--- title: Comparison of OSD results between software calculation and excel spreadsheet using ‘Swinburne Method’ description: "**OSD Swinburne Method (MSMA 1)  ** 1. Project file MiTS 2 [here](https://largefilehosting.s3.ap-northeast-1.amazonaws.com/ProjectSharing/Client%20Project%20-%20Saiful/Project%20File%20-%2012279-backup-2.10.39.0-060723102500.zip) 2. Software Report [here](https://largefilehosting.s3.ap-northeast-1.amazonaws.com/ProjectSharing/Client%20Project%20-%20Saiful/Software%20calculation-12279.zip) 3. Manual Excel Spreadsheet [here](https://docs.google.com/spreadsheets/d/1LVa9oYn4HpD7myveC9hwIv70H4_9NVDjR-wtiXhNZew/edit?usp=sharing) 4. Linear interpolator [h](https://www.johndcook.com/interpolator.html)[e](https://www.johndcook.com/interpolator.html)[re](https://www.johndcook.com/interpolator.html) **kindly informed that you will need to download the manual excel spreadsheet and software report*…" url: "https://mes100.com/docs/comparison-of-osd-results-between-software-calculation-and-excel-spreadsheet-using-swinburne-method/" updated: "2026-10-03" category: Benchmark / MSMA tags: - Pond --- # Comparison of OSD results between software calculation and excel spreadsheet using ‘Swinburne Method’ **OSD Swinburne Method (MSMA 1)  ** 1. Project file MiTS 2 [here](https://largefilehosting.s3.ap-northeast-1.amazonaws.com/ProjectSharing/Client%20Project%20-%20Saiful/Project%20File%20-%2012279-backup-2.10.39.0-060723102500.zip) 2. Software Report [here](https://largefilehosting.s3.ap-northeast-1.amazonaws.com/ProjectSharing/Client%20Project%20-%20Saiful/Software%20calculation-12279.zip) 3. Manual Excel Spreadsheet [here](https://docs.google.com/spreadsheets/d/1LVa9oYn4HpD7myveC9hwIv70H4_9NVDjR-wtiXhNZew/edit?usp=sharing) 4. Linear interpolator [h](https://www.johndcook.com/interpolator.html)[e](https://www.johndcook.com/interpolator.html)[re](https://www.johndcook.com/interpolator.html) **kindly informed that you will need to download the manual excel spreadsheet and software report* ## ****Objective**** 1. Comparison between software calculation and manual calculation. To ensure that the results are the same 2. Software extract the correct value from Design Chart/Table in MSMA 1 ## ****Project Development details**** Area: 0.687 ha 100 m of overland flow 520 m flow in an open drain Catchment area average slope 1% MSMA 1st Edition ## **OSD Sizing Procedure (MSMA 1 – Swinburne Method)** | **Manual Excel Spreadsheet** | **MiTS Software** | | --- | --- | ### **Select storage type to be used at the site** - Below-ground storage - Formula used to calculate PSD and SSR (referring to below-ground storage formula) ### **Determine the area of the site that will be drained to the OSD storage system** - Area: 0.687 ha - 100 m of overland flow - 520 m flow in an open drain - Catchment area average slope 1% - MSMA 1st Edition ### **Determine the amount of impervious and pervious areas draining to the OSD storage system** **Pre-development** - Impervious = 0 ha   - Pervious = 0.687 ha **Post-development** - Impervious = 0.4809 ha - Pervious   = 0.2061 ha ### **Determine the time of concentration, tc and tcs** | Refer design chart 14.1 Nomograph for Estimating Overland Sheet Flow Times, to![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/tc-excel.jpg?resize=1000%2C412&ssl=1)From Design Chart 14.1, tc = to + td = 10 min | In MiTS softwareUsing Time of Concentration for Natural Catchment Equation 14.6![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/MiTS-Tc.jpg?resize=800%2C245&ssl=1)Calculated from Equation 14.6, tc = 10 min | | --- | --- | **Calculate the Pre-Development flows, Qp** | **Pre-Development** 1. Calculate rainfall depth,P30 and P60  using Equation 13.2 2. Determine FD from Table 13.3 3. Calculate Rainfall Intensity using Equations 13.3 & 13.4 4. Calculate Qp = CIA![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/P30-excel.jpg?resize=800%2C229&ssl=1)P30  = 48.091 mm, P60 = 62.045 mmPd = 32.32 mmHence, *I *= Pd/tc = 32.32 / (10/60) =193.94 mm/hr![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/Qp-excel.jpg?resize=800%2C166&ssl=1)Qp = CIA = 0.230 m3/s | **Pre-Development** 1. Calculate rainfall depth,P30 and P60  using Equation 13.2 2. Determine FD from Table 13.3 3. Calculate Rainfall Intensity using Equations 13.3 & 13.4 4. Calculate Qp = CIA![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/04/image6.png?resize=300%2C186&ssl=1)P30  = 48.09 mm, P60 = 62.05 mmPd = 32.32 mm![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/04/image5-1.png?resize=720%2C496&ssl=1)Hence, *I *= Pd/tc = 32.32 / (10/60) =193.94 mm/hr, Qp = CIA = 0.230 m3/s | | --- | --- | **Calculate the Post-Development flows, Qa** | **Post-Development** 1.Calculate rainfall depth,P30 and P60  using Equation 13.2 2. Determine FD from Table 13.3 3. Calculate Rainfall Intensity using Equations 13.3 & 13.4 4. Calculate Qp = CIA![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/P30-post-excel.jpg?resize=800%2C245&ssl=1)P30  = 48.091 mm, P60 = 62.045 mmPd = 38.04 mm. Take tc as nearest = 15 min. Hence, *I *= Pd/tc = 38.04 / (15/60) =152.18 mm/hr![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/Qa-excel.jpg?resize=800%2C169&ssl=1)Qa = CIA = 0.23 m3/s | **Post-Development** 1.Calculate rainfall depth,P30 and P60  using Equation 13.2 2. Determine FD from Table 13.3 3. Calculate Rainfall Intensity using Equations 13.3 & 13.4 4. Calculate Qp = CIA![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/image12.png?resize=517%2C330&ssl=1)P30  = 48.09 mm, P60 = 62.05 mmPd = 38.04 mm![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/image3.png?resize=708%2C406&ssl=1)Hence, *I *= Pd/tc = 38.04 / (15/60) =152.18 mm/hr, Qa = CIA = 0.230 m3/s | | --- | --- | **Determine the required PSD for the site** **(Equation 19.1 with Equations 19.1c and 19.1d for below-ground storage)** | ![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/PSD-excel.jpg?resize=1000%2C260&ssl=1) | ![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/PSD.jpg?resize=800%2C451&ssl=1) | | --- | --- | **Determine the required SSR for the site** **(Equation 19.2 with Equations 19.2c and 19.2d for below-ground storage)** | ![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/SSr-excel.jpg?resize=1000%2C742&ssl=1)Therefore, the required SSR (with 20% added for safety factors) = 161.314 m3 | ![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/SSR.jpg?resize=500%2C285&ssl=1)![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/20.jpg?resize=500%2C121&ssl=1)Therefore, the required SSR (with 20% added for safety factors) = 161.075 m3 | | --- | --- | **Determine storage Dimensions** | ![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/tank-excel.jpg?resize=900%2C102&ssl=1) | ![](https://i0.wp.com/mes100.com/wp-content/uploads/2019/05/image9.png?resize=501%2C182&ssl=1) | | --- | --- | ### *Related* [![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/10/me-small.jpg?resize=100%2C100&ssl=1)](https://mes100.com/author/admin/)[Ngu Soon Hui](https://mes100.com/author/admin/) I’m the [Benevolent Dictator for Life](https://en.wikipedia.org/wiki/Benevolent_dictator_for_life) for MiTS Software cum Editor of this website. Read more [here](/about-ngu-soon-hui/). You can also contact me at soonhui@mes100.com