Module 6: Routing Concepts Theodore G. Cleveland, Ph.D., P.E, M. ASCE, F. EWRI 21-23 October 2013...
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Transcript of Module 6: Routing Concepts Theodore G. Cleveland, Ph.D., P.E, M. ASCE, F. EWRI 21-23 October 2013...
Module 6: Routing Concepts
Theodore G. Cleveland, Ph.D., P.E, M. ASCE, F. EWRI
21-23 October 2013
Module 6 1
Routing simulates movement of adis discharge signal (flood wave) through stream reaches.
Accounts for storage within the reach and flow resistance.
Allows modeling of a basin comprised of interconnected sub-basins
Module 6 2
Previous modules Storage : similar ideas, recall HMS is NOT
a hydraulic model. Routing used to connect sub-basins
together into an integrated hydrology model.
Module 6 3
• Watershed– Losses
– Transformation
– Storage
– Routing
• Precipitation– Meterology, Climate
Runoff Fraction of precipitation
signal remaining after losses
Hydrologic and Simplified Hydraulics
HMS – Basin Component
Module 6 4
Hydrologic Cycle Components in HEC-HMS (circa 2008)
Land Surface and Vegetation
Channels Reservoirs
Infiltration Loss
Snowpack
Rainfall, P(t)Snowfall
Snowmelt
Runoff Runoff
Percolation Loss
Evapo- transpiration
Discharge, Q(t)Module 6 5
Routing is the process of predicting temporal and spatial variation of a flood wave as it travels through a river (or channel) reach or reservoir
Two types of routing can be performed: Hydrologic routing Hydraulic Routing
We will concern ourselves with hydrologic routing
Module 6 6
Hydrologic routing techniques use the equation of continuity and some linear or curvilinear relation between storage and discharge within the river. Lag Routing (no attenuation) Modified Puls (level pool routing) Muskingum Routing
Module 6 7
Hydraulic routing techniques solve full versions of the St. Venant Equations for 1-dimensional free surface flow.
Generally these are handled in HEC-RAS, but a subset (simplified hydraulics) available in HMS Kinematic wave Muskingum-Cunge
Module 6 8
Applications of routing techniques: Flood predictions Evaluation of flood control measures Assessment of effects of urbanization Flood warning Spillway design for dams Detention pond design
Vital for multiple sub-basin systems simulations
Module 6 9
Problem: you have a hydrograph at one location (I) you have river characteristics (S = f(I,O))
Need: a hydrograph at different location (O)
This is a “routing” situation. The “river” can be a reservoir or some similar
feature
Module 6 10
T
SOI
Upstream Hydrograph Downstream Hydrograph
Module 6 11
SOIT )(
These “bar-heights” related by the routing table (like the storage-discharge table in prior module)
Module 6 12
As a process diagram:
Routing Model
Inflow (t)
Outflow (t)
Stream resistance properties
Stream geometric properties Wedge and Prism Storage
Module 6 13
Typically a hydraulic analysis (external to HMS) used to build a storage-discharge table
Module 6 14
Typically – multiple sub-basins. Routing to move outlet from a sub-basin to main outlet.
Module 6 15
Typically – multiple sub-basins. Routing to move outlet from a sub-basin to main outlet.
Time
Run
off
These two must transit the “rose” sub-basin
Module 6 16
Typically – multiple sub-basins. Routing to move outlet from a sub-basin to main outlet.
Time
Run
off
These two must transit the “rose” sub-basin
Run
off
Time
Composite
“routed” to the outlet
Module 6 17
The routing relationships are usually developed external to HEC-HMS Like rainfall and external hydrographs, use
external tools to develop the storage-discharge relationships
Module 6 18
Example 6 – Illustrate Routing Data Entry Ash Creek Watershed
▪ Subdivide into three sub-basins
Parameterize each sub-basin Use Lag Routing (simplest model) Examine results.
Module 6 19
Routing is of two types: Hydraulic Hydrologic
Routing tables built outside HMS, then information imported.
May need hydraulic programs to develop routing tables
Module 6 20