Examples discharge analyses (Princeton's hometown stream, the author's hometown stream in NJ, Santa Ana River in CA, the Colorado River in the Grand Canyon).

1. Stony Brook,
Princeton, NJ

2. A rainy day
Gage
height (ft)
Peak of discharge
8am Wed 4/13
http://waterdata.usgs.gov/nj/nwis/uv/?site_no=014010
00&agency_cd=USGS
Peak of rainfall
7pm Tues 4/12
http://www.srh.noaa.gov/data/obhistory/KTTN.html
Discharge
(cfs)
 lag time of 13 hours

3. A really rainy day
Hurricane Irene,
last August

4. Peak Annual Discharge 1953-2011
Stony Brook at Princeton, NJ
10000
Tropical Storm Doria
Hurricane Floyd
9000
8000
Peak annual discharge (cfs)
7000
6000
5000
4000
3000
2000
1000
0
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
year
Sensitivity of recurrence interval analysis to peak events?

5. Recurrence Intervals
Stony Brook, all data
100000
Discharge (cfs) 10000
1000
1 10 100 1000 10000
Recurrence interval (years)
Recurrence Intervals
Stony Brook, w/o 2 largest events
100000
10000
1000
1 10 100 1000 10000

6. Recurrence Intervals
Stony Brook, all data
100000
Discharge (cfs) 10000
RI of 13,500cfs
1000
~1000 yrs (0.1%)
1 10 100 1000 10000
Recurrence interval (years)
Recurrence Intervals
Stony Brook, w/o 2 largest events
100000
10000
RI of 13,500cfs
~10000 yrs (0.01%)
1000
1 10 100 1000 10000
Both trendlines fit logarithmically

7. Rahway River,
at Springfield, NJ
(LG’s hometown stream)

8. 10000
9000 Rahway River at Springfield, NJ
Hurricane Floyd
Peak Annual Discharge
1938-2010
8000
7000
Hurricane Agnes (as a kid,
More work
LPG’s basement full of water, and 1980’s – mitigation proposed -
cfs
6000 had fun paddling the floating (dikes, retention basins) $$$
sandbox around…) $$$
5000
4000
3000
2000
1000
0
1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

9. 10000
Hurricane Irene
Rahway River at Springfield, NJ
9000 Peak Annual Discharge August 2011
1938-2011
8000
7000
cfs
6000
5000
4000
3000
2000
1000
0
1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

10. 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…

13. Dave Pringle ’88

14. Santa Ana River,
Los Angeles area, CA

15. 1938
1969
2007
1955

16. 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…
The Santa Ana River, in flood in 1938.
http://en.wikipedia.org/wiki/Los_Angeles_Flood_of_1938

17. 50000
45000 Santa Ana River, Santa Ana, CA
Peak Annual Discharge
40000
1923-2010
35000
30000
crs
25000
20000
15000
10000
5000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

18. 50000
―50-yr flood‖ of 1938
45000
40000 Santa Ana River, Santa Ana, CA
Peak Annual Discharge
35000
1923-2010
30000
In response:
crs
25000 channelization,
flood control dams
20000
15000
10000
5000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

19. 50000
―50-yr flood‖ of 1938
45000
40000 Santa Ana River, Santa Ana, CA
Peak Annual Discharge
35000
1923-2010
30000
In response:
crs
25000 channelization,
flood control dams
20000
15000
10000
5000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

20. Chase scene from
“Terminator 2”
Santa Ana River - note intense development of the
area, and artificial straightening and channelization of the

21. Santa Ana River
with water.
without water.

22. 50000
45000 …channelization, however, does not remove all
dangers of floods; there were major floods in
40000
1969, 1980, 1983, 1992, and 1994, with the last
35000
said to probably be a 100-year flood
30000
―100-yr
crs
25000
flood‖
20000
15000
10000
5000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

23. 50000
45000
40000
35000
30000
crs
25000
20000
15000
10000
5000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

24. ―100-yr
1000000
flood‖
100000 ―50-yr flood‖
10000
cfs
1000
Santa Ana River, CA
100 Recurrence Interval
1923-2009
10
1
1 10 100 1000
years

25. Colorado River,
southwestern US

27. gauging station
http://snobear.colorado.edu/Markw/Tye/grand_canyon_01.html

28. Colorado River at Grand Canyon
Peak Annual Discharge 1920-2006
250000
What happened
200000 here? Ideas?
150000
cfs
100000
50000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

29. 1953
Daily Discharge
for 1 year
2007

30. Glen Canyon Dam

31. Lake Powell
Glen Canyon Dam

32. Glen Canyon Dam

33. Lake Powell
Glen Canyon Dam

34. Colorado River at Grand Canyon
Peak Annual Discharge 1920-2006
250000
Dam goes
200000
on line
150000
cfs
100000
50000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

35. 1953
pre-dam Daily Discharge
for 1 year
2007
post-dam

36. 1000000
Recurrence intervals
before and after Glen Canyon Dam
Discharge (cfs)
100000
pre dam
post dam
10000
1 10 100 1000
Recurrence interval (years)

37. Lake Powell
Glen Canyon Dam

38. at river mile 84.4
(Downstream of Glen Canyon Dam)
Sept 2007 ~10,000cfs

39. 2008 High-Flow Experiment from 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…

41. March 8-
9, 2008

42. at river mile 84.4
(Downstream of Glen Canyon Dam)
Sept 2007 ~10,000cfs
March 2008 ~10,000cfs

43. Lake Powell
Hoover Dam
Glen Canyon Dam

44. Lake Mead
Hoover Dam

45. Hoover Dam

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

48. Water Use in Southwest Heads for a Day of Reckoning
NYTimes September 27, 2010

49. 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…

50. 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..