Changes

==Sizing==

==Sizing==

It is recommended that a standard sizing approach be used for all OGS units to ensure they are evaluated based on a consistent methodology. The attached OGS Review Calculator has been developed to facilitate application of ISO 14034 ETV test data through a standard approach applicable to all OGS MTD designs.   The following methods and processes are built into the tool:

It is recommended that a standard sizing approach be used for all OGS units to ensure they are evaluated based on a consistent methodology. The attached OGS Review Calculator has been developed to facilitate application of ISO 14034 ETV test data through a standard approach applicable to all OGS MTD designs. The following methods and processes are built into the tool:<br>

* Rational Method used as a basis for flow calculations (Q = CiA, where C is the site runoff coefficient, i is the rainfall intensity and A is the drainage area) - Alternatively, provide bubble link to definition of rational method

'''Rational Method''' used as a basis for flow calculations:<br>

<math>Q = CiA</math>

**<math>C</math> is the site runoff coefficient,  

**<math>i</math> is the rainfall intensity, and;

**<math>A</math> is the drainage area)

* Target treatment is based on capture and treatment of the average annual runoff volume for the site using ISO 14034 verified sediment removal test results for 7 surface loading rates

* Target treatment is based on capture and treatment of the average annual runoff volume for the site using ISO 14034 verified sediment removal test results for 7 surface loading rates

* Linear interpolation is used to calculate sediment removal efficiencies between the ISO/ETV tested surface loading rates

* Linear interpolation is used to calculate sediment removal efficiencies between the ISO/ETV tested surface loading rates