How to perform hydrological study of a particular area

Using MiTS, users can generate the inflow hydrograph using the MSMA module.

Project References :

Project file for Detention Pond Rational Method

Project file for Detention Pond Time-Area Method

Steps to develop inflow hydrograph #

Rational method #

1. Create a project under MSMA module. At the main tab, click on the MSMA > click “Add” at the project view on the left side. “Create New MSMA Project” dialog box will pop up > Input the project name and at the “Type” dropdown, choose “Pond” > “Method” dropdown will appear after “Pond” is chosen. The Rational Method will automatically chosen > click “Create”.

2. Click on the project that was created. At the pre-development tab, you may choose the rain gauge location at the dropdown and insert the values related to the project location. Then, Tc can be calculated by clicking the arrow.

3. In this example, Bransby William equation is used for the Tc calculation method. To change the equation used, go to Options > Project Settings > Det. Facility > Design > change Tc Calculation Method.

4. You can change the stormwater design ARI according to your requirement. Then, click “Calculate”.

5. Then, you will be able to insert the values at the post-development tab. Insert the values related to the project location. Then, Tc can be calculated by clicking the arrow.

6. Click “Calculate” at the bottom part. 

7. After clicking “Calculate”, you will be prompted to proceed to pond sizing.

8. Since our purpose is only to generate the inflow hydrograph, the pond size and the outlet design will not be regarded in this design. However, you still need to input all the values in order for you to be able to analyse the project. Considering we already completed the detention pond design, we can proceed to click “Analyse” at the input tab.

9. Upon successful analysis, the inflow hydrograph can be obtained at the output tab. Hover to the  Graph tab, the inflow hydrographs are available according to the storm duration.

10. To export the graph to excel file, go to Output tab > click Export. Make sure that you are at the graph tab before clicking Export. Then “Save As” dialog bar will pop up. At the “Save as type”, you can change to .xlsx or .xls.

Time-area method #

1. Create a project under MSMA module. At the main tab, click on the MSMA > click “Add” at the project view on the . “Create New MSMA Project” dialog box will pop up > Input the project name and at the “Type” dropdown, choose “Pond” > “Method” dropdown will appear after “Pond” is chosen > change the method to Time-Area Method > click “Create”

2. Click on the project that was created. At the pre-development tab, you may choose the rain gauge location at the dropdown and insert the values related to the project location. Then, Tc can be calculated by clicking the arrow.

3. You can change the stormwater design ARI according to your requirement. Then, click “Calculate”.

4. Then, you will be able to insert the values at the post-development tab. Insert the values related to the project location. Then, Tc can be calculated by clicking the arrow.

5. Click “Calculate” at the bottom part. 

6. After clicking “Calculate”, you will be prompted to proceed to pond sizing.

7. Since our purpose is only to generate the inflow hydrograph, the pond size and the outlet design will not be regarded in this design. However, you still need to input all the values in order for you to be able to analyse the project. Considering we already completed the detention pond design, we can proceed to click “Analyse” at the input tab.

8. Upon successful analysis, the inflow hydrograph can be obtained at the output tab. Hover to the  Graph tab, the inflow hydrographs are available according to the storm duration.

9. To export the graph to excel file, go to Output tab > click Export. Make sure that you are at the graph tab before clicking Export. Then “Save As” dialog bar will pop up. At the “Save as type”, you can change to .xlsx or .xls. 

Obtaining the coordinate of the area location #

If you are not sure of the nearest rain gauge location needed to be used, you can use the longitude and latitude of the location.

From google maps #

You may refer to the coordinate of the location stated on the left side of the google maps page. For the above location, you may input the latitude and longitude as the example below. You will see that the software will propose the nearest rain gauge location.