Statistical Characterization of Extreme Hydrologic Parameters for the Peripheral River System of Dhaka City
Sarfaraz Alam,
Muhammad Sabbir Mostafa Khan
Issue:
Volume 3, Issue 3, June 2014
Pages:
30-37
Received:
26 June 2014
Accepted:
8 July 2014
Published:
20 July 2014
Abstract: Selection of appropriate probability distribution function is one of the most important steps of frequency analysis. Due to the existence of large number of distributions, hydrologists follow different methods to select the best one. In this paper, annual maximum, minimum water level and discharge of five peripheral rivers, namely Buriganga, Turag, Tongi, Balu and Lakhya around Dhaka city have been analyzed to compute the basic statistics and fit them with sixty two probability density functions (PDF). Three goodness-of-fit (GoF) statistics, namely Chi-square, Kolmogorov–Smirnov and Anderson Darling were used to rank each of the distribution. Furthermore, ranks obtained from three GoF were used to compute overall rank of all distributions for each hydrologic parameter. The study reveals that, four different distributions were found best fit for four extreme cases. Dagum (4P) and Chi-square (2P) fit best for annual maximum and minimum water level respectively, whereas Cauchy and Johnson SB were found for annual maximum and minimum discharge respectively. Moreover, ranks of frequently used distributions, namely General Extreme Value (GEV), Log-Pearson III (LP3), Log-normal (LN) and Gumbels were compared with the best fit distributions and did not give satisfactory results. The method used in this study would be helpful for flood frequency analysis of other rivers of Bangladesh. This may also be used for evaluation of best fit distribution of river system for other countries as well.
Abstract: Selection of appropriate probability distribution function is one of the most important steps of frequency analysis. Due to the existence of large number of distributions, hydrologists follow different methods to select the best one. In this paper, annual maximum, minimum water level and discharge of five peripheral rivers, namely Buriganga, Turag,...
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Water Quality Status of Recreational Spots in Chittagong City
Md. Lokman Hossain,
Sultana Kamrun Nahar Nahida,
Md. Iqbal Hossain
Issue:
Volume 3, Issue 3, June 2014
Pages:
38-44
Received:
27 August 2014
Accepted:
3 September 2014
Published:
20 September 2014
Abstract: The study was conducted to learn about water quality status at potential recreational spots in Chittagong City. Water samples were collected from six recreational spots. Derived parameters namely; Conductivity, Turbidity, Color, Odor, pH, Dissolve Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Sulfate and Nitrate of the collected water samples were compared with the standard value of the respective parameters. The study revealed that water conductivity of Karnafully Shishu Park (1400 µs/cm) and Jatisongho Park (1430 µs/cm) could satisfy the standard level (1500µs/cm) and the other spots exceeded the limit. Water collected from Foy’s lake was a bit turbid (5.07 ntu) but it did not significantly exceed the expected limit (5 ntu). The study also revealed that water of Foy’s Lake was darker (55 Hazen) compared to the standard (20 Hazen). In case of odor, all the spots’ water was unobjectionable except Chittagong Shishu Park and Jatisongho Park. BOD and DO content were satisfactory for all the spots. But COD was higher at Chittagong Shishu Park, Karnafully Shishu Park and Zia Smriti Complex. Nitrate concentration was also found satisfactory in water of all spots except Chittagong Shishu Park (19.33 ppm). All the parameters were under the desired levels for recreation with few exceptions. Although very small, to extend the recreational facilities for the urban people, these unwanted level of different physical and chemical parameters should be mended on an urgent basis.
Abstract: The study was conducted to learn about water quality status at potential recreational spots in Chittagong City. Water samples were collected from six recreational spots. Derived parameters namely; Conductivity, Turbidity, Color, Odor, pH, Dissolve Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Sulfate and Nitrate of the ...
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