By Katrina Marland

I think that we can all agree that water is pretty important. We use it in everything from manufacturing to agriculture, and then, of course, there’s that other small detail: Water is essential to life on this planet. There’s not a single living thing on Earth that doesn’t need water.

Credit: Horia Varlan

Today is World Water Day. Starting back in 1993, the United Nations General Assembly has designated every March 22nd as a day to recognize the importance of protecting freshwater and managing it properly for everyone’s benefit. Forests and water are more connected than just about anything, so here at American Forests, World Water Day gives us a lot to think about. Here are just a few things that forests do to keep water clean and flowing:

Manage water in cities

Where there are cities, there are a lot of impervious surfaces, like streets and sidewalks. This means that when it rains, the water washes over those surfaces — picking up all kinds of nasty things along the way — then collects in the city’s water-management system, which usually isn’t designed to handle a much higher volume. This is why, when it rains in the city, you sometimes see what looks like a very dirty river running down the street — there’s nowhere else for it to go. Trees intercept the water as it falls and can even filter it, which means less (and cleaner) water hitting the city’s stormwater-management systems all at once. This also saves a lot of money in stormwater management, which many cities like Portland are finding out.

Filter and regulate water

The USDA Forest Service estimates that 180 million people across the nation depend on forests for the water they drink, so it’s pretty clear that you can’t talk about clean, drinkable water without mentioning forests. As trees absorb water, they filter out pollutants. Trees are so good at this natural process that forests actually provide natural filtration for about half the water supply in the U.S. Many sources of water in the U.S. are also from forested areas, especially mountain snowpack and rivers. Trees are vital to those locations, keeping the water clean and flowing at a steady rate so that it moves from forest to faucet throughout the year, instead of all at once.

Shade water

Unless you’re cooking something, you usually like your water cool, right? So do the many species of plants and animals that live in it. Trees play a big part in regulating the temperature of the water in rivers, streams and other ecosystems where the forest meets water. Their shade keeps the water cool, which helps regulate the oxygen levels — very important, especially to fish like salmon, who are particularly sensitive to changes in water temperature and composition.

What can you do for World Water Day? One of the most important things you can do is educate yourself on the many aspects of the issue. Keep up with new information by joining our online community, and following us on Facebook or Twitter for even more environmental news.

Then, help to educate other people. Share the things you’ve learned with friends and family. Share these resources on your blogs, Facebook pages and other social networks. Email them. Get the word out there about how vital a role forests play in providing and protecting the water that we all depend on.