Management of flow of water and cultivation of economically useful plants in North Bihar shallow wetlands

Premlata Mehta, Smiriti Yadav, Mamta Sinha, Dinanath and Jainendra Kumar*

Department of Botany and Biotechnology, College of Commerce, Patna 800 020 (Bihar)

* jainendra@dbbtcoc.edu.in

Abstract

Most of the North Bihar wetlands are reverine originating from a number of flooded rivers. A majority of them are shallow being a few feet in depth. These vast tracts of lands can be exploited for the cultivation of some economically viable plants like Euryale ferox, Trapa bispinosa, Vetiviera zizanoids, Saccharum species, etc. The paper discusses a scheme for management and conservation of these wetlands and presents a cybernetic management system for the maintenance of a desirable ecosystem comprising different economically productive taxa.

Introduction

Wetlands of Bihar belong to the North Indian wetland zone which extends from Gangetic plains to the coastal and freshwater wetlands of Rajasthan and Gujarat with approximately, 1,10773.35 hectares of land. Wetland areas in Bihar lie between the western part of the region affected by the river Gandak and the eastern part of the region affected by the tributaries of the river Kosi representing 76378.95 hectares in total.

Fig. 1. Asian wetland regions

The region between the large Gandak and the Kosi rivers is intersected by many small and medium interfan rivers like Bhutahi Balan, Panchi, Kharadg, Burhi Gandak, Bagmati and Kamla and their tributories/channels. The networking of the channels flows down a slope towards east and south producing several water-logging low level areas usually referred as “Chaurs” (Kumar, 2006). These large areas are supposedly quite productive due to high degree of accumulation of organic contents. These water bodies are unutilized or under-utilized. They must be conserved, grown with suitable fibre or food crops and other plants, and managed accordingly.

Identification of potentiality and suitability selection of wetlands: A number of economically significant plants can be grown in these wetlands after analysis of the following characteristics.

1. Depth of the water body,
2. Water quality,
3. Water availability,
4. Water circulation, and
5. Nature of soil nutrients.

For the above mentioned analyses, an over-all survey of the area would be necessary in terms of –

1. Definition of the individual segments,
2. Study of the size and depth of each segment (tract),
3. Study of flora and fauna inhabiting the tracts,
4. Study of chemical characteristics,
5. Study of mineral contents, and
6. Study on schemes for suitable exploitation.

Suitability selection of the wetland segments would have to be done on the basis of growth requirements of the plants that can be grown there. It would also depend on the location, depth, mineral content, pH and other water characteristics of the tract. A tract suitable for Trapa bispinosa would not be as good for Euryale ferox or for a medicinal amphibious herb like Tamarix, Osbeckia or Acorus calamus ( Kumar, 2006). A suitable tract for fibre plants like Saccharum or Vetiviera species would be shallow and marshy. A modern method to check the suitability of a wetland for a specific plant or plants would be to use a computer-based expert system (Gillard, 1998; Rao, 1998) where co-ordinates of the water characteristics and plant characteristics would be combined and matched to identify the most adaptive plants that can be best grown in the given wetland.

Management of flow of water: It requires careful planning for control measures for inflow and outflow of water. Mostly, inflow is completely unregulated in these water bodies. Control of inflow may be done through channelising the incoming water into dugout ponds, deep wells and artificially created shallow wetland pockets around the natural wetland. It would help maintain the required depth. Outflow can be achieved by draining water for irrigation purposes and other hydrological needs. System of controls would have to be based on the origin, size and depth of the body and duration of water logging (Mahajan, 1989).

Ecological management: Changes in ecological parameters lead to changes in the composition of flora. Hence, cybernetic management system is needed to manage a particular seral stage of plants. Deep water plants with large free floating leaves such as Trapa and Euryale would require pH and COD levels higher than the grasses like Sachharum munja or Vetiviera zizanoids. Any seral stage gradually tends to modify the habitat making it more suitable for the next seral stage, Cybernetic management calls for a control of input if output grows more than required. If pH of a system gets increasing, the amount of inflowing water with lower pH would have to be enhanced. The strategy would, however, warrant the next step involving higher water outflow so that the body does not retain more water and gets unsuitable for the existing crop.

References

Gillard, P. 1998 Expert systems used to disseminate complex information in agriculture and horticulture, PCAI Mag.

Kumar, J. 2006 Cybernetic management of wetlands (A model for North Bihar). Flood Plain Wetlands of Bihar (Proceedings of the National Seminar on “The Environmental status and appropriate use of Flood Plain wetlands of Bihar held at B.N. College, Patna on 14 and 15 May, 2005) : 50-55. Naward, Patna (India).

Mahajan, K.K. 1989 Indian Wetlands: an overview and their management. Wetland Conservation. Environmental Community Centre, Udaipur, India.

Rao, P.J. Expert system in agriculture, Proceedings of IFAC Workshop on Expert System and Agriculture, International Academic Publishing, Bejing, 1998.