Seeking assistant to restructure Watershed for rainwater harvesting.

Dear Experts,  I am building a model farm to demonstrate the efficient use of water and healthy way of producing agriculture output. Hence, I have setup watershed to receive and store rain water, practicing cheaper and efficient farming techniques, organic fertilizers, created a mini-forest for fruits and temperature reduction and much more. Though I have created a watershed structures, I was unable to direct the rain water to the storage - I see a failure in creating a slope in the fields to narrow the water to the passage. I am in need of help to rectify the errors in my farm so that I should be able to store the rain water.   Thanks Murthi