Cover Image
close this book Measuring drought and drought impacts in Red Sea Province
close this folder 3. Drowght, food stress, and the flood and rainfall record for Red Sea Province. Roy Cole
View the document Summary
View the document Introduction
View the document Precipitation In Red Sea Province
View the document Flood and rainfall records: problems and possibilities
View the document A definition of drought
View the document The flood record
View the document Drought and the flood record
View the document The rainfall record
View the document Drought and the rainfall record
View the document Conclusion
View the document Discussion
View the document Limitations of the study
View the document References
View the document Appendix 3.1. Annual floods for nine khors In Red Sea Province and Khor Gash in Kassala Province.
View the document Appendix 3.2. Annual flood 2 scores for nine khors in Red Sea Province and Khor Gash in Kassala Province.
View the document Appendix 3.3. Annual rainfall in mililmetres for 19 gauging stations in eastern region, Sudan.
View the document Appendix 3.4. Annual rainfall z scores for 19 gauging stations in eastern

The flood record

Prior to the 1950s, no flood records were collected in Red Sea Province except inundated area in feddans in the Tokar Delta. In the late 1950s and early 1960s, the Government of Sudan began collecting precise figures on flooding in five watersheds in Red Sea Province. In the mid-1970s, three additional stations were added The collection of data was relatively stable throughout the 1960s and 1970s. In 1988, the National Water Corporation had no budget for the monitoring of any of the watersheds except Khor Arba'at which is part of a permanent monitoring programme.

For each month in which flooding occurs, data is collected at the gauging stations on the following topics:

1. Date of each flood.

2. Duration of each flood in hours.

3. The maximum discharge of each flood in cubic meters per second.

4. The total volume of each flood in cubic meters.

Permanent flow, where it occurs, is treated separately on a month by month basis and added into the grand total for the station by month and year.

The following table lists the gauging stations, The date they began operating, the "e they terminated operating, and the authority responsible for maintaining the stations. By "present" it is meant that the station is still in use.

Table 3.2. Flood gauging stations of Eastern Region.

Station

Location

Start

End

 

Authority

 

Aiterba

Coast

1977

Present

National

Water

Corporation

'Arab

Interior

1960

Present

National

Water

Corporation

Arba'at

Coast

1957

Present

National

Water

Corporation

Baraka

Coast

1900

Present

Tokar

Delta

Board

Gash

Interior

1964

Present

Gash

Delta

Board

Gwob

Coast

1958

Present

National

Water

Corporation

Kass

Interior

1974

Present

National

Water

Corporation

Sallum

Coast

1958

1968

National

Water

Corporation

Tahamyam

Interior

1976

Present

National

Water

Corporation

'Udrus

Mountain

1960

Present

National

Water

Corporation

The table below presents the means, standard deviations and coefficients of variation for all watersheds of record.

Table 3.3. Means, standard deviations and coefficients of variation for ten watersheds In Eastern Region.

Station

Mean Annual

Standard

Coefficient

 

Flood (m3)

Deviation

of Variation

Aiterba

7174940

6721840

94%

'Arab

13586209

13219465

97%

Arba'at

25123895

22512259

90%

Baraka

76322*

44137

58%

Gash

67579*

25517

38%

Gwob

4185013

6630691

158%

Kass

8346966

8347522

100%

Sallum

4880734

4896680

100%

Tahamyam

1813798

2738385

151%

'Udrus

2583461

2847960

110%

* Data available only in feddans inundated. In the Sudan, 1 feddan is equivalent to 1 acre.

Both the standard deviation and coefficient of variation for the Khor Arba'at data are much lower if the outlier flood of 1987 (190 million m3 and 7 standard deviations above the mean) is removed from the calculation. The mean, standard deviation and coefficient of variation including the extreme value are 30630044, 37001635, and 121% respectively.