外文翻譯---臺灣地區(qū)的水土保持生態(tài)工程方法

1、<p><b>　　附錄</b></p><p>　　Ecological engineering methods for soil and water conservation in Taiwan</p><p>　　Huei-Long Wua and Zheng-yi Fengb</p><p>　　aSoil and Water

2、 Conservation Bureau, Council of Agriculture, Nantou City 540, Taiwan</p><p>　　bDepartment of Soil and Water Conservation, National Chung Hsing University, Taichung 402, Taiwan</p><p>　　Abstract

3、:This paper describes the development of Taiwan's localized ecological engineering methods to make the mitigation works more effective. To strengthen the soil and water conservation and protection of the ecological e

4、nvironment, comprehensive mitigation planning is necessary with considerations that include balancing the safety, ecology, and landscape, and treating the whole watershed as a unit. To demonstrate the achievement of the

5、promotion of the ecological engineering methods in Taiwa</p><p>　　Keywords: Water and soil conservation; Ecological engineering methods; Hazard mitigation; Habitat; Erosion control</p><p>　　Arti

6、cle Outline</p><p>　　1. Introduction</p><p>　　2. Ecological engineering methods and habitats</p><p>　　2.1. The functions of ecological engineering methods </p><p>　　2.2

7、. The functions of the ecological corridor </p><p>　　2.3. Some drawbacks of conventional engineering</p><p>　　3. Planning and design of stream mitigation using the ecological engineering methods

8、</p><p>　　3.1. Fundamental concepts </p><p>　　3.2. The principles of integrated design for streams</p><p>　　4. Selected examples of the ecological engineering methods of Taiwan</

9、p><p>　　5. Inspection of the ecological engineering methods in Taiwan</p><p>　　6. Integrated mitigation for debris flow Torrent—an example of Hua-shan Creek in Gu-keng County, Taiwan</p><

10、;p>　　7. Integrated mitigation for a stream—an example of Ding-zi-lan-keng Creek in Taipei County</p><p>　　8. Challenge for promoting ecological engineering method in Taiwan</p><p>　　9. Conclu

11、ding Remarks</p><p>　　Acknowledgements</p><p>　　1. Introduction</p><p>　　One of the important measures in soil and water conservation in Taiwan is the ecological engineering method.

12、 It can be an index of protection and restoration for ecology. In 2001, the Soil and Water Conservation Bureau (SWCB) in Taiwan began to promote the innovative ecological engineering methods. Disaster prevention, ecologi

13、cal conservation and recreation have been interwoven by the adoption of ecological engineering. Ecological engineering methods are suitable for regions with medium size flo</p><p>　　For ecological engineerin

14、g, two major approaches were adopted: develop new techniques and apply newly developed ecological engineering methods. The tasks for promoting ecological engineering methods include the development of reference drawings

15、for ecological engineering methods, ecological investigations, habitat improvement, establishment of ecological indexes, development of vegetation methods in landslide areas, and holding a series of conferences for ecolo

16、gical engineering methods. The meth</p><p>　　2. Ecological engineering methods and habitats</p><p>　　2.1. The functions of ecological engineering methods</p><p>　　(1) Improving the

17、revival ability of ecosystem (for large scale hazards such as landslide and debris flow): Ecological engineering methods can be suitable for mitigation of large scale natural hazards if the works are designed to provide

18、the ability of revivification for the natural environment, ecosystem, and the corresponding peripheral characteristics. </p><p>　　(2) Improving the protective ability of ecosystem (for medium scale hazards s

19、uch as scouring of streambank and streambed): The methods should consider porous materials that will form many voids to provide shelter and protection for both aquatic and terrestrial animals. The mitigation should consi

20、der overall characteristics of watersheds and maintain the connections to the original natural stream environment, and avoid changing the current ecosystem or a single purpose construction.</p><p>　　(3) Impr

21、oving the recoverability of ecosystem (for small-scale hazards such as surface erosion): Original local materials such as local stones, local woods, and local plants should be adopted for mitigation and the methods shoul

22、d have the ability to improve the recoverability of ecosystem.</p><p>　　(4) Improving the functions of streams (for the streams with mitigation done): Design of stream mitigation and rehabilitation should co

23、nsider incorporating the local environment, potential purpose of recreation and compatibility of future residential construction. The functions of stream mitigations can be improved with the incorporation of the ecologic

24、al engineering methods such as building recreational area, scenic streambank, and ecological buffer zone.</p><p>　　2.2. The functions of the ecological corridor</p><p>　　The objective of creatin

25、g an ecological corridor is to retain or rebuild the major routes for local fauna's needs for survival, breeding, food, and migration. The role of the ecological corridor includes conduit, habitat, filter, barrier, s

26、ource, and sink (Noss, 1991). Some examples of ecological corridors in Taiwan are discussed below. </p><p>　　(1) Improvement of longitudinal ecological corridor </p><p>　　In 2003, at Liu-chung C

27、reek in Tainan County, a longitudinal ecological corridor (a fish passage) as well as a sediment control check dam were constructed upstream. A census of fish species was conducted at pre-construction, during-constructio

28、n, and post-construction. The pre-construction investigation shows fewer fishes existed in the upstream due to 1.3 m gap in the creek, which prevented fish from migrating upstream. After the corridor was implemented

29、 with a fish passage, the number of fish i</p><p>　　(2) Construction of longitudinal corridor</p><p>　　Hou-fan-zi-keng Creek is located in Taipei County in northern Taiwan and it is abundant wit

30、h various species. In July 2001, Typhoon Nari caused the collapse and erosion of the banks. The creek changed its course and caused severe sedimentation. The habitats in the creek were destroyed and the survival of many

31、aquatic animals was threatened. In order to revitalize the ecology, non-cement based ecological engineering methods were used, including wood-log pile shoring for bank protection and arc-sh</p><p>　　(3) Impr

32、ovement of lateral corridor using gentle slopes</p><p>　　In the debris flow mitigation at Chung-ho Village in Taipei County, gentle slopes of streambank protection were designed to fit the topographical flat

33、 area. The gentle slopes serve as an interaction base for both aquatic and terrestrial animals ensuring the continuity of the lateral corridor. </p><p>　　(4) Example of pitfalls due to lacking gentle slope&l

34、t;/p><p>　　The bank mitigation design for debris flow of Da-tsu-keng Creek in Taipei County was 1:1 sloping with slit dams. There was no designated gentle slope. When a deer entered the creek for food, it fell

35、into the channel which is 3 m lower than the bank and could not climb back up by itself. Out of fear, the deer cried out and dashed down in the creek. With great effort, people rescued it. This should teach us a les

36、son about the importance of having a gentle slope zone and ecological corridor.</p><p>　　2.3. Some drawbacks of conventional engineering</p><p>　　Natural streambanks allow water seepage. Organic

37、 matter and minerals in the ground will be carried by groundwater entering a stream. Natural porous materials enable the exchange of water, which maintains water quality. Using concrete in preventing flood and erosion is

38、 considered safer than natural streambanks. However, it will break the continuity of groundwater. Also, some channelized streams were built with smooth vertical concrete revetments. Such design will cause problems such a

39、s difficulty</p><p>　　Tall slit dams will cut off longitudinal ecological corridors. For a perennial stream, a slit dam will block fish migration. A fish passage should be considered. Check dams with drops h

40、igher than 1 m can hinder fish migration also. For flow regulation works, a concrete paved streambed will make pool, shoal, and riffle disappear; and water quality will be easily degraded.</p><p>　　3. P

41、lanning and design of stream mitigation using the ecological engineering methods</p><p>　　3.1. Fundamental concepts</p><p>　　(1) Consider balance in safety, ecology and landscape </p><

42、;p>　　Consider the priority and balancing of safety, ecology and landscape according to the regional characteristics. Safety shall be the first considered for the hillslopes near urban areas. In contrast, ecology shoul

43、d be the major factor for mountain hillslopes with various ecological systems. For other areas safety, ecology and landscape should evenly considered.</p><p>　　(2) Develop suitable mitigation according to lo

44、cal environment</p><p>　　Create integrated design to be compatible with local environments such as regional ecological resources, natural hazards, environmental characteristics, landscape scenery, historic m

45、onuments, and resident opinion.</p><p>　　(3) Perform integrated planning and design for watersheds</p><p>　　Plan hazard mitigation and rehabilitation by taking watersheds as a whole unit includi

46、ng, building natural ecological district, environmental protection area, improving habitats, and recreation areas, etc.</p><p>　　(4) Create aqueous environments</p><p>　　Construct facilities for

47、 aqueous ecological environments such as pool, shoal, riffle, backwater, slack, flow deflectors, fish passage, and artificial wetland. Building boulder revetment and rearranging existing rocks in streambed is an excellen

48、t method to control the flow speed and to create the above aqueous environments.</p><p>　　(5) Create the terrestrial environment</p><p>　　Construct facilities for terrestrial ecological environm

49、ents such as vegetation, garden, and terrace.</p><p>　　3.2. The principles of integrated design for streams</p><p>　　(1) Build a natural ecological environment </p><p>　　Provide nea

50、r nature works which help pool, shoal, rapids, riffle, slack, backwater, and flood terrain to develop naturally.</p><p>　　(2) Design flood detention ponds according to landforms</p><p>　　In miti

51、gation of streams we can use open areas, such as flood terrain, playground, wetland, agricultural pond, terraces, as flood detention ponds.</p><p>　　(3) Comply with the original course of streams</p>

52、<p>　　It is important to comply with the original course of a stream for streambank mitigation and avoid equal-width or parallel design for channel.</p><p>　　(4) Avoid interfering with habitats</p>

53、;<p>　　To better preserve habitats, necessary construction should be planned away from ecologically sensitive areas that might be affected.</p><p>　　(5) Design gentle slopes for streambanks</p>

54、<p>　　In order to provide the ecological corridor for interchanges between aquatic and terrestrial animals a gentle slope of streambanks less than 1V:1.5H is suggested.</p><p>　　(6) Put stones in strea

55、m courses and streambanks to generate porosity and voids</p><p>　　The voids between stones create shelters and habitats for animals. For aquatic animals to find shelter, forage, rest, sleep, and breed, the h

56、abitats constructed by concrete structure can be improved by adding surface stones.</p><p>　　(7) Obey the following five principles to efficiently reduce the construction impacts on environments </p>

57、<p>　　a. Use porous materials on structure faces to create roughness and voids to enhance habitats. </p><p>　　b. Lower height of dams and minimize size of structures.</p><p>　　c. Make slope

58、s of streambanks gentle to create ecological corridors.</p><p>　　d. Use natural materials in construction for diversity.</p><p>　　e. Make interfaces between structures and make permeable ground

59、for water circulation.</p><p>　　4. Selected examples of the ecological engineering methods of Taiwan</p><p>　　Selected examples of the ecological engineering methods of Taiwan are introduced as

60、following. </p><p>　　(1) Stone revetment </p><p>　　The main purpose of stone revetment is to protect the toe of streambank and avoid erosion. In particular it can prevent piping caused by seepag

61、e. Well-constructed stone-paved revetment can be considered a retaining wall that withstands active earth pressure of streambank. Stones and the finished surfaces have a natural appearance. The spaces and voids between t

62、he stones are advantageous to habitats and better vegetation than concrete revetment. The best stones are those washed down the stream in</p><p>　　(2) Stone revetment with concrete lining</p><p>

63、;　　When safety is more of a concern due to rapid current erosion, and it is deemed beneficial to protect the habitats, an inner concrete lining is used behind the surface stones in addition to the above stone revetment.

64、A concrete lining provides a stronger resistance to flooding. Although the ecological function may be somewhat reduced due to the concrete lining, the backfill with gravel behind the concrete lining can drain off water i

65、nto the streambank. The surfaces of stone revetment still have </p><p>　　(3) Streambank protection using wood-log piles</p><p>　　The method can be rapidly constructed at low cost and easily adap

66、ts to the sinuous geography of streams. It is suitable for slow current streams or section of gentle slopes. The completed revetment is low, and it is easy to complete reforestation and beautification. The wood piles rot

67、 naturally and are decomposed by microorganisms, thus becoming merged to the environment without sacrificing their functions. The method cannot be applied to high erosion potential or rapid current section. </p>&

68、lt;p>　　(4) Wood stakes and coir-log revetment</p><p>　　The method is applied to current velocity less than 3 m/s, and where urgent, temporary, and quick treatments are required. The method adopts coi

69、r-log for backfill materials. The finished revetment has the characteristics of lower height and permeability. The coir-log rolls are made from plant fibers and will decompose eventually. Similar to wood-log piles, wood

70、stakes and coir-log revetment would rot and become part of the environment. </p><p>　　(5) Boxed gabion revetment</p><p>　　The method is applied to high erosion potential and fast flow velocity s

71、ections. The cobbles and gravels confined in gabions provide better resistance than stone revetment for flooding. The permeability is high to easily drain off groundwater and rainfalls. In addition, when the deformation

72、of revetment is not uniform and excessive, the flexibility of the boxed gabions can provide good compatibility for large deformation. The porosity of the gabions makes it possible for frogs, snails, and other</p>

73、<p>　　(6) Arc-shape stone streambed sill</p><p>　　In perennial streams, the method can be adopted to prevent the stream from eroding vertically and horizontally, to stabilize the streambed, and to reduc

74、e velocity of flow. By applying the arching effect, the method transfers the pressure of running water to the streambank. There is only compression pressure between the stones and no tension. The connected and chained co

75、nstruction is more stable than a single stone. By the stone streambed sills, the stream water will descend to create a diversifi</p><p>　　(7) Slant streambed sill </p><p>　　The method can reduce

76、 the velocity of flow, stabilize the flow, prevent streambed from scouring, and let the flow course remain stable. It adopts concrete and stone mattress in rapid flow section to reduce velocity and regulate the gradient

77、of stream. It also forms a natural looking stone surface landscape.</p><p>　　5. Inspection of the ecological engineering methods in Taiwan</p><p>　　Properly designed ecological engineering metho

78、ds are effective for restoration of ecosystem. During planning and design stages of mitigations, the factors such as safety, ecology, landscape, geomorphology, and hydrology were considered by the SWCB. It was found that

79、 the ecosystems reinstate gradually after using the ecological engineering methods. Through the two-year ecological investigations directed by SWCB for Liu-chung Creek in Tainan, Mu-dan Creek in Taipei County, and Tou-b

80、ain-keng Creek</p><p>　　The average annual rainfall of the world is about 500 mm. However, the rainfall in Taiwan is from 2500 to 3000 mm annually. During Typhoon Mindulle (2 July 2004), within onl

81、y three days, the abnormal high rainfall was measured up to 1159 mm in central Taiwan, and up to 2066 mm in southern Taiwan, nearly the average annual rainfall of Taiwan. On 24 August 2004 there came Typhoon Ae

82、re, which caused many mitigation works applying ecological engineering methods to be damaged. Therefore, it is obviou</p><p>　　After the Chi-Chi earthquake in 1999, the SWCB paid more attention to the aspect

83、 of safety and ecology in mitigating of streams. Some projects, constructed by ecological engineering methods, were still safe and stable during the calamity of heavy rainfall in Typhoons Mindulle and Aere. Field reconna

84、issance determined that about ten streams in which mitigations using ecological engineering methods were just complete, survived the severe flooding of Typhoons Mindulle and Aere. Only some arc-shape </p><p>

85、;　　After Typhoons Mindulle and Aere, there were 821 projects (a total of 390 ha) treated with the landslide source control with staking and wattling method had been inspected. Only 164 projects showed damage (102 sl

86、ight damage and 62 serious damage). The damage area is about 58 ha. Therefore, the effective stabilized area is more than 85%. The 15% damage area mostly showed local scouring or collapsing caused by the tremendous

87、rainfalls. However, there was no major hazard such as debris flow and lar</p><p>　　6. Integrated mitigation for debris flow Torrent—an example of Hua-shan Creek in Gu-keng County, Taiwan</p><p>

88、　　Hua-shan Creek is not a perennial stream. Water flow only appears during heavy rainfall for a couple of days. Therefore, the aquatic life form in the creek is very rare. The geological condition in the watershed of Hua

89、-shan Creek is generally unstable with high potential of debris flow. The mitigation for the creek considered safety first, and ecology second. The disasters of the debris flows were triggered by a heavy rainfall event i

90、n 2000 and Typhoon Toraji in 2001. As a result, the stream cha</p><p>　　There are few residents in the Hua-shan Creek area. Relocating people will be the long-term safety solution because there is no omnipot

91、ent engineering method that can ensure the safety of people living in a dangerous habitation. However, due to important indigenous cultures and for rural development, the inhabitants, the government, and SWCB concurred t

92、o commence the integrated design of the mitigation for Hua-shan Creek.</p><p>　　The major mitigation of Hua-shan Creek is presented as follows ([SWCB, 2004], [Wu, 2002a], [Wu, 2002b], [Wu, 2002c] and [Wu, 20

93、02d]): </p><p>　　(1) Source zone: For treatment of landslide source zone, it is necessary to investigate the locations, possible sliding areas and volume of the landslide first. The landslide source control

94、with staking and wattling method mentioned previously was adopted. </p><p>　　(2) Sedimentation control: It is often found that the streambed is eroded seriously in both vertical and horizontal directions aft

95、er debris flow occurrence. As a result, the streambed could remain unstable and easily induce sliding. It provides the source of sediments which can be transported to downstream and again erodes the streambed. The scenar

96、io repeated from upstream to downstream periodically. For sediment control, series of low check dams were used for applying ecological engineering met</p><p>　　(3) Transportation zone: In this zone, slit dam

97、s and a series of low check dams were adopted to reduce the energy of debris flow as well as erosion of streambed. Application example is demonstrated for the No. 1 and No. 2 slit dams, stone dam, and a series of low che

98、ck dams. </p><p>　　(4) Deposition zone: In this zone, the slit dams and sedimentation basin based on the ecological engineering methods were designed. The vegetation was applied in the wide-open streambed. D

99、ue to limitations while acquiring the land, a large sedimentation pond was not possible in this project. </p><p>　　(5) Dredging pathway and educational area: The debris flow area after mitigation is planned

100、as an educational park. The sidewalk in the left bank was used as recreational area and for the study of ecology. The sidewalk will also be used as a dredging pathway if future debris flow occurs. To quickly drain rainfa