1. Retard and block the on-rush of water.
2. Remove the in-flowing water getting collected at the site
3. Lay the foundation for the dam
4. Reinforce and stabilize it by steadily building up the dam.

The swiftly flowing thought stream also calls for a fourfold effort if it is to be dammed. We have to:-

1.Restrain and check the influx of unwholesome thoughts.
2.Abandon unwholesome thoughts already arisen.
3.Arouse wholesome thoughts not yet arisen.
4.Stabilize and develop wholesome thoughts already arisen.

The effort, in each case, has to be an all-out one. It has to pick up intensity in keeping with the seriousness of the task. For the fourfold effort of restraint, abandonment, development and stabilizing, one has to arouse an interest, make an exertion, put forth energy, make up one’s mind and give of one’s best in endeavour.

This is the Right Effort that matures into Right Mindfulness and Right Concentration to complete the Noble Eightfold Path leading to Wisdom and Deliverance.

‘Whatever streams are there in the world Ajita, so said the Lord.
Mindfulness keeps them in check.
This, I say, is restraint of streams
By wisdom ‘tis that they are dammed’. - Sutta Nipâta .v.1035.