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River Co n servation as a Component of Flood Disaster. Management. Edwin E. Herricks Emeritus Professor of Ecological Engineering.
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RiverConservationas a Componentof FloodDisaster Management Edwin E. Herricks Emeritus Professor of Ecological Engineering
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 will always 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.
ActionandPersistence: 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 and produces 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 be characterized 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: think beyond the immediate human concerns in disasters, recognize that disasters are virtually impossible in ecosystems, and 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
Thirty years later! 。EnlMronfm叫EnoineerinQ & Scien
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.
Note the green on rocks, already primary production is well established. q
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.
BirdCommunityIndices 1. Species richness 3.Diversity 4.Evenness 2.Density Pielou's Evenness Index(mean±SD) damagedarea nondamagedarea damaged area nondamaged area River No.ofSpecies(mean±SD) damagedarea nondamagedarea damagedarea nondamagedarea 7 1.5 Birds/Ha(mean±SD) 200 6 5 4 3 2 1 0 2.0 ShannonIndexH'(mean±SD) 150 1.0 1.5 100 1.0 0.5 50 0.5 0 0.0 0.0 1 2 3 nonbreedingseason 4 5 6 1 2 3 nonbreedingseason 4 5 6 breedingseason 1 2 3 nonbreedingseason 4 5 6 1 2 3 nonbreedingseason 4 5 6 breedingseason breedingseason breedingseason Pielou'sEvennessIndex(mean±SD) River-side No.ofSpecies(mean±SD) ShannonIndexH'(mean±SD) 300 250 200 150 100 50 0 7 6 5 4 3 2 1 0 1.5 2.0 1.5 1.0 0.5 0.0 Birds/Ha(mean±SD) 1.0 0.5 0.0 1 2 3 4 5 6 breedingseason 1 2 3 nonbreedingseason 4 5 6 breedingseason 1 2 3 nonbreedingseason 4 5 6 1 2 3 nonbreedingseason 4 5 6 breedingseason nonbreeding breedingseason 7 6 5 4 3 2 1 0 Shannon Index H'(mean± SD) 200 Birds/Ha (mean±SD) Forest No.of Species(mean±SD) 2.0 1.5 1.0 0.5 0.0 Pielou'sEvennessIndex(mean± SD) 1.5 150 1.0 100 0.5 50 0.0 1 2 3 nonbreedingseason 4 5 6 breedingseason 1 2 3 nonbreedingseason 4 5 6 breedingseason 1 2 3 nonbreeding season 4 5 6 breedingseason 0 1 2 3 4 5 6 survey nonbreedingseason breedingseason survey survey survey
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.
