River Conservation as aComponent of Flood Disaster

Management

Edwin E. Herricks

Emeritus Professor of EcologicalEngineering

In the 2013 Water Management Forum announcement the Kaohsiung organizers identified that water treatment and disaster prevention in urban areas are major concerns for the City government.

The urban focus provides singular difficulties for river conservation, particularly when both effectiveness and prevention are clear goals.

The difficulties posed by urban areas on water resources management are primarily associated with the limited options available to managers, planners, and engineers in meeting conservation needs.

In urban areas protection from loss of life and property will always be the primary objective – ecosystem protection will be secondary.

People produce pollution so there willalways be a challenge of quality.

Space is limited so there will always be a compromise between providing natural environments and meeting human needs.

Time is also an issue. Ecosystems operate on time scales very different from election cycles, and urban growth creates constant change that provides new threats to ecosystems almost daily.

With these challenges it is safe to ask what can be done to meet City objectives?

I will suggest that what is needed is intent, information, available practices, action and persistence!

Intent:

It may be self-serving, but simply having this forum provides an indication of intent. I also note the previous forums held by the City to address various aspects of disaster management.

I also looked at City organization and Department plans and found very positive signs of intent.

In 2010 the Sewerage Systems Office of Kaohsiung City Government and Water Resource Department of Kaohsiung County to be the new Hydraulic Engineering Bureau.

A review of the annual administrative plans for the Hydraulic Engineering Bureau found a mix of water and wastewater improvement projects and landscape/river conservation efforts. A demonstration of intent to address a wide range of problems.

What is important to me is that Kaohsiung now has a structure to deal with watershed scale management approaches

The watershed structure allows coordinated approaches to dealing with urban problems considering the full influence of upstream areas!

Information:

Information is critical to any management program and it appears to me that the Kaohsiung City government is taking a proactive approach to information.

The hope I have is that the information exchanged in this Forum, combined with the capabilities provided in city government, will lead to more effective execution to facilitate conservation and achieve the needed protection.

In terms of information, I hope that I can share some information today that will add to the repository being developed by the City.

What is important is that the information must be used. Used to identify new approaches to existing practice, used to challenge thinking that will better integrate natural systems and ecosystem protection in City projects, and used to inform the public.

Available Practices:

The availability of practices is, and will be,a major challenge for the City.

Let me explain!

The typical requirement for a project is the use of best available practice in implementation. This is based on a long history of engineering success where practices are refined over time and assurances can be given to the client for practice success

The result is that engineering practices are slow to change. This slow change is driven both by engineering conservatism, and the expectations of clients that money invested will produce a quality product.

When faced with new challenges, engineering practice tends to be evolutionary rather than revolutionary!

When I evaluate the present situation, from the perspective of an ecologist/engineer who has spent 40 years working on developing ecologically relevant engineering practices, I see that Taiwan is ahead of the game! Since early 2000 I have lectured on Ecological Engineering in Taiwan and worked with colleagues to demonstrate ecologically relevant practices.

Manuals of Ecological Engineering practice now exist for Taiwan and a generation of engineers have been exposed to concepts of Ecological Engineering.

What is important is to maintain a proactive approach to engineering design that addresses more than standard practice.

This Forum is a part of the process to improve, and possibly even innovate in engineering practices related to watershed and disaster management in Taiwan.

Action and Persistence:Tacking action, and persisting in support for a course of action are possibly the most difficult issues faced by any governmental body.

Action is complicated by something called the Black Swan Theory proposed by Nassim Taleb.

The basic sense of this theory is that because rare events are rare there is little support to persist in preparations that may have high cost and produce inconvenience.

Associated with the rare event is also the blame game! When there is an event, twenty/twenty hindsight allows critics to blame outcome on poor preparation.

The result is that it is very difficult to prepare for disasters. This is particularly true when climate change may be producing conditions where event magnitude and frequency are changing.

To facilitate effectiveness and provide protection in this changing environment is a clear challenge to government that requires innovation in economic, social, political, as well as engineering areas!

Earlier I asked “With these challenges it is safe to ask what can be done to meet City objectives?”

I can suggest what might be done in the area of Ecological Engineering and also provide a few insights or information that can contribute to the effectiveness of programs to provide protection for people when disasters occur.

My first insight is to encourage the recognition that a human disasters are not necessarily ecological disasters. In fact ecosystem services may reduce disaster effect and the resilience of ecosystems may improve the effectiveness of post- disaster management.

In human terms a disaster can be characterized as:

An event that damages built systems andproduces a loss of life.

Disasters produce economic, social and cultural change.

Disasters can be local, regional, national,or extend beyond political borders.

In ecological terms a disaster can becharacterized as:

An event produces change beyond the capacity of natural homeostatic mechanisms to sustain biological structure and function.

Disasters really don’t happen in ecosystems because spatial and temporal scales must be considered!

In reality, ecological disasters can only be defined in human terms.

The differences between human disasters and ecosystem disasters are associated with the fundamental characteristics of living systems. In living systems, stress is a constant and all life has developed mechanisms to cope with a range of stressors.

The result is that living systems have the capacity to deal with stress (homeostatic processes) and continue near normal activities during, and after a stress event.

With this living system capability in mind, let me provide examples will encourage you to:

1)think beyond the immediate human concerns in disasters,

2)recognize that disasters are virtuallyimpossible in ecosystems, and

3)Understand that the fundamental resilience of ecosystems plays an important role in disaster management.

Let me provide some examples.

In the US, Mt. St. Helens erupted a bit more than 30 years ago. A large area was laid waste and the term ecological disaster was used more than once.

In ecosystem terms, the eruption was an event that provided a starting point for the ecosystem.Scientists have conducted studies to define damage, characterize and quantify changing conditions over time, and provide new foundations for ecological theory.

Before

。 EnlMronfm 叫EnoineerinQ & Scien

Immediately After

Thirty years later!

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The Mt. St. Hellen’s area has not recovered to a pre-eruption state, but then no ecosystem really recovers to an exact pre-disturbance state. What has happened is that the restoration mechanisms have kicked in and over 30 years we find that ecosystem structure, function, and services have recovered over large areas. We can expect a trend to previous conditions over the next several hundred years!

Note that I suggested recovery times of 100’s of years.

Although ecosystems may be damaged quickly, they will take time to recover full function. At Mt. St. Hellens, organisms that survived the eruption immediately began activity, supporting recovery.What takes time is for the development of complex ecosystem interactions involving many species, some with long life histories.

Let’s consider an event closer to you here in Taiwan.

In August 2009 Typhoon Marakot struck Taiwan. The typhoon produced the highest rainfall seen in the past 50 years, over 2500 mm of rain fell in three days. Landslides and flooding were common in Tsengwen River (drainage are 1,117 km2), the third largest river in Taiwan and the Kao Ping River (3,257 km2) the largest/longest river in Taiwan.

Typhoon Marakot was indeed a human disaster. Lives were lost, property destroyed and millions were affected by economic factors.

The question might be asked about the ecological effect of Typhoon Marakot.

There was damage to ecosystems. Landslides denuded landscapes and debris flows filled rivers. Habitat was altered and organisms killed. But what were things like a few months later?

Human recovery in damaged villages has been slow, but there was immediate evidence of ecological recovery in rivers.

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The Kao Ping River within 2 months of Typhoon Marakot!

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Note the green on rocks, already primary production is well established.

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There is evidence of sediment that will be reworked.

Fish have survived and are spawning - see early life stages!

And food resources for fish are also present.

Colleagues from the Kaohsiung Medical University performed a number of follow- up studies in the affected areas. These studies included both aquatic organisms and birds.

Studies of aquatic organisms showed positive response over time.

1. Species richness

2. Density 3. Diversity

4. Evenness

Bird Community IndicesR

iver

Riv

er-

side

No.

of

Sp

eci

es(

mean

±SD

)

Fore

st No.

of

Speci

es(

mean

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)

76543210

12

3 4 56

breeding season

nonbreeding

76543210

1 23

nonbreeding season

4 56

breeding seasonsurve

y

300

250

200

150

100

50

0

1 23

nonbreeding season

4 56

breeding season

Bir

ds

/ H

a

(mean

±S

D)

2.0

1.5

1.0

0.5

0.0

1 23

nonbreeding season

4 56

breeding season

Sh

annon I

nd

ex H

'(m

ean

±S

D)

2.01.51.00.50.0

1 23

nonbreeding season

4 56

breeding season

survey

Sh

an

non

In

dex H

'(m

ean

± S

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0.0

0.5

1.0

1.5

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nonbreeding season

45

6

breeding season

Pie

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's E

ven

ness

In

dex(m

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0.0

0.5

1.0

1.5

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nonbreeding season

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breeding seasonsurve

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6543210

7

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nonbreeding season

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breeding season

No

. o

f S

peci

es(

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an

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D) damaged

areanondamaged area

0

50

100

150

200

1 23

nonbreeding season

4 5 6

breeding season

Bir

ds

/ H

a

(mean±

SD

)

damaged area

nondamaged area

0.0

0.5

1.0

1.5

2.0

1 23

nonbreeding season

4 5 6

breeding season

Shannon Index H

'(m

ean±

SD

)

damaged area

nondamaged area

0.0

0.5

1.0

1.5

1 23

nonbreeding season

45

6

breeding season

Pie

lou

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ness

In

dex(m

ean

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damaged area

nondamaged area

0

50

100

150

200

1 2 3 4 5 6

nonbreeding season

breeding season

survey

Bir

ds

/ H

a

(mea

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These results indicate that a short time after the typhoon recovery had begun and that over time we can expect improvement to a “full” recovery, just as we noted for Mt. St. Hellens.

The take-away message is that disasters damage ecosystems, but recovery begins quickly, although it may take some time for full recovery.

Another take-away message is that post- disaster management can take advantage of ecosystem resilience to maximize ecosystem services and provide ecological benefits in urban areas. This is particularly true when it is possible to ecologically engineer in post-disaster management.

If recovery can be enhanced by good engineering design, it will be useful to have additional guidance on where to engineer and what to engineer.

The question of where to engineer is based on the basic mechanisms of recovery.

To start recovery processes, we either need to have organisms survive the event, or have a way to get new organisms to a place where they can prosper.

Thus the question of where is answered by understanding that ecosystem recovery is dependent on:

1)sources of colonizing organisms,

2)a pathway for movement from thesource area to the damaged area, and

3)good habitat in the damaged area thatwill support colonizing organisms.

Thus we must identify where organisms will come from, how they can move easily from source to destination, and where they will find a home on arrival.

It is easy to characterize locations in a watershed, any point will be either upstream or downstream of a point fo reference.

A network of channels define where water flows. This water will provide the path of least resistance for organism movement.

To get rapid recovery, we need an open path to the location where we plan a project. At this location we need to provide the habitat that provides a “home” for organisms.

UPSTREAM

DOWNSTREAM

The key i part of a source a recovery.

ssue is free move stream to another, reas to areas under

ment from one which relates going

Superimposed on the channel network is a changing mix of species and functions that dominate different locations in a watershed.

Younger fish

Insectivores Higher

production

Greater age variability

Greater trophic variability

Older fish

Piscivores

Lower production

Less age variability

Less trophic variability

0100

20120

40 60 80

YEAR

NUMBER OF SPECIES

BIOMASS

NET PRODUCTIVITY The result is a changing matrix of biological communities that have characteristics associated with watershed location. Each of these communities will respond to change and events over different time scales.

Several take-away messages are providedby these ecological realities.

The first is that a system view is necessary, and system level control is helpful. The fact that Kaohsiung has a Hydraulic Engineering Bureau that can work on a watershed scale is encouraging.

Next, it is important to protect upstream areas so that sources of organisms that can rapidly colonize damaged areas are readily available.

This is a point that focuses on action and persistence. Although protection of upstream areas may have general conservation, aesthetic, or recreational support, protection these areas are essential for urban management.

The maintenance of connections is also critical to assure transport under low flow conditions to sustain ecosystems. This requires not only physical connectivity and flow, but the prevention or mitigation of blocks to transport created by water quality problems.

Finally, it is critical to have habitat appropriate to the location in the watershed to provide “home” for colonizing organisms.

What is important here is that expectations for recovery, or possibly only maintenance, must be adjusted to watershed location and engineering must be tailored to the needs of organisms expected in that watershed location.

Thus ecosystem resilience, and mechanisms of recovery, should be considered as a basic part of every design, whether for river conservation, flood protection, or more general watershed management improvements.

It should be recognized that the limitations of urban areas can be opportunities for Ecological Engineering designs.

My final insight is focused on understanding time a bit better in the overall structure of disaster management. I have already discussed how ecological time frames can be quite long. I would now like to discuss how change through time is an important consideration in Ecological Engineering.

I have used the term change to identify the influence of an event. It is possible to better characterize an event, and even place an event in a category, using measures of magnitude, frequency, and duration.

MAGNITUDE – The magnitude of an event is assessed based on comparison to historical events. This is dependent on a measurement system, such as rainfall amount. Magnitude can also be assessed related to spatial scale where greater magnitude is associated with greater area of effect. Magnitude can also be related to the time scale of an effect, where greater magnitude is associated with time to response.

What I think is interesting is that to assess magnitude, we still have to consider time, either in a historical context where we use comparisons with a previous event (the 100 year flood) or the length of time needed for a response.

So although magnitude is not only time related, time features heavily in how we think of magnitude.

Duration – Is a simple measure of thetime a given condition persists.

Duration is important biologically because duration and magnitude are related in biological responses. High magnitude, short duration events produce acute responses that may result in death. Low magnitude, long duration events may produce chronic responses that result in disadvantage to organisms.

Duration will typically be defined by the event, say the number of days in a typhoon or the time flow exceeds a given level, but changes produced by an event may persist and extend effects (example landslides or river sedimentation associated with a typhoon).

We usually set arbitrary time limits to assess duration, but we should note that event effects, if extended, confound the interpretation of later events.

In my assessments I define duration in relation to a time of exposure for a defined life stage or life history.Duration in an ecological context also considers community dynamics.

For example a biological measure can be the familiar time based EC50 while the stress duration for an ecosystem from a typhoon will consider species loss and recovery.

Frequency – is simply a measure of the number of times an event of a particular magnitude is repeated in a defined time period. Of importance is both the number of events, and the time interval between events.

I judge the importance of frequency in relation to organism life history, which sets a general time frame for the frequency assessment.

To illustrate these points, consider thefollowing:

0 0

80

Duration

20

0

60Magnitude 40

80

100

40

20

0

100

80

60Magnitude

In toxicology stressors are characterized as a surface in three dimensional space defined by magnitude, duration, and frequency.

Although relatively simple in concept, the reality is that homeostatic mechanisms in living systems produce many possible responses to stressors that can be related to magnitude and duration/frequency of exposure relationships.

Lethal Effects

Lowagnitude

short long。

High magnitude

Duration

The reality for urban systems is very complicated. Urban environments contribute a wide range of pollutants to receiving systems and although generation of pollutants may be relatively constant, delivery, particularly for non- point sources can be highly variable.

A characterization of rainfall/runoff relationships is both simple in terms of hydrograph determination, and complicated in terms of parameter concentration during runoff events.

The take-away message from this part of my presentation is that we do have a means to develop expectations for effect and we can develop engineering designs to minimize magnitude, influence duration, and possibly even control the frequency of some events.

That said, disasters are still disasters, and the preparation for disasters will have to deal with uncertainty, that again requires persistence with action.

I would now like to summarize and bringmy presentation to a close!

In the Forum description I note the following:

In addition, when referring to urban watershed treatment we can’t but address the issue of flooding improvement. Rather, we need to better it along with floodway improvement, river conservation, waste water treatment, bank treatment and extreme climate prevention in urban areas. Moreover, we must enhance our disaster prevention management as well as monitoring management in order not merely to facilitate the effectiveness, but protect Kaohsiung citizens from the fear of flood disaster and ensure their safety and property.

I am pleased to participate in this Forum because the organizers clearly recognize the need for a systems view.

I will simply argue that the river conservation objective can most effectively be met if the overall management program, with specific project designs, integrate ecological realities.

I will not argue that I have presented all of the ecological realities needed for effective management, but I have presented several take-away messages that should help as the Kaohsiung government, and agency, planning, product selection, and project implementation proceed.

Questions?