Employer: Tehran Engineering and Technical Consulting Organization, Tetco
Location: Tehran
Project duration: 24 months
Brief introduction to the project and its goals
Restoration is a purposeful activity to expedite the return of an ecosystem to its original state, considering the ecosystem resilience. Restoration of a river consists of omission and deletion of the damages imposed on an ecosystem by man in order to maintain river ecosystem functions. The restoration will support fauna and flora, ecotourism, flood management plans and urban design and landscape of urban rivers.
The major results of river restoration are improving the quality of life and welfare of citizens by creating pleasant natural spaces that guarantees the ecosystem integrity. A few results that can be foreseen through Tehran rivers restoration plans are:
• Return of river valleys ecosystem to its original state or the closest new equilibrium.
• Improvement of its flood volume passage
• Improvement of its water quality
• Providing mental and spiritual benefits for citizens by presence of water footage in the city
• Creating walking, biking and jogging spaces adjacent to river
• Educating the society regarding the necessity of environmental protection measures
• Creating playground for kids
• Generating value added for adjacent residential and commercial properties
• Implementing no-action plans that results in a reduction in maintenance costs heavy construction options
• Taking advantage of water sound to improve noise pollution
• Improvement of life indices near the river valley, such as temperature, moisture and pollutants concentrations that can have effects on Tehran air quality condition
Lastly, but not the least, river restoration will improve the natural capability of a river for bioremediation.
Darakeh and Farahzad Rivers
Darakeh and Farahzad rivers are two major rivers in Tehran that the development of the last three decades made them be part of the city.
The development of Tehran did not follow its morphology and land characteristics. With its development and in an effort to control the floods that are the most dangerous threats for Tehran, these two rivers are canalized and diverted from their original locations and buildings have been built on rivers and/or their fringes. After construction of West Flood Diverter in 1970s, the connection between north and south of these rivers are lost. The historical length of these two rivers (from outer north to south) was approximately 62.5 km. The length of Farahzad and Darakeh rivers are 17.5 and 18.5 km from northern Tehran to West Flood Diverter, respectively. South of this point, no evidence of rivers is on the surface and 26.5 km of river length is either constructed over or buried.
Historical locations of Darakeh and Farahzad Rivers, 1900
Current locations of Darakeh and Farahzad River, 2016
Two major tributaries to Farahzad River are Moradabad and Behrood floodways. The catch basin for this river is approximately 22 km2. Two major tributaries branches to Darakeh River are Khoshk and Abdolabad floodways. The catch basin for this river is approximately 25 km2.
The average discharge of Darakeh and Farahzad are 0.45 and 0.2 m3/sec, respectively. The major sources for these two rivers are springs and Qantas in dry seasons from the mountains, but in other seasons, floods are the major contributor.
List of actions required to take in the process of river restoration
The following list is the major actions required during the restoration process, please note that not all of the actions may be applicable to all length of the two rivers
• Land Acquisition
• Collection of Construction Debris
• Waste Collection
• Wastewater collection system, treatment and reuse
• Soil remediation for contaminated soil in contact with waste leachate and wastewater
• Improvement of damaged slopes and
• Placement of surficial soil suitable for vegetation
• Ecological Water Requirement (EWR) plan
• Repair of vegetation cover and wildlife rescue plan
• Promoting Eco-tourism
• Stakeholders participation
• Water resources management
Pilot Design
During the conceptual phase of the plan, a short (50 m) length of Farahzad river is considered to be a pilot length and some of the actions required for restoration is implemented in this length to not only have a showcase, but also to practice execution of the actions list. The pictures below show the pilot design.
Removal of construction debris manually, using labors released from rehab (because of drug addiction)
Slope stabilizations with stonewalls (the slopes formed after destruction of illegal housings in the river banks)
Removal of garbage and debris from river and river beds