2/25/10

Vaccinating our city against watershed disease

Vaccination is the most successful and cost-effective method of preventing infectious disease.  But the process was slow to spread after it was successfully tested by Edward Jenner in 1796, because it's a little painful, and the reason why it works isn't obvious to the average citizen. 

Vaccination works by stimulating our natural immune system.   It works with nature, rather than against it.  And vaccination works best when everyone is vaccinated, because then the disease can't find enough unvaccinated people to spread.

A sick watershed

Today, we have a similar situation with our lakes and streams.  In wild landscapes, rainwater sinks into the ground.  Sometimes during large storms, water does run over the surface into nearby streams, but soon the floodwaters are trapped and filtered in wetlands, where they linger on the way to our lakes. So all water flowing into the lakes is filtered by flowing through the ground, or through the wetlands.

By paving the uplands and filling the wetlands to make shopping centers, we changed the natural system--our lakes and streams became "diseased."  The signs of this disease are vanishing wildlife, dry streams, dirty lakes, and floods near University Avenue.

The prescribed cure? 

Vaccinate the landscape by building rain gardens and small artificial wetlands.  This landscape approach has many similarities to vaccination:
  • Nearly every impervious surface--roof or road--needs a rain garden.
  • Nearly every channel for water needs to incorporate a wetland.
  • Nearly everyone has to become part of the solution.
  • Since the underlying science isn't obvious (groundwater is invisible), city officials and informed citizens have to assert strong leadership.
  • It's a little "painful" at first.  But here there's a difference--for rain gardens are truly beautiful. 
This "vaccination" approach is a method that works with the grain of our landscape.  Any other approach, like burying streams, or channelizing floodwaters with riprap so they rush to the lakes, is working against nature.  As such, these old stormwater techniques are doomed to be either expensive, to be ugly, or to fail.

The "leech doctor"

Despite its obvious success, vaccination has always had its detractors.  Old medical traditions died hard.  The same is true today of city infrastructure.   Once, paving the land and channelizing streams seemed like the modern thing to do.  And it did work for a while.  When the patient is young and vigorous, you can apply a leech to suck some blood, without much ill effect.

But today, with our mature city landscape, "vaccinating" with rain gardens and wetlands is the only sensible solution.  They must be part of EVERY new construction, resurfacing, and redevelopment.  They must be part of the greenway plan. 

If you hear of any new city plan that does not incorporate rain gardens and artificial wetlands, then you are listening to...THE LEECH DOCTOR.

Strong leadership needed

In Madison, there's a lack of strong leadership concerning our diseased lakes and streams.  The system is broken.  When each rain garden by itself is bound to have little effect, we need bold and coordinated action. 

Nowhere is this more obvious than in the City's proposal to allow each resident along the greenway to adopt their own landscaping plan. 

What if we allowed each citizen to mix their own smallpox vaccination?  What if we wrote a check to each resident along University Avenue and said, you get your section paved?  Wow!  This is not a serious proposal for a serious problem.

Yes, it won't be easy to fix the watershed upstream, so that flooding in the greenway (and along University Ave.) is less severe.  So, where's the strong leadership to get hard things done?  Why is our alder just being an apologist for outmoded stormwater solutions?  Where's the Mayor?

Greenway featured on WORT radio program

Today, Lisa Coleman--representing City Engineering, and David Newby--a resident, discussed plans for the Greenway on the radio.

You can hear a podcast of the program--click on "In Our Backyard," Wednesday February 24, 6:30 pm.

The Greenway is the second topic during the program, and the discussion lasts about 5 minutes.  It's mostly a summary of what has happened so far.

Of particular interest were Lisa's comments about landscaping.  You may recall that at the last meeting, neighbors found details about the greenway plans skimpy, and requested the meeting of Feb. 25 specifically to learn more about landscaping plans. 

On the radio, Lisa provided a preview of her presentation at the next meeting.  Lisa said she had agreed to more landscaping, and that at the meeting she would present two options.  The City will...
  1. Plant some new shrubs and trees to replace ones that are lost--but this will occur only outside the channel filled with riprap; or
  2. Simply write a check to people whose property borders the greenway.  They can use the money for plantings of their own choosing on the greenway easement.  She says this will provide more freedom, and people won't have to wait for a lot of red tape. 
At that last meeting, we were presented with three options.  The first was one already soundly rejected by residents (bury the stream with a road on top).  The third option involved doing nothing about the erosion, so that also was not really an option.

So it looks like the same approach again--a charade where the city pretends to present options--appears to be flexible--when they really have just one outcome in mind.

The channel should be part of the landscaping plan

For Option 1 above, Lisa said that trees and shrubs would be planted outside the ripraped channel.   Well, in our narrow ravine, that doesn't leave much.  The cross-sectional diagram on plans shows a strip of riprap 18 feet wide.   With a channel this wide, then details about the channel itself are of critical importance:
  • Can the channel width be varied, or can it be curved, to avoid large trees?
  • Will the channel have pools, check dams, or vegetation?
  • For riprap, can residents be guaranteed that natural fieldstone will be used--rather than limestone rubble with edges sharp as glass?  Or do we learn that "natural stone was out of stock" when the dump truck arrives.
  • What provisions will be made for watering the plantings while they become established?
These questions are part of the "landscaping" discussion.

What's at stake in the greenway

It's about more than just the wildlife and trees in this one lovely spot.  If neighbors accept the despoiling of this place, then other neighborhoods are going to experience the same short-sighted process.

We're going to get an 18-foot-wide swath of rubble, and lose 65 trees, because the city seems incapable of planning to handle stormwaters upstream.  Large rain gardens could be planted on terraces to handle street runoff, as in Portland, Oregon.  A beautiful retention basin/rain garden could be created in the park.  Church parking lots could be modified to control runoff.  But none of this has been considered in this project, so instead we get enough riprap to nearly obliterate the ravine.

Engineering has no budget for maintenance of projects like this, so instead we get enough riprap to last till the next ice age, without any maintenance.  The whole approach and process needs to change.

A watershed plan could save everyone's time

After the last meeting, an editorial about the controversy praised the democratic process.  I certainly am grateful for the many hours that Lisa Coleman and Alder Chris Schmidt have put into communicating with citizens.   And citizens also have put in many long hours, researching alternatives and debating with one another.  But I fear much of this was time wasted, digging ourselves out of a hole that was created by poor planning--by a flawed process. 

What we need instead is a watershed approach, with many more tools in the kit than just tons of riprap and a chainsaw. We need a willingness to try new ways of handling rain where it falls.

*    *    *

You can review here what "Friends of the Hillcrest-Upland Greenway" thought about the last meeting, and what they hope to learn at the Feb. 25th meeting.

2/23/10

Green streets for Madison

If Madison is going to "get serious" about problems of flooding and pollution in our lakes, then we have to build rain gardens for street runoff. 

The intersection of University Ave. and Midvale Blvd has seen frequent and serious flooding. 

According to Alder Chris Schmidt, "A few years ago Madison and Shorewood Hills went through a big exercise regarding stormwater that heads to University Ave. Both sides hired consultants, and after studying the issue it was found that to stop flooding on University Ave without adding extra storage space and outflow potential, one would have to convert all City of Madison land in the watershed to detention ponds and every property owner in the watershed--thousands of homes and businesses--would need to install raingardens and rain barrels."

Apparently, the rain garden and detention pond solution was considered too radical, and "not a guaranteed fix."  So instead, they opted for adding a second "box culvert" to carry floodwaters from the University Ave. area to Lake Mendota, via Willow Creek.  The expensive culvert is more of a "guaranteed fix" for the flooding, but not for the pollution--sediment carried by Willow Creek is creating a "delta" where the creek meets University Bay. 

The culvert work is scheduled for next summer.  Rather than trying to solve problems in the larger watershed, the culvert is just a band-aid.  The same old approach--one band-aid at a time.

Along with roofs, streets and parking lots are the largest source of runoff during storms.  You would think that, if rain gardens have already been identified as part of the solution, they would be included in every street reconstruction, or other major construction, but that has not been the case.  Last summer, Midvale Blvd was resurfaced--but no rain gardens.

Madison's experiment with rain gardens for street runoff

Last spring, when streets in the West High School area were resurfaced, the city gave residents the option of installing a rain garden on the terrace.  About two people per block chose this option, providing a decent test for the design.  Some residents hired their own garden consultants to design somewhat more elaborate rain gardens.  One resident I talked to was very happy with the outcome.

This rain garden near West High School, built by the City on the terrace, handles runoff from the street.

Here's where water in the gutter enters a pipe, which leads to the rain garden.  It's necessary for residents to keep these clear of debris.  It seems doubtful this small opening can handle much of the stormwater from a block of street.

During the same resurfacing project, grates were installed to drain runoff from some sidewalks and driveways into rain gardens.

The City now has a terrace rain garden program--the City will pay 75% of the costs of installing and planting a rain garden on your terrace, provided the spot meets certain standards.  More details here.

Madison and the USGS also conducted research to test how well prairie vegetation, when planted in rain gardens, helped ground to absorb the water.  It turns out that when you plant the proper plants, they are very efficient in draining water into the ground.  More.

In my opinion, this program is a step in the right direction, but not nearly enough.  Each rain garden is isolated, and the grates where water enters the garden can easily become clogged.  In many cases, the terraces in Madison are not large enough--they should be enlarged to create a chain of interconnected pools. 

Madison needs more than a few rain gardens per street--we need "green streets."

Unlike Madison, the City of Portland "benefits from comprehensive thinking and planning. In Portland, urban design, multi-modal transportation systems, watershed health, parks, open spaces, and infrastructure systems are all enhanced by integrated planning, design, and budgeting." 

Portland is a leader in using strategies that manage stormwater runoff, enhance community and neighborhood livability, and strengthen the local economy."

In Madison, it's one band-aid at a time. Stormwater projects are planned with little thought to what else could be done upstream to reduce the problem.

Siskiyou Street in Portland, Oregon

"A street that uses vegetated facilities to manage stormwater runoff at its source is referred to as a Green Street."

In the Siskiyou Green Street project below, the street was narrowed, creating larger terraces for bigger rain gardens.



 
Plan for the Siskiyou Green Street Project. Click to enlarge.

"Stormwater runoff from 10,000 square feet of NE Siskiyou Street and neighboring driveways flows downhill along the existing curb until it reaches the 7-foot wide, 50-foot long curb extensions. An 18-inch wide curb cut allows this water to enter each curb extension. Once water is within the landscape area, the water is retained to a depth of 7 inches by a series of checkdams."

"Depending on the intensity of a rain event, water will cascade from one "cell" to another until plants and soil absorb the runoff or until the curb extensions reach their storage capacity. The landscape system in place infiltrates water at a rate of 3 inches per hour."

If a storm is intense enough, water will exit the landscape area through another curb cut at the end of each curb extension and will flow into the existing [storm sewer] street inlets.  With the new stormwater curb extensions now in place, nearly all of NE Siskiyou’s annual street runoff, estimated at 225,000 gallons, is managed by its landscape system. In fact, multiple simulated flow tests have shown that the curb extensions at NE Siskiyou Street have the ability to reduce the runoff intensity of a typical 25-year storm event by 85 percent.

"Where communities struggle with ever-increasing impervious areas and degraded water quality, these simple landscape approaches can have a measurable positive impact." Source.

The project had benefits in addition to stormwater--beauty, calming of traffic, community education about water quality, and community spirit. 
Community involvement

"The success of neighborhood stormwater projects like the NE Siskiyou Green Street is dependent on community involvement. The residents were active participants in the design process. Multiple "street side chats" were conducted during the summer of 2003 to determine how much parking to remove and what planting schemes they desired, as well as to answer any questions and address any concerns."
"In a unique partnership, the City and the neighborhood residents have agreed to share responsibilities in maintaining the landscaped stormwater curb extensions."

Sunset Village would be an ideal place to try the Siskiyou plan
  • Low traffic & low residential density
  • Residents already love their stream and want to restore it to health
  • Serious stormwater problems downstream need solutions (Greenway erosion & University Ave flooding)
  • Lack of curbs means lower expense modifying streets
  • Gradual slopes in neighborhood are friendly to rain gardens. 
*    *    *
More photos from Portland.

Last chance for full moon seen from the ice

Photo with permission by Andre WagnerFlickr link.

This Sunday, Feb. 28, is your last chance this winter to see a full moon rise over Madison, from Lake Mendota.  That evening, sunset will be at 5:45 pm, and monrise at 6:13 pm.  

If you're uncomfortable walking on the ice after dark, try Feb. 27, when the full moon will rise at 4:53 pm, before sunset.

Tips on icewalking here.

2/19/10

Stormwater control at Mt. Olive must be improved

The former Mt. Olive Church--proposed site for senior housing.

"A proposed three-story senior citizen housing project on Mineral Point Road is drawing fire from neighbors who say the building would be too big for their quiet neighborhood."  Source

Residents are concerned that the project, to be located on the site of the former Mount Olive Lutheran Church, would
  • increase traffic in the area
  • be out of character, compared to size of surrounding houses
  • increase stormwater runoff.
Stormwater is already a problem in the greenway below, and on University Avenue, where serious flooding occurs. This site--plus two other churches in the area--already make a big contribution to
stormwater runoff from their large parking lots and roofs. 

It's hard to bring these established properties up to modern stormwater standards. But when a property is redeveloped--that's an opportunity for improvement that shouldn't be missed.

A variety of new and effective stormwater controls are available

• green roofs
• rain gardens
• infiltration buffers
• porous pavement

Just downstream from the Mt. Olive property, there's an eroded ravine that is scheduled to undergo costly repairs--in part because of the runoff from Mt. Olive. The redevelopment of the Mt. Olive property should be part of the solution to the problems in the Hillcrest-Upland Greenway.

In order to protect Madison's lakes, and to prevent flooding downstream, the goal should be to retain as close to 100 percent of stormwater on-site.  Unless we use the full toolbox of stormwater controls, residents downstream will be paying the price. And people who love our lakes will be paying the price.

This is where the floods that damaged our ravine came from...

 This property is one cause of the erosion in the greenway, because a large percent of the current property is impervious to rain. Any new development should seek to keep 100% of the rainfall on site.

 More parking areas to the E and N of the Mt. Olive church.
 
 Large piles of snow--waiting for the thaw. Just downstream, spring runoff will cause erosion in the ravine.

 A shallow depression (called a swale) runs through the parking lot--visible here as ice. This swale is one of the upper tributaries of Sunset Village Creek.  Stormwater in this swale needs to be retained on-site.

Slide show on the Mt. Olive property.

2/11/10

A rain garden in Sunset Village park

The greenway is being modified to repair the sewer, stop erosion, and handle stormwater.  And yet an obvious part of the solution has been ignored ....

THERE ARE NO PLANS TO CONTROL STORMWATERS UPSTREAM.

At the last meeting, I asked engineer Lisa Coleman about this.  She said, "If we tried to make improvements in the watershed, we'd never get anything done."

It's not really Lisa's fault ...  She's been given an overly narrow job--fix the ravine.  Period.

What is at fault is a dysfunctional process in the city.  Things are done piecemeal.   Nature is destroyed to save nature.  There's no larger vision.  We need to make changes in the process.

Upstream from the greenway--where the stream runs through the park.

A rain garden for the park

Just upstream from the greenway, there's a park where the stream runs open for a block.  It's pretty here, but the stream is bordered by relatively boring grass.  It could be a stunning, luxuriant, beautiful rain garden filled with flowers!

A small dam below the bridge could help hold back floodwaters. The dam would have a small outlet, so normally no water would pool behind the dam.  But during heavy rain, the pool behind the dam would fill, reducing the strength of floods downstream.  The basin can be enlarged slightly to increase flood retention, without cutting any trees.

This retention basin, doubling as a beautiful garden, can protect our investment in a new sewage line and landscaping downstream in the ravine.

WHY IS THIS PLAN NOT PART OF THIS DEBATE ?

This simple plan doesn't require coordination over a whole part of the city. It's a single small spot in a single park. What's so hard about that?

C'mon, Madison ... get your act together.


A large rain garden at the corner of Struck Street and Watts Road.  A small retention basin in Sunset Village Park could look like this.

Likewise, a large rain garden at the southeast corner of the greenway can take stormwaters from S. Owen Drive before they get into the ravine.

2/10/10

Sculpting the ravine can save trees

Check dams, stone slabs, or soil-filled bags can be used to sculpt the ravine and steepen the slope.  Variations like these could save some of the trees near the channel.

Deltalok USA makes soil-filled bags which can be stacked to create a sloping wall, on which vegetation can be established.   Roots from plants then infiltrate the bags, holding them together and making the wall more or less permanent.  The "lok" in the product's name refers to a spiked plate placed on top of each bag, intended to keep the bag above it from shifting.

Some of us would like to see Deltalok bags used for landscaping within the greenway, but Lisa Coleman is opposed to this, because she fears that if vegetation does not become established, then bank reinforcement could fail in a flood.

Of course, at the east end of the greenway and upstream from the present storm pipe, flooding would not be an issue.  Deltalok could be used here to shore up the sides of two large rain gardens.

Deltalok bags used for a wetland restoration, showing before and after vegetation grows.  A smaller version of this might work at the east end of the greenway, where floods won't occur.

The issue is how to sculpt the valley with Deltalok bags, without placing them where floodwaters reach.  Except at the east end, the valley is tight--without technical help, residents cannot determine whether this can be done.

Another issue is whether vegetation can be established on the bags.  Shade will make it more difficult, although (unfortunately) there is going to be more sun after 65 trees are cut.   I suspect that ferns can be established in the bags, if the right soil is used, and if they are watered during summer dry spells.  Ferns would be beautiful and relatively tough.

For residents next to the greenway, Deltalok bags might be suitable for preventing erosion on their properties.

Deltalok can help save trees

The sides of the ravine are steep in places, and yet the channel has to be wide enough to accomodate floodwaters.  If during construction, the channel is made wide, and if the sides do not slope much, then it follows that the higher slopes must be graded, and so more trees will be cut.

But if we can sculpt the ravine, leaving steeper slopes, then fewer trees need be cut.  Likewise, if there's a magnificent tree close to the channel, it might be saved if the slope below it is shored up by Deltalok (or even stone, if in the area that floods).

So--if the ravine is graded with a shallow slope, with the channel relatively straight and uniform, more trees are cut.  But if the ravine is sculpted, and varied as terrain and big trees require, then more trees are saved.

More ways to reinforce slopes, to sculpt the ravine

Here's a similar product--soil-filled rolls--sculpting a backyard on Falles Ct.


Along Starkweather Creek, layered stone slabs were used to reinforce the bank.  With these, our channel could be made more narrow, to save trees, in a few places where necessary.

Tim Kessenich has established ferns on the north-facing slope where the stream runs through his property.

If you don't sculpt the greenway, and don't use field stones, this is what you get. Below Glenway golf course.

Photos of Deltalok projects near water.

2/6/10

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

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.



2/5/10

A dialogue with Lisa Coleman about the "chain of rain gardens" idea

The "chain of rain gardens" idea involves creating several rain gardens upstream from the present stormwater pipe.  In this area, there is no danger from floods, because the existing pipe will carry the bulk of the floodwaters. 

I've also proposed a chain of reinforced rain gardens downstream, where the floods occur.  These would have to be armoured in some way to prevent erosion from floodwaters--and one method could be Deltalok bags.  Here's my original proposal.

The following is Lisa Coleman's initial response to the proposal.

Lisa: We have used a very similar product to the Deltalok system along Starkweather Creek (see photo below), with, in my opinion, unacceptable results.

David: How were the results unacceptable?

Lisa: Unacceptable in that we installed and planted under the original contract, then had to re-plant plugs and reseed (for an additional $20,000). Vegetation is still not established- now nearly 3 years after original installation.

At Starkweather... the plantings were watered both times post-installation by the installers. Both times wiped out by flooding and sustained high water levels....

 Difficult to get vegetation established, and without vegetation, the product eventually fails. As you mention, this is a particular concern in this shady environment.

David: Difficult, yes. But not impossible? What if more intensive methods are used, rather than love it and leave it? Why don't we use this project as a trial for developing better methods to establish vegetation? From my own experience with woodland gardens, I know that keeping the area wet during dry spells is the key to growing woodland plants.

Lisa: I wouldn’t endorse a solution in which the structural integrity of the solution relies on establishment of vegetation when it’s clear that vegetation could be difficult to establish here. My goal is to fix the erosion, not to do field trials for vegetation establishment.

Also with the storm water velocities that we are talking about here, I don’t think this is a good application of this product.

David: Stormwater velocities will vary, according to location and topography. Certainly, back from the channel, water velocity will not be an issue. And at the E end of the greenway, the existing pipe can handle the big floods, allowing a resurrected channel to the North with Deltalok reinforcement to the side to handle lower-velocity flows .

Lisa: The only place where there would be room to install the product in the project as planned would be right along the bank of the channel. This is where I am concerned about velocities.

 A potential application of the Deltaloc product in my opinion would be for homeowners to use it for terracing of their backyards, further back from the channel. In that case the product would not have to stand up to the velocities in the channel, and the homeowner would be responsible for establishment (or not) of vegetation. But our project addresses the channel itself (and remember we are trying to disturb as little as possible that we don’t absolutely need to disturb) – what homeowners wish to do with their yards further up the slope is their business.

 Remember that once we are done with the project, we are not going to have the ability to access the area to make repairs, so we need something that’s going to work as installed, and continue to work, no matter how well vegetation does or doesn’t establish.

David: For access, why can't we have a central channel, with the bottom reinforced with interlocking blocks. The bottom undulates, creating pools. A bobcat can use the channel as a track, delivering any needed repair materials.  Any rain garden at the far east end will have easy access.

Lisa: I wouldn’t recommend reliance on volunteers for an aspect of a design that is critical to the design function of the project. Based on our experience with volunteers, while they are well-intentioned, sometimes when push comes to shove the work doesn’t get done.

David: This particular location is ideal for volunteers. It's the backyard of residents. And if volunteers don't step up, can the city let a contract for maintenance of vegetation while it gets established? Eventually, tree roots will infiltrate the Deltalok bags, and make them pretty solid.

Lisa: For two items above…we generally try to design our projects to require as little maintenance as is feasible, as this makes the best fiscal sense and is mindful of our limited resources and many projects and areas to maintain. We do have a few vegetation maintenance contracts.
*    *    *

Location for one rain garden, to be located  in the former bed of the now-buried stream.  You are looking upstream (east) from the new stormwater pipe outfall (right).  The garden would extend from the middleground back past the wood pile.

Location for a second rain garden, to take stormwater from S. Owen Dr.  Looking east to Owen Drive.  This long E-W garden would be located to the right of the path in the snow, which is on the top of the buried stormwater pipe.

Starkweather Creek.  Soil-filled bags are visible in layers on either side.

Slide show on attempt to vegetate banks of Starkweather Creek.
Deltalok USA--for more about the soil-filled bags for bank reinforcement.

2/4/10

Anvil chorus on a winter lake

University of Wisconsin seen from L. Mendota.  Photo by Spencer9.

Lake Mendota "is asleep for the winter, but it is dreaming.  Marie feels that she can hear the dreams of the lake running through the ice, like thoughts in a language we don't know.  The ice begins to creak.  It makes banging noises, and groans, and makes little pings and snippy-snap sounds, and sometimes there are long, drawn-out booms, like cannonfire heard from a distance.  The cracks and adjustments in th ice can be heard racing from island to island and across the bays, traveling for miles and moving very fast, giving out stereo sounds.  Apart from that, the world seems quiet, without wind, without any clicking or rustling of branches, without any sound of a living thing.  Overhead, the misty river of the Milky Way turns slowly with the handle of the Little Dipper around the North Star.  The north Star is motionless, and everything else in the sky is moving.  A meteor crosses the sky--just a zip in the corner of Marie's eye, and it's gone."

From The Wild Trees, by Richard Preston, p.66-7.   I substituted Lake Mendota for Lake of the Woods.

 
View from L. Monona.  Photo by Spencer9.

Why all the noise?

As air temperature changes, the ice is constantly expanding or contracting.  When the ice contracts, it pulls away from the shore, or forms cracks in the middle.  These voids fill with new ice.  When the ice expands again, the added ice is too much for the space between the shores, and so the ice pushes against the shore, bulldozing up the soil into ridges.  Or the expanding ice pushes against itself to create pressure ridges in the middle of the lake.  There is always a big pressure ridge off the tip of picnic point. 

When the wind blows, it also pushes on the ice, creating more cracks and pressure ridges.

All of these motions are accompanied by cracking sounds.  Sound travels much faster in ice than in air, and ice is an excellent conductor of sound--so cracks anywhere on the lake can be heard loudly and at once.  One crack may propagate quickly over a long distance, creating the strange "stereo" effects.
The ice is completely safe, despite all the frightening sounds.

Tips for your trip 

  • Dress warmly, especially on feet.  Pick a time with little wind.  A hood is warmer than a hat

  • A pole or walking stick helps.

  • A flashlight helps getting down to the ice.

  • Take some hot cocoa and maybe a folding chair.  Leave the booze behind, unless you want a Darwin Award.

  • If you see open water (unlikely), avoid it by at least 10 feet.

  • The hazzard from pressure ridges (near shore or in middle) is mainly from slipping on the sloping ice.
  • Wait 2-3 days after a heavy snowfall for slush to freeze.

2/2/10

A chain of rain gardens--reinventing stormwater channels

In response to a previous article, where I proposed a chain of rain gardens in the greenway, I received comments that led me to wonder if my proposal had been clear enough.  So here's another stab at describing the idea.

The "chain of rain gardens" concept is an attempt to reinvent how stormwater channels are designed.

In the past, stormwater channels have been straight, sterile, ugly, and built to last with little maintenance for a long, long time.  The old concept was to take the stormwater downstream as fast as possible.  But standards are changing fast, and it's time for Madison to design something better.

I'm proposing a simple alternative--rather than a channel, make a chain of connected pools.  The pools can be of whatever size that works.   Think of this concept as a cross between a regular storm channel and many rain gardens.  Or think of it as a chain of connected rain gardens that are reinforced on the sides and bottom to withstand floods.


Series of wetland pools created with the Deltalok soil-filled bags and locking plates, before and after growth of vegetation. 
More photos thanks to Deltalok.


The design needs to handle the two extremes of floods and keeping the plants healthy during dry spells (with rain barrels and soaker hoses).

Advantages of the chain of pools concept:  To...
  • mimic the appearance of a natural stream
  • slow the floodwaters
  • create some pleasing variety
  • incorporate native vegetation
  • give wildlife a place to drink
  • return water to the ground from lingering pools.
I'm not proposing a rain garden next to an old-style stormwater channel.   Instead, combine the two. 

And, I'm not proposing one giant rain garden to absorb all the floodwaters.  Whatever fits the space is OK with me!  Together, the chain of pools creates a larger rain garden.  The water in each pool will linger after a storm, slowly recharging the ground. 

Our greenway can benefit all Madisonians by being an "outdoor laboratory," where we can experiment with various kinds of plantings and reinforcement.

If engineers tell us there's no inexpensive alternative to dumping tons of rubble (called riprap) into the ravine, I'd counter by saying: "Let's take the challenge, and invent our own alternative."  I believe it can be done--Madison can be a leader.

I suspect that worries about maintenance may be holding us back from coming up with a better, more modern design.  Sure, riprap will last 100 years without maintenance. But what's wrong with a little maintenance?  We do it with buildings, with roads... with whatever we care about. So why can't a little maintenance be done on stormwater structures, especially if the result is something less expensive, more beautiful, and better for the environment?

In writing this blog, I've learned that green infrastructure is rapidly developing.  With such rapid progress, it doesn't make sense to build for a hundred years. Instead of a clunky, ugly design that will last forever, let's come up with a smart design that's lean and mean--just enough to prevent erosion; no more than is needed. 

Madison seems behind in the urban green revolution. This controversy isn't just about one greenway--it's the opening shot in an effort to lead Madison to a greener future.  It's an issue for all of Madison.
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Deltaloc bags restore a streambank in residential North Vancouver, Treetop La. Our climate is relatively harsh, but vegetation can be established with a sustained effort.
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The chain of rain gardens concept has already been tried in the Siskiyou Green Street Project in Portland, Oregon.

Letter from City Engineering about next meeting

Hello Hillcrest and Upland neighbors,

I wanted to advise you of the date for the next public meeting.

We have scheduled a meeting for the evening of Thursday, February 25th, to be held at the Sequoia Library from 7pm to 9pm. I will be doing a mailing next week which will contain all of the details of the meeting, but I wanted to get the date out there to you in advance.

I also wanted to provide you with a tally from the public comment sheets from the last meeting. The tally of those preferring each option is as follows:
  • Option 1 (Replace Sanitary Sewer via open-cut, Install Storm Sewer Pipe, Fill Over): 0 votes
  • Option 2 (Replace Sanitary Sewer via open-cut, Rebuild Channel and line with riprap): 16 votes
  • Option 3 (Rehabilitate/Line Sanitary Sewer, Leave Channel as-is: 3 votes
  • None of the above: 4 votes
 Of the neighbors directly adjacent to the project, the tally is as follows:
  • Option 1:                0 votes 
  • Option 2:                6 votes 
  • Option 3:                1 vote 
  • None of the above:  2 votes 
Of other interested citizens, the tally is as follows:
  • Option 1:                0 votes 
  • Option 2:              10 votes 
  • Option 3:                2 votes 
  • None of the above:  2 votes  
At this point, we anticipate progressing with the design for Option 2. At the meeting we plan to present some potential options for landscaping.

I've copied everyone on this email that provided their email address at the other meetings - feel free to pass on to other interested parties.
Regards,
Lisa Coleman

2/1/10

A rain garden street for our neighborhood?

A guest article by Elizabeth McBride

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?