Rain Gardens in Dane County

Why rain gardens fail

2011-12-06T11:22:00.000-08:00

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Rain gardens are supposed to put runoff back into the ground.

But they don't do their job if the runoff never gets into them, if they overflow before the water sinks in, or if their bottoms are impervious. I'll address the first two issues here.

Many large rain gardens--for example, those taking runoff from parking areas--aren't graded properly. The runoff never gets into them. Obviously, no one is checking to see if they really work. I'll give three examples from parking lots.

Metcalfe's Sentry

In this large lot, there are 3-4 long islands between rows of parking, which are supposed to receive runoff from the gutters through gaps in the curb.

These gardens fail because the basins aren't much lower than the gutter. No water flows in.

And, there is nothing to deflect the swift flow in the gutter towards the garden.

Madison Gas & Electric visitor's parking

At this lot, we have--at the center of the lot--a filtration chamber. It was designed to filter the toxic stuff dripping from vehicles, before the runoff gets to nearby Lake Monona. The filtration was a cooperative project by MG&E, DNR, and other agencies to see how efficient filtration could be.

The filters reside in an underground concrete bunker--the setup cost $50,000. It basically does the job a larger rain garden could do.

While this wasn't a rain garden, they did measure how effective the parking area was at gathering water and feeding it to the filters. Since the parking area wasn't graded to be an effective catchment basin, it sent 30% of the water to surrounding streets. Only 70% of the water falling on the pavement actually went to the filters.

The area within the red line drained to the filters. The area between the red and yellow lines drained to the street--wasted.

So a rain garden (or filtration system) is no more effective than the grading and inlets to the garden. If the grading isn't carefully done, you've wasted a lot of money.

Terrace rain gardens on Eaton Ridge

These were among the first rain gardens on terraces, built by the City.

Rain garden inlets on Eaton Ridge were too small, and quickly became clogged.

Terrace gardens built by the City on Adams St had better entrances.

Sequoya Commons

This is a beautiful rain garden, with a large capacity. For the most part, it is well-graded. Nevertheless, a small portion of the north end of the parking area drains to the street, via the entrance to the lot.

My real purpose for mentioning Sequoya is that you can see this garden does reject some water. I saw if overflow once in a heavy storm.

On another occasion, when the garden was full of water, a steady stream of clear water seeped from the garden into the storm sewer. While this escaping water didn't get into the ground, at least it was clean and free from sediment.

The bottom line

Before you build a garden, always watch where the rain goes during a storm.

Test the grade by pouring water on the pavement.

Don't pay the contractor till you see if the garden actually works.

If necessary, build a berm of earth or asphalt to correct the flow.

Rain gardens in New Zealand

2011-10-07T21:48:00.000-07:00

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New Zealand is an island country with keen environmental awareness. Perhaps that's because they experienced some environmental disasters after colonization by Europeans.

Sheep and deer overran and denuded the country. Erosion followed. Species disappeared at an alarming rate.

So it's not surprising that their capital city--Aukland--has some interesting rain gardens. Recently, I found the following photos on the internet.

The photos are mostly rain gardens for streets and sidewalks. If we're going to improve the lakes, we have to start dealing with street runoff in a big way! (Click on photos to enlarge.)

"This rain garden on sloping ground adjacent to a public road has deep baffles to ensure water ponds evenly and to prevent erosion and a wide concrete apron next to the road. People are separated from the relatively large vertical drop by a fence."

"Rain gardens treating road runoff in Hamilton and North Shore. The rain gardens are planted with native flaxes, rushes and sedges. The rain garden on the left has a fine gravel mulch; the rain garden on the right has organic mulches in planted areas and large stones around the overflow and around the inlet to protect them from erosion."

The Waitakere Civic Centre."Rain gardens usually have a dense perennial ground cover."

See the frequently asked questions from the New Zealand site here. They cover some interesting points I haven't seen mentioned in Wisconsin. For example, good rain garden plants are those that typically grow at the borders of temporary wetlands.

Rain gardens bring countries together

2011-06-21T13:46:00.000-07:00

Rain garden, corner of Struck St. and Watts Rd.

Recently, I passed one of my favorite rain gardens on the way to Woodman's. It's a large garden draining a parking lot, at the corner of Struck St. and Watts Rd. I saw a group of people working on the garden, and decided to stop and find out about the garden.

They were an extended family of five Mexicans, who only spoke Spanish--so I can't provide many details.

Head of the group was Romeo (right), from the state of Chiapas, next to the border with Guatemala. He has a business working in gardens--they were removing weeds. He was assisted by three women--two of them sisters. They came from the state of Veracruz, on the Gulf coast.

The women (Elsa, Guadalupe, and Ana) said they had been in the US only a short while.

Americans go to Mexico for vacation, or sometimes to study--medical school, for example. Mexicans come here to work or on cultural exchanges. Since NAFTA, I'm amazed at how integrated we've become on this continent.

For example, when I was in Cabo San Lucas two winters ago, I talked to a number of Mexicans on the street. Many knew where Wisconsin is--and some even knew about Madison. One had been to Milwaukee.

Do you know where Chiapas is?

How many states are there in Mexico?

Her name is Eowyn.

City requests proposals for planting in existing rain gardens

2011-06-13T20:18:00.000-07:00

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On June 14, bids are due on a project to plant and maintain rain gardens in Madison. Some of the gardens have already been constructed, while others are in the process of construction. Glenn Clark is the project manager. Work will start about June 21 and end about Sept. 20.

Existing gardens to be planted
Starkweather Creek rain garden
Marston Ave. rain gardens 1-5
Bernie's Beach bio-retention basin
Allied Drive bio-retention basin
Prairie planting at Beld St. and Wingra Dr.
Kipp rain garden
Westmorland Park rain garden
Vilas Park bike path
Vilas Beach

Newly constructed rain gardens to be planted
609 Gilmore St
2114 E. Mifflin St.
2106 E. Mifflin St.
Ivy Street rain gardens A and B
1000 Edgewood Ave.

The RFP calls for purchase of 4,896 plants, so you can see that "green infrastructure" is fast becoming part of our economy--a source of jobs.

# # #

See the RFP here. There is a map of the garden locations on p.55, and species lists on p. 45.

From snowbank to sea

2011-05-24T22:50:00.000-07:00

Reprinted from my "Save Our Stream" blog.

One warm day in March, years ago, my son Chris and I were walking in Forest Hills cemetery. Everywhere, snow banks were melting into rivulets, coursing down the asphalt.

Chris asked: "Daddy--Where does the water go?"

As I explained about the water running into the sewer, then into the lake, then into the Mississippi River, suddenly a thought struck: "Why not actually show him where it goes? Why not?"

So on spring vacation a few weeks later, we set out, planning to take the small highways always along the rivers, till we reached the Gulf of Mexico. We stopped here and there. In southern Illinois, Chris learned "there's no such thing as clean coal."

Abandoned strip mine for coal in southern Illinois.

Chris makes a new friend in the rain.

We visited a ghost town along the Mississippi, a place that had been abandoned when the river changed course and left a river town high and dry. I was amazed to run into some Wisconsin beekeepers there--this was the winter home for their bees.

On a lonely road along the Mississippi flood plain, we found a box turtle crossing the road.

Chris admonished the turtle as he helped it to the side of the road: "Don't you know you could get hurt?"

Finally, we reached New Orleans, where Chris sat in a park, munching an apple.

Actually reaching the Gulf of Mexico proved a bit more of a challenge than I had imagined. Because if you try to drive along the river, the road ends miles before you reach the Gulf. We tried to hitch a ride on a mail boat headed to Pilot Town, beyond the road. But they were full. Later, I was able to hitch a ride on a private plane, that flew out an over the last spot of marshy land.

On our way back, we didn't feel obliged to follow the river, so we stopped at the Natchez Trace National Park.

A "living history" volunteer offers Chris a wild strawberry at the Natchez Trace.

I'm not sure who learned more--Chris or myself. But it was a good chance for bonding, both father and son, and people with the landscape. It was one chapter in my growing appreciation for our natural waterways.

Having seen the unbroken lifeline of waterways, from snow bank to the Gulf, it's not so strange to start thinking about the "chain" of runoff. I'm talking about each step in the journey of a water drop, from where it falls on your roof, to... wherever it goes.

Your rain garden is one of the first steps in that chain, and one of the most interesting. It's an opportunity for children.

How to build a large rain garden on your terrace

2011-05-23T21:54:00.000-07:00

Building this garden doesn't have to cost anything. Once established, little maintenance is required. The basic idea is to dig out the terrace, to below the sidewalk level.

The garden shown above was built by botany professor Bob Kowal at 537 Gately Terrace. I described it in a previous post.

Before you begin, there are two important issues to think about:

Find a source of native plants

There are sales about Madison in the spring. Or, you can beg plants from neighbors. If they have a garden of native plants, there's a good chance they have extras.

Native plants require less maintenance, and are very attractive. Pick plants appropriate for your conditions--sun or shade. Link to plant lists.

Unless your sidewalk is on a hill, you probably won't get a lot of water in the garden--so you don't have to worry about finding wetland plants.

Some native woodland plants like sweet woodruff spread rapidly. You can plant these first, and let them fill out the terrace. Later, as you get other plants free from your friends, you can add them.

Find a place for the soil you remove.

It's going to be a lot of soil! For my first garden, I separated the soil from the roots, which was a lot of work. Then I was able to spread the loose soil on my front lawn, rake it smooth, and seed it.

For my second terrace garden, I advertised on Craig's List--"Clean fill offered." Within an hour, someone responded, then parked a trailer next to my future rain garden. Not having to move the soil, or separate it from the turf saved much time and work.

I've also used soil removed from rain gardens to make little dams about my yard, or to fill in gullies in the neighborhood.

Why dig out the soil?

With the garden below the sidewalk, rain flows from the sidewalk to the garden. Your garden gets extra water, so it's more luxuriant.

But another important reason is to allow plenty of room for leaves to accumulate. Never rake your terrace again! The leaves smother most weeds. Gradually, the soil will become very rich as the terrace fills with composting leaves.

Digging all the soil from sidewalk to curb makes an attractive garden. However, you may want to bevel the edge on the sidewalk side, for added safety. (But no one has sued Bob during the last 15 years!)

To be on the safe side, call diggers hotline. My garden is over the gas line, but I didn't get deep enough to hit the pipe.

When you finish digging, enrich the soil

The "Catch 22" of this job is that you've removed the top foot of good soil. There's a good chance that what's left is gravel or clay. So, you have to enrich the soil enough to get your plants started.

Add compost if you have it. I added coffee grounds from the neighborhood coffee shop (now in short supply). Bob Kowal added bales of oak leaves he bought at Forest Lawn Cemetery. Or, you can dig deeper, then add back some of the best soil you removed.

Planting

Put the plants in clumps of the same kind, with plenty of room between each plant (about 18", because they will grow). Put the taller plants towards the center of the terrace.

Finish by mulching, to stop the weeds and keep in the moisture. Grass clippings make good mulch. Bark isn't a good idea of your garden will overflow, because bark will float away. Water until your plants become established.

Maintenance

For the first few years, keep enriching the soil. If some plants don't thrive, replace them with others. Be sure you remove maple seedlings, before they become too large to pull easily. Watering is needed only during drought times.

Future site of terrace rain garden. Pour water to make sure sidewalk tilts toward garden.

Spreading the removed soil on the lawn nearby.

Rain garden in winter, ready to absorb spring meltwater.

Next spring--rain garden on May 12. Not bad for the first year.

Medium-sized terrace garden. Doesn't look as good, but there's less soil to move. Bevel the edges.

Slide show of flowers in the garden here.

How to build a small rain garden on your terrace

2011-05-23T21:00:00.000-07:00

How to create an easy rain garden on your terrace--one that drains puddles !

1. Pour some water to make sure it will flow to your garden. Sidewalks usually tilt towards the street, but not always.

2. Dig out a series of deep squares about 8 inches from the sidewalk, to make a trench 8" or a foot deep.

3. Using a sharp shovel, bevel the edges of the trench you made. The shallow bevel on the sidewalk side will make it safer for pedestrians.

4. Enrich the soil with compost--especially if you dug down to gravel or clay. You can also enrich with grass clippings, leaf litter, or coffee grounds.

5. Add native plants for your condition--sun or shade. Suggestions here. Don't plant them too close--they will grow!

6. Add some mulch around the plants to prevent weeds and keep them moist. (Bark mulch may float away! Grass clippings make good mulch.)

Water until they become established. Don't rake in the fall--let leaves accumulate to enrich the garden.

What to do with the soil you removed?

Use the blocks of turf you removed to create little dams elsewhere in your yard. These pools can become additional rain gardens.
If you separate the soil from the roots, you can scatter the soil on your lawn or garden.
Fill an eroding gully in your neighborhood. Make sure the soil is stabilized with vegetation.

Terrace rain gardens catch sidewalk runoff

2011-05-23T20:24:00.000-07:00

On May 11, a hailstorm knocked maple flowers onto the pavement. Rivulets traced patterns in the yellow flowers, showing where the runoff goes. It's clear that most sidewalk runoff flows into the street, where it's flushed quickly by sewers to the lakes.

In my neighborhood--built in the 1950s--the turf bulges above the sidewalk. So runoff is channeled along the sidewalk until the next driveway, where if usually escapes to the street.

In some level areas, the water just puddles on the sidewalk. In the winter, these puddles can freeze, creating a hazard. In the photo above, you can see where puddles are forming on the left.

If you dig out the turf next to the puddles, you can create a lovely rain garden--one that also drains the puddles. The garden will be lush, because it gets an extra dose of water.

This long slope channels a lot of runoff to the street.

This driveway channels runoff from the downspout to the street.

Rain gardens on the terrace, on either side of the drive, would catch runoff from the sidewalk, drive, and roof.

Terrace rain garden in action--taking water from the sidewalk.

The bottom line

Rain gardens on the terrace can help replenish groundwater, beautify neighborhoods, and eliminate annoying sidewalk puddles.

Trillium spectacle west of Madison !

2011-05-21T12:34:00.000-07:00

About 5 miles SW of Cross Plains, there's an amazing spectacle of wild trillium flowers in the woods. It's located on the south side of Moen Valley Rd. Map. I've never seen so many trillium in my life!

The flowers are visible from the road, for several miles.

A few miles further from Madison, you can visit a lovely restored oak savanna and prairie at the Pleasant Valley Conservancy.

Pleasant Valley Conservancy--View from top of the ridge.

Directions to the Conservancy.

How I became a woodland gardener

2011-05-20T22:17:00.000-07:00

If you have lots of shade, and no money for plants--

here's an easy method.

I used to have a traditional yard--almost entirely grass, with shrubs around the edges.

Along the side, between my house and the next, it was very shady. Grass would hardly grow there, but the weeds did. I’d mow it twice in the summer to lop off the scraggly weeds. The mower would kick up clouds of dust--I’d have to hold my breath. In the fall, I raked leaves--creating more clouds of dust.

My yard (right) used to be as barren as the left side of the fence.

Every springtime, I noticed lots of violets had colonized since mowing last fall. They were pretty--it seemed a shame to mow down all those pretty flowers. Gradually it dawned on me--maybe the violets were better than dust and weeds, mowing and raking.

So I stopped mowing between the houses. It was a big step--I had been trained all my life to mow. It’s what men did in the yard.

But nothing bad happened--lightning didn’t strike me dead. Violets flourished, growing thicker and more luxuriant. I had clumps of several kinds--white, blue, and purple.

Still, things weren’t perfect. After the violets finished blooming, weeds tried to crowd in. Tall, scraggly dandelions, and three other green opportunists. So I pulled the obvious weeds, once or twice in the summer. In the fall, I let the fallen leaves remain.

Next year, the violets were even more luxuriant. The soil was getting richer! It wasn’t blowing away as dust, and the fallen leaves were turning into compost.

A fence divided the narrow strip between the two houses. My neighbors’s side remained a desert. But my side was becoming steadily greener and more interesting.

A friend with a large garden of woodland plants offered me plants she was culling. She had species that would spread, and had to be periodically thinned out.

As I snapped them up, she shared a few principles of design:

Put the plants in clumps of three to five (single plants in a row look unnatural).
Put the taller plants near the center of a grouping, or to the rear.
Don’t put the plants too close together--they will grow.
Make little access pathways through the garden, so you avoid compacting the soil.
Don’t worry--you can always move plants later if you don’t like where they are.

I’m a spontaneous guy, so when plants were available, I’d just throw them into the ground, without thinking too much about where. I did use her design principles--somewhat--though I didn’t have a plan on paper.

I was amazed--most of the plants took hold and thrived. Gradually, I stopped mowing more shady spots in my back yard. First, they’d go to violets. Then, as hand-me-down plants became available, I’d pull up the violets, and plant natives. But I liked violets too, so I left some clumps.

Volunteer plants add variety

One spring day, before the grass started growing, I noticed a strange, brownish spike growing in my front lawn. A “volunteer.” Not knowing what it was, I transplanted it into my garden. It turned out to be a lovely, mottled trillium. The next year, a jack-in-the-pulpit volunteered. Again, I moved it.

Now that I’m five years into my love affair with native plants, things are really taking off. All those plants are spreading, so I have my own “extras” to colonize new areas, such as my terrace.

Terraces are good for gardens, because if you remove soil to below the sidewalk, the garden will take runoff from the pavement--ensuring luxurient growth. Select spots where the pavement tilts towards your garden.

Getting rid of grass

If you want to create a woodland garden in one year, existing grass is a problem. One way is to lay down newspaper in early spring, and put dirt or leaves on top--to kill the grass.

But with gradual conversion, the grass simply melts away. The natives and accumulating leaves crowd out the grass. I remove any that remains when I weed twice a year.

The garden designs itself

During my first weeding in May, I look to see which plants are vigorous. I have several species which are rather aggressive--so I trim them back, giving their shyer neighbors more room. Then I move a few plants around, maybe adding a few plants to a thin clump, till things look right. I weed out the dandelions and creeping Charlie.

I look for seedlings that became established last fall--such as trillium or jack-in-the-pulpit. For me, these are in short supply, since I never received “extras” of these. Then I transplant them to clumps that need “beefing up,” or into new areas of lawn that I am transforming. As I find these little “volunteers,” I mark them with a little flag, till I have time to transplant them.

During April, you wonder if anything is going to come up. Gradually, little green shoots show their heads. Just as you are despairing whether anything made it through the winter, suddenly... little green heads and spikes are popping up all over. Over the next few weeks, your garden is transformed from barren to blooming. It's magical!

May is the best tine of year in my woodland garden. Many species are coming into flower, one after another. It’s fascinating to wander down the paths and take stock--see who’s doing what. How the children grow! Each year, the jack-in-the-pulpit sends up new shoots near the parent plant.

Yards have odd corners that are perfect for woodland gardens.

Most essential--enriching your soil

My house was built in the 1950s on clay. Topsoil under the grass is thin. When you rake the lawn every fall, you are removing most of the organic material that normally would enrich the soil. So it’s essential that you don’t rake your woodland garden!!

Even though I started with poor soil, my woodland garden is a success.

For best results, you need to do more than not raking to enrich the soil. My neighbor Bob Kowal, a retired botany professor, actually brought in bales of oak leaves he got from the cemetery. Since I have about 50% lawn now, I use my grass clippings as mulch, and I compost weeds and the leaves I rake.

Some woodland gardeners use free wood chips provided by the City. These make nice pathways. Or, you can use them as mulch around groups of plants. After about 5 years, the chips break down to enrich the soil.

Rich soil and mulch help to retain moisture.

Essentials--enough water

A natural forest is like a giant sponge--soaking up and holding onto all the rain that falls. The urban forest doesn’t retain as much water, so you’ll have to supply extra during dry periods. Some years I have to water frequently--other years, hardly at all.

The two best ways to water are to use soaker hoses, and direct your downspouts to your woodland gardens. You can hook up rain barrels to your soaker hoses.

Pour a gallon of water to observe which way your driveway and sidewalk tilts--then build gardens where they will receive extra runoff from the pavement. Don’t let any water escape from your property without using it!

Essentials--weeding

You will need to weed 2-3 times a year. Mulching helps keep the weeds in check. You have to keep on top of the creeping Charlie--weed Charlie in May, when you can see the purple flowers.

For the most part, native plants can compete with weeds. But your conditions may not be perfect, and some of the weeds, like garlic mustard, are very invasive. And your neighbors are busy exporting weed seeds, like dandelions.

Woodland garden VS lawn The woodland garden is...

Far more interesting than a lawn, and more beautiful.
It attracts wildlife, replenishes groundwater, and promotes health of the lakes.
You don’t have to rake or spend money on gas, fertilizer, weedkiller, or lawnmower repairs.

Is it more work?

If you count the planting--yes, it is more work.

But once the garden is established, it’s somewhat less work than a lawn. All you have to do is weed, mulch, and perhaps water.

What about mosquitoes? I don’t notice any difference. Mosquitoes aren’t produced in the woods. For breeding they require standing water--such as roof gutters or an old tire someone tossed into the bushes.

A source for plants--your biggest challenge

If you have shade, your next step is to find a supply of woodland plants. There are sales about town.

But more and more people are starting woodland gardens. So chances are, there’s someone in your neighborhood who has extra plants to share. A vigorous garden produces lots of seedlings. Ask your neighbor if you can have some of these tiny plants.

Since I started my garden, I haven’t paid a dime for plants. All it cost was about $50 for soaker hoses.
Now that I’ve got all those native plants with quirky personalities--I’m starting to find out about them. Wild ginger is really amazing--but that’s another story.

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Equipment needed
Shovel
Trowel
Weeder
2 small bins for holding/transporting soil, weeds, or mulch.
Two plastic garbage cans with lids for holding soil, weeds. (Use lids to shovel soil onto when transplanting plants.)
Four (or more) 50’soaker hoses
Hose to get water from spigot to soaker hose.
Four way junction to split water to four soaker hoses.
Wire staples, to hold down soaker hoses
Plastic water can
Downspout extenders (or PVC flexible drain pipe)

At least two composters. Several inexpensive plastic ones are made.
If your yard is fenced, you can use a short segment of chicken wire fencing to close off a corner of your fence, turning it into a triangular container about 6-8 feet on a side.

Shade-tolerant plants in my garden

Trillium (two species)
Jack-in-the-pulpit
Wild ginger
Wild geranium
Jacob's ladder
Sweet woodruff
Celandine poppy
False forget-me-not
Solomon seal
May apple
Ostritch fern
Pulmonaria
Snake root
Merry bells
Virginia bluebell
Bleeding heart (not native)
Windflower (not native)
Lamium (not native)

Lake Mendota garden designed by Richard Fayram

2011-05-07T07:07:00.000-07:00

Doug and Sherry Caves built two large rain gardens at their new house on Lake Mendota. It's located at 2317 Middleton Beach Rd.

The gardens were designed by Richard Fayram--part of the entire landscaping when the Caves' new house was completed. It sits on low-lying land, formerly a wetland bordering the lake. Click on photos to enlarge.

The first garden is in the front, between the house and the street. It takes runoff from the garage, and a small portion of lawn to the left. Because the soil was compacted during construction, this one drains very slowly. I saw two mourning doves use it for a bath, and the frogs like it.

Same garden, seen from the house.

There's a second and much larger rain garden in the front yard. This one receives rain from the roof of the house, much of the yard, and even some from the street. Sedges are visible on the left. Marsh marigold is blooming.

This one drains much faster, because it's close to the lake. If it overfills, water empties via a small spillway here (the gravel on the left).

This garden is beautifully sculpted and graded. When very full, water extends onto the front lawn, into the foreground.

Water comes from the street and front yard via PVC pipe. It descends over several silt socks towards the main body of the garden.

View from the lakeshore towards the house.

The Caves were not required by any DNR regulation to build the garden. They simply built the garden out of concern for health of the Lake, and enjoyment of native plants.

Fayram said: "The design reflects my usual strategy of integrating rain gardens into the overall landscape design, and grading as a design feature rather then just adding them to a yard.

One design feature here is a stone base under the building overhangs and decks. This helps deal with roof runoff directly on a site that has a lot of water moving through it."

# # #

View a slide show of all the photos here.

Groundwater--unseen beneath our feet

2011-05-02T23:06:00.000-07:00

About groundwater, its biology, and the springs about Lake Wingra.

Recently, I opened the beautiful booklet put together by the Friends of Lake Wingra, about that lake. There were some colorful maps showing the watershed of Lake Wingra. I was fascinated to notice that the watershed for the surface runoff is a little different from the watershed for the groundwater.

The water from rain gardens in much of Sunset Village trickles to Lake Wingra. But the surface runoff from only a corner of Sunset Village drains to Lake Wingra. Instead, most of the surface runoff goes to Lake Mendota. So your rain garden helps two lakes--it keeps dirty runoff out of Mendota, and replenishes springs that feed Wingra.

"Wingra's springs are a precious natural feature that can be viewed and enjoyed by the entire community. Cool, clear water bubbling up from the ground enchants youngsters and instills a sense of wonder for the natural world. On a hot summer day, a few minutes rest beside a cool spring can calm and rejuvenate us.

Spring water entering the lake year-round improves water quality and provides a unique habitat for many plants and animals. In winter, wildfowl flock to the open water and animals come to drink.

Groundwater makes up about a third of Lake Wingra's source-water," and helps keep Wingra Creek flowing.*

But because urbanization causes water to run into storm sewers rather than sinking into the ground, the flow of springs around Lake Wingra has declined. The map below shows the location of active springs that ring the lake.

The red dots show locations of active springs.

Because groundwater is the same cool temperature year-round, the air around the springs is delightfully cool in summer, while in deepest winter, the spring sustains a patch of green.

Big Spring, on the south shore, is so large it forms a creek you can navigate in a canoe. If you go there early on a summer morning with a picnic breakfast, the mist hangs over the creek. As you enter the mouth of the creek, it's as if you are stepping into a cooler.

In winter, the beaver like to swim in the water of the creek that always remains open. They will emerge and travel on the ice along the shore of Lake Wingra, alternately running and then tobogganing on their bellies.

The unseen world

While these springs are spectacular for themselves, they are more--the only visible evidence of the unseen biosphere beneath our feet. It's a paradox--we stand on solid ground, and yet it's the surface of an ocean as well.

The trickling, percolating waters down there are alive. Coating the surface of every grain of sand and gravel is a film of bacteria that purifies the contaminants urban stormwater. Probably most of the top mile of rock that girds this planet is actually alive with bacteria. Some of them metabolize so slowly they would seem to be in suspended animation. Individual bacteria could be thousands of years old--and maybe much older.

The only other evidence is the water that comes from your tap, pumped by the city from the same mysterious world beneath our feet. It's a commons--a resource for all. Nurture your commons.

Spring on the NW shore near Arbor Drive.

Click on photos to enlarge them. Or see slide show here.

Spring just S of the one above--it's twin.

The green is mostly watercress. Peppery flavor, makes good soup!

Spring just S of Big Spring

Big Spring, seen from the trail in Gallistel Woods

Click here to take a photographic tour of the springs and their surroundings. All photos 12/15/09 by David Thompson.

* Lake Wingra: a vision for the future. By Friends of Lake Wingra, 2009. You can download a copy of the document here.

Rain garden poster

2011-05-02T23:00:00.000-07:00

Click on the image to enlarge. You can order the poster here. Purchase one and donate it to your school or library, to help spread the word.

Critters--"under the hood" of your rain garden

2011-04-14T14:20:00.000-07:00

If you are reading this blog, you probably know the advantages of rain gardens:

Absorb the runoff from your roof, sidewalk, or street.
Filter dirty runoff from pavement.
Recharge the soil and the groundwater. The soil acts like a giant sponge to store and slowly recharge our lakes and streams.

A filter just traps things; in the case of storm water, we're talking about sediment and pollutants. But rain gardens and the soil below them are much more than filters. So let's peep below your garden, to see what's going on.

The soil harbors millions of organisms per cubic inch. Not only bacteria, but fungi, larger microbes like amoebas, and multicellular critters--like earthworms, insects, millipedes, centipedes, mites, spiders, and all kinds of creepy-crawlies. No doubt you're familiar with these larger inhabitants of the soil--the ones you can see.

But in the size range smaller than visible, yet much bigger than the microbes, is a whole world of animals. Legions of wiggling things, rooting between the tiny grains of soil. All these, from the worms to the microbes, are eating, breaking down, and metabolizing the pollutants that sink into your rain garden. If one critter won't eat that oil from the street, or that antifreeze, the next one will.

At great cost to taxpayers, the sewage plant tries to recreate what's going on in the rain garden, in order to digest your sewage. But your rain garden does it without a pipe, does it locally, and for no cost.

In a rain storm, when pollutants wash off our streets and down the storm sewer, they head straight to the lakes. Once there, bacteria and algae try to break them down. But it's harder to do in the lakes. There isn't as much oxygen, and there aren't as many critters as in your rain garden . So the lakes start to stink, and who wants to swim where pollutants are being digested? Better to let your rain garden do it.

It used to be that most of our water pollution came from big pipes--sewage plants or factories discharging into our lakes and streams. Once we cleaned those pipes up, it came as a surprise that our waterways were still going downhill. The culprit turned out to be "nonpoint source pollution." This is shorthand for pollution from a myriad of tiny sources-- your dog... your auto... your lawn. Most of these tiny sources are spilling onto pavement, and rain gardens can trap and purify those pollutants.

There are a myriad of sources of pollution, so we need a myriad of rain gardens. Sure, you can pick up after your dog, and use less fertilizer. All excellent ideas. But the rain garden is the final trap for the nasty little things that slip by our defenses.

All those ravenous little monsters in your rain garden are just waiting for their next meal.

Rain garden critters 2--How do they survive between rains?

2011-04-14T14:14:00.001-07:00

If you were to examine a little wet soil from your rain garden, and put a drop on a microscope slide, you'd probably see a lot of rotifers. Barely bigger than amoebas, they still consist of many cells.

Rotifers... Males are "degenerate*"--how cool is that?

art by Elizabeth Buchsbaum

They vary in shape from ones attached to the bottom that look like flowers, to fat forms that float near the surface. But all have what looks like a rotating wheel for a mouth.

What's interesting is how these aquatic creatures survive the dry spells between rains...

"Some rotifers can withstand drying" better than most microscopic critters. "In this almost completely dried state they may live for years. As soon as moisture appears, they swim about and feed actively. Because of this capacity to resist drought, rotifers can live in places that are only termporarily wet, such as roof gutters, cemetery urns, rock crevices, among moss, and" in rain gardens.

"When the water evaporates, the animal contracts to a minimum volume and loses most of its water content. Somtimes the animal itself dies but its contained eggs survive until moisture returns."

So, whether it's wet or dry, they are always ready to help break down the pollutants that wash into your garden.

* Degenerate means smaller and more simplified. Why am I reminded of Homer Simpson?

Quotes from Animals Without Backbones, by Ralph Buchsbaum, 1948.

Rotifers try "abstinence only"--for 30 million years

2011-04-14T14:03:00.001-07:00

Our aim is to bring you the latest news--to help you appreciate our lakes and streams. And what's more engaging than a rotifer? Rotifers live in temporary pools of water, like your bird bath or rain garden.

Rotifers are tiny multicellular animals that live in pools of water. For one kind of rotifer, no males have ever been found.

Photos with permission by Aydın Örstan.

Talk about a dry spell!

One kind of rotifer, the Bdelloid rotifers, haven't had sex for 30 million years. For three centuries since their discovery, no one has seen any eggs or male rotifers. Just females. Ouch!

This had scientists scratching their heads, since theory argues that sex has many advantages. It's supposed to help rabbits keep one step ahead of the foxes, in the evolutionary arms race. Giving up sex is thought to be an evolutionary dead end--less than 1% of animal species reproduce without sex.

So what gives with the rotifers? How have they turned "no sex" into a good deal?

Rotifers do have one mortal enemy--it's a tiny fungus. If rotifers ingest fungal spores, the spores catch in their throats, sprout, and digest the rotifer from the inside out. If spores of the fungus are present in your bird bath, it won't be long before all the rotifers are dead.

And rotifers can't use sex to jazz up their biological defenses against the fungus. Now scientists at Cornell have discovered that the rotifers escape from the deadly fungus--by a kind of "hide and seek" strategy.

Dry up and blow away

It turns out that rotifers are one of the few kinds of animal that can survive completely drying out--and they can do this at any stage in their life cycle. When your rain garden dries up, the rotifers turn to dust, and are blown about from place to place. They can survive for as long as 9 years as dust. Then, add a drop of water, or a film of moisture on some moss, and they come back to life within an hour!

The fungus can also survive drying, but not for so long. And they don't blow about so readily. So when the rotifer lands in another damp spot, the chances are--there won't be any fungus there. The rotifers take a long drink, plump up, and go about their business, filtering tiny particles of food out of the water. But whatever their business is, it isn't... sex.

Reported in Science, 29 January 2010, p. 574-6

More on rotifers--Aydın Örstan's wonderful blog on invertebrate animals.

Wikipedia article.

My previous post on rotifers.

Terrace rain gardens you can do yourself

2011-04-14T13:52:00.001-07:00

Terraces--the space between the sidewalk and the street--are the wild west of city infrastructure. The wide-open spaces. They are a resource right under our noses, ignored by most.

Owned by the city, but within the personal space of homeowners, they are a delicate issue. The city treads softly here. But tread it must, for the good of the community.

My neighbor Bob Kowal, 537 Gately Terrace, has developed a novel kind of rain garden on his terrace. Bob is a retired professor at the UW Botany Department.

If you look at his terrace garden, you wouldn't notice anything unusual, except that it's extremely luxuriant. And it fills the entire terrace, from driveway to driveway.

But the secret of this particular design is it's depth. Before planting, he removed the sod and earth to a depth of 12-18 inches below sidewalk level. Depth allows two important things:

Runoff from the sidewalk can flow unimpeded into the garden. This increases water available to the plants by about 50%.
In the fall, leaves can be left to compost in the garden. Over the years, these decomposing leaves enrich the soil, without bringing the surface above the sidewalk.

Next, Bob mixed the remaining soil with coffee grounds recycled from a nearby coffee house. Finally, he planted mostly native plants, plus a few exotics which require no maintenance. The only maintenance required is a little weeding, especially of maple seedlings.

This supercharged rain garden runs on caffein.

Soon, I'll give detailed instructions how to construct a terrace garden. Remember, removing the soil is absolutely essential--and, it's a LOT of work.

Battle of the Bulge

Here's the reason why removing soil is so important: Over the years, the soil in the terrace begins to bulge upward as tree and grass roots expand. This bulge prevents water from leaving the sidewalk, so instead it often flows to the driveway, then onto the street. The groundwater isn't recharged. Icy patches form on the sidewalk in winter.

Likewise, the bulgeing terrace creates a slope to the street, shedding water and eroded soil onto the street. The terrace becomes a desert island, surrounded by pavement. Terraces are often neglected--but instead, these overlooked spots can become a beautiful oasis, and improve the health of our lakes.

Neglected: There's an eroding, weedy terrace on every block.

Sometimes better than the City's design

Near West High School, the city has built a number of experimental rain gardens on the terraces, in cooperation with residents. These gardens take runoff from the streets, an excellent idea. But these gardens don't fill the entire terrace, and aren't as deep. Probably the soil wasn't improved as thoroughly. The entrances for most of these rain gardens have become clogged.

Terrace rain gardens can start to expand the rain garden movement beyond just serving downspouts at homes. They can handle runoff from sidewalks now, and with some improvements, streets as well.

I'm especially enthusiastic about the Adams Street rain garden project, where nine terrace gardens were planted with community involvement. Many of these gardens take runoff from the street.

Compelling advangtages of terrace rain gardens

Beautiful garden, separates your yard from the street
Nearly maintenance free
Infiltrates sidewalk runoff, improves the watershed
Recycles leaves, coffeehouse waste, and street sweepings--like buds & seeds in the spring
Prevents icy puddles in winter on sidewalk
No need to periodically "edge" the grass along your sidewalk
No need to rake, mow, fertilize, or water your terrace grass
Prevents soil erosion from sloped terraces into gutter
Flexible--you can expand the size as you have time.
Better than downspout garden in your front yard--Direct your downspout here, save yard space
May save money on your water bill (I'm checking on this)

Disadvantages

Removing the soil is a lot of work, and you need some place to put removed soil. If the city had a progarm for removing the soil, for free, terrace rain gardens could really take off.
Cost of the plants (I get all mine free as throwaways from neighbors)
Sidewalk must slope toward terrace, at least in some places.

Questions and answers

Why do so many rain gardens look "anemic," with few, small, unhealthy plants?

Remember, most rain gardens are new. They will improve with age, if maintained. Secondly, when you make a rain garden, you dig down into poorer soil. So it's very important to improve the soil at first, and to keep the fall leaves in the garden.

Can't I just pile mulch or compost on my terrace grass, then plant some native plants? That's easier than digging out the soil.

Yes, many people do that. But this causes the garden surface to hump even more above the sidewalk. Rain will run into the sidewalk, depriving your garden of much moisture. You'll lose other advantages as well.

Isn't the City's plan for rain gardens better, since it takes water from the street, and I can cost-share with the city?

It all depends on local conditions, and how the water flows. You have to observe that. If the slope is right to take a good flow from the street, then the City's design may be best. If your sidewalk slopes away from your terrace, again the City's design may be best. But the City design is going to cost you, and you can do Bob Kowal's design for free (plus sweat).

My street was reconstructed, and now the terraces are low enough to take rain from my sidewalk. So, do I really need to do anything?

No, you are set! The reconstruction has fixed the main problem--that bulge on the terrace. Your terrace will still absorb rain. But now it's easier to plant a garden, since you don't have to dig out the soil as much. A garden with native plants will require less maintenance than grass.

Won't the City object if I put a garden on the terrace?

I'm checking on this. Technically, the City has to approve what you do with the terrace. But hundreds of people are planting their terraces--even with vegetables--and no one has been thrown in jail. Be sure to call the Diggers Hotline before you dig!

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Related article on Guerrilla Gardening here.

A rain garden street for our neighborhood?

2011-04-14T13:50:00.000-07:00

A guest article by Elizabeth McBride

Gardener extrordinaire

I used to think of a rain garden as a trendy “green” gesture, something you could pat yourself on the back for having but not all that effective in the scheme of things. Today my thinking changed.

I attended a class on rain gardens at the UW Arboretum taught by landscape architect Molly Fifield Murray, the Arb’s education director. She showed us the numbers for Dane County: When you subtract the water we lose through storm runoff, evapotranspiration, and groundwater pumping from the amount of rain we receive, we’re left with a deficit. That means the city has to dig deeper and deeper wells at greater and greater cost to keep us hydrated. It also means springs and streams are drying up, which we homeowners may not notice but is apparent in the Arboretum, where a number of springs have been lost.

Hearing this, I realized that the space I inhabit—my house, my driveway, my walkway—is an impermeable barrier that upsets the natural water cycle. Creating a rain garden is not a frill—it’s my responsibility. It’s part of what I owe for the privilege of occupying this piece of the planet.

The other thing I learned from Molly is that rain gardens are not that hard to make. Another landscape architect had discouraged me from attempting the job myself. I needed a specialist—him! Not so. Sure there’s some digging involved and a few calculations to do to ensure the garden is sufficiently large so that run-off from the gutter doesn’t form a standing pool. But it doesn’t seem very complicated.

I picked up a how-to manual from the Arboretum bookstore, and I’ll investigate the city’s program, which offers a rain garden workshop, as well as plants at a reduced price. This spring, I’ll visit Adam Street in the Vilas neighborhood, which was the state’s first “rain garden street.” Wouldn’t it be great if our neighborhood had a rain garden street, too?