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in yields of agricultural crops, decrease in natural with the small income they would earn for their
fertility and productivity of agricultural lands, livelihood.
decrease in siltation over the agricultural lands etc.
The positive impacts as identified in the fisheries 330 OKA, T. (Disaster Prevention Research
sector were: increase in fishing areas, fish Institute, Kyoto University, Gokasho, Uji, Kyoto
production and income of the fishermen, role in 611-0011, Japan); AHMED, S.M.U. & BALA,
partial fulfillment of fish demand in the country, S.K. (Institute of Water and Flood Management,
increase in employment opportunity in the fisheries BUET, Dhaka). Numerical Analysis of Flash
sector, the increase in revenue income of the Flood in the Monu River Basin Caused by Heavy
government etc. The negative impacts as identified Rainfall on June 6, 2001. IWFM Res. Bull., 2004,
in the fisheries sector were: increase in fish 5, 17-25.
diseases, overtopping of fishponds during rainy
season and increase in social conflicts etc. The The rainfall runoff into the Monu River on June
negative impacts as identified in the hydrological 5 and 6 was calculated and flooding upstream of
sector were: water pollution and untime/sudden the Monu Railway Bridge was simulated. The
flood, shortage of animal food and hamper in fish calculated hydrograph of rainfall runoff
culture in ponds and Dobas etc. The negative discharge agreed well with the observed results,
impacts as identified in the socio-economical and the major rainfall runoff mechanisms were
sector were: decrease in employment opportunity clarified. The initial stage of the flooding
and income of the farmers, damages of educational process upstream of the Monu Railway Bridge
institutions etc. The drainage congestion badly can be simulated using a two-dimensional finite
affected the housing, sanitation, electricity and difference model.
medical facilities. The negative impacts as
identified in health sector were: deficiency in pure
drinking water, malnutrition and health hazards of 331 RAHMAN, M.M. & HAQUE, A.
the people especially the children; increase of (Institute of Water and Flood Management, BUET,
water borne diseases, increase of mosquitoes Dhaka). Local Scour at Sloped-wall Spur-dike-like
resulting in increase of malaria, dengue fever etc. Structures in Alluvial Rivers. IWFM Res. Bull.,
and increase of bite of venomous animals and 2004, 5, 1-9.
insects. Environmental Impact Assessment (EIA)
on different sectors showed that the total The effect of side slope on the prediction of the
Environmental Impact Value (EIV) was negative maximum local scour depth around sloped-wall
by 119. The EIA study revealed that the drainage spur-dike-like structures has been investigated
congestion is severely hindering the growth ot the using two existing prediction methods where slope
socio-economy of the region. The study was useful factors have been considered, The first one was
to make some recommendations. The drainage developed from experimental data and is empirical
congestion in Beel Kuralia is suggested to be in nature while the second one was developed
mitigated by removing the cross bunds and sluice using an analytical treatment by considering the
gates constructed across the River Baral and the flow concentration in the restricted region of scour
River Chiknai Dredging of those rivers and other hole. Both of the above approaches are applicable
canals, Jolas etc. connecting Beel Kuralia is for clear-water scour. With the aid of the analytical
suggested to be made. To fulfill the fish demand in model, the slope factors for the empirical formulae
the locality and for the country as a whole, unused have been extrapolated for milder side slopes. The
ponds, borrow pits, ditches along the roadsides etc. results of the above two methods together with the
of the Beel Kuralia region are suggested to be re- maximum measured local scour depth around a
excavated and reformed where fish culture is spur-dike-like structure in an alluvial river have
suggested to be carried out. In this regard, financial been compared and discussed with particular
supports can be made by the national government emphasis on the effect of side slope on estimates of
to the real fishermen, so that they can at least the maximum local scour depth.
sustain in their native land, the Beel Kuralia region
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