All things environmental

Musings about the environment and all it touches, from education to city planning

The energy revolution, as seen from the business pages

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I always enjoy reading the business pages of the Globe  Mail.  For one thing, it’s not an echo chamber of what I usually read.  For another, it often gives a snapshot of what moneyed people – our movers and shakers – care about.

Today’s headlines (January 22 2020) give the impression that we are well into an energy revolution, with fossil fuels on the way out, surprisingly quickly.  But also, one gets the impression that Canada is sleepwalking when it comes to energy.

Take these two headlines:

Tesla’s valuation tops $100-billion as stock rally continues

Daimler profits fell by half in 2019, despite strong sales

Interesting, isn’t it?  One of the best run car companies can’t make a profit, tied as it is to the internal combustion engine.  Tesla, the maker of electric cars (and battery packs and solar cells) has surpassed the valuation of GM despite all naysayers.  Three other headlines add context; Germany is well aware of the need to transition “German energy shift will be like an ‘open-heart surgery,’ Economy Minister says”.  Some of this is a fallout of dieselgate, obviously. “Volkswagen pleads guilty to all Canadian charges in emissions-cheating scandal.” “German prosecutors probe Mitsubishi for suspected illegal defeat devices.”

But Canada seems to think that investments in oil are justified; consider “Teck oil sands project splits Canada’s indigenous people, poses challenge for Trudeau”.  This despite headlines such as Oil falls as surplus forecast overshadows Libya disruptionorHalliburton takes $2.2-billion charge on slumping shale activity”.

This is all happening while the powerful are meeting in Davos.  One who is not sleepwalking through the transition is Trump, obviously; he is engaged in active rearguard, sabotage action as reported here “Trump dismisses climate pessimism at Davos, boasts of U.S. economic strength”.  This earned him a rebuff from the Globe’s Eric Reguly: “Donald Trump condemned climate activists at Davos. His hero Maggie Thatcher would not have done the same.” (He’s not the only one to react, obviously; Mark Carney is quoted in the Guardian as siding with Greta Thunberg, for instance.)

But getting back to the issue of Canada sleepwalking, the same issue of the Globe has this headline “Climate not considered a top 10 risk by CEOs: surveywhile columnist Gary Mason blasts AlbertaAlberta needs to wake up to a rapidly changing world – and to stop listening to the deniers”.

It’s worth quoting Mason a bit (he’s behind a paywall – the whole opinion piece is worth reading):

There isn’t a day that goes by now, it seems, that doesn’t include some ground-shifting announcement in the fight against climate change.

Last week, for instance, the European Union laid out a €1-trillion ($1.45-trillion) plan to lower carbon emissions and get the continent carbon-neutral by 2050. That amounts to nearly one quarter of the European Commission’s annual budget, money that will be used to underwrite the new “green deal” announced in December, which will affect the economies of virtually every member state.

As big as that development was, however, it took a back seat to the news that broke recently on Wall Street: the revelation that Larry Fink, head of the world’s largest asset manager BlackRock, had written to clients and fellow chief executives to say his firm will be making investment decisions in the future with environmental sustainability as a central mantra.

Mason goes on to lambast the Alberta government for hosting a summit of deniers including Conrad Black. But elsewhere in the paper is this interesting opinion piece, by an Albertan researcher: Alberta has a rare rare-earth opportunity on its hands – if it chooses to seize it

Meanwhile, the federal government is wrestling with whether to approve the giant tar sands mine proposed by Teck: “Teck oil sands project splits Canada’s indigenous people, poses challenge for Trudeau”.

There is no lack of opposition to this.  You can read an open letter from First Nations here.  But I will leave the last word to U Lethbridge professor Jim Byrne, in a facebook post:

 Vancouver-headquartered Teck Resources Limited will go bankrupt within a few years if they proceed with the massive oil sands mine plan for Alberta. The company has told shareholders the price of oil for the next 40+ years will remain in the $70-$90 US range. That’s absolute foolishness given the very rapid expected rise of electric vehicles, and electrification of most transportation and other energy sectors across global societies. Electrification will eliminate the need for fossil fuels with 1-3 decades. TECK’s proposed development is climate science denial… an absolutely blind, lemming-state that fails to recognize the climate emergency we are already experiencing globally, and assumes that somehow one of the most expensive, and environmentally damaging fossil fuel resources will continue to have a market. The global price of oil will continue to decline as humanity needs less and less oil given electrification. The federal government should save TECK from their suicidal, blind #FossilFuel beliefs!

“Blind, lemming-state”.  Jim has a talent for the turn of phrase.  I’ll stick with sleepwalking.

Written by enviropaul

January 22, 2020 at 12:10 pm

Hamburg’s green ring, canals, and other videos

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This is the second post that features videos in German, from NDR. (The first installment is here.)

The first is about Hamburg’s “Green Ring”, a nearly continuous band of parks and wild lands that surround the city.  It starts with a night-time survey of bats, in the west; continues with kingfishers; moves east with the Boberger dunes (a pocket “desert” left behind by the glaciers); wild habitat for birds and insects in the moors behind Harburg, in the south.

The second is about the canals – or specifically, about the group that keeps them clean – and educates kindergarten-age kids about them.

These are the only two that have a clear environmental theme, but there are many others that I want to keep track of; anyone interested in Hamburg – yes, it’s a great place to visit – may want to take a look; as for me, I’ll want to look at them again and again until I understand everything they talk about.  Two, both from NDR on Youtube, are long ones: one hour about the unique farmers’ market under the Ubann, the Isestrasse market; the other, about the Elbe on the east side, one and a half hour, ideal for those who like old ships, and country life.  Another from NDR is about the fancy homes along the Elbe and the Alster (quite fun, but really about how the one percenter of Hamburg lives).  The last one is short – just an homage to the river as it flows past the city, again on the (wilder and more natural) east side.  Here are the links:

The Isestrasse and its market:

The east side of the Elbe:

The fancy homes along the Elbe and Alster:,dienordstory724.html

The homage to the Elbe:


Written by enviropaul

January 21, 2020 at 5:05 pm

Canals in Germany

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Here are three videos about canals in northern Germany.  They are in German – I’m putting them here in my blog so that I don’t lose their URLs; I want to watch them again as a way to improve my understanding of the language.  And maybe some of my readers will do the same – or already understand German.  In which case, enjoy!

Canals, big and small, are found all over Germany.  The first video is about the canal that links the North Sea and the Baltic, via the Elbe and the Trave (Hamburg and Lübeck, if you will).  It profiles a couple who work and live in a barge, in this instance carrying rapeseed.  Very peaceful, beautiful scenery, slowly going down the historic canal, through no less historic towns such as Mölln.

The second video is about the Elbe lateral canal.  Still peaceful, much more industrial.  The canal was built after the war for two reasons.  The first was to facilitate the movement of bulky goods in a north-south direction.  You’d think that barges could just make their way up the Elbe river nearby; but there is a strong current, and while going downstream is fine, upstream would take too much energy, hence the canal.  The other reason to build the thing was political; the Elbe was the border between East and West Germany, and the West Germans, along with NATO, felt that a waterway completely in the West would be more reliable.  It is pretty spectacular, with large locks and an even larger ship lift, at the time the biggest in the world at 38 meters rise.

The third video is about the east-west canal, the Mittelland canal.  This is a giant canal that crosses the whole of the country, linking Poland to the Netherlands, in the process crossing rivers such as the Weser and the Elbe, over the biggest water bridges in Europe. Canals have quiet, predictable waters and are perfect for moving heavy stuff – minerals, grain, containers, etc – at a fraction of the cost and the energy needed even by railway, the next most efficient system.  But canals also create a shortcut for invasive species.  Zebra mussels, originally from the Black Sea, appeared in western Europe after the Danube-Rhine canal was completed.  The Mittelland canal is suffering from its own invasion of a fish from the Black Sea, the Schwartzmaul Grumpel (?) It’s a rather cute thing: lacking a swim bladder, it just walks at the bottom of the canal.  But, hey, it’s an invasive, out-competing native fish;  I’ll try to find what its name is (in English) to look it up. (Found it: neogobius melanostomus, the blcak-mouth goby)

I’ve added a fourth video, this one much shorter, but with narration in English; inexplicably, the NPR video about the Mittelland Canal does not feature the Magdeburg water bridge, a little marvel of engineering (imagine crossing a major river on a bridge that carries a canal – a bit unreal).

Anyways, here are the videos.  If interested in German, enjoy!  Otherwise, just look at the scenery…

Written by enviropaul

January 21, 2020 at 11:21 am

Portrait of the Alster, an urban river (part 4)

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City hall locks: the reason why the Alster lake exists

Part four: a marvel of flood control

Mühlenkamp street flood, June 2011

The winter of 2011 had been quite wet in Hamburg, but spring unusually dry.  Then on June 6, it was as if the heavens had opened: half a meter of rain in a few hours.  (The average precipitation in Hamburg is 733 millimeters.  Per year!)  Streets flooded.  Mühlenkamp, the main street in the Winterhude neighborhood where Dinah and I lived a few years later, was completely covered in ankle-deep water.

This is ironic.  I had gone to Hamburg in part because of its reputation for innovative, comprehensive flood control systems.  But then I dawned on me: the 2011 summer flood could have been so much worse.  Thankfully Hamburg was well prepared, even if nobody would ever expect eight months’ worth of rain to fall on a single day.

What the city expects, though, is that enormous cloudbursts will become more frequent, as a result of climate change.  Climatologists told the city to expect drier summers, on average – but also to be ready for exceptional weather of all sorts.  After 2011, nobody is in denial in Hamburg.

The city is actually quite vulnerable to flooding.  The obvious threat comes from its main river, the Elbe.  The city is close enough to the sea that the Elbe is tidal – any coastal flooding, any storm surge in the North Sea will cause the river to back up.  This is precisely what happened in the killer flood of 1962.

Hamburg now has a number of defenses against an Elbe flood.  Downtown is protected by dikes (designed by architect Zaha Hadid, no less), and other neighbourhoods like Hafen City have innovative strategies.  But what happens in a local cloudburst?  What happens if it is the Alster itself that floods?

This is actually quite a conundrum.  The dike that prevents the city from being submerged by a cresting Elbe needs an outlet: the waters of the Alster have to go somewhere, otherwise the city would flood from within.  And the Alster and its tributaries do collect most of the rain that falls on the city.

Past city hall locks, the canals at low tide

The pump house at Schaartor locks








The answer lies in the very last of the dams that cross the Alster, the 1846 Schaartorschleuse located where the Alster flows into the Elbe.  The dam may be closed completely if the Elbe backs up in a flood condition, preventing a backflow into the city.  But then the Alster itself is at risk of backing up, as it did in 1962.  In response, the city built a pump house, completed in 1967.  This pump house is a remarkable insurance policy against the worse possible combination of local downpour and North Sea flood. It is home to three giant pumps, bärenstarke Pumpen (“bear-strong pumps”) that can each pump 12 m3/sec up 4.5 meter, if needed.  That’s the equivalent of more than 50 Olympic-size swimming pools per hour.  Each pump is powered by a 740kW motor (or 1000 horsepower).  Not cheap – but ever since then there hasn’t been a flood downtown.

In nice weather, the role of the Schaartor dam and its partner at City Hall, Rathausschleuse, is to keep the level of the Alster lake relatively constant, between 2.85 and 3.2 meters above sea level.  The operators at the pump house constantly monitor digital readouts of the water levels everywhere in the system, and can remotely operate the various dams.

For instance, that same year, there was another downpour, a smaller one, on February 6th. The level of the Alster at Bäckerbrücke, upstream of the Fuhlsbüttel lock, rose from its normal minimum depth of 50 centimeters to a value of 2.5 meters. To relieve the flood, the Fuhlsbüttel dam was fully opened. This released a mini tidal wave that poured into the canal downstream and the Alster lake.  That is such a large volume of water that the sudden water release was absorbed without significantly increasing the level of the lake.

The porous pavements in the dense Katharinen-quartier, a 131 apartment complex downtown

This is just one example of how surface water bodies – lakes, ponds, creeks, wetlands – are effective in storing excess waters and preventing floods.  This is a part of what Hamburg does well: green infrastructure.  Green infrastructure means providing storage for excess rain, and that can be done by turning the city into a sponge: green spaces, green roofs, floodable lands and detention ponds all help.  Hamburg is aggressively working on expanding these measures simultaneously.  And of course, acting like a sponge also means that there is more water gently released to the streams during the dry spells, helping the fish habitat.

This is not to say that high tech is not important.  For instance, an intelligent algorithm is used to regulate the flow of the Ammersbek river, a tributary of the Alster, by operating the Kupferteich and Mühlenteich weirs on the Ammersbek and the Wohldorfer Schleuse on the upper Alster.  Storage space is created ahead of expected rainstorms.  This has been shown to reduce peak flow by about 15%.  It may not sound like much, but that may make the difference between being flooded or not.

In red, the newly designated floodable land along the Ammersbek


But, as with water quality, it may be the transparency and accountability of City Hall that makes all the difference.  Detailed, updated floodplain maps are available on line.  And a map of water levels at various points of the Alster and tributaries is also available in real time online.  Openness helps foster public acceptance.

Floods, droughts and fish kills, algae, it isn’t easy to live with a river within a city. Nature can’t be tamed that easily.  The Alster can be temperamental.  Nobody in Hamburg would want to bury it, though.  It is much too much what defines the city.  Besides, how worse would have all these floods been if not for the river and its tributaries flowing freely out in the open.  And what would everybody do with their time, if they couldn’t fish on the canals, sail on the lake, jog on the trails? Yes, the Alster is definitely a jewel.

I caught the bug – I fell in love with this urban river. I’d love to clone it, somehow. I catch myself wondering what Vancouver and Burnaby would be like if the Brunette River, Burnaby lake, and all the streams that lead to it had been left to flow free.  Burnaby has preserved some; Vancouver, none, Renfrew ravine excepted.  Surrey and Langley are much better, many of the rivers and creeks still intact.  But they have protected little of what could have been a network of riparian trails, which is unfortunate; many people don’t appreciate what they have in their backyards.  But if there is any lesson from Hamburg, it is the importance, for the health of a city, of integrating all its surface waters, its ponds, creeks, and rivers, into its development.

Written by enviropaul

January 14, 2020 at 5:51 pm

Portrait of the Alster, an urban river (part 3)

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The Fuhlsbüttel dam on the Alster, with the meander-style fish ladder on the left

Part three: the fish stream

I love the Alster, Hamburg’s urban river.  But I wouldn’t have wanted to be there in late July 2018.  There was a large fish kill; by Fuhlsbüttel dam, hundreds of carcasses of pike, tench and other fish were floating belly up, stinking.  This was not a result of toxic pollution.  Simply, the weather had been dry and hot, the Alster and its tributaries had slowed down, warmed up, and become somewhat stagnant.  Fast flowing, cool waters are rich in dissolved oxygen; stagnant water, not.  The level of dissolved oxygen dipped below 4 parts per million in the main stem, even lower in tributaries like the Tarpenbek.  The fish, basically, suffocated. City worked armed with hooks and nets removed about five tonnes of dead fish. And it wasn’t just the Alster, it wasn’t just Hamburg; this scenario repeated itself in small streams throughout northwest Germany.

(And if that wasn’t embarrassing enough, Hamburg’s triathlon, the world’s largest, had to be cancelled.  The swim segment take place in the lake, but the warm stagnant waters had been invaded by a bloom of blue-green algae.)

Hamburg climatologists have warned that climate change is producing warmer and drier summers. The fish kill is an instance of what the city can expect to happen more often.  Quite a challenge.

A map of the Alster watershed. The river is in blue, city limits dotted line, the built-up area in grey, and the combined sewer outlets in red

It may be just a temporary setback, though, because the quality of fish habitat in Hamburg has remarkably improved since the 80’s.

Much of the deterioration of the water quality can be traced to the development of the sewer system: from 100 kilometers of pipe in 1865, there was almost 5000 kilometers by 1985.  Much of the older pipes discharged directly into the Alster and its tributaries.  Already in the late 19th century the lake had become green with slimy algae, and the invasive pondweed Elodea Canadensis was impeding barge traffic.  But the completion of the sewerage net by the late 80s finally improved the situation: the new main sewers intercept the sewage before it flows into the Alster system, sending it to the central treatment plant.  It is only when there is a deluge that this works only partially with the excess overflowing into the lake and river.  The city has also built 15 very large sewage storage tanks to address this issue.  As a result, the water quality is now much better.  Mayflies and other critters that require good water quality have reappeared.  To ensure that this trend continues, the city has installed nine automated water quality monitoring stations that the public can access online in real time – Hamburg believes in transparency and accountability.

A different issue for the Alster fish habitat, however, is fragmentation.  Following the completion of the original dam that created the lake in 1235, eight dams were built upstream on the main stem of the Alster.  The river had always been used to float logs, but the peat extracted upstream and the building stones had to be shipped down by barge; it was easier to construct dams and locks than roads in what was then up-river wilderness.  Eventually an 8-kilometer trench was dug to connect the Alster with the Best river, creating the first canal for barge transport between Hamburg and Lübeck, 91 km long, completed in the early 1500s.  Barge traffic continued on the small canal well into the 19th century.

But of course, these dams fragmented the waters and prevented fish migration, affecting eel and salmon, in particular.  This is something that the city has decided to remedy: as of 2015, it has completed the construction of three fish ladders, two for the downtown locks (Rathausschleuse and Mühlenschleuse), one upstream of the lake at the Fuhlsbüttel dam. Three more are in the works (Poppenbüttel, Wohldorf, and Saseler Damm).  By 2022 fish will be able to swim from the Elbe all the way across the city to Schleswig-Holstein, should they want to.

The fish ladder at the Fuhlsbüttel dam is the most interesting.  In 2000, the city installed a small hydroelectric power plant (110 kW, enough for 200 households) to take advantage of the 4-meter drop at the dam.  In order to protect the fish (so that it does not get entrained into the turbine), the inlet was oversized to ensure slow flow towards the turbine.  The fish ladder itself has generous dimensions; a full flow of 0.5 m³/s is allocated for it, even if that reduces the flow available to generate hydropower (a maximum of 3.6 m³/s, thus a sacrifice of potential power of 12% – fish do matter).

There are dams and weirs across many of the tributaries, and some have fish ladders as well.  For instance, the old grain mill on the Ammersbek, now a heritage site, has been refitted with a small hydroelectricity generator.  The site has a simple fish ladder and an education centre.  When I visited in June 2017, there was a good flow in the ladder. A sign says it is used by trout, eel, burbot, pike, perch, roach, and gudgeon.

Detail of the fish ladder on the Fuhlsbüttel dam

The gentler fish ladder on the Ammersbek













This is all great – it shows that there is public and government support for fish protection, even within a city.  Northern Germans may not be fish people like Westcoasters are salmon people; but they eat large quantity of fresh water fish as well as seafood, many people fish in the city streams, many people volunteer their time restoring the stream banks or leading educational trips for kids. Hamburg cares about fish, and doesn’t stint on measures to protect them.

And yet, there was a huge fish kill.  Would the completion of the fish ladders have prevented it?  Unlikely.  Fish ladders do help connect the habitat, and fish may migrate away from the bad spots.  But the dead fish at Fuhlsbüttel were collected mere meters away from a ladder.  None of these systems can replace fresh rain and cool water.

But there is something else that may also help the fish: groundwater.  Cool groundwater gradually seeps into surface streams, helps maintaining streamflow during dry periods.  Anything that contributes to recharging groundwater helps fish, indirectly.  But groundwater recharge, in the form of green infrastructure, is also a key component of flood prevention. This is what the last section of this four-post series describes.

The fish ladders so far


Written by enviropaul

January 14, 2020 at 4:51 pm

Portrait of the Alster, an urban river (part 2)

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The Alster Lake, with downtown and Jungfernstieg at the horizon

Part two: the lake

The Alster Lake is the liquid heart of Hamburg. It is its focus, its vista, its orientation tool.  Taxi drivers and cyclists have to decide whether to go clockwise or counterclockwise around the lake.  Church spires are landmarks across the lake.  The busy city takes a breath and relaxes by the lakeside.  People meet on the shores of the lake. An example among many, from Norbert Suxdorf:

When I was small, my mother pushed me on a pram on the bank of the lake. When I was older, she took me on an Alster steamer and bought me an ice-cream on the landing at Rabenstraße. As a boy I skated on the Alster – at the time, there were still freezing cold winters. We bathed in the Upper Alster in summer. Later I could take the Alster steamer to work – from Mühlenkamp to city centre.  I’ve paddled and rowed on the Alster, and I’ve sailed my dinghy on the lake for many years.  It is a beautiful, but sometimes also treacherous area, with a view of the city centre and the green banks.

The lake is also a source of inspiration

Jungfernsteig is at the southern end of the lake, a broad promenade by the water side.  It is the city’s foremost boulevard, filled with unhurried strollers – flanieren is an art form in German cities, especially where there’s water.  The place is relatively devoid of vegetation now, but it was once lined with the linden trees planted in 1665.  It was where high society would gather and show off marriageable daughters (hence the name, which translates as maiden’s walk).  It is now lined with chic boutiques – but the relaxing effect of the water nearby can’t be denied.

Alster lake and the downtown canals

But the Alster lake is completely artificial; it was created when a dam and mill were built across the river in 1235.  The Jungfernstieg is actually part of the old embankment, holding back the 184-hectare lake.  (There was an error in the design, and the lake flooded an area much larger than anticipated, leading to endless lawsuits and countersuits – in Latin.)

This was nearly eight centuries ago, back when no German had ever eaten a potato. This is hard to imagine – the Alster is now such an integral part of the city.  The lake is filled with sailboats and rowboats; joggers and cyclists go around it.  But even that should not be taken for granted.  It was only recently (1953) that the city completed the continuous 7.6-kilometer public pathway around the lake.  Since then the city has expanded the green areas, preserved wetlands for nesting sites, and encouraged nearby homeowners to maintain bird and bat habitats.

One of the shorelines along the newly created lake was named Schwanenwyk (Swans’ beach or swans’ landing).  Hamburg has had a long association with swans.  Legend has it that terrible things would befall the city should the swans leave; a 1664 edict forbade anyone to insult the swans.  Despite this, terrible things did happened to Hamburg (the fire of 1824 and the firebombing of 1943, to name a few) but the swans are still there, coddled like the ravens of the Tower of London.  To ensure that they stay put, in winter they are transferred to the Eppendorfer Millpond, a small nearby lake that is kept ice-free all winter.  The whole operation can be seen below (as well as on this BBC video here, with narration in English).  One of the stranger municipal jobs is that of “swan father”, tasked with looking after the 120 or so majestic birds (including maintaining the pumps that stir the waters of the millpond to keep them ice-free).

At the opposite end of the lake are two parks that may symbolize the relationship between the city and its water.  Near the left bank, before entering the lake is the stately 148-hectare Stadtpark; near the right bank, the smaller (15 hectares), wild Eppendorfer Moor.

Stadtpark was originally the private hunting reserve of Adolf Sierichs (1826-89), a land baron that developed much of Winterhude.  The architect and city planner Fritz Schumacher designed the park, which opened in 1914, following Jugendstil principles.  He made sure to incorporate a great many water features; the park could be reached from the Alster by boat using the Goldbek canal, something still commonly done by canoeists.  The park suffered during World War II, but not only from the bombing.  The lawns were torn up for vegetable gardens, and the forest cut down for firewood. After the war the grounds were covered in huts for the homeless in the destroyed city.  None of this is obvious now; only the practiced eye of a forester would notice that the trees of Stadtpark are all quite young.  A nice example of resilience.

Toy sailboat in Stadtpark’s pond, with Schumacher’s (former) water tower in the background

Schumacher’s original plan for Stadtpark











(In fact, few of the 1.8 million trees in Hamburg are old.  All trees within the then city limits were cut down by the French occupation forces under Napoleon, from 1806 to 1812; many of the ones replanted later were lost to the fire and the firebombing.  The leafy canopy over the city attests to how nature can bounce back.)

Eppendorfer Moor has also come back from the brink.  It is a small wetland with open water in the centre, home to rare and endangered ferns. Peat was once cut there.  There were attempts at drainage for farming.  The 76th regiment had their shooting range there.  After the war, there were plans to fill the wetland with the piles of rubble created by the bombings.  This plan was thwarted, at the last minute, by a night-time planting operation led by Werner Hoffmann, head of the municipal gardens department.  This show of support by the locals was enough to force the politicians to reconsider.  This action brought in non-native species, unfortunately, but it saved the bog.  If this doesn’t demonstrate how attached the citizens are to their open waters, I don’t know what does.

Protecting open waters, of course, helps protect biodiversity, as I mentioned in the previous post; but also, it makes a healthy fish habitat possible.  Hamburg has its own version of our “salmon-in-the-city” programs; I’ll describe it in the third post of this series.

Suxdorf, Norbert 2015.  Experiencing the Alster: Hamburg’s loveliest riversides.  Hamburg: Koehlers

Written by enviropaul

January 14, 2020 at 4:06 pm

Portrait of the Alster, an urban river (part 1)

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Canoeing on the Alster, paddling through Hamburg

Part one: the green corridor

Hamburg, Germany, was founded in 832 at the site where the Alster river enters the larger Elbe river.  The city has grown along both streams and the people of Hamburg divide themselves into two tribes, the Alster people and the Elbe people.  Dinah, who grew up near the Elbe, is definitely an Elbe girl; me, I am an Alster boy.

I know, that’s a bit weird given the stereotype: Elbe people are working class, mixed, open-to-the-world, while Alster people are bourgeois, inward looking, conservative.  But it was along the Alster that Dinah and I spent six months in Hamburg, and I fell in love with the stream.  (And the stereotypes are just that, old clichés that don’t quite fit the modern reality.)

I fell in love with the Alster, I think, because the river came to represent what is, to me, unique about Hamburg: a special way to live with water and with nature.  The Alster and its tributaries were never buried into sewers, the river is clean, full of life, and is present in anyone’s mental map of the city. Its river banks are green and home to parks and a continuous urban trail, the Alster Wanderweg.  More than that, its lake is the defining heart of the city.

This is quite a claim for a river that is actually rather small.  It is only at most 30 meters wide while going through downtown – a stone’s throw. By comparison the Seine is over 100 meters wide as it flows through Paris. The Elbe, Hamburg’s other defining stream, is over a kilometer wide at Wedel on the western end of town, and through it flow waters that have come from Prague or Pilsen, Dresden or Berlin.  The 56 kilometer-long Alster, in contrast, is completely enclosed within the metropolitan Hamburg region, most of it flowing through Hamburg proper.  But its main stem and tributaries are spanned by more bridges than are in Venice, London and Amsterdam combined (2496 at last count), a fact that locals never cease to repeat to visitors.  This is because of Hamburg’s truly unique approach to urban development: its refusal to bury its streams and creeks, no matter how small, into storm drains.  Retaining its streams means that the city has great aquatic habitat, natural flood control, and wonderful green spaces starting with the corridor along the Alster.

Dinah and I caught the Wanderweg trailhead a few blocks from the Ohlstedt station, the terminus of the U1 metro line.  Ohlstedt is a leafy, prosperous neighbourhood.  It is on a bit of a glacial hillock, and where the river has carved its way into a sunken valley one feels immersed into a complete wilderness.  Oh, except for the little campsite around a bend, noisy with kids, the only urban campground in Hamburg.

If you look at the north end of the city on a map, you notice the Alster flowing between big green patches, two of the largest and oldest parks of the city, Wohldorf and Duvenstedt.  The Wohldorf forest has been a part of Hamburg since 1440, originally as a wood reserve, like Stanley Park in Vancouver.  But as early as 1770 the 278-hectare forest was protected as a park, and is now rich in centuries-old beech, oak, and ash trees, scented woodruff and cowslips, flycatchers and owls, wild boars, otters and deer.  The Duvenstedter nature reserve upstream, larger at 785 hectares, is home to forest and bog vegetation, including Hamburg’s only raised bog.  In autumn, people trek in to witness red deer and fallow deer bellow during the rutting season – yes, within city limits!

A bit downstream is the 86-hectare Rodenbeker Quellental, another city forest, rich in beech and hornbeam, famous for its woodpeckers; the site is left as natural as possible, including dead trees, for the birds to find nesting sites.  There is a small lake fed by springs with a few steep banks, where kingfishers dig up nests.  But the site is not natural; the lake was dug up in the 1300s to serve as a source of clay.  (Much of the ponds in town, such as at Trabrennbahn, have the same origin: since there is little building stone available in the region, most buildings, from the middle-ages onwards, were built of brick from the local clay.)  A bit further down is Hainesch-Iland park, a 71-hectare woodlot, where the curious can see twelve bronze-age burial mounds and traces of coppicing and ancient agriculture.  The mill across the small stream dates from the 14th century and was in operation until 1969.  It is now a restaurant – on our walk, Dinah and I stopped there for a break of tea, coffee, and kuchen.

Wellingsbüttel Manor gatehouse (1757), one of the unexpected buildings that one encounters on the trail.

Many cities have large parks – think Central Park in Manhattan, Stanley Park in Vancouver.  Among other roles, these amenities are essential for maintaining biodiversity. But few cities have managed, like Hamburg, to fully connect their parks with green corridors.  I rely on Val Schaefer’s Urban Biodiversity to understand why this connectivity is so crucial.  Schaefer mentions that utility corridors or train tracks, for instance, provide habitat for small mammals, birds, and insects; greenways are better and linear riparian habitats better still.  Species diversity is high in all of these because of the so-called edge effect, where different habitats meet.  Greenways, especially when integrated to storm control structures, may also provide temporary wetland habitats; riparian corridors even more so.

But it’s not just intrinsic habitat that is important; connectivity is key.  Schaefer writes

Greenways encourage interbreeding among plant and animal populations. The corridors provide opportunities for animals in particular to move from one green space, such as a park, to another.  Populations from these different fragments of green space have a better opportunity to interbreed, forming a larger metapopulation.  In addition to increasing the likelihood of finding a breeding partner in the first place, this adds to the genetic diversity of the species, improving resistance to disease and improving the resilience of the species.

Because Hamburg has kept all its creeks alive, its biological connectivity e is, at least to my eyes, unprecedented.  In contrast, most of Vancouver’s creeks are lost underground.  Surrey has done a better job of preserving its creeks and ravines in a relatively natural state – but few are, as in Hamburg, coupled with greenway trails.

Bikes and kayaks at Poppenbüttel

Another aspect of biodiversity protection in Hamburg that pleasantly surprised me is the extent to which programs are coordinated across various departments and diverse groups.  Much of the biodiversity enhancement initiatives supported by the government are delegated to citizen groups such as NABU; it is the equivalent of, say, Vancouver giving a grant to Sierra Club to create salmon habitat.  In Hamburg, this approach seems to be systematic (as I mentioned about the smaller Seebek stream).  NABU volunteers indeed offer guided tours of the upper Alster, with focus on trout habitat created by the group.  I also came across a guidebook on how to protect bird and bat habitat when doing renovations (the old brick facades of Hamburg make good nesting sites) – the surprise was to see it published by the ministry of housing, not environment.  Somehow, silos get broken across government divisions.

Dinah and I kept walking downstream along the continuous greenway, past smaller parks with names such as Hohenbuchen, Teetz, or Henneberg.  The shores are natural looking, which is unexpected considering that since the middle ages, a full ten dams and millraces have been built across the river, six of them within Hamburg city limits.  It is green, with a full canopy, reeds and cattails along the banks.  Every now and then a break in the trees reveals an old house or a meadow with horses.  At the Poppenbüttel dam kayakers are setting off.  We continue until Fuhlsbüttel dam – from this point on downstream, the river is canalized.  We get back on the train – urban transit is easy to take for granted, but there are six U-bahn or S-bahn stations that give access to the trail, in what is the wildest, most natural part of the river.

Ohlsdorf, the green cemetery

The Ohlsdorf train station at Fuhlsbüttel is also the access point to the main cemetery.  As in Père Lachaise in Paris, celebrities are buried here and attract tourists, but here the similarities stop: Ohlsdorf is all green.  It is what the Germans call a Park Cemetery, and at 391 hectares it is the world’s largest.  Most graves are under a broad tree canopy.  It is a managed environment, not a natural one; there is a huge landscaping effort that goes into maintaining the rhododendron shrubs and other greenery that surround the tombs.  It makes our own cemeteries look sadly sterile, with their geometric rows of graves between closely-mowed lawns.  The locals recognize the cemetery for the amenity it is: a quiet place to walk and meditate, but also another piece of forest within the city limits where bird songs can be heard.

Downstream from the Fuhlsbüttel dam the Alster takes on distinctly civilized aspect, bound within the masonry shores of its former life as a working canal, opening up onto the large Alster lake.  I spent a lot of time along the lake and the canals – I will leave that for a later post, part two of this series.

But this is why I became an Alster boy.  I still can’t get over how the river has brought nature into the city.


Schaefer, Valentin, Hillary Rudd & Jamie Vala, 2004. Urban Biodiversity: exploring natural habitat and its value in cities. Concord: Captus Press.


Written by enviropaul

January 14, 2020 at 11:37 am