Water samples collected from twenty five ponds of coastal area were analyzed by HPLC for the presence of organophosphorus, pyrethroid and carbamate pesticide residues. The results reflected slight contamination of some of the water samples with residues of diazinon, chlorpyriphos (organophosphorus insecticide), carbaryl and carbofuran (carbamate insecticide). The concentration of diazinon and chlorpyriphos ranged from 2.31 jig/L to 5.60 pg/L and 0.0 to 3.80 pg/L respectively. Among carbamate pesticides, carbofuran identified in two samples, ranging from 1.40 to 3.71pg/L, carbaryl was detected in two of the samples which ranged from 1.32 to 6.40pg/L, and pyrethroid (cypermethrin) was not detected in any of the samples. However, the residue level was also within the acceptable ranges according to the WHO guideline value (1993) of water quality. But, its presence in surface water as WHO-recommended limits is a matter of concern. In Bangladesh consumption ofpes::c.Jcs has been increased with the introduction of high yielding varieties of rice in recent years But. the widei> cultivated high yielding variety is highly vulnerable to pests and diseases, and 40; : of the crop loss can be attributed to attack by pests and insects in Bangladesh which is a significant loss (Bagchi, et al. 2008). So, the use of pesticide is now an integral part of agriculture for pest control. More than 100 species of insects, 600 weed species. 1500 plant diseases and 1500 species of nematodes are being controlled by pesticide (Brady 1990). As a result, the production of improved variety of rice has significantly increased in recent years. Although pesticide is beneficial for pest control, it also poses a harmful effect to our environment such as the pollution of surface and ground water. After application of pesticide in the crop field it is degraded in the soil by the soil microorganism to some extent but many of the toxic pesticides are transported into surface and ground water by agricultural run off rain water from the crop field. Ultimately, the surface and ground water may be highly contaminated due to this agricultural run off pesticide (Bagchi, et al. 2008). Asiat. Soc. Bangladesh, Sci. 40(2): 319-323, December 2014

Emergent vegetation or trees are important riverine features and essential in hydraulic engineering including flood management and river restoration. Clearing up trees along river banks has been pointed out as a contributing factor to the severity of flood damages including financial losses and even fatalities. Thus, the effect of riparian vegetation on river flow must be clearly understood. The hydraulics and morphological patterns in a riparian vegetated sandy compound straight channel were carried out in the Hydraulics Laboratory, School of Civil Engineering, Universiti Teknologi Malaysia. Two-line steel rods with tandem and staggered arrays to simulate as rigid emergent vegetation were placed along the riparian zone of an asymmetrical straight channel. The Manning’s n, depth-averaged velocity, boundary shear stress and morphological changes during shallow and deep floods are discussed in this paper. The findings prevailed that the staggered array riparian vegetation generated 4.5% flow resistance higher than the tandem array. The vegetation also altered velocity distribution which contributed to the boundary shear stress patterns in a compound straight channel. The flow velocity profiles were also related to the morphological changes in the channel.

Asset management system is a crucial element of a utility project because it helps a company to inspect the asset inventory systematically. Besides, it improves productivity and proficiency of companies to position them better and increases their return on investment. The traditional system of data collection is very tedious in producing an asset inventory system. This study offered a mobile mapping system (MMS) by using 360-degree cameras to reduce the time and cost involved in data acquisition. The aim of this study was to locate, digitise, measure, and tag the assets along the street network. The efficiency of these 360 technologies was investigated to obtain asset data for a 3D street view utility mapping and provide important information. The obtained image will be used to determine the location of observed asset. The digitising process was required to label the detailed asset information as well as map the asset. This technology consists of a combination of camera, Global Navigation Satellite System (GNSS), and Inertial Measurement Units (IMU). The efficiency of this technology was tested by mounting it on a vehicle such as car or motorcycle. The geo-referenced images were derived by using sensor models and were pro-cessed to produce a 2D information mapping for utility purposes. The study resulted in producing a digital map with Geographical Information System (GIS) spatial data and 360-degree imagery. Having such a system in place allowed to track the overall achievements of asset inventory, and thus utilised efficiency.

Floods happen when the flow of water exceeds the river banks and flow through the floodplain area, which is known as overbank flow. Flood causes damage to infrastructure and buildings and loss of life. Therefore, this paper investigates the characteristics of pattern river development; width, depth, and flow within the channel. This physical modelling discusses the pattern of the river by employing the current meter and point gauge equipment to collect and record the data along the channel. The discharge of 0.2 L/s and 0.5L/s were used for nonflooding and flooding cases. The non-flooding and flooding cases were identified by using a rectangular flume known as “Flexible Channel Flume”. The flume used in this study has 4.95 X 0.69 X 1.26 m of the rectangular main channel with a non-fixed-bed. As a result, the flooding case shows the depth of the channel increasing at the upstream and decreasing at the downstream compared to the non-flooding case with changes of velocity and manning’s roughness coefficient n.

The concentrations of pesticides were determined using high performance liquid chromatography (HPLC) of 15 pond water and 10 canal water samples around the paddy or vegetable fields from Sadar Upazila, Lakshmipur (Coastal area). The analysis showed that some water samples were contaminated with organophosphorus and carbamate pesticides. The residue level of diazinon ranged from 0.315 to 0.441 μg/l whereas the carbaryl ranged from 0.136 to 0.204 μg/l. The level of carbofuran was found in the range of 0.373 to 2.208 μg/l, which were above the maximum acceptable levels of total and individual pesticide contamination.