Malcolm McDowell Woods
Urban Almanac

The problem with melted snow is …

By - Apr 8th, 2010 04:00 am
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By Bailey Hackbarth

photo by Nedral via flickr (cc)

It’s no secret why Wisconsinites love their winters. From kids sledding down snow-covered hills or skating on icy ponds to moms and dads sipping cider during a snowfall, joy is as abundant as the snow itself. We know we love it. But what’s not so well known is what happens after the last snowflake has fallen, when the accumulated slosh disappears and April showers retire snow plow-ers.

Well, it doesn’t just vanish into the fresh spring air.

The melted snow and ice, coupled with the showers that melt them, will often flood into city streets, pushing our local waterways to their brims. This flooding is entirely natural and crucial to ecological rejuvenation. A river system like Milwaukee’s is home to millions of micro-organisms that depend on flooding for reproduction. In fact, at the Urban Ecology Center’s Washington Park location, a central lagoon is flanked by two overflow wetlands that commonly flood with rainwater during springtime. These wetlands, considered “ephemeral ponds” for the way they fill with rainwater then dry up in mid-summer, are crucial breeding grounds for toads, salamanders and other amphibians.

In an urbanized setting like Milwaukee, however, these ponds suffer from the fact that storm water tends to run down our roofs, yards and roads, all the while accumulating nasty ingredients like automobile oil, grease, animal waste, fertilizer and pesticides. This concoction races over impermeable surfaces (streets and sidewalks) and eventually settles into soft, permeable pond soil or the city’s sewer system.

You may know that in much of Milwaukee our combined sewer system collects and treats not only household waste water but also storm water. During a storm, the Milwaukee Metropolitan Sewerage District’s system of underground piping, pumps, and tunnels takes in millions of gallons of rainwater. This water, which may be mixed with toxic contaminants, must be thoroughly cleaned prior to being returned to Lake Michigan.

Unfortunately, the system of tunnels, pumps and purification tanks isn’t perfect. During the very largest of our rainstorms, the normal wastewater treatment process that takes on the city’s sewage before releasing it back into the lake is simply overwhelmed. Add leaky pipes into the mix, and we have a situation in which a sewage-storm water mix gets periodically dumped into our rivers or the lake. Though we’ve drastically reduced this volume from past amounts (thanks to our new extra-capacity deep water tunnel), we still dump around one billion gallons per year. Our only other options are accepting sewage backups in our homes and businesses when the system is overwhelmed (which nobody wants), or finding creative ways to prevent the storm water from exceeding the system’s capacity in the first place.

The Milwaukee River, photo by k.stuedel via flickr (cc)

When we dump sewage into the lake or let runoff reach its shores, we face a multitude of public health and ecological troubles. Beaches close. Stenches swell. Eutrophication — a fancy word for the over-concentration of nutrients in an ecosystem — dramatically reduces fish numbers and allows some algae to spread unchecked. Plus, the lake we’re dumping sewage into is the same lake we’re drinking from!

One way to prevent over-capacity sewerage volume is by brainstorming some smarter alternatives. The MMSD is working on large-scale solutions like adding to the deep water tunnel and restoring/expanding many water-storing wetlands in this urbanized area. But residents can do our part, too. Here at the Urban Ecology Center, our Riverside Park building was the first commercial site in Wisconsin to collect rainwater in large cisterns for flushing our toilets. When you really think about it, why should we use the über-clean water that’s gone through the Milwaukee water works’ rigorous and energy-intensive decontamination process for such a humble purpose?

Picture a drop of Lake Michigan water. Sucked through an intake pipe lining the lake floor a mile offshore, it joins with millions of others on its way through a gauntlet of cleaners where it’s coagulated, mixed, settled, filtered, chlorinated and fluorinated – then treated with ozone, phosphorous, and ammonia — before finally being pumped miles to our homes … just so we can flush our toilets.

Sure, we need purified water for drinking, cooking, and washing (cryptosporidium, anyone?), but why for toilets?

photo by B.Finnegan, via flickr (cc)

Although we can’t all flush with rainwater right now, there are a host of things you can do to limit your impact on our treasured lake. In a recent UEC newsletter, we proposed a simple water conservation plan for our readers — the 100 Gallon Challenge:

We suggest that you purchase a rain barrel (sold by MMSD, available at the UEC and other retailers like Outpost for $45) and place it under a downspout by your house. Properly utilized, this barrel prevents 55 gallons of water from seeping down the sewer during heavy rainstorms. You can simply dump the water out once the storm passes and the system is back to normal operation, or you can use it to water your lawn or wash your car!

Second, pay attention to the weather. Should rain be in the forecast, wait to use excess water until after the storm has passed. If we held off on laundry, dishwashing, or other water-intensive household tasks until after storms subsided, each household could save an average of 55 gallons of water per storm. Combine this with your rain barrel’s collection, and voilà! More than 100 gallons saved!  If everyone pitches in, these 100 gallons add up to millions for the city, lessening the overwhelming load on the sewer system and deep tunnel. During a rainstorm, check out www.mmsd.com and click on “Storm Update” – the department will constantly refresh the operational status of its tunnels.

If you’d like to take your water conservation a step further, consider creating a rain garden. These gardens are sunken plots that are relatively simple to plant and help hold storm water in your yard instead of allowing it to drain into sewers.  The gardens create a temporary shallow pond of rainwater, which disappears as the native plants slowly absorb it, allowing it to filter gently into the earth.

The next time you enjoy those cool April rains, consider taking a stroll down your city streets in the newly clean and humid air for a quick look at your friendly neighborhood river or wetland.  Observe the remarkable natural phenomena that line the river’s mudflats or thrive in the pond’s depths.  These life-giving floods won’t last forever, so make it a habit to see their unique progression as the weeks go by. Your heart for Mother Nature – and your inner ecologist — will thank you for it.

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