DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.
-
Upload
geraldine-ramsey -
Category
Documents
-
view
218 -
download
2
Transcript of DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.
![Page 1: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/1.jpg)
DES 606 : Watershed Modeling with
HEC-HMS
Module 13Theodore G. Cleveland, Ph.D., P.E
29 July 2011
![Page 2: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/2.jpg)
Channel Routing
• Example 5 illustrated lag-routing for simplistic channel routing.
• Lag routing does not attenuate nor change shape of the hydrograph
• Conflicting arguments on where applicable• probably adequate for hydrographs that stay
in a channel (no floodway involvement) and travel distance is short (couple miles).
• Other methods are required where attenuation and shape change is important
![Page 3: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/3.jpg)
• Methods that attenuate and change shape of hydrographs in HMS include
– Storage• a type of level pool routing
– Muskingum • a type of storage routing that accounts for
wedge (non-level pool) storage
– Kinematic • A type of lag routing where the lag is related
to channel slopes and accumulated reach storage – considered a hydraulic technique
Channel Routing
![Page 4: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/4.jpg)
• Consider each individually using an example
– Develop required input tables– Enter into HMS– Examine results
Channel Routing
![Page 5: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/5.jpg)
• Channel storage routing is essentially an adaptation of level pool reservoir routing– Principal difference is how the storage
and discharge tabulations are formed.
• In its simplest form, the channel is treated as a level pool reservoir.
Channel Routing
![Page 6: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/6.jpg)
• The storage in a reach can be estimated as the product of the average cross sectional area for a given discharge rate and the reach length.
Channel Routing
![Page 7: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/7.jpg)
• A rating equation is used at each cross section to determine the cross section areas.
Channel Routing
![Page 8: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/8.jpg)
• A known inflow hydrograph and initial storage condition can be propagated forward in time to estimate the outflow hydrograph. – The choice of t value should be made so that it is
smaller than the travel time in the reach at the largest likely flow and smaller than about 1/5 the time to peak of the inflow hydrograph
– HMS is supposed to manage this issue internally
Channel Routing
![Page 9: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/9.jpg)
• Consider a channel that is 2500 feet long, with slope of 0.09%, clean sides with straight banks and no rifts or deep pools. Manning’s n is 0.030.
Channel Routing Example
![Page 10: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/10.jpg)
• The inflow hydrograph is triangular with a time base of 3 hours, and time-to-peak of 1 hour. The peak inflow rate is 360 cfs.
Channel Routing Example
![Page 11: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/11.jpg)
• Configuration:
Channel Routing Example
Q(t)
t
Input hydrograph
Routing Model
Output hydrograph
![Page 12: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/12.jpg)
Channel Routing Example
• Data preparation– Construct a depth-storage-discharge table– Construct an input hydrograph table
• HMS– Import the hydrograph and the routing table
information– Simulate response
![Page 13: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/13.jpg)
Depth-Storage
A1A2
A3A4
Length
Depth
AreaA1
A1+A2
A1+A2+A3
• Compute using cross sectional geometry– Save as depth-area table (need later for
hydraulics computations)– Multiply by reach length for depth-storage
![Page 14: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/14.jpg)
Depth-Perimeter
W1W2
W3W4
Length
Depth
Wetted PerimeterW1
W2
W3
• Compute using cross sectional geometry– Save as depth-perimeter table (need later for
hydraulics computations)
![Page 15: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/15.jpg)
Depth-Discharge
• Compute using Manning’s equation and the topographic slope
![Page 16: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/16.jpg)
Inflow Hydrograph
• Create from the triangular input sketch
![Page 17: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/17.jpg)
HEC-HMS
• Create a generic model, use as many null elements as practical (to isolate the routing component)
![Page 18: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/18.jpg)
HEC-HMS
• Storage-Discharge Table (from the spreadsheet)
Note the units of storage
![Page 19: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/19.jpg)
HEC-HMS
• Meterological Model (HMS needs, but won’t use this module)
Null meterological model
![Page 20: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/20.jpg)
HEC-HMS
• Set control specifications, time windows, run manager – simulate response
Observe the lag from input to output and the attenuated peak from in-channel storage
![Page 21: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/21.jpg)
HEC-HMS
• Set control specifications, time windows, run manager – simulate response
Observe the lag from input to output and the attenuated peak from in-channel storage
Lag about 20 minutes
Attenuation (of the peak) is about 45 cfs
Average speed of flow about 2 ft/sec
![Page 22: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/22.jpg)
Muskingum Routing
• A variation of storage routing that accounts for wedge storage
Level-pool
Wedge storage
MuskingumMuskingum-Cunge
Kinematic WaveInflowDepth-Up
OutflowDepth-Down
Q
![Page 23: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/23.jpg)
• Muskingum routing is a storage-routing technique that is used to:– translate and attenuate hydrographs in natural
and engineered channels– avoids the added complexity of hydraulic
routing.
• The method is appropriate for a stream reach that has approximately constant geometric properties.
![Page 24: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/24.jpg)
• At the upstream end, the inflow and storage are assumed to be related to depth by power-law models
![Page 25: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/25.jpg)
• At the downstream end, the outflow and storage are also assumed to be related to depth by power-law models
![Page 26: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/26.jpg)
• Next the depths at each end are rewritten in terms of the power law constants and the inflows
![Page 27: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/27.jpg)
• Then one conjectures that the storage within the reach is some weighted combination of the section storage at each end (weighted average)
• The weight, w, ranges between 0 and 0.5. – When w = 0, the storage in the reach is entirely
explained at the outlet end (like a level pool)– When w = 0.5, the storage is an arithmetic mean of
the section storage at each end.
![Page 28: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/28.jpg)
• Generally the variables from the power law models are substituted
• And the routing model is expressed as
• z is usually assumed to be unity resulting in the usual from
![Page 29: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/29.jpg)
• Generally the variables from the power law models are substituted
• And the routing model is expressed as
• z is usually assumed to be unity resulting in the usual from
![Page 30: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/30.jpg)
• For most natural channels w ranges between 0.1 and 0.3 and are usually determined by calibration studies
• Muskingum-Cunge further refines the model to account for changes in the weights during computation (better reflect wedge storage changes)
![Page 31: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/31.jpg)
In HEC-HMS
• Use same example conditions• From hydrologic literature (Haan, Barfield,
Hayes) a rule of thumb for estimating w and K is– Estimate celerity from bankful discharge (or deepest
discharge value)– Estimate K as ratio of reach length to celerity (units of
time, essentially a reach travel time)– Estimate weight (w) as
)1(2
1
0
0
cLS
qw
![Page 32: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/32.jpg)
In HEC-HMS
• Use same example conditions
![Page 33: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/33.jpg)
In HEC-HMS
• Use same example conditions
Results a bit different but closeDifference is anticipated
Muskingum Parameters
![Page 34: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/34.jpg)
In HEC-HMS
• Change w to 0.0, K=20 minutes, NReach=2– Level Pool
Results almost same as level-pool model
Muskingum Parameters
![Page 35: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/35.jpg)
In HEC-HMS
• Change w to 0.5, K=20 minutes, NReach=2– Lag Routing
20 minute lag routing
Muskingum Parameters
![Page 36: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/36.jpg)
Muskingum-Cunge
• More complicated; almost a hydraulic model• Data needs are
– Cross section geometry (as paired-data)– Manning’s n in channel, left and right overbank– Slope– Reach length
• Will illustrate data entry using the same example
![Page 37: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/37.jpg)
Muskingum-Cunge
• Cross section geometry– “Glass walls”
![Page 38: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/38.jpg)
Muskingum-Cunge
• Associate the section with the routing element– Other data included
![Page 39: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/39.jpg)
Muskingum-Cunge
• Run the simulation– Result comparable to level-pool.
![Page 40: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/40.jpg)
Summary
• Examined channel routing using three methods– Level pool routing (Puls)– Muskingum – Muskingum-Cunge
• Selection of Muskingum weights allows analyst to adjust between level-pool and lag routing by changing the weighting parameter
• All require external (to HMS) data preparation– Muskingum-Cunge hydraulically “familiar)
![Page 41: DES 606 : Watershed Modeling with HEC-HMS Module 13 Theodore G. Cleveland, Ph.D., P.E 29 July 2011.](https://reader030.fdocuments.us/reader030/viewer/2022032606/56649eb75503460f94bc153a/html5/thumbnails/41.jpg)
Summary
• Parameter estimation for Muskingum method requires examination of literature external to HMS user manuals
• Instructor preferences for routing– Lag routing (if can justify)– Level-pool– Muskingum-Cunge (as implemented in HMS) – very “hydraulic”– Muskingum (I would only choose if had calibration data)– Kinematic-wave