Risk handled in the Waterfall model

The client only gets to see the product at the very end of the deveoplment and if it is not what they want, it is too late. The problem is the huge gap between requirement analysis at an early stage in the project and acceptance testing near the end.



We can't go backwards in the waterfall model as it is a sequential software development model.
To overcome this drawback, waterfall provides for feedback to the immediately preceding steps and in reality, any step may necessitate changes in any of the preceding stages.


For example:

During system testing, architectural design fault is revealed
During user acceptance, a problem with the specification becomes evident

so the reality of the waterfall model is that development does not proceed linearly, step-by-step. Instead there is commonly frequent feedback to earier stages, requiring rework.