| Author | Namtip Rattapan |
| Call Number | AIT Thesis no. 225 |
| Subject(s) | Runoff--Thailand--Bangkok--Statistical methods
|
| Note | A thesis submitted in partial fulfillment of the requirements
for the degree of Master of Engineering in the Asian Institute of Technology, Bangkok, Thailand. |
| Publisher | Asian Institute of Technology |
| Abstract | A five-acre block of a hypothetical but typical residential area of Bangkok was selected as the drainage area for the purpose of calculating a peak inlet hydrograph. The design peak flow was computed using both the Chicago Hydrograph Method, and the
Rational Method. The Chicago Hydrograph Method was adopted to develop a design
storm pattern for Bangkok of 5 year frequency and 120 min. duration for application as an input to the drainage area. The drainage area was divided into strips to simplify calculation, and losses due to infiltration and depression storage in each strip were subtracted from the design storm to obtain the net supply of
runoff. Detention due to overland flow in each strip was determined and applied to compute the flow rates at the end of a strip. The
combination of these outflows from tributary strips were routed
along a street gutter to a street inlet which fed a lateral sewer.
By a simplified time-offset method, storm water in the lateral sewer was routed through its total length to compute-the inlet hydrograph
for the typical drainage area. The peak of the inlet hydrograph
was taken as the design runoff for determining the size of the
lateral sewer. In the Rational Method, a five-year intensity-duration frequency curve for Bangkok was used to obtain the rainfall intensity for the time of concentration of the typical drainage area. Multiplication of the selected rainfall intensity by the estimated value of the runoff coefficient and the size of the
typical drainage area resulted in a design runoff which was used
to compute the size of the lateral sewer. The design peak flow obtained in the computations from the Chicago Hydrograph Method (29.04 ft^/sec or 0.822 m /sec )was 3 about 10 ft /sec (0.283 nr /sec) higher than that computed by the Rational Method (19.1 ft /sec or 0.541 m /sec). A lateral sewer size, approximately 6 in. larger would be required by the higher design flow rate. However, it was considered that some of the
assumptions and estimations made in application of the Chicago Hydrograph Method, necessitated by a lack of experimental data, could be improved on with further measurements in the field. |
| Year | 1968 |
| Type | Thesis |
| School | Student Research Before 1980 |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Thesis (Year <=1979) |
| Chairperson(s) | Pescod, M.B. |
| Examination Committee(s) | Schulz, E.F. ;Pichai Boonyakanjana ;Arbhabhirama Anat |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1968 |
