GEORGIA ARCHIVES WEEK OCTOBER 7-15, 2006

Return to Flood Home page Flood programs and information. Links to other information. Flood of 1929 Floods of 1912-1914 Flood of 1908 Flood of 1888 Preface to Flood Informaton
Preface to Flood.

Floods Happen.

by Bill Wells, Reese Library, Augusta State University. 2006.

 

“The Savannah River is a stream bold in all of its features,” wrote Augusta, Georgia ’s 1914 weather bureau officer-in-charge Eugene D. Emigh.[1]     The Savannah River is formed by the union of the Seneca and Tugaloo Rivers some one hundred miles above Augusta and has its cultural and physical ties to both Georgia and South Carolina.  Emigh wrote, for its size, the Savannah is a “restless river” with intermittent stretches of water “rushing over the granite bed” and “resting in placid pools.”   Overall the river made a rapid passage to Augusta with a 257-foot drop over the sixty-four miles immediately preceding Augusta.  The last “rapids” are about six miles above Augusta but once past the city the river turns into a slow, meandering course to the sea.  

 

Part of the river’s rush to Augusta is the up-state topography.  The “catchment” area above Augusta entails a geological formation of the Piedmont Plateau with its foundations of granite and gneiss.   The elevation of the plateau ranges from 200 feet above sea level in the east to 1000 feet in the west.  Further north, the mountains reach 2000 feet with some well beyond.  All the height, combined with hard surfaces, made natural runways for water run-off. At that time, the only factor preventing larger run-off was the dense forests of the 7,294 square mile watershed.  The denseness of the forest acted to absorb the moisture through the roots or by evaporation.  The concern was the large deforestation for agricultural purposes.  Emigh cited that the watershed above Augusta shrank during the 1859 to 1912 period from 70% to 19%.  The result was by 1909 only 25% of the catchment area remained forested.  A positive factor of the period was during the peak rainfall periods of January, February, March, and April the land was being plowed for new crops and this plowed land was “ideal” for rainfall storage.

 

The ideal river height level for the Savannah River was 20 feet.  This level afforded water transportation as well as allowing logging companies to float logs out the swampy regions south of Augusta.  River water would not enter Augusta until the 32-foot mark (pre-levee) and was not a real danger to the businesses until the 34-foot mark.  Emigh noted, “At 36 feet a wide area of the business and residence sections is covered to depths of 1 to 3 feet.”

 

It was held that water run-off was caused by two causes.  Primary was direct falling rain and secondary a gradual supply from saturated soil or from the forest floor. It was more common in cultivated lands following a slow but steady rainfall.  Emigh argued this was truer for long rivers, but the short span of the upper Savannah River “freshets” came from the delayed flow when one rain supersaturates the soil and is followed by another rain a few days later. This combination of rapid run-off and soil saturation presented the greatest possibility of flooding.  However, by 1914 the number of days the Savannah River, at Augusta, was above the 20-foot mark increased with the “expansion of agricultural and contraction of forest area.”[2] The theory that plowed ground would hold more water was shown that the forests were needed to help control run off as well.

 

Emigh’s study of rainfall versus river height produced interesting comments. He concluded,

 

   Starting from the initial stages below 16 feet, the normal amount of rise in the Savannah River at Augusta for each inch of rain in 24 hours over the catchment area with the ground in moist condition is 8.5 feet.  This remains true until rain has brought the river to its 29-foot stage.  Any surplus of water above that necessary to cause a 29-foot stage has a value of about 3 feet for each inch of rain.[3]

 

Year

Rainfall, January-April

Days of 20 feet or over.

1903

24.6

23

1906

17.8

14

1908

19.8

24

1909

18.2

12

1912

25.2

25

Means

21.1

20

Emigh, 51.

Interestingly, rises above the 34-foot level were negligible with the greater rises occurring at the 16-foot level.  He dismissed any calculation of rainfall that would not bring the level to 20-feet and theorized that it would take some twelve inches of rain during the first four months of the year to bring the river to the 20-foot mark.


Unknowingly predicting the Flood of 1929, Emigh predicted, “If precipitation be of short duration but great intensity, it occasions a high stage that keeps the river above 20 feet for several days.”  Rain, soil saturation, or run-off was not the only considerations of Emigh.  The “flashy” nature of the river itself had to be included in the estimations.


The freshets of the Savannah River have a long history.  The greatest was the flood of 1796, reaching an average of 40 feet making it the greatest pre-levee flood in the city’s history.  The 1929 (post-levee) flood marks the greatest in height, but the 1930 flood exceeded in volume of water flowing past Augusta.


Table 2.--Annual peak stages and discharges for the Savannah River at Augusta, Ga. (02197000) for the period 1796 - 1985

[ft, feet; ft3/s, cubic feet per second]

Water

year

Date

Stage

(ft)

Discharge

(ft3/s)

 

Water

year

Date

 

Stage

(ft)

Discharge

(ft3/s)

 

Water

year

Date

Stage

(ft)

Discharge
(ft3/s)

1 1796

Jan.  17

40

360,000

 

1909

June

5

 

28.7

87,300

 

1947

Jan.

22

23.97

86,000

1840

May   28

37.8

270,000

 

1910

Mar.

2

 

26.4

69,800

 

1948

Feb.

10

23.90

83,200

2 1852

Aug. 29

37.4

250,000

 

1911

Apr.

14

 

19.1

32,800

 

1949

Nov.

30

26.61

154,000

3 1864

Jan.   1

34.9

185,000

 

1912

Mar.

17

 

36.8

234,000

 

1950

Oct.

9

20.10

32,500

1865

Jan.  11

36.9

240,000

 

1913

Mar.

16

 

35.1

156,000

 

1951

Oct.

22

22.32

46,300

1876

Dec. 30

28.6

86,400

 

1914

Dec.

31

 

24.3

48,000

 

61952

Mar.

6

21.53

39,300

1877

Apr.  14

31.4

119,000

 

1915

Jan.

20

 

28.2

61,000

 

1953

May

8

20.80

35,200

1878

Nov. 23

23.5

51,500

 

1916

Feb.

3

 

31.0

82,400

 

1954

Mar.

30

17.39

25,500

1879

Aug.   3

22.0

44,000

 

1917

Mar.

6

 

29.2

68,000

 

1955

Apr.

15

16.77

23,900

1880

Dec.  16

30.1

102,000

 

1918

Jan.

30

 

25.5

45,500

 

1956

Apr.

12

14.70

18,600

1881

Mar.  18

32.2

130,000

 

1919

Dec.

24

 

35.0

128,000

 

1957

May

7

14.08

18,000

1882

Sept.12

29.3

93,300

 

1920

Dec.

11

 

35.4

133,000

 

1958

Apr.

18

22.91

66,300

1883

Jan. 22

30.8

111,000

 

1921

Feb.

11

 

35.1

129,000

 

1959

June

8

18.65

28,500

1884

Apr.  16

28.0

81,000

 

1922

Feb.

16

 

32.0

92,000

 

1960

Feb.

14

20.58

34,900

1885

Jan. 26

27.5

77,000

 

1923

Feb.

28

 

28.0

59,700

 

'1961

Apr.

2

20.56

34,800

1886

May   21

32.5

135,000

 

1924

Sept.22

 

28.0

59,700

 

1962

Jan.

9

20.09

32,500

1887

July 31

34.5

173,000

 

1925

Jan.

20

 

36.5

150,000

 

1963

Mar.

23

19.52

31,300

1888

Sept-11

38.7

303,000

 

1926

Jan.

20

 

27.3

55,300

 

1964

Apr.

9

24.16

87,100

1889

Feb.  19

33.3

149,000

 

1927

Dec.

30

 

24.0

39,000

 

1965

Dec.

27

20.62

34,600

1890

Feb. 27

22.9

48,500

 

1928

Aug.

17

 

40.4

226,000

 

1966

Mar.

6

21.50

39,300

1891

Mar. 10

35.5

197,000

 

1929

Sept

27

 

46.3

343,000

 

1967

Aug.

25

18.10

26,500

1892

Jan. 20

32.8

140,000

 

1930

Oct.

2

 

45.1

350,000

 

1968

Jan.

12

20.94

35,900

1893

Feb. 14

25.0

60,000

 

1931

Nov.

17

 

19.9

26,100

 

1969

Apr.

21

22.24

45,600

1894

Aug.   7

24.0

54,000

 

1932

Jan.

9

 

30.4

93,800

 

1970

Apr.

1

17.68

25,200

1895

Jan.  11

30.4

106,000

 

1933

Oct.

18

 

30.3

92,600

 

1971

Mar.

5

23.30

63,900

1896

July 10

30.5

107,000

 

1934

Mar.

5

 

28.5

73,200

 

1972

Jan.

20

20.36

33,700

1897

Apr.   6

29.3

93,300

 

1935

Mar.

15

 

27.4

63,700

 

1973

Apr.

8

21.63

40,200

1898

Sept. 2

31.3

117,000

 

1936

Apr.

8

 

41.2

258,000

 

1974

Feb.

23

20.13

32,900

1899

Feb.   8

31.0

113,000

 

1937

Jan.

4

 

30.1

91,400

 

1975

Mar.

25

22.24

45,600

1900

Feb.  15

32.7

138,000

 

1938

Oct.

21

 

30.1

91,400

 

1976

June

5

20.27

33,300

1901

Apr.   4

31.8

124,000

 

1939

'Mar.

2

3

24.10

90,900

 

1977

Apr.

7

20.50

34,200

1902

Mar.   1

34.6

175,000

 

1940

Aug.

15

 

29.40

239,000

 

1978

Jan.

26

21.98

43,100

1903

Feb.   9

33.2

147,000

 

1941