Often in a 'land' birth, the midwife will hold a heated cloth on the perineum to help prevent tearing. In the water, I was surrounded by warmth, and even though it was my first labor and delivery, I never tore. Water also helps to reduce the level of fear, as a woman is more relaxed and less stressed. Fear during labor is definitely counterproductive and can slow labor down. Fear during the delivery can cause a woman to push beyond was she should and lead to some severe tearing.
Water is a soothing natural element.
Even the sounds of water can be relaxing. If a woman has a low risk pregnancy and is progressing well through a labor without complication, water is a wonderful option for pain control. She never cried, needed no suctioning of mucus, and opened her eyes and looked around at her new family in a gently and quiet lit room. As there were fewer traumas to my body, healing time was relatively quick. Used under License.