French Drain Measurements

To stop some ongoing water infiltration issues we decided to install a french drain to channel the water away from the house. Thanks to Mr. French I know everything I will need to know to do this project (I hope). First, for some decent rough measurements, I will of course have to take more accurate depth measurements once I get below the foundation of the house but I need a rough starting point so I will know where the drain needs to start and how deep.

Not a lot to see in the pictures but I spent this rainy day taking measurements and figuring out how and where to dig the trench.