In the 1960’s and 1970’s, a large part of coastal Bangladesh was converted into ‘polders’- embankments that were put up to protect land from tidal action and the uncontrolled flooding of the rivers. This was a major landscape change that allowed the cultivation of wet season paddy, while protecting houses and property from the forces of nature. An estimated 1.2 million hectares was reclaimed in these decades, a process still going on in the areas that emerge from the braiding coastal rivers and the sea, the so-called char lands.
What is a polder?
A polder typically has three elements:
- The embankment surrounding it that keeps out the water from the surrounding river and sea,
- The drainage canals, commonly called ‘khal’, inside the polders that remove excess water particularly at low tide, and
- The gate or ‘sluice’, which, situated at the head of the canal, is opened at low tide to release the water from the polder or kept closed in times of water shortage to serve as reservoirs.
Taking a closer look, the polders are best seen as a mosaic of low-lying and high areas. The differences in height are subtle though – and are generally in the order of 30-50 centimeters on average but going up to a meter deep; yet this makes all the difference on what one can do in a certain area: growing paddy or cultivating fish, or even going for a dry crop at the right time of the year.
The challenge is how to manage this patchwork of high and low-lying areas, while balancing the interests of land users. Though this is the touch-stone of internal water management, by and large little has happened in the coastal polders of Bangladesh.
The missing middle: what polders of Bangladesh and sites in East Africa have in common
In October by good fortune two CGIAR Research Program on Water Land and Ecosystems (WLE) projects met when Frank van Steenbergen, coordinator of the ‘Harnessing floods to enhance livelihoods and ecosystems services’ in Ethiopia and Sudan met Manoranjan Mondal when he visited Fultala, Polder 30, Khulna, Bangladesh.
Mondal leads the WLE project: ‘Community water management for improved food security, nutrition and livelihoods in the polders in the coastal zone of Bangladesh’ (WLE projects do not come in short words). The community crop and water management project is implemented by International Rice Research Institute (IRRI) with a range of partners, including the Blue Gold program that works on better water management and poverty alleviation in more than 100,000 hectares of land in the coastal belt.
According to van Steenbergen, the big learning experience was that after years of water discussions, very little has improved water management on the ground – this applies to the polders in Bangladesh as well as the flood-based farming sites in Sudan and Ethiopia. “In Sudan for instance we expect to increase water productivity by a factor of 2 through internal water management within the amazing extensive fields over there.”
Mondal fully agrees: “There is a world to gain with ‘down to earth’ local water management. It is the missing middle”.
From risky sesame to high yielding rice
The activities of the community crop and management project in the Fultula concerned the improvement of water management to boost agricultural production. Previously, traditional paddy (aman) was the main wet season crop and sesame was the main dry season crop. But in the last three years the sesame was destroyed by pre-monsoon rainfall at maturity. Farmers were hoping that the land would dry out quickly enough to grow sesame early in the dry season to avoid the early rainfall.
In previous years however that never happened. With better internal water management, water levels could be controlled through the polders and two subsequent crops of high yielding rice could be grown, increasing production at least two-fold.
The changes were driven by the Water Management Groups set up with the help of the Blue Gold Program. These groups have a wide agenda – from operation and maintenance to promoting local economic development. The activities in Fultula focused on the delineation of polder sub-units – of high and low land areas – and the development of small drains within and between these areas. Interestingly use was also made of the ubiquitous small village roads constructed over the years that usually define the boundaries between the land units. The culverts in these roads were equipped with simple shutters, allowing the water to be controlled.
The controlled drainage thus created a new farming system.
For van Steenbergen, the community water management project activities in Futulal, Polder 30 were an eye-opener. During this trip to Bangladesh, he was reviewing a large program for coastal polder water management where he saw that these action research activities were a gem, not only showing what can be done in this particular type of setting but also how many opportunities for polder water management are not utilized.
According to Mondal, it was a challenge to get the ownership right. This area as in other areas had its own local rivalry. “We got the political leader of the area to come and spend half a day to resolve this. After that everybody has been running with the results.”
The improved drainage system and the higher value cropping system go hand-in-hand. By making drains around the plots for instance, water can be drained during the panicle setting and flowering period. At these times, the uptake of fertilizer is very important, so if the land is inundated, the costly fertilizer is washed away. The water is then better drained out at this period.
What is being done in Fultula hopefully is the shape of things to come: managing water within the polders. Improved internal water management can take many forms depending on the polder: controlling water levels in both high and low lying areas; ensuring timely drainage to free up land for a dry season crops; supplementary irrigation to ensure yields in the kharif (aman) season; creating fresh water storage in khals and ponds. The in-polder water management is strongly linked to the production systems and can contribute to increased production or the cultivation of an additional crop.