INTELLIGENCE MEMORANDUM PRELIMINARY APPRAISAL OF THE EFFECTS OF RECENT FLOODS IN NORTH VIETNAM

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP85T00875R001700020036-9
• Release Decision: RIPPUB
• Original Classification: T
• Document Page Count: 17
• Document Creation Date: December 22, 2016
• Document Release Date: April 16, 2010
• Sequence Number: 36
• Publication Date: September 1, 1971
• Content Type: IM

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DIRECTORATE OF
INTELLIGENCE
Top Secret
4 s; J ! yn a qa ,
Intelligence Memorandum
%~L
Preliminary Appraisal Of The Effects
Of Recent Floods In North Vietnam
NGA Review Completed
Top Secret 25X1
September 197
Copy No. 62
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CENTRAL INTELLIGENCE AGENCY
Directorate of Intelligence
September 1971
PRELIMINARY APPRAISAL OF THE EFFECTS
OF RECENT FLOODS IN NORTH VIETNAM
Summary and Conclusions
1. The floods that hit North Vietnam's Red River Delta during the
last two weeks of August apparently rank with the most serious ever
recorded (see Figure 1). Little loss of life has been detected, but damage
to the, country's important rice cr ,p was severe, with potential losses of
up to 15% of the crop. Some of she loss probably will be made up by
replanting, and in any case imports of food from Communist allies can
be expected to cover the remaining deficit. Disruption to the transportation
system isolated Hanoi from other regions of the country and also from
Communist China. Repairs to the transport system probably will be rapidly
accomplished. Industrial installations incurred little physical damage,
although some production was temporarily halted as a result of side effects
of flooding. Photography of 3 September indicates that the flood waters
had begun to receed by that time, though rail connections between Hanoi
and China were still cut. Provided there are no further heavy rains, recovery
work should move ahead rapidly.
2. The flooding in the Red River Delta is not likely to have a
significant effect on the flow of supplies to the Panhandle of Ncrth Vietnam,
or on the annual military resupply of the Laos Panhandle. Over the years
the enemy has built extensive stockpiling facilities in the southern part of
the country, particularly along major access roads leading from North
Vietnam into Laos, and movement of stockpiled materiel probably will begin
as usual in Oct,)ber.
Note: This memorandum was prepared by the Office of Economic Research
and coordinated within CIA.
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Flooding in the Red River Delta of North Vietnam
BAC THAI
THANH
HOA
THANH
HA B A. C ,
Severe flooding
Q Moderate flooding
- Province boundary
0 10 20 Miles
0 10 20 Kilometers
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Discussion
Chronology of 1971 Floods
3. North Vietnam's Red River Delta, the country's breadbasket and
most populous region, was subjected to a siege of floods during the last
two weeks of August from extremely heavy rainfall, which came on the
heels of higher than normal precipitation in the preceding month. The course
of the flood can be traced in press reports that depict serious localized
flooding commencing in mid-July mainly in the provinces of Ha Tay, Ha
Bac, and Nam Ha, urgent repairs to levees, and thousands of hectares of
rice seedlings and transplants washed out. On 15 August, storms took out
a one-halt' mile section of levee in Dong Anh ward, a suburb of Hanoi.
It was probably this damage that caused the closing of the Hanoi-Dong
Dang railroad, known to have been out of operation since 20 August.
4. Thereafter, the flood level apparently continued to increase.
On the 29th, a Nhan Dan editorial again emphasized
the ,1ecessity of protecting property and provided general instructions for
the care of displaced people.
Pharr Van Dong in a speech on 31 August characterized the
flooding as even worse than the catastrophic 1945 flood, but he implied
that the greatest danger had passed. Press reports on 4 September indicated
that restoration work was in progress.
Historical Comparisons
5. Floods in the Red River Delta are a perennial hazard from June
through September. The delta is a flat plain criss-crossed by rivers and
manmade drainage and irrigation canals interwoven into a vast mosaic of
ricefields. Viet Tri, at the head of the delta 100 miles inland, is only 43
feet above sea level, and the average slope of the delta to sea is less than
6 inches per mile. In this flat environment, levees are essential to protect
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the land from flooding by the rivers that cross it. By constricting the greatly
expanded volume of floodwaters, however, the levees accentuate the threat
created when the river level is above the level of the surrounding land.
The Red River has flowed as much as 39 feet above the land in the Hanoi
area, a' situation that suggests the magnitude of flooding that would occur
should the levees be breached. Levees protecting Hanoi and areas upstream
rise 42 feet to 49 feet above the adjacent land. Secondary levee systems,
averaging 20 to 40 feet, are intended to contain floods if the primary levees
are breached, and these are backed up by 3 to 4 foot levees around
individual rice fields. It is extremely difficult to drain these compartments,
particularly when the bordering rivers are in flood and may be flowing
above the elevation of the compartment. Moreover, persistent rains and
prolonged soaking such as has occurred this season tend to weaken and
undermine the entire levee system. As a result of the very gradual gradient
of the river, floods stand for relatively long periods of time. Typically,
the high-water period is not made up of a single flood with gradual upsurge
and downfall, but rather it includes several floods, each of which may cause
the river to rise far above the average summer water level.
6. Breaks occur somewhere in the levee system almost every year.
One of the most significant floods occurred in 1915 when levees were
breached in 48 places. In this instance, about 95% of the 268,000 hectares
of land in Ha Tay Province were flooded. On 30 July 1926, three breaches
occurred in levees not far from Hanoi. Two were closed within two weeks,
but one remained open to flood over 250,000 hectares of land on the left
bank of the Red River. The 1945 flood, to which Pham Van Dong referred,
destroyed about 200,000 hectares of the rice crop. The North Vietnamese
claim that 2 million people died in the ensuing famine. French estimates
place the number at about 500,00!' The high death rate was due to a
combination of food shortages and distribution problems complicated by
the Japanese occupation of the country.
7. Comparisons of monsoonal precipitation at selected points in the
delta and in the northern part of the country are shown in the following
tabulation:
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Lang Son
(Northeast)
Lao Cai
(Northwest)
Tuyen Quang
(North)
Bac Giang
(Delta)
Hanoi
(Delta)
Haiphong
(Delta)
Nam Dinh
(Delta)
Mean a/
Greatest a/
1971 b/
July
August
July
August
July
August
11.0
11.0
20.9
23.9
20
15
11.9
13.3
22.6
31.9
25
30
11.7
11.5
20.0
18.4
5-10
15
11.4
12.4
--
--
30
15
12.1
12.8
27.0
19.1
30
15
10.7
14.1
22.0
42.0
12
15
9.1
13.1
20.5
24.2
15
10
a. NIS data that cover 20-40 years of recordkeeping.
b. DIA precipitation charts which depict rainfall to
the nearest 5 inches, and from interpolation of these
data.
Data for this season show that rainfall in 1971 was well above average -
in some areas ranking with the greatest ever recorded. The heaviest period
of rainfall in the delta reportedly took place during 13 to 19 August.
Higher than average precipitation in the extreme northwestern part of the
country flowing down the Black River, Clear River, and Red River also
added to the delta's flood stage near Viet Tri, where these rivers converge.
Inundated Area
8. An aerial reconnaissance flight on 30 August provided
photographic coverage of approximately 60% of the Red River Delta,
probably at or near the time of flood cresting. Only the extreme eastern
and western portions of the delta were not covered. Inundation is evident
in the traditional flood plain surrounding Hanoi and heaviest in the provinces
of Ha Bac, Hai Duong, and Ha Tay. Less severe flooding was observed
in the lower delta in Flung Yen, Thai Binh, and Nam Ha Provinces. No
breaks were observed in the levees protecting Hanoi nor in those upstream
from the city. The only large city known to have been flooded is Hai Duong,
about halfway between Hanoi and Haiphong (see Figure 2). Water reached
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roof-top level in some villages, although, in general, villages are safely on
high ground while surrounding fields are inundated.
9. Aerial photography of 3 September shows that the flood was
receding but that large areas still were inundated. Some additional flooding
was observed south of Viet Tri although the area probably was not under
cultivation. This photography also confirmed the continued obstruction to
through-travel on the Hanoi-Dong Dang rail line.
Extent of Damage: Agriculture
10. Damage to agriculture apparently is more serious than to any
other sector of the economy, with losses to the tenth-month rice crop
approaching those of past disastrous years. Tenth-month rice, normally
harvested in October-November;, accounts for two-thirds of annual rice
production. Measurement of inundated areas usually devoted to tenth-month
rice shows that some 180,000 hectares are heavily flooded, and several
thousand additional hectares are lightly flooded, resulting in potential
destruction of as much as 15% of the total tenth-month crop. In terms
of rice paddy, the tonnage could be in excess of 400,000 tons. Allowing
for standard waste in milling, the potential loss represents almost 300,000
tons of polished rice. j l Although a large part of the flooded rice has likely
been destroyed either from washing action or from being submerged too
long, some of it probably can be salvaged. Furthermore, replacement of
some of the destroyed seedings will be possible although late planting usually
results in low yields.
11. Other crop losses arc believed to be small. Part of the agricultural
lands flooded in August are too low to be cultivated during the wet season
because they are often inundated by a single heavy rain. Thus these lands
are reserved for all of the fifth-month rice crop as well as most of the
secondary foods (corn, sweet potatoes, beans, and peanuts) and industrial
crops (oilseeds, cotton, Jute, and tea) planted during the winter-spring dry
season. There is no indication as yet of livestock losses.
12. Repair of damage to agriculture's physical facilities probably will
require months to complete. Breached levees and washed out irrigation
stations are common throughout the flooded area Housing
1. Production of polished rice in 1970 is estimated to have been about
2.9 million tons.
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will have to be restored while stricken villagers share quarters with their
more fortunate neighbors. Rebuilding of the levees must be given a high
priority because of the continued threat of monsoon rains during September.
Replanting of a portion of the damaged tenth-month crop is also a prime
objective. Accomplishing all these tasks simultaneously obviously would tax
the capabilities of the peasantry and, toward this end, the regime has pressed
into service many army units for the coming weeks.
Transportation
13. Main transportation arteries were badly disrupted during the last
half of August, although the extent of possible physical damage cannot
be ascertained because of standing water. Inundation of the important Yen
Vien rail junction north of Hanoi severed the two rail links with Communist
na - the Hanoi-Dong Dang line and the Hanoi-Lao Cal line
JThe Yen Vien junction probably was put out of operation by 20 August
when diplomatic communications revealed a closing of railroads to
international travel. The highway running northeast from Hanoi toward
China also was cut. Rail and road connections from Hanoi to Haiphong
were also flooded. Rail access from Hanoi to the southern part of the
country also was severed with a washed out railroad bridge at Ninh Binh.
Road connections to the south suffered only nominal damage
14. In the southern provinces of Nghe An, Ha Tinh, and Quang Binh,
where military supplies currently are being shifted in preparation for delivery
into southern Laos, there has also been some flooding. On 2 September,
a major rail-to-road transshipment facility in the Vinh area reported that
"due to flooding" an unidentified new system for shipping was to be
utilized. Overall, however, the problems in the south are minor and should
not hamper the enemy's upcolming dry season supply push in Laos.
15. The closest recent parallel to the difficulties being experienced
with North Vietnamese transport was in September 1968 when heavy rains
coupled with two typhoons caused extensive flooding in the Hanoi-Haiphong
area. At that time the road and rail networks which had not yet been
fully restored following the partial bombing halt were particularly hard hit.
Despite the widespread flooding, the North Vietnamese were able to restore
the transport system relatively quickly and, a month after the water had
subsided, with little apparent difficulty were able to begin a massive transfer
of their logistical base to the southern North Vietnamese Panhandle.
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Thai
Nguye
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qm a,. f 1 U L, P 0 I~
Dlrth~_
~ h 7 Binh I )P17 bridge
Ro ro d 'bridge %' O N K I N
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16. This year the main lines of communication also are likely to be
restored soon after the flooding subsides. Temporary repairs to rail and
road beds will probably not be difficult. During the course of the war the
North Vietnamese have demonstrated considerable ability and experience
in carrying out quick repairs to restore vital lines of communication.
17. In any case the disruptions to transport caused by flooding in
northern North Vietnam will not have any significant direct bearing on
the enemy's ability to support the war in southern Indochina, although
there could be temporary and localized supply problems caused either by
bottlenecks or by diversions of military personnel to flood work. Over the
.0-, _ \ ' ~Hoa . Ha ng
`~efnh
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years the enemy has built up extensive stockpiles in southern North
Vietnam, particularly along the major access roads leading from North
Vietnam into Laos, and the advent of the northeast monsoon in October
will see the Communists beginning to move this material into southern Laos.
Industry
18. Of the few major industrial facilities observed in photography,
none was damaged by flooding. These included the manufacturing plants
in Hanoi, the Bac Giang powerplant, and the Thai Nguyen Iron and Steel
Complex. Some shutdown of industry apparently took place, however, as
a radio broadcast on 27 August pointed out that the electricity, coal,
construction materials, forestry, and construction branches should try to
"resume" operations as soon as possible. The outages that have occurred
probably have stemmed from disrupted supplies, washed out power lines,
or inability of workers to reach their jobs. Storms and flooding reported
in Quang Ninh Province may have obstructed coal mining operations,
particularly in the open pit mining areas.
The principal
industrial "cost" inflicted by the flood will be production forgone. At most,
this will probably put a crimp in the annual plan fulfillment of some
factories, but the overall effect on industrial output will probably be
marginal.
Population
19. The incidence of death resulting from recent flooding is believed
to be low.
Probably the greatest hazard at this time would come from exposure,
communicable disease in crowded living conditions, or infection from raw
sewage and other harmful substances in flood waters. Although some 5
million people live in the provinces primarily affected by the floods, there
is little basis with which to judge the numbers that have had to be evacuated
and exposed to unhealthy conditions.
Foreign Aid
20. North Vietnam's losses from the flood can be readily offset by
imports from its Communist allies.
On September, both the USSR and Communist China broadcast public
offers of assistance, and the USSR claimed to be sending medicines, food,
and other emergency goods.
25X1,
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21. The potential loss of food from flooded rice crops presents the
most significant category of supplies to be replaced. The rate of food
imports in the first half of 1971 appears to be about the same as in 1970,
when 660,000 tons were delivered, as shown in the following tabulation.
If the additional import requirement is set at the maximum estimated loss
of 300,000 tons, total food imports in 1971 would exceed the 1968 level.
However, if part of the damaged rice can be salvaged or replanted, the
total imports this year may not be as great as in 1968. At current prices,
300,000 tons of rice would be worth about $45 million. This tonnage in
substitute wheat flour is worth about $30 million. The total value of
Communist economic aid to North Vietnam in 1970 was in excess of $500
million.
Thousan
d Metr
ic Tons
1965
1966
1967
1968
1969
1970
1971 a/
Communist
countries
60
65
460
800
750
660
310
USSR
Negl.
5
165
270
320
445
190
China
15
40
200
420
370
150
80
22. Requirements for other types of goods should be small. Most of
the flood damage has taken place on the land and along transportation
route:,. Restoration requirements, therefore, will entail manpower,
earthmoving equipment, and perhaps some steel and cement. Beyond 'this,
there seems to be no urgent requirement for imports of specialized
equipment.
23. North Vietnam's maritime facilities should be able to cope with
any increase in imports required. Seaborne imports into North Vietnam
during August did not reflect internal transportation difficulties. Imports
for the month were 125,400 tons, which compares with an average of
124,300 tons during the month of August in each of the years 1967 through
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1970. There was also no evidence of significant congestion in Haiphong
harbor. The seaborne import of the additional frodstuffs resulting from
tLe flood damage - say 300,000 tons - could be spread over a period
of six months and, at 1,650 tons per day, should not present an excessive
burden on the country's port capacities or on the main internal transport
system.
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