Systematic index frame for functional assessment of constructed wetlands Hui-Ting Chang a , Lei Yang a , Shin-Cheng Yeh b , Ho-Wen Chen c, * a Department of Marine Environment and Engineering, National Sun Yat-Sen University, 70, Lienhai Rd., Kaohsiung 80424, Taiwan, ROC b Graduate Institute of Environmental Education, National Taiwan Normal University,162, Heping East Road, Section 1, Taipei, Taiwan, ROC c Department of Environmental Science and Engineering, Tunghai University,181, Section 3, Taichung Port Road, Taichung City 40704, Taiwan, ROC article info Article history: Available online 26 December 2012 abstract Constructed wetlands (CWs), a form of natural or ecological engineering, are used for wastewater clar- ification as well as water resource conservation and restoration around the world. To assess the ecological and environmental functions of CWs, this paper proposes a systematic index system using a rate-level method to reflect the subjective and objective value of the wetland as well as to quantify its functional capacity. The systematic index framework, consisting of hydrology and ecology, along with landscape, socio-economic and service factors, is developed using the DPSIR (Driving Force, Pressure, State-Impact and Respond) model. Information on wetlands in Taiwan including the construction, operational status, and water purification ability, together with questionnaires, is collected. The results indicate that hydrological conditions and the types of plants in wetlands are the major determinants of the success of constructed wetlands. According to questionnaires answered by experts, the functional assessment system is composed of six oriented components, 13 main indicators, and 29 sub-indicators. The six components are Protection of Water Resources, Landscape and Environmental Maintenance, Ecosystem Health, Cultural Assets, Social/Economic Services, and Operations and Management. This research will provide an assessment of the implementation of constructed wetland efficiency and multi- objective planning of constructed wetlands, and may serve as a reference for the government in amending the wetlands law in Taiwan. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Rapid industrialization and urban exploration in the 20th century has lead to degradation of environmental quality and loss of natural resources. Carlisle et al. (1998), reported that more than 60% of the world’s wetlands are quickly disappearing due to economic and political incentives for their destruction, along with a lack of consideration of the wetland ecological environment (Hey and Philippi, 1999; Sonntaga and Coleb, 2008). Therefore, many environmental organizations have highlighted the importance of wetlands for global development, ecosystem functions, service functions, and social economy (Benyamine et al., 2004; Mitsch, 2005; Pereira and Cooper, 2006). Since 1995, the government of Taiwan has paid greater attention to the importance of wetlands protection and management. The government currently provides research funding to support the construction and maintenance of wetlands. To date, there are 75 constructed wetlands in Taiwan. According to the classification of the Urban and Rural Development Branch of the Construction and Planning Agency of the Ministry of the Interior (URDB) in 2007, these 75 wetlands can be sorted into 2 international-level, 41 state- level, and 32 regional-level wetlands (URDB, 2007). Over the past 15 years, the government has announced various management strategies and regulations (shown in Fig. 1). However, the lack of a systematic framework to assess the water quality improvement and ecological conservation functions of constructed wetlands has hindered the performance improvement of CWs. For this reason, the Public Construction Commission (PCC) in Taiwan has begun the use of engineering life-cycle assessment to ensure the sustain- ability of constructed wetlands (Report No.0950277, 2006). Addi- tionally, other research and government organizations have also proposed their own methodologies for constructed wetland func- tion assessment. Generally, most researchers agree that the benefits of a wetland come from the basic structural, ecological, and social service functions embedded in it, and these functions can be used to evaluate the performance of a wetland (Loiselle et al., 2001). For example, Smith et al., in 1995 uses the areas of hydrology, removal of pollutants, and habitat features as indicators for evaluating the * Corresponding author. Tel.: þ886 4 23590121x33636; fax: þ886 4 23595941. E-mail address: hwchen@thu.edu.tw (H.-W. Chen). Contents lists available at SciVerse ScienceDirect Ocean & Coastal Management journal homepage: www.elsevier.com/locate/ocecoaman 0964-5691/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ocecoaman.2012.12.009 Ocean & Coastal Management 73 (2013) 145e152