Urban Water Issues in the Megacity of Tehran

Abstract

Iran (the Islamic Republic of Iran) is a country in Western Asia considered as the second populous nation in the Middle East region. The main environmental issues in Iran are air pollution, water quality and quantity crisis, municipal and industrial wastes, and climate change. Tehran, the capital of Iran with a population of near nine million, as a megacity suffers from various environmental and social problems, such as severe air pollution, water crisis, and slums. Water management is particularly important for Tehran as it affects the daily function of the capital, its sustainable development, and health of the citizens. The per capita renewable water is now reached to a critical threshold level in Iran. Furthermore, the withdrawal to availability ratio, as a water scarcity index, is estimated to be more than eighty percent, which shows severe water stress. In such dry condition of Iran, Tehran’s misallocation of water consumption through different categories of usage, i.e., agricultural, domestic, and industrial, has caused such important issue for the country that without resolution leads to an unfortunate chaos. Furthermore, the current per capita consumption of treated water in the city of Tehran is twice to three times of the international average. High-quality drinking water consumption for domestic and sanitary uses is another main challenge for Tehran. In addition, a significant fraction of treated water is leaked due to old water pipe systems. Additionally, sewage of the residential areas, surface runoff, and natural pollution due to geological structures can increase the chance of water resource pollution. Groundwater is one of the main sources of water supply in Tehran, but after it turns into wastewater, it is discharged away directly or with some treatments into surface waters and exits the city. This process decreases freshwater tables and reduces the water availability in the long term. Management of the nutrients is not advanced either. Nutrients of the soil are consumed in agriculture and discharged with the wastewater into the aquatic ecosystems, where they can trigger some environmental problems such as water pollution. Thus, sustainable water management (SWM) is crucial for Tehran. Applying a SWM in the megacity of Tehran may only become achievable by using an integrated water resource management, which is a process that manages the land, water, and related resources in a way that preserves the ecosystem while maximizes the social and economic comfort. Access to safe water, efficient economy, and sustainable ecosystem need to be revised in the water policies for Tehran. Engaging private sectors, creating revenue opportunities by water reuse activities, managing water-use allocation, and sustaining financial resources, above all, are the most important approaches toward a sustainable water management in it. In this chapter, we first look at the current water issues in Iran, especially Tehran. Then, by looking at the management strategies available for water resources and wastes, we analyze the shortcomings and the challenges. Finally, we summarize the opportunities and possible solutions to the water issues in the megacity of Tehran.