According to Ben Urbonas, president of the Urban Watersheds Research Institute, these nutrient contaminants tend to be more of a problem in closed water systems,like lakes, where concentrations can build up.

VOA: standard.2010.08.04

The rain harvesting systems mean that a family member no longer has to walk long distances to get water.

VOA: special.2009.07.27

As part of the plan, the Army Corps of Engineers built roads, canals and water-control systems throughout South Florida.

VOA: special.2010.09.21

The systems are especially useful for those who are too sick to go a long way for water.

VOA: special.2009.07.27

These include transportation and communications systems, water and power lines, and public institutions including schools and hospitals.

VOA: special.2010.04.02

Eric Hartman,the director, described the water collection systems in blog postings from Tanzania earlier this month.

VOA: special.2009.07.27

And to do that, we need a lot of surveys and geological surveys on water preservation systems.

VOA: standard.2009.10.06

"If you have an imbalance, or literally too much nitrogen and too much phosphorous getting into those systems, you can essentially deplete the oxygen in that water.

VOA: standard.2010.08.04