CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations ...
-
Upload
gladys-carroll -
Category
Documents
-
view
219 -
download
0
Transcript of CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations ...
![Page 1: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/1.jpg)
HYDROLOGIC ANALYSIS
CE 3372 – Lecture 10
![Page 2: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/2.jpg)
Outline Hydrology Review Rational Method Regression Equations Hydrographs
![Page 3: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/3.jpg)
Hydrology
“The science dealing with the occurrence, circulation, distribution, and properties of the waters of the earth and it’s atmosphere”
-Dictionary.com
![Page 4: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/4.jpg)
![Page 5: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/5.jpg)
![Page 6: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/6.jpg)
![Page 7: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/7.jpg)
Estimating Runoff
![Page 8: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/8.jpg)
Peak Flow/Discharge
Discharge [L3/T]- Volume of water through a given cross-sectional area at a period of time
Peak flow corresponds to maximum water levels reached during a rainfall event
Flood Timelapse
![Page 9: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/9.jpg)
Rainfall Frequency Frequency
(Return Period) and probability (AEP) are related
Frequency (years) = 100 / Probability (%)
Ex: 2-year =100 / 50%
![Page 10: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/10.jpg)
HCFCD
![Page 11: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/11.jpg)
Hydrologic Analysis
Rational Method HCFCD Discharge-Area Curves (1960s) TxDOT and USGS Regression Equations Clark Unit Hydrograph Soil Conservation Service (SCS) Unit
Hydrograph Method Johnson & Sayre Curves and
Generalized Regression Equations TR-55 Method
![Page 12: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/12.jpg)
![Page 13: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/13.jpg)
![Page 14: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/14.jpg)
PEAK FLOWS
![Page 15: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/15.jpg)
Rational Method
Qp = CiA
whereQP= peak runoff [L3/T]
C = a dimensionless coefficient i = rainfall intensity [L/T] A = drainage area [L2]
![Page 16: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/16.jpg)
Rational Method - C
![Page 17: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/17.jpg)
Rational Method - i
Qp = CiA
Rainfall intensity (I) = total amount of rain (rainfall depth) falling over a given time of concentration [L/T]
![Page 18: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/18.jpg)
Rational Method - i
Pd = depth of rainfall (in. or mm) for AEP design storm of duration
tc = drainage area time of concentration (hr.)
![Page 19: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/19.jpg)
Depth-Duration Frequency
United States Geological Service Report (USGS), Asquith (1988)
![Page 20: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/20.jpg)
Drag picture to placeholder or click icon to add
IDF Curve
s
![Page 21: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/21.jpg)
Rational Method - i
![Page 22: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/22.jpg)
Time of Concentration (Tc) Time required (after start of rainfall
event) for most distant point in watershed to begin contributing runoff to the watershed outlet
TxDOT recommends 10min to 300min
![Page 23: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/23.jpg)
Kerby-Kirpich Method
Applicable to watershedsarea: 0.25 sq. mi. to 150 sq. mi.main channel slopes: 0.002 to 0.02 (ft/ft)main channel lengths: 1 to 50 miles (Roussel et al. 2005)
![Page 24: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/24.jpg)
![Page 25: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/25.jpg)
![Page 26: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/26.jpg)
NRCS Method
Applicable for: small watershedsmajority overland flow (so timing of the peak flow is not significantly affected by the contribution flow routed through underground storm drain systems.)
![Page 27: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/27.jpg)
![Page 28: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/28.jpg)
![Page 29: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/29.jpg)
![Page 30: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/30.jpg)
Wate
rshed L
en
gth
![Page 31: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/31.jpg)
Wate
rshed S
lope
![Page 32: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/32.jpg)
Rational Method
Qp = CiA Find tc to calculate intensity Plug and chug
![Page 33: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/33.jpg)
HC
FCD
Sit
e R
unoff
C
urv
es
![Page 34: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/34.jpg)
REGRESSION EQUATIONS
![Page 35: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/35.jpg)
TxDOT Regression Eq.
Regression equations are used to transfer flood characteristics from gauged to ungauged sites Done by using watershed and
climatic characteristics as explanatory or predictor variables
Reliable > 10 sq. mi. drainage area Only for non-urbanized
watersheds
![Page 36: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/36.jpg)
TxDOT Regression Eq.
![Page 37: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/37.jpg)
![Page 38: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/38.jpg)
![Page 39: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/39.jpg)
![Page 40: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/40.jpg)
USGS Regression
Note: USGS developed the regression equations for TxDOT
Omega-EM is omitted
![Page 41: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/41.jpg)
HYDROGRAPHS
![Page 42: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/42.jpg)
Hydrograph
Graph – Flow vs. Time
![Page 43: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/43.jpg)
BeforeRain
AfterRain &watermovesto
streams
![Page 44: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/44.jpg)
Hydrographs
Permeable Low infiltration
![Page 45: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/45.jpg)
![Page 46: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/46.jpg)
![Page 47: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/47.jpg)
Methods of Developing UH’s
From Streamflow Data Synthetically
Snyder SCSClarks
“Fitted” Distributions
![Page 48: CE 3372 – Lecture 10. Outline Hydrology Review Rational Method Regression Equations Hydrographs.](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d805503460f94a65016/html5/thumbnails/48.jpg)
TO BE CONTINUED