Drought in Bangladesh

According to definition of CCD “drought” means the naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious hydrological imbalances that adversely affect land resources production systems.

 

Drought is a "creeping phenomenon," The effects of drought accumulate slowly over a considerable period of time, and may linger for years after the termination of the event. Drought impacts are spread over a larger geographical area than are damages that result from other natural hazards. Like floods, Bangladesh is also vulnerable to recurrent droughts. After 1971 Bangladesh has experienced droughts of major magnitude in 1973, 1978, 1979, 1981, 1982, 1989, 1992, 1994, and 1995. Although droughts are not always continuous in any area, they do occur sometimes in the low rainfall zones of the country. As listed above, Bangladesh experienced consecutive droughts in 1978-1979, 1981- 1982, and 1994-1995. The droughts of 1994-95 in the northwestern districts of Bangladesh led to a shortfall of rice production of 3.5 million tons.

 

Two critical dry periods are distinguished. Rabi and pre-Kharif drought (January - May), due to:
(i) the cumulative effect of dry days;
(ii) higher temperatures during pre-Kharif (> 40 degrees Celsius in March-May); and
(iii) low soil moisture availability.

 

This drought affects all the Rabi crops, such as HYV Boro, Aus, wheat, pulses and potatoes especially where irrigation possibilities are limited. It also affects sugarcane production. Kharif droughts in the period June/July to October, created by sub-humid and dry conditions in the highland and medium highland areas of the country (in addition to the west/northwest also the Madhupur tract is drought prone). Shortage of rainfall affects the critical reproductive stages of transplanted Aman crops in December, reducing its yield, particularly in those areas with low soil moisture holding capacity.

 

Considering the Agro ecological Zones (AEZ) database and land resources inventory map at 1:1,000,000 scale, BARC has identified and mapped drought prone areas of Bangladesh for Rabi and Pre-Kharif seasons. Recently BARC has reviewed this concept and produced three different maps for Rabi, Pre-Kharif and Kharif seasons.

 

The drought maps has been revised by BARC to produce three maps for Rabi, Pre- Kharif and Kharif seasons. The drought severity classes defined in the maps are slight, Moderate, severe and Very severe related to the yield losses of 15-20%, 20-35%, 35-45%, and 45-70% respectively for different crops. Areas (in M ha) affected by drought in different crop seasons are given in Table 1.1

 

Table 1.1 Summary of Drought Severity Areas in Bangladesh by Crop Season (in M ha)

 

Drought Class	Rabi	Pre-Kharif	Kharif
Very Severe	0.446	0.403	0.344
Severe	1.71	1.15	0.74
Moderate	2.95	4.76	3.17
Slight	4.21	4.09	2.90
No Drought	3.17	2.09	0.68
Non-T.Aman			4.71

 

The northwestern part is prone to drought mainly because of rainfall variability in the premonsoon and the post-monsoon periods. Inadequate pre-monsoon showers, a delay in the onset of the rainy season or an early departure of the monsoon may create drought conditions in Bangladesh, and adversely affect crop output. Since it puts severe strain on the land potential. it acts as a catalyst of land degradation through reduced soil moisture and water retention, increased soil erosion, decline in soil organic contents and overexploitation of sparse vegetation. Human interventions in the form of land abuse and mismanagement have exacerbated these actions during the spells of periodic droughts. An analysis of the relative effects of flood and drought on rice production between 1969-70 and 1983-84 shows that drought is more devastating than floods to aggregate production.

 

Mitigation of Drought
In the early 1970s and 1980s in the drought-prone areas of northern Bangladesh the agricultural development projects were developed to provide ground irrigation through thousands of Shallow and Deep Tube Wells. Since scarcity of water was the main obstacle against intensive agriculture pumping up groundwater helped grow crops year round. Through thousands of shallow and deep tubewells, HYV paddy was introduced to hundreds of acres of marginal and sloped lands.

 

Since land is being over used and degraded due to pressure of population, effective population control, judicious land use and sustainable agricultural practices are urgently required to mitigate droughts. The carrying capacity of the land resource in Bangladesh has been critically surpassed. Use of land for production of two or three crops a year may be limited. Because of this soil is not getting sufficient rest to recover its health. The marginal lands should not be used for agricultural purposes. Public awareness is needed to handle land degradation and to protect land from misuse and over use. Agrochemicals should be carefully used.

 

The problem of land degradation may be studied to develop sustainable land use. A national land use policy is urgently needed to utilize land in judicious manner. Rehabilitation programs should have effective mechanism to minimize the impact of drought. Steps are required to develop national programs for drought preparedness (similar to flood and cyclone preparedness). Early-warning schemes have to be undertaken to inform the population of drought-prone areas and introduce drought-relief measures for the affected people as part of the national planning strategy/ national program for drought preparedness {similar to flood and cyclone preparedness). Attempts are being taken to update the drought data jointly with BARC and DAE in the drought affected aman rice areas. Efforts for mitigation for such droughts are quite inadequate due to lack of fiscal resources.

 

 

Chronology of droughts of historical significance

 

1791	Drought affected Jessore district. Prices had risen to twice and three times of their usual levels.
1865	Drought proceeding famine occurred in Dhaka.
1866	Severe drought in Bogra. The rice production of the district was hit hard and the price went up three times its normal level.
1872	Drought in Sundarbans. The rainfall was deficient and in several lots the crops suffered to a great extent.
1874	Bogra was affected and the crop failure was much greater. The rainfall was extremely low.
1951	Severe drought in northwest Bangladesh and substantially reduced rice production.
1973	One of the severest in the present century and was responsible for the 1974 famine in northern Bangladesh.
1975	This drought affected 47% of the entire country and caused sufferings to about 53% of the total population.
1978-79	Severe drought causing widespread damage to crops. Reduced rice production by about 2 million tons and directly affected about 42% of the cultivated land and 44% of the population. It was one of the severest in recent times.
1981	Severe drought adversely affected crop production.
1982	Caused a total loss of rice production amounting to about 53,000 tons. In the same year flood damaged about 36,000 tons of rice.
1989	Most of the rivers in NW Bangladesh dried up and several districts, such as Naogaon, Nawabganj, Nilpahamari and Thakurgaon; dust syndrome occurred for a prolonged period due to drying up the topsoil.
1994-95	This drought was followed by that of 1995-96, caused immense damage to crops, especially in the case of rice and jute the main crops of NW Bangladesh. These are followed by bamboo-clumps, a major cash earning crop of many farmers in the region. In the recent times, this was most persistent drought in Bangladesh.

 

 

 

Source: National Action Programme (NAP) for Combating Desertification in Bangladesh

Department of Environment, Ministry of Environment and Forest and
IUCN – The World Conservation Union