Examples of discharge analysis

Stony Brook,

Princeton, NJ

Discharge

(cfs)

Gage

height (ft)Peak of discharge

8am Wed 4/13http://waterdata.usgs.gov/nj/nwis/uv/?site_no=014010

00&agency_cd=USGS

lag time of 13 hours

Peak of rainfall

7pm Tues 4/12

http://www.srh.noaa.gov/data/obhistory/KTTN.html

A rainy day

A really rainy day

Hurricane Irene,

last August

Sensitivity of recurrence interval analysis to peak events?

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Peak a

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ual d

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Peak Annual Discharge 1953-2011Stony Brook at Princeton, NJ

Tropical Storm DoriaHurricane Floyd

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Recurrence interval (years)

Recurrence Intervals Stony Brook, all data

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Recurrence IntervalsStony Brook, w/o 2 largest events

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Recurrence Intervals Stony Brook, all data

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Recurrence IntervalsStony Brook, w/o 2 largest events

RI of 13,500cfs

~1000 yrs (0.1%)

RI of 13,500cfs

~10000 yrs (0.01%)

Both trendlines fit logarithmically

Rahway River,

at Springfield, NJ

(LG’s hometown stream)

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cfs

Rahway River at Springfield, NJPeak Annual Discharge

1938-2010

Hurricane Agnes (as a kid,

LPG’s basement full of water, and

had fun paddling the floating

sandbox around…)

Hurricane Floyd

1980’s – mitigation

(dikes, retention basins)

$$$

More work

proposed -

$$$

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Rahway River at Springfield, NJPeak Annual Discharge

1938-2011

Hurricane Irene

August 2011

Cranford inundated by flood waters; power could be out for five to seven days

By the Cranford Chronicle

Monday August 29, 2011 Cranford has sustained severe damage from Hurricane Irene. Residents were

ordered to evacuate on Saturday, and had to be out by 8 p.m. Those who live in a 100-year flood zone

area, the order was expanded to include a 500-year flood zone area…

The meandering Rahway River had always been one of the things that drew people to Cranford. Families

rented canoes from the local canoe club to paddle through town. Joggers ran along winding paths along the

river’s banks. Cranford’s ties to the water helped earn the Union County township the nickname "Venice of

New Jersey…―

But this weekend, the river shocked much of the town when it broke through dikes and overflowed earthen

dams to flood residential neighborhoods and downtown streets…

The damage in Cranford is immense. Areas of Cranford not touched by a flood before were inundated… A

release from Cranford Police Department on Sunday event said "the Cranford Municipal Building and Police

Department has been shut down due to flooding and severe damage. The Police Department is running out of

a mobile command post."

Mayor Dan Aschenbach said the damage is staggering: Nearly 1,300 residences — or more than 15 percent

of the township’s houses — have significant flood damage. Of those, nearly 200 houses had water up to the

first floor. Seven have already been condemned. More than 6,000 residents lost power…

http://connect.nj.com/user/njocranford/index.html

Dave Pringle ’88

Santa Ana River,

Los Angeles area, CA

1938

20071955

1969

The 1938 Los Angeles flood (in early 1938) was a major flooding event that was

responsible for inundating much of Los Angeles, Orange and Riverside counties,

California. The flood was caused by a pair of oceanic storms that swept inland

across the area in February and March 1938, causing abnormal rainfall across

much of coastal Southern California. 113[ to 115 people perished in the flood,

which was one of the most catastrophic disasters in area history.[ The flood

caused the destruction of roads, bridges, and buildings, stranded hundreds of

people, and resulted in the flooding of three area rivers and their tributaries; these

were the Santa Ana, Los Angeles and San Gabriel Rivers…

The flooding event of 1938 was…considered a

50-year flood, meaning that it has a 2 percent

chance of occurring any given year. The flood

resulted in $40 million of damages, and …heavily

affected public opinion on the safety of area

rivers, and as a result, the US Army Corps of

Engineers was prompted to begin channelization

of the river, and construction of more flood

control dams…

http://en.wikipedia.org/wiki/Los_Angeles_Flood_of_1938

The Santa Ana River, in flood in 1938.



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Santa Ana River, Santa Ana, CA Peak Annual Discharge

1923-2010

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Santa Ana River, Santa Ana, CA Peak Annual Discharge

1923-2010

―50-yr flood‖ of 1938

In response:

channelization,

flood control dams

Santa Ana River - note intense development of the

area, and artificial straightening and channelization of the

river

Chase scene from

“Terminator 2”

Santa Ana River

with water.

without water.

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…channelization, however, does not remove all

dangers of floods; there were major floods in

1969, 1980, 1983, 1992, and 1994, with the last

said to probably be a 100-year flood

―100-yr

flood‖

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Santa Ana River, CA Recurrence Interval

1923-2009

―50-yr flood‖

―100-yr

flood‖

Colorado River,

southwestern US

http://snobear.colorado.edu/Markw/Tye/grand_canyon_01.html

gauging station

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Colorado River at Grand Canyon Peak Annual Discharge 1920-2006

What happened

here? Ideas?

Daily Discharge

for 1 year

1953

2007

Glen Canyon Dam

Lake Powell

Glen Canyon Dam

Glen Canyon Dam

Glen Canyon Dam

Lake Powell

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Colorado River at Grand Canyon Peak Annual Discharge 1920-2006

Dam goes

on line

Daily Discharge

for 1 year

1953

2007

pre-dam

post-dam

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Recurrence intervals before and after Glen Canyon Dam

pre dam

post dam

Glen Canyon Dam

Lake Powell

Sept 2007 ~10,000cfs

at river mile 84.4

(Downstream of Glen Canyon Dam)

On March 5, 2008, Secretary of the Interior Dirk Kempthorne pulled the levers

at Glen Canyon Dam to release high flows into the Colorado River… Water

was released through Glen Canyon Dam's powerplant and bypass tubes to a

maximum amount of approximately 41,500 cubic feet per second for about 60

hours. The experiment was designed to enhance the habitat in the canyon and

its wildlife, and learn more about these complex natural systems…

2008 High-Flow Experiment from Glen Canyon Dam

March 8-

9, 2008

at river mile 84.4

(Downstream of Glen Canyon Dam)

Sept 2007 ~10,000cfs

March 2008 ~10,000cfs

Lake Powell

Glen Canyon Dam

Hoover Dam

Lake Mead

Hoover Dam

Hoover Dam

Lake Mead from Hoover Dam, down to 55% capacity (April 2012)

NYTimes September 27, 2010

Water Use in Southwest Heads for a Day of Reckoning

NYTimes September 27, 2010 by Felicity Barringer

Water Use in Southwest Heads for a Day of

Reckoning

A once-unthinkable day is looming on the Colorado River…For the first time, federal

estimates issued in August indicate that Lake Mead, the heart of the lower Colorado

basin’s water system — irrigating lettuce, onions and wheat in reclaimed corners of

the Sonoran Desert, and lawns and golf courses from Las Vegas to Los Angeles —

could drop below a crucial demarcation line of 1,075 feet.

If it does, that will set in motion a temporary distribution plan approved in 2007 by

the seven states with claims to the river and by the federal Bureau of

Reclamation, and water deliveries to Arizona and Nevada would be reduced….This

could mean more dry lawns, shorter showers and fallow fields in those

states, although conservation efforts might help them adjust to the cutbacks.

California, which has first call on the Colorado River flows in the lower basin, would

not be affected…

NYTimes July 21, 2011 by Julia Pyper

A Paradox for the West's Plumbing System: Flood on the

Top, Drought on the Bottom

The Colorado River…(is) a life source of the more than 30 million people who rely on

it…But in recent years, the Colorado River has become less reliable. Since

1999, abnormally low precipitation totals and hot and dry conditions have brought reservoir

water levels close to record lows. The multiyear drought, the most severe since

documentation began more than 100 years ago, has put the water supply in the thirsty

Southwest in jeopardy.

This year, heavy snowpack and spring precipitation have brought the region some relief by

partially refilling the reservoirs. But…the southern end of the Colorado River continues to

stop shy of the Sea of Cortez, where it used to run until the late 1990s.

The paradox is that this season stands in such stark contrast to the past 11 years of

drought, highlighting the types of variability that climate change can wreak on the

hydrological cycle. "It's not at all uncommon for the basin to have high runoff years in a

longer period of drought," said Pamela Adams… "We can see that in both the past 100

years of data, plus you can see it in the tree-ring data."

Concerns regarding the reliability of the Colorado River system to meet the future needs of

Basin resources in the 21st-century are heightened, given the likelihood of increasing

demand for water throughout the Basin, coupled with projections of reduced supply due to

climate change," wrote the authors of the report..

Examples of discharge analysis

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