influenced and subject to storm surge.
VLSL1 Gage
Geometry data provided to LMRFC courtesyGeometry data provided to LMRFC courtesyof the New Orleans District USACEof the New Orleans District USACE
