19 TODAYS MATERIAL Supplemental Reading 3 parts on week 10 website Hydrology PREVIEW MATERIAL Hydrology Annual precipitation across the USA during 1996 Source Redrawn with data from the National Atmospheric Deposition Program ID: 572099
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Slide1
GEOL 10 LECTURE
19
TODAYS MATERIAL:
Supplemental
Reading
(3 parts) on week 10 website
Hydrology
PREVIEW MATERIAL:
HydrologySlide2
Annual precipitation across the USA during 1996
.
Source: Redrawn with data from the National Atmospheric Deposition Program
Brooks et al., 2013. Hydrology and the Management of Watersheds, 545 p.Slide3
http://rpmga.blogspot.com/2011/05/where-did-rain-guage-originate.html
www.glogster.com
Precipitation is measured with rain gagesSlide4
methods of calculating the mean rainfall on a
watershed:
Arithmetic mean
Thiessen polygon
Isohyetal
Brooks et al., 2013. Hydrology and the Management of Watersheds, 545 p.Slide5
River Flow (Discharge) Slide6
Measurements of stream channel cross sections and velocities
needed to
estimate the mean velocity of a streamSlide7
http://ut.water.usgs.gov/publications/fs245-96/Slide8
USGSSlide9
Todd Kraemer of Pacific Watershed Associates measures low flow at Jacoby Creek for flow study of 4 creeks in Arcata.Slide10
Cross-Section Q measurements are time consuming. It is much easier to simply measure the height of the water surface.
This is a
manual stream
gaging
station on the Fitzroy River,
Rockhampton
, January 2011. Note the historical reference to heights of previous floods: 1918, 1954, and 1991.Slide11
River “
Stage
”Slide12
River “
Q
”Slide13
Stage-Discharge
Rating CurveSlide14
The streamflow gage on the
Willamette River near Salem
, Oregon, is one of many in the Willamette Valley and is typical of the more than 7,000 active USGS gages on streams and rivers in the U.S. and Puerto Rico. Most stations monitor river stage (elevation of the water surface), which is then converted to discharge (flow volume per unit time) by use of a stage-discharge rating curve.Slide15
Methods of separating
baseflow
from
stormflow
; I and
II are
different approaches.
Brooks et al., 2013. Hydrology and the Management of Watersheds, 545 p.Slide16Slide17
http://www.alevelgeography.com/wp-content/uploads/2013/07/storm-hydrograph2.jpgSlide18
Modelled versus observed water heights for the Mary River at Gympie, Queensland, together
with observed
rainfall. While there is reasonably good agreement in this instance, as can be seen from the differences between the red and green lines, actual river height can vary from what we expect based on modelled results due to data and model limitations. Slide19Slide20Slide21Slide22Slide23
“flashy”Slide24Slide25
Most of the largest known floods of the Quaternary Period resulted from breaching of dams formed by glaciers or landslides.
Types:
Ice-Dam or Landslide-Dam Failure
Lake Overflow (many kinds)
Volcanic Eruption
Ice Jam or Snowmelt
Meteorological/Rainfall (most common)Slide26
The late-Pleistocene Missoula floods in the Pacific Northwestern United States were some of the largest ever to have occurred on Earth. The floods resulted from the repeated breaching of an ice dam formed from a lobe of the Cordilleran Ice Sheet that blocked the present-day Clark Fork River and created an immense lake known as glacial Lake Missoula.
http://hugefloods.com/LakeMissoula.htmlSlide27
http://hugefloods.com/9-Giant-Current-Ripples.html
https://youtu.be/eH8JEKBvz5w
https://www.facebook.com/photo.php?fbid=1706816592929897&set=a.1381433965468163.1073741827.100008047171155&type=3&theaterSlide28Slide29
Usoi
Dam in
Tajikastan
, formed by a landslide in 1911, created 16 cubic-kilometer Lake
Sarez
, the largest lake in the world resulting from a landslide. Five million people live in the valleys downstream of the dam. Even partial breaching of the dam could cause catastrophic flooding. Complete failure of the dam could result in the deadliest natural disaster in human history.Slide30