Studies on the Bangladesh Agro-Ecological Zone (Aez) Based Road-Transportation Engineering on Agro-Productivity

Subodh Kumar Sarkar

Superintending Engineer, RHD, Rajshahi Road Circle, Rajshahi and PhD Fellow of American World University, California, USA, Bangladesh Study Centre, 27, Kakrail, Dhaka-1000.

E-mail: subodh59@yahoo.com and Mobile No 01711-275341.

Accepted 19 December 2012

Abstract

The Road Transportation engineering which consists the characteristics of the road/bridge design systems are known to have direct impact on the agro-productivity. Being a hydromorphic land-soil-agro-climate, Bangladesh has been scientifically divided in to 30(thirty) Agro-Ecological Zones as per its land-soil crops and agro-climate. Keeping this view in mind a piece of research was conducted to study the Agro-Ecological Zone (AEZ) Based road–bridge-transport engineering on the agro-productivity as it influences the agro-productivity expressed by enhancement of agricultural production per unit of land using the soil resources. The studies were conducted with the major objectives such as to i. Analyze the AEZ based agro-production situation; ii. Estimate the catchments and bridge-culvert dimensions, iii. Effects of road–transport design systems on agro-productivity, iv. Develop a bridge as per command drainage keeping no mid-pier and without affecting the bio-diversity and agro-productivity of the target area. The results indicated that the AEZs studied differ in their bridges and culvert dimensions which were found volumetrically inadequate to discharge or drain out the catchments water load in time causing water stagnation. The engineering designs of the structures were found to have mid pillars which obstacle streams. The total road-bridge-transport integrated system was found to have contributed positively for agro-productivity, and as indicator of environmental degradation, reducing the sustainability of the development in the country. The results showed that about 74% of the bridges on metalled rural roads of the studied AEZs lost the expected functioning even from the beginning, increasing water congestion up to 23 days. The transportation over the roads decreased and de-speeded due to side-breaking of the roads, especially of the bridges indicating about 37% under use status. The reasons of such less effectiveness of the infrastructures as expressed by the Focus Group Discussion (FGD) among others, were the non-sharing of the works with the beneficiaries and related ministries specially for the design and site selection of the structures. Finally a model non-pier bridge design was recommended which is now recently constructed typically for the southern AEZs of the country and generally for the other AEZs, which increases agro-productivity of the area by 19% in terms of crop yield.

Keywords: Transportation Engineering, Agro-Ecological Zone (AEZ) and Drainage Command Area.