Abstract Sustainability of water resources is vital especially for developing countries such as Iran which are located in the Middle East and North Africa (MENA) region where water is scarce. To balance the high demand of water for economic growth and at the same time preserve the environment for present and future generations, sustainability of water resources should be considered by monitoring and data mining. For this purpose, several quantified indices have been proposed and applied worldwide recently. In this paper, the Canadian Water Sustainability Index (CWSI) proposed by PRI, has been trailed for the case of Ahwaz County, a community located in South West of Iran fed by Karun River. Required data for the composite CWSI score which is the average of five major theme-based components (i.e. resource, ecosystem health, infrastructure, human health capacity) was collected according to the PRI evaluation method. In addition to the standardized CWSI, the final index was also calculated considering weight estimation for the five components by pair-wise comparison, using Expert Choice version 2000. Results showed that application of this index as a policy tool, with some modifications in weights, was satisfactory for the educational case study and could be replicated for other communities in Iran.
J. Bio. & Env. Sci. 2014 improvement and ultimately guide appropriate action and policy-making towards better service delivery and improved resource management. The Canadian Water Sustainability Index (CWSI) has been developed by the Policy Research Initiative (PRI) for evaluating the well-being of Canadian communities with respect to fresh water resources. This index integrates a range of water-related data and information into a series of 15 indicators, classified in five major theme-based components (i.e. resource, ecosystem health, infrastructure, human health capacity). The CWSI which is the arithmetic average of scores of the indicators provides a holistic profile of a community’s key water issues, allowing for comparison and analysis (PRI, 2007). As mentioned above the main purpose of this research is to assess the water resources sustainability and well being in the Ahwaz County located in South West of Iran fed by Karun River. In the absence of any local index, the Canadian Water Sustainability Index (CWSI) has been used. Material and methods In the absence of any local index, the CWSI has been trialed for the Ahwaz County in Iran. Most of the water and wastewater data for calculation CWSI indicators in this community were collected form the local (AWWC, 2006) and national sources (NWWEC, 2006), while the demographic information were acquired from the latest census carried out (SCI, 2006). In this study, the standard CWSI score which is the simple average of five major theme-based components was first calculated according to the PRI evaluation method. Furthermore, the index was also calculated considering weight adjustments. For this purpose, importances of five components relative to each other were first estimated on the basis of an internal data analysis and weights were further calculated by pair-wise comparison, using Expert Choice version 2000. In this regard, arithmetic weights were considered for the components. On this basis the final CWSI of the five components were calculated according to the following formula: N i i i1 CWSI (1) N Where: w i1 X w i X i refers to component i of the index for a particular community W i is the weight applied to that component. Finally the standardized CWSI score was compared with the weighted average. Study Area Ahwaz City is the center of Khuzestan province, located in South West of Iran (Fig. 2). Ahwaz County (City of Ahwaz and subsidiary cities) has a population of 1,166,287 people (NWWEC, 2006). Karun River, the most important river of Iran, passes through this county which is located about 12 meters above the sea level (Fig. 2). This river is the main source of supplying drinking water to the citizens and abstraction from the ground water resources is negligible. Total length of the water supply network is 2349 km which covers 278,000 connections (AWWC, 2006). Fig. 2. Province – Iran. Location of Ahwaz County in Khuzestan The flow rate of Karun river, measured at Ahwaz station, are 90 m 3 /s in low water seasons, 2500 m 3 /s high water season and about 5000 m 3 /s in maximum floods. This River suffers from discharge of pollution loads from industrial, agricultural, agro-industrial and domestic sources. Increasing water withdrawal from and wastewater discharge to the river has 188 | Attari et al.
J. Bio. & Env. Sci. 2014 endangered the aquatic life of this important ecosystem. Furthermore, the drinking and in-stream water quality standards have been violated in many instances (Karamouz et al., 2008). Result and discussion The indicators of CWSI for Ahwaz County were calculated according to the mentioned methodology. Results for estimation of each of the 15 subcomponents, grouped in the 5 thematic components, are summarized below. 1. Resource: This component, evaluated at the river basin scale, scores the natural endowment of freshwater and comprises three indicators of Availability, Supply and Demand as follows: 1. a. Availability: This indicator assesses the annual amount of renewable fresh water available which is 21.8 BCM for the population of 1,166, 287 persons for Ahwaz County. Considering the Falkenmark water stress indicator as a bench mark, the score for this component would be Ra = 100. three indicators of Stress, Quality and Fish as mentioned below: 2. a. Stress: This indicator is intended to reflect the pressures imposed on ecosystem by pollution as well as excessive water use. In Ahwaz County, 20.5 BCM of water is removed from the ecosystem which leads to score of Es = 85. 2. b. Water Quality: This indicator assesses the quality of water with respect to protection of aquatic life. For this purpose CWSI relies on the Water Quality index (WQI). This tool was also employed for the case of Ahwaz County which provided a result of Ewq=85. Water quality is an important factor for preservation of human life and aquatic ecosystem. Even if water may be available in adequate quantities, its unsuitable quality limits the uses that can be made of it. Although the natural ecosystem is in harmony with natural water quality, any significant changes to water quality will usually be disruptive to the ecosystem. 1. b. Supply: This indicator considers the seasonal variability of the supply only as the ground water resources depletion does not occur in Ahwaz. Using discharge time series of the Karun River at Ahwaz location, run-offs exceeded 5% and 95% of the year are 244 (m 3 /s) and 1715 (m 3 /s) respectively. By dividing the last tow fig.s, the score for this component would be Rs = 0. 1. c. Demand: This indicator assesses the current level demand of water on the basis of water license allocations. In Ahwaz County, the total amount of water consumed for municipal, irrigation and industrial use were 1.3 BCM in 2006. This amount in relation to the total amount of renewable freshwater (21.8 BCM), scores Rd = 94. 2. Ecosystem Health: This component examines the health of the river basin's aquatic system with Quality of surface water is affected by the environment, climate condition, and seasonal variation, and land-use, natural and man-made pollution of watershed. Considering growth of water use for different consumptions (e.g. domestic, agricultural, and industrial) and discharge of wastewaters in rivers, several water quality parameters are usually monitored along rivers in different periods. However, there is a need to combine results of such measurements in the form of composite indices which are understandable to political decision makers, non-technical water mangers and general public (Simoes et al., 2008). A number of indexes have been developed to summarize water quality data in an easily expressible and easily understood format (Sanchez et al., 2007). A water quality index provides a convenient means of summarizing complex water quality data and facilitating its communication to a general audience. 189 | Attari et al.