Karen Jennings

Annotated Bibliography

Topic: Paleofloods

Allen, J.E. and Burns, M., 1986. Cataclysms on the Columbia. Portland,

Oregon: Timber Press, 213 p.

This book follows the career of J. Harlen Bretz who was the first person to

suggest that large floods had influenced the topography of eastern

Washington. Bretz spent most of his life trying to convince others that

the geomorphic features of the Columbia plateau was produced by massive

amounts of water flowing through the area in a catastrophic flood. The

book also explains the history of the series of glacial lakes in Northern

Idaho and Montana that were dammed by ice, which broke to flood surrounding

areas about once every 50 years for 2000 years. This pattern of flooding

has carved out most of the topography now visible in the Pacific Northwest.

Cataclysms on the Columbia. is written in order to explain the geology to

the lay person, and as such, is written in a similar style to the John

McPhee books. The book is clear and easy to follow, and contains many

interesting photographs of the features described. I especially enjoyed

the two introductory essays which talk about how great geologists are. :)

The only complaint I have about the book is that it tended to over-vilify

geologists who did not agree with Bretz's interpretations.

Baker, Victor R., 1994. Geomorphological understanding of floods.

Geomorphology, 10, p. 139-156.

This paper is a philosophical essay about the problems associated with

current flood-frequency analysis. Baker outlines the problems of using

statistics to generalize unique flood events, and the fallacies of

extrapolating from historical flood data to determine larger flood

magnitudes. The paper also addresses societal issues, such as the

scientific prejudice that hard, quantitative data is necessary in order to

justify a particular research study. Baker goes further to discuss the

difference between prediction and understanding of flood processes. He

points out that because scientists fail to address the theoretical

questions that will help them to understand floods, opting instead for the

quantitative/engineering route, the flood predictions that are made are

really just experiments to see if nature will conform to our current level

of understanding. Baker also uses the essay to express his strong opinion

about the inability of flood scientists to convey an understanding of flood

processes to the public. This miscommunication leads to societal myths

about flooding such as 'one hundred year floods happen on the dot every one

hundred years.' Baker feels that the attempts of flood scientists to

explain flooding processes to the public using statistics and mathematics

has led to the public's misconceptions, and that a more qualitative

approach may help to remedy the situation. The last portions of the essay

discuss how geomorphological analysis of paleoflooding could help to remedy

many of the problems currently plaguing flood science by 1) Proving a much

larger record of flooding (perhaps as large as 10,000 years or more) to

work with, and 2) providing a means to better understand qualitative flood

processes.

I found this paper extremely fascinating to read, and if it wasn't so long

I might have brought it to the class for discussion. Baker questions many

of the assumptions that researchers use to validate their science (for

example, that nature can be quantified at all), and raises many questions

about the applicability of statistics to assessing human risk. He uses

many wide and interesting examples to support his arguments, from flood

accounts in Arizona, to the explosion of the space shuttle Challenger, to

anonymous reviews of his own papers. The paper, however, does take quite a

while to wade through. The total length is 17 pages, and it written in a

very wordy fashion that prevents the paper from being 'an easy read.' I

also felt that Baker was doing more engineer-bashing than was necessary to

make his point. However, I would strongly recommend that other scientists

read this paper, if only because it caused me to challenge my own

assumptions about science in general.

Costa, John E., 1986. A history of paleoflood hydrology in the United

States, 1800-1970. EOS, 67, no, 17, p. 428-439.

This article is a general literature review of paleoflood studies up to

the year 1970. According to Costa, interest in studying paleofloods

originated with studies trying to reveal evidence of Noah's Flood using

what we now know to be glacial deposits in New England. In 1840, Agassiz

published a paper in Europe that identified drift and till deposits to be

glacially derived. This explanation, along with the rising popularity of

uniformitarianism, put paleoflood studies on the back burner for 40 years.

The next large paleoflood study was completed by Dana in 1882 using flood

terraces in the Connecticut River Valley to estimate flooding from glacial

melt. The paper continues to outline other major paleoflood studies,

including Bretz's 1923 descriptions of the Lake Missoula Floods in eastern

Washington. The number of paleoflood studies increased dramatically around

1970 due to flooding by Hurricanes Camille and Agnes that caused large

amounts of property destruction and loss of life. The hurricane floods

prompted the federal Flood Disaster Prevention Act, which in turn brought

renewed attention to paleoflood studies.

The article is short and straightforward. It provides a chronological

sequence of studies that is easy to follow. I found the perspectives of

19th Century geologists to be thought-provoking, and it was interesting to

follow the progression of the field over the years. This paper is most

useful for readers who want to find out about how paleoflood analyses

evolved throughout history, and who the founders of the field were.

Ely, L.L, Enzel, Y., Baker, V.R., Cayan, D.R., 1993. A 5000-year record of

extreme floods and climate changes in the southwestern United States,

Science, 262, p. 410-412.

Using slackwater flood deposits in stable, bedrock channels, the authors of

this paper examined the flood history of several streams in Arizona and

Utah. They found that the slackwater deposits were strongly correlative

between the different streams, and were able to match times of increased

flood frequency to previously known times of climate change, such as the

Medieval Warm Period and the Little Ice Age. The study also found that the

largest floods tended to happen when there was a climatic change from cool

to warm conditions. These large floods are thought to have been caused by

winter storms and tropical cyclones.

This is an important paper because of the implication of this study that

suggest that global climate change may be delineated by examining

paleoflood deposition in different river systems around the world. It also

says a lot for studies that Anders and I are persuing, which are looking

for evidence of regional climate changes across New England. The paper is

short, and although it is jam-packed with information, it is not difficult

to read.

Ely, L.L, Enzel, Y., Baker, V.R., Kale, V.S., and Mishra, S, 1996. Changes

in the magnitude and frequency of late Holocene monsoon floods on the

Narmada River, central India, Geological Society of America Bulletin, 108,

p. 1134-1148.

The authors of this article began their study as a response to several dam

proposals along the Narmada River. This river has experienced some of the

largest historical floods in the world, and it was important to understand

whether historical flooding patterns on the river were the norm. The

results of the study found that the large floods occurring on the Narmada

river since 1950 have not been exceeded in the past 3000 years.

Additionally, the 1700 year record of paleoflood deposition showed an

increase in flood frequency and magnitude in historic times. A correlation

with other paleoflood studies in tropical regions, as well as the timing of

the historical megafloods suggests that the cause of increased flooding is

a regional climate change. Tropical cyclones that coincide with the

summer monsoon season tends to trigger widespread flooding due to the

increased amounts of rapid precipitation.

I found this paper to be quite fascinating since it shows that floods have

actually become larger in historic times, and not necessarily due to land

use changes. The paper is a bit longer than some of the others in the

bibliography, but it is easy to read and contains lots of great

stratigraphic columns and photos.

Kochel, R.C. and Baker, V.R., 1982. Paleoflood hydrology. Science, 215, no.

4531, p. 353-361.

This paper outlines the methods for using sedimentology and geomorphology

in order to determine the timing and frequency of paleofloods. The authors

do a step by step guide through the different processes contributing to

slackwater deposition, and describe the types of channel features that will

best preserve that deposition. Slackwater sediment sequences are described

in detail, as well as the methods used to determine paleoflood stage and

discharge. The second half of the paper uses these methods to evaluate the

flood history of the Pecos River in Texas.

I felt that this paper is a good introduction on

'how-to-study-paleofloods.' I also liked how the paper describes the

benefits of using sedimentary paleoflood chronologies over using

statistical methods from historical data. I think this paper is a good

guide to the paleoflood science discipline, especially because of the large

amounts of description involved in describing the flood deposits. The

paper is a bit long for the typical Science paper, but I did not find it

difficult to read.

Smith, D.G., and Fisher, T.G., 1993. Glacial Lake Agassiz: The

northwestern outlet and paleoflood, Geology, 21, p. 9-12.

This study addresses pieces of evidence in the Clearwater valley of Alberta

and Saskatchewan to show that Glacial Lake Agassiz drained during a

catastrophic flood that flowed to the northwest, emptying into Glacial Lake

McConnell. The majority of evidence used in this study is based on the

morphology of the Clearwater River Valley, which is an underfit stream.

Radiocarbon dating of sediment and boulder deposits aided the

interpretation, as well as paleocurrent directions determined from

cross-bedding.

This paper is an interesting comparison to some of the others in this

bibliography because it describes flooding as the result of a catastrophic

release of water from a glacial lake, rather than flooding due to increased

precipitation. I am not very fond of the way this paper is written,

however. I feel that it makes a lot of large jumps in its interpretations

without necessarily having the data to back it up. I would also have liked

to see a better descriptions of methods and evidence used, especially since

this paper is attempting to dispute the previously held belief that Lake

Agassiz drained to the south along the Mississippi River. Additionally,

the abstract suggests that a northern drainage of the lake would have

influenced climate, but this issue is never addressed in the body of the

paper.

Wohl, Ellen E., 1992, Bedrock benches and boulder bars: Floods in the

Burdekin Gorge of Australia. Geological Society of America Bulletin, 104,

p. 770-778.

Whol uses the channel morphology of a bedrock gorge in Queensland,

Australia to determine the frequency, magnitude, and hydraulics of large

floods through the gorge over the past 1,200 years. High velocities,

stream power and boundary shear stress influenced the location of boulder

bars, levees, and potholes. These features record seven floods that have

passed through the gorge, with magnitudes ranging from 11,000 to 30,000

m3s-1. The paper successfully integrates channel morphology and hydrology,

and describes the connection between the two.

This paper is an excellent example of how geomorphology can be used to

determine the hydraulics and hydrology of paleofloods that have occurred

within one stream system. The paper is well-written, although it does get

technical in some places. I was also impressed with the figures which I

thought were well-captioned and well-explained.

Wohl, E.E., Fuertsch, S.J., Baker, V.R., 1994. Sedimentary records of late

Holocene floods along the Fitzroy and Margaret Rivers, Western Australia,

Australian Journal of Earth Sciences, 41, p. 273-280.

This study evaluated paleoflood frequency and discharge in the Margaret and

Fitzroy Rivers of Western Australia. The two rivers are located in a

seasonal tropic region, with the Margaret River flowing into the larger

Fitzroy River. Both rivers have 30 years of recorded gauge data, and were

determined to have a channel morphology well-suited to preserving detailed

and accessible flood records. Slackwater deposits and other paleostage

indicators were used to reconstruct past flood stages. Organic material

was radiocarbon dated to determine flood ages. The study found that six

major floods occurred along the Fitzroy River in the last 2,000 years,

ranging from 5,000 to 30,000 m3s-1. The Margaret River contained 4,000

years of paleoflood record, showing 13 floods ranging from 2,000 to 20,000

m3s-1.

This paper is well-written and easy to follow. It is a good paper to look

at for an example of how to use paleoflood analysis. The paper is also

interesting for it's comparison of flood numbers and discharges on

different rivers, and addresses possible reasons that they do not strongly

correlate.