Aeration effects on erosion and water circulation in circular and rectangular ponds | |
| Author | Chowdhury, Md. Alimuzzaman |
| Call Number | AIT Thesis no. AE-95-35 |
| Subject(s) | Ponds Aquaculture |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources, and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The aeration effects of two pond configurations (circular and rectangular) on sedimentation, erosion and water circulation were evaluated under unlined and lined (upper 503) slope . Velocity of water movement was measured at two different aerator positions and at various locations in pond water. Aeration effect on dissolved oxygen (DO) and temperature mixing were also determined. With 300 h of continuous aeration, the overall sedimentation and erosion rates were 39.2 and 31.0 ml/m2 /h in circular unlined pond and 6.0 an d 5.2 ml/m2 /h in lined circular pond, respectively. In comparison, 47.8, 39.2 ml/m2 /h and 7.5, 6.5 ml/m2 /h sedimentation a nd erosion rates in rectangular pond with unlined a nd lined slope, respectively. In circula r pond, the maximum velocities at aerator positions-1 & 2 were 17.5 and 9.3 cm/s (position-1 & 2 indicates tangential and cross flow direction), compared to 10.5 and 12.5 cm/s in rectangular pond under the same positions-1 & 2 (position- 1 & 2 indicates flow direction parallel to long and short section), respectively. Aeration took 35 and 45 min to destratify DO and temperature in circular and rectangular pond, respectively. There was no significant variation in soil texture between two pond dikes. Percentage of sand deposition was higher near the bottom edge and decreased towards the center, but the pattern of clay deposition was reversed. The lining of slope reduced the sedimentation and erosion by 85 3 in both types of ponds. In case of unlined situation, about 85 3 erosion occurred in the upper 50 3 of the slope area. The sediment deposition rate was higher at the center in circular pond than that in rectangular pond. Dike erosion was homogeneous in circular pond but it varied significantly in rectangular pond. The aerator position in circular pond did not cause great variation in velocity of water movement but in rectangular pond the velocity varied greatly. Overall, with the respect to sedimentation, erosion, water circulation and mixing, the circular pond was more advantageous than the rectangular pond |
| Year | 1995 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Lin, Chang Kwei |
| Examination Committee(s) | Yakupitiyage, Amararatne;Salokhe, V. M. |
| Scholarship Donor(s) | The Bangladesh Government and Asian Development Bank |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1995 |