Artificial rainfall plans in drought prone areas

Staff Correspondent : According to a United Nations survey, Bangladesh ranks seventh in the Asia Pacific region in terms of groundwater extraction. And 90 percent of water extracted from underground is used for irrigation. After Dhaka, the water level is falling rapidly in the northern districts of the country. The government is taking the initiative to introduce spring irrigation system or artificial rainfall in 74,800 hectares of land in North Bengal to prevent wastage of underground water.
Although this irrigation method is considered as an effective means in different countries of the world, its use is very less in Bangladesh. Only tea gardens are watered beforehand in this manner. This water is sprinkled like rain with a device called sprinkler using surface water. With it, water can be sprinkled like a stream of rain on both sides up to a distance of 150 feet in the garden or paddy field. It is easy to water large gardens and crops with sprinklers. Four to 1600 liters of water per hour can be sprinkled at a distance of 10 to 15 feet in a 360 degree circle using sprinklers.
Bangladesh Water Development Board (BWAPDA) is planning irrigation in this way by updating feasibility study of North Rajshahi Irrigation Project and feasibility study of rehabilitation of existing light irrigation projects in Dinajpur, Thakurgaon and Panchagarh districts. A survey project proposal of Tk 9 crore 65 lakh 58 thousand from BWDB was sent to the Planning Commission and the matter was discussed in the PEC (Project Evaluation Committee) meeting recently. The commission recommended the introduction of artificial rainwater irrigation system. The commission agreed. BWDB will study whether this is possible in the context of Bangladesh.
In 2023, Institute of Water Modeling (IWM) on behalf of Water Resources Planning Organization (WORPO) conducted a study on hydrological investigation and modeling of surface and ground water conditions of upland Barendra region of Rajshahi, Chapainawabganj and Naogaon. It has emerged that the situation in Barendra region is getting worse day by day due to climate change. Water-stressed areas are increasing. Between 1985 and 1990, the average groundwater level in the Barendra region was below 26 feet. At that time the water level in the highest Tanor fell to 68 feet.
The average water level in 2010 was 50 feet due to additional groundwater extraction for various purposes like food water, irrigation, fish farming. In 2021, the average groundwater level dropped further to 60 feet. In the same year, at a place in Gomstapur of Chapainawabganj, the water level was 153 feet. Out of 214 unions in this region, 87 unions are very high and high water crisis areas. The water level has dropped the most in Porsha six and Nachol four unions. 37 Unions of 9 upazilas including Godagari, Tanor, Gomstapur, Niamatpur and Sapahar are facing very high-water crisis. In the study, researchers identified 40 unions as ‘high water crisis’ and 65 unions as ‘medium water crisis’ areas.
BWDB wants to reduce excessive use of groundwater. Regarding the artificial rainfall in irrigation, Director General of BWDB Muhammad Amirul Haque Bhuya told, ‘Irrigation systems such as artificial rainfall or fountains are available in different countries of the world. I will investigate whether this is possible in our country. The survey project is being undertaken keeping in mind various issues including this.
The commission has asked to assess if the project based on the study project will have any adverse impact on the water availability of Ganga-Kapotaksh, Garai and Ichamati rivers. Also, directions are given to explore the feasibility of providing irrigation facilities through buried pipe system from primary, secondary and tertiary canals to reduce land acquisition.
Joint Chief (Irrigation) of Agriculture, Water Resources and Rural Institutions Department of Planning Commission. Enamul Haque said, “In the project, it will be possible to irrigate about 74,800 hectares of land directly through gravity force and accordingly resources will be kept for the construction of open primary, secondary and tertiary irrigation canals.” At present, almost 90 percent of the irrigation activities in Barendra area depend on groundwater. As a result, the ground water level of the area is going down. Integrated irrigation design needs to be included in the scope of study to ensure irrigation facility through surface water in Barendra area.
He said, “Water transport efficiency through buried pipe is about 95 percent. Besides, joint management of BWDB and BMDA may be considered while carrying out feasibility study on laying buried pipe. On the one hand, it will be easier to reach the water on the land, and at the same time, it will be possible to prevent wastage of water. On the whole, the project can be accepted.
According to the Planning Commission, analysis of seasonal water demand during the life of the project including analysis of seasonal navigable limit, depth and water flow of Padma River in the last 30 years should be included in the feasibility study. It has to be verified whether the withdrawal of water for this project will have any adverse effect on Ganga-Kapotaksha Irrigation Scheme, Garai River flow and Ichamati River Rejuvenation Project in Pabna district during winter. These issues were not taken into account in detail in the survey updated in 2006.
After 2006, BMDA has expanded the irrigated area by extracting surface water from Padma river and using it for irrigation purposes through various projects. A detailed survey needs to be done taking these issues into consideration. Apart from this, the commission stressed that the changes in the course of the rivers under the project area and irrigation activities as well as the impact on agriculture, fish production and the environment will also be included in the survey.
BWDB said that the Bangladesh Water Development Board has taken steps to carry out the survey for irrigation facilities in Rajshahi, Chapainawabganj and Naogaon districts and rehabilitation of existing light irrigation projects in Dinajpur, Thakurgaon and Panchagarh districts. The estimated cost of the survey project is Tk 9 crore 65 lakh 58 thousand and the duration is two years.
The main objective of the project is to update the previous survey of North Rajshahi Irrigation Project considering the changing land use patterns and current conditions for irrigation facilities in the project area, to formulate the infrastructure design of the existing light irrigation projects in Dinajpur, Thakurgaon and Panchagarh districts, development of the project agricultural area after environmental and social survey and subsequent investment. Assist in preparation of DPP (Development Project Proposal) by costing the projects.
Head (Additional Secretary) of Agriculture, Water Resources and Rural Institutions Department of Planning Commission Chhayeduzzaman told, “It is necessary to check whether the existing canals can be brought under the irrigation network by avoiding land acquisition in the project area and whether the reservoirs (beel) can be used as reservoirs or not.” Optimum utilization of existing irrigation canals and reservoirs in the project area should be ensured.