This reduces drag in the water caused by loose hair.

The use of a diatom filter, which can reduce the number of free parasites in the water, may help.

This will further reduce the solubility of iodine in the water.

The lily pads reduce the amount of oxygen in the water, which has slowed the lake's ability to decompose organic material.

When algae are encouraged in this way, sunlight is blocked and the oxygen reduced in the water below.

It is a pest of waterways because its dense mats reduce oxygen in the water.

It is added to tap water to reduce bacteria in the water.

Some swimmers also shave areas of exposed skin before end-of-season competitions to reduce friction in the water.

This fragmented the river, altered its flow, reduced oxygen levels in the water, increased sedimentation, and changed the flood regime of the system.

This action reduced the outdated risk of salt and mineral percentages in the water.