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This paper investigates changes in the visual perception of a stream landscape due to remediation work (i.e., the construction of a stone revetment, which is a common ecological engineering technique in Taiwan) in the Nan-Shi-Ken stream. Various images of the Nan-Shi-Ken streambank before and after remediation were collected. The visual preference ( P ) and perceived naturalness ( N ), which were selected as indices of visual perception, were quantified using a questionnaire survey. The image characteristics were analyzed by the image spectrum method and presented by the spectrum-frequency slope ( S ). Furthermore, the relationship between S and the visual perceptual reaction was presented. The results of this study demonstrate that P and N increase with increasing vegetative cover on a stone revetment after stream remediation. P and N were highly correlated with S and proportional to S . S provides an index to assess P or N for a stream landscape change due to variation in vegetation. [ABSTRACT FROM AUTHOR]

Kaohsiung City is the second largest city in Taiwan and suffers from serious floods during the wet season, but it also badly needs water during the dry season. As economic development advances and pollutants increase, water pollution and shortage of water resources become issues of concern for local people in Kaohsiung. A project has been proposed by the city government and executed by the authors to establish a system of sustainable water management in urban areas. In this system, the Caogong Canals, irrigation channels which were established 170 years ago during the Ching Dynasty of China and are still used today for irrigation, were renovated to bring stable and clean water to the urban areas. It is planned to pump clean water into the canal from a river near the city. In this project, 12 constructed wetland systems, functioning as wetland parks, stormwater storage tanks or eco-detention ponds, were built in the city, and the Caogong Canals are planned to connect all these urban constructed wetlands in the second stage of the project. [ABSTRACT FROM AUTHOR]

Many studies have demonstrated that plants have the ability to affect flow velocity, and plant materials have been investigated for their potential to be used as a buffer zone to prevent riverbank erosion. However, relatively few studies have investigated the effects of plant characteristics on flow conditions. In this study, an artificial channel was constructed to (1) investigate the nature of the morphological changes undergone by aquatic Oenanthe javanica DC (water celery) macrophytes in response to different channel flow velocities and (2) identify the tolerance limit of aquatic macrophytes under different flow velocity conditions. Results show that the morphology of Oenanthe javanica DC exhibits the following variations under different flow velocities: as flow velocities increase, growth rate slows and plant shoots become shorter and softer, thereby increasing plant flexibility. These variations were accompanied by a decrease in root length and root anchorage capacity. In response to different flow velocities, a nonlinear relationship in growth rate between total new green leaves and yellow leaves was also observed. The number of vascular bundles in new shoots was found to decrease in a flowing water environment, compared with the number of vascular bundles in terrestrial environments. The average density of vascular bundles, however, was found to increase as flow velocity increased, most likely to provide a compensatory structural support mechanism. Results of this research identified a suitable range of flow velocity for water celery as 0.05-0.30 m s−1, which is approximately equal to the average flow velocity of dredged rivers in Taiwan. Because of its abundant growth in Taiwan and its ability to adapt to the range of velocity conditions found in Taiwan's dredged rivers, water celery was found to be an appropriate planting material for intertidal zones and reservoir bank protection. [ABSTRACT FROM AUTHOR]

Abstract: Because of thriving tourism in recent years, concrete constructions have been installed by creeks in order to protect the safety of tourists, but the effect of concrete structures on the habitats and the mobility of certain species is still unknown. This study evaluates the different effects of various water bank substrates in terms of the influence on Hynobius arisanensis''s (Maki) motility in Alishan National Park. Comparing the concrete area with two other areas where primitive streams flow by, it was observed that concrete structures lead to increased flow velocities, shallower water depths and poorer water quality. In the biological motility assessment, moss, rock, wood, clay and concrete as distinct water bank substrates were used to test the climbing ability of H. arisanensis. Based on the seasonal humidity changes in winter and summer of Alishan area, H. arisanensis''s climbing ability was tested in two conditions, high humidity/high temperature and high humidity/low temperature. It was determined that climbing ability dropped rapidly with increasing slope angles. It was observed that the climbing ability of H. arisanensis is slightly decreased in low temperature. Regarding the upper limit of design slope suitable for H. arisanensis are: wood and concrete are ≤45°, moss surface ≤60° and clay surface ≤30°. The results here can provide insights for future engineering projects on creek banks to benefit H. arisanensis conservation. [Copyright &y& Elsevier]

Abstract: Because the photosynthesis ability of old artificial forest stands is inferior to that of young stands, the utilization of these logs is benefit to the sequestration of carbon dioxide. Hence, construction of wooden patios, trails, and retaining wall to substitute concrete ones could reduce the carbon dioxide emission in Taiwan. According the research data, the energy consumption during wood processing was very low, so did the carbon dioxide emission. Because concrete was replaced and about 50% of wood consists of carbon which is from carbon dioxide sequestration, both the utilization of wood and artificial forest planted could reduce the carbon dioxide concentration. The purpose of the study was to evaluate the effects of carbon dioxide emission and sequestration by using wooden structure in both wooden leisure and eco-technological facilities. Results shown when check dam constructed by ACQ treated Japanese cedar following O&D (outdoor) method and CNS3000 K4 criterion with 40 years lifetime could reduce about 30 tons of carbon dioxide emission, which is equivalent to the carbon dioxide expiration of 92 persons per year. On another case, 61 tons of carbon dioxide emission was reduced, which is equivalent to the carbon dioxide expiration of 190 persons per year. If the high energy consumption materials, such as steel and cement, could be substituted by wood or wooden material, it could be beneficial to the sustainable management of the earth environment. [Copyright &y& Elsevier]

Abstract: Ecological engineering is the design of sustainable systems, consistent with ecological principles, which integrate human society with its natural environment for the benefit of both. In 2001, the government of Taiwan began to use ecological engineering as a therapy to nurse the damaged environment and found it worthwhile for further promotion for Taiwan''s ecological environment. In recent years, the threat to amphibian animals is becoming more and more serious. The problem that concrete is mostly applied as a construction material on lakeshores in Taiwan has resulted in the obvious decrease of the habitats on which amphibian animals rely; hence, the need to develop the relevant design specification considering protecting the amphibian is imperative. Chirixalus idiootocus, an endemic species in Taiwan, is a small brown tree frog widely distributed in altitude ranging under 1500m [Chen, W.S., 2003. 31 Frogs in Taiwan. Wild Bird Society of Taipei, pp. 62–63 (in Chinese)] with its unique breeding habitat [Kuramoto, M., Wang, C.S., 1987. A new Rhacophorid Treefrog from Taiwan, with comparisons to Chirixalus eiffingeri (Anura, Rhacophoridae). Copeia 4, 931–942]. Since its uniqueness and importance, it has been a good indicator to reflect the environmental change. However, the understanding of this species is still too little and the methods to protect them have not been developed yet. The goal of this study was to understand the impacts of different substrates, gradients, and humidities of lakebank slopes on the activity of Chirixalus idiootocus. Experiments were carried out on the samplings collected in the field at Chang-Pi Lake. Among the experimental results obtained in this study, the ability of jump height and jump length were 12.93–14.03cm and 38.15–39.19cm, respectively. The male group (♂) showed the best adhesive ability on awn grass (5.11×10−2 N/g) at 45° slope, and the (♀) group performed the worst on sand (0.43×10−2 N/g) at 75° slope. Female frogs showed significant worse performance than male in jump height, jump length, and adhesive abilities, so were considered a target reference to design bank slopes based on their vulnerable behavioral capacity. With better comprehensive results obtained in this study, suggestions for the bank slope designs were thus proposed as a useful reference for ecological engineering promotion in Taiwan. [Copyright &y& Elsevier]

Abstract: With the increase in industrial development and improper land uses, Taiwan has faced the extinction crisis and is seeing the signs of nature, revenge in the forms of frequent landslides, floods, and debris flows in recent years. The government has strongly promoted the concept of ecotechnology in the hope of maintaining the ecosystem and its integrity. However, the application of ecotechnology is still in its infancy, so there is currently no objective evaluation standard to assess its effectiveness. Deficiencies in the scientific approach to quantify the results are due to current disputes and bottlenecks in its implementation. In order to seek reasonable and feasible methods to overcome the deficiencies in the implementation of the scientific approach, this study collected domestic and international ecological evaluation models to develop innovative processes that utilize ecological, safety, and cost indices. First, the commonly used ecotechnology methods for river embankment were acquired from the governmental departments. Second, the ecological, safety and cost indices for the acquired ecotechnology methods and construction sites were analyzed and quantified using fuzzy theory. Third, indices of ecotechnology methods were linked with those of construction sites for the PROMETHEE technique evaluation for suitable ecotechnology method selection. A practical construction case located in Shihmen reservoir watershed was chosen for evaluation and verification. The results show that the developed model can provide useful information for decision making while performing ecotechnology engineering. [Copyright &y& Elsevier]

Abstract: Ensuring that water resources development in harmony with aquatic environment is the major water policy of Taiwan in the 21st century, Taiwan''s water authority has adopted several methodologies, such as utilizing ecological engineering techniques, establishing integrated water resources management configuration, involving the public in decision-making processes, etc., and applying them in the field. Significant consequences in ecological engineering were obtained in several cases, such as for Ta-Chia Creek, where wire cages, tires, and boulders were installed to improve the stream habitat, and for Wu-Lao Creek, where natural water purification facilities were constructed to reduce river pollution. Although the sustainable methodologies have been widely accepted by hydraulic engineers in Taiwan, lack of engineer-friendly evaluation indices or methods hindered the further progress of river ecological engineering projects. This research applied a non-metric multidimensional–scaling (MDS) analysis to measure the assemblage change of river aquatic habitat. A dike construction project at Chu-Lan Creek was selected for verification in this study. The analyzed results showed that the dike construction project did affect the aquatic habitat in Chu-Lan Creek. The proposed MDS analysis successfully captured the effect of the construction. The MDS method could be used to evaluate the improvement or damage of aquatic habitat by a traditional hydraulic approach or a new ecological hydraulic developed technique in Taiwan. [Copyright &y& Elsevier]

Abstract: In order to reverse the trend of deteriorating ecological environment, Taiwan launched a movement to use ecotechnology to redirect construction. This policy requires that in addition to meeting function and safety requirements, all infrastructure constructions must minimize their impact on the ecology. This paper describes how this policy is implemented and gives the guidelines for ecological construction. It also used two types of infrastructure construction—slope stabilization and debris flow mitigation; and river flow management—to illustrate how the ecotechnology principle was applied to infrastructure construction. Observation so far indicates that this is the right approach for Taiwan: these new constructions endure the test of typhoons and heavy rains and reduce natural disasters; ecology recovers very well; the cost is lower than the conventional methods; and by hiring local people to do local construction, we have observed some positive change in people''s attitude about their communities. [Copyright &y& Elsevier]

In this paper, a brief description of the status of ecological engineering methods in Taiwan is given. A case example reviewing recent efforts to save the endangered Formosan landlocked salmon and results of fish population monitoring are described. [Copyright &y& Elsevier]