Wadi Hanifah Comprehensive Development Plan
Landscape Performance Benefits
- Removed 17.7 million cu ft of industrial and municipal waste, enough to fill a football stadium, from an area of 4 sq miles.
- Increases riparian habitat by re-naturalizing 115 acres with indigenous plant species and 35 acres with seeded native grasses and perennials. Through self-propagation these areas expanded by an additional 47 acres between 2010 and 2015.
- Supports 15 bird species, 9 fish species, 3 mollusk species, 2 amphibian species, and 3 reptile species as observed on-site.
- Sequesters 89,145 lbs of atmospheric carbon annually in 28,021 newly-planted trees.
- Reduces potable water consumption by 92.5 million gallons per day with the use of bioremediated urban wastewater for park amenities and irrigation.
- Attracts 200,000 visitors per week, re-establishing the social, cultural, and recreational significance of the wadi for Riyadh residents.
At a Glance
Moriyama & Teshima Planners
Former Land Use
Riyadh, Saudi Arabia
Drainage basin: 1,738 sq miles; riverbed: 74.6 miles; designed urban parkland: 3,709 acres
The Wadi Hanifah and its tributaries form a unique 1,737-square mile natural basin that surrounds Saudi Arabia’s capital, Riyadh. By the 1980s, urban growth had led to the over-extraction of riverbed resources, industrial and raw sewage contamination of groundwater, flooding, and widespread ecosystem collapse. Under the direction of the Arriyadh Development Authority, the 2001 Wadi Hanifah Comprehensive Development Plan established a strategy for the environmental restoration of the wadi corridor, which was to be accompanied by the construction of the world’s largest wastewater bioremediation facility. The master plan included an Environmental Appraisal, a Water Resources Management Plan, a Land Use Plan, and a 10-year implementation program that served as a catalyst for an ambitious reinvestment in Riyadh’s public open spaces with 9 major public parks integrated into a 31-mile continuous river park corridor. The parks serve as public gateways to a vast network of interpretive and recreational trails while respecting local practices by providing outdoor family “privacy rooms,” adequate parking, and sanitary facilities. Local materials, including native plant species, are employed throughout the reclaimed basin.
The Arriyadh Development Authority’s 1994 Strategy for Wadi Hanifah recognized that the wadi’s restoration would only succeed within an integrated, long-term, watershed-scale management framework. This meant that initiatives within the urbanized perimeter of Riyadh would have to be conceived and pursued in concert with other interventions in adjacent tributaries, rangelands, and agricultural areas. The 2001 Comprehensive Development Plan also called for a bioregional renaturalization approach based on plant species indigenous to Riyadh’s arid desert setting. But the lack of established local environmental restoration expertise and infrastructure posed significant logistical challenges. As a result, the consultant’s mandate became one of capacity building and locally-appropriate technical innovation.
The Comprehensive Plan first established watershed-based water management and land use plans, which are both administered by a newly-created Wadi Hanifah Directorate. River corridor cleaning and flood-profiling interventions in the implementation stage were complemented with the construction of check dams in the upper desert catchment areas. These initiatives are now being extended into the 10 main Wadi Hanifah tributaries. Following the identification of key species indigenous to Wadi Hanifah, the Arriyadh Development Authority and its contractors collected cuttings and seeds from the least damaged portions of the wadi and began the process of growing thousands of trees, shrubs and grasses in new greenhouses and nurseries. These plants were installed in 35 different configurations of planting cells that were constructed by the thousands along the wadi bed. The cells consist of gravel-topped planting beds that become local incubators for seed propagation between cells.
- A total of 43.5 miles of river corridor were re-profiled to a more naturalistic streambed configuration with multiple pools and weirs to increase habitat value, oxygenate water, and slow water down during flash flood events. This involved moving 88.3 million cu ft of soil (cut and fill), the narrowing or removal of 26.6 miles of roadways, and the removal of 23 miles of pipes and overhead utilities.
- Continuous publicly-accessible open spaces were provided along the wadi and into surrounding residential areas through the introduction of 9 major parks, 5 lakes (totaling 62 acres), 4.6 miles of pedestrian promenades, and 29 miles of recreational trails.
- Each of the 9 parks highlights a different feature of the river system, such as dams, lakes, and the wastewater bioremediation facility itself. 3 of the parks provide residents opportunities to interact directly with the bioremediated water.
- In the Riyadh section, both the river and urban wastewater are treated through a bioremediation process that uses a food chain approach to capture nutrients and pathogens. This water is then used as a central feature in 3 of the main public parks.
- A total of 1,805 planting cells were installed in 35 distinct configurations adapted to micro-conditions along the riverbed. These serve as hotbeds for seed propagation and promote renaturalization. The cells include a total of 28,021 ornamental trees (7 different species or varieties), 6,000 date palm trees, 40,166 shrubs (20 different species or varieties), and 44,719 grasses (8 different species or varieties). A total of 35 native plant species were reintroduced.
- 10 check dams in wadi tributaries help reestablish desert tablelands and rangelands.
- Over 2,000 lay-by parking stalls ensure public accessibility. Parking spaces were consolidated in less ecologically sensitive areas along the length of the wadi.
- 3,100 custom-designed lighting fixtures (for both functional and feature lighting) ensure nighttime accessibility.
- 30 toilet blocks are provided to avoid contamination of the river corridor.
- 730 signs throughout the project facilitate environmental interpretation and wayfinding.
- Local materials are used almost exclusively, including limestone blocks for structures and aggregates for recreational trails.
The High Commission for the Development of Arriyadh was created in 1974 by the Saudi government to oversee the development of Riyadh’s metropolitan area. It is chaired by the Governor of Riyadh and includes representatives from various ministries, the Riyadh municipal government, the Saudi Electricity Company, the Riyadh Chamber of Commerce and Industry, and 3 city residents. As a nationally-constituted body, the Commission possesses significant independence and authority over the planning and implementation of metropolitan initiatives affecting municipal and private entities, including the establishment of stream corridor development setbacks and the removal of non-conforming or detrimental land uses.
The Arriyadh Development Authority (ADA) is the High Commission’s executive, technical, and administrative branch and has legal authority to control, coordinate, and implement infrastructural projects in Riyadh. As the primary client for large-scale construction projects, the ADA maintains a privileged relationship with private local contractors and providers such as nurseries.
After conducting environmental and archaeological assessments in the 1980s, the ADA adopted a Strategy for Wadi Hanifah in 1994 and began enforcing the removal of pollution sources and most industrial activities. In 2001, the ADA commissioned Moriyama Teshima Planners and Buro Happold to produce a Wadi Hanifah Comprehensive Development Plan for the entire Wadi Hanifah Reserve, which includes watershed areas within Riyadh as well as adjacent rangelands, tablelands, and tributaries. The Implementation Strategy for the plan includes 2 separate components: the Wadi Hanifah Restoration Project, which focuses on short-term actions such as the cessation of detrimental activities, flood performance, water quality, and channel streambed rehabilitation, and the Wadi Hanifah Development Programme, which focuses on long-term actions such as the further rehabilitation of natural environments and landforms, protection of ecologically valuable lands, clean-up of large contaminated sites, and development of recreation and leisure amenities including significant cultural sites. The public parks and bioremediation facility were undertaken to complement and support these initiatives by providing the means of decontaminating and recycling municipal wastewater.
The design strategies used in the Implementation Strategy reflect the specificity of local environmental and cultural conditions:
- The restoration of streambeds and adjacent rangelands to original, pre-overgrazing, vegetated coverage employs traditional Saudi technologies of check dams (earthen structures about 3 ft high, sloped at a 1:20 ratio, and capped with local quarried stone) and micro-catchments (small crescent-shaped earth mounds of about 1 ft in height) still used today to capture water and nutrients for agricultural production.
- To encourage broad public use while recognizing the privacy expectations of Saudi families, the design of the main public parks incorporates family “rooms”: limestone-walled enclosures high enough to screen views from adjacent public spaces and large enough to accommodate extended families for barbecues – the most popular outdoor activity for Saudis. Adjacent parking bays provide convenient access to these rooms, and the proximity of recreational trails and play areas allows for a range of social interactions. As a result, the Wadi Hanifah park system exhibits a degree of social and economic diversity not found in other municipal public spaces.
- Given its complexity, geographical extent, and expected multi-decade time to completion, the restoration of Wadi Hanifah benefitted from a highly centralized administrative structure managed by the Arriyadh Development Authority (ADA). Even in that context, the ADA and the design consultant made a strategic decision to introduce public amenities at the same time as environmental restoration activities. Interpretative and educational programs with local elementary schools were also implemented early on. This tie-in between ecological and social benefits increased public awareness and support for the project, which helped the ADA enforce new environmental policies (such as the removal of industrial polluters) and implement more ambitious initiatives such as the bioremediation facility. As the consultant observed, “once the general public buys into the vision there is no going back.”
- The rate of deterioration for equipment finishes, such as signage and lighting fixtures, proved much more rapid than anticipated. The client wanted darker finishes to reduce dust marks but even manufacturer finishes with a high-yield ultraviolet warranty of 5 years showed significant bleaching after only 2 years.
Benches, chairs, tables, and table umbrellas: Landscape Forms
Litter receptacles, bike racks, bollards, and signage: Custom design, Moriyama &Teshima Planners Ltd.
Client: Arriyadh Development Authority, Saudi Arabia
Landscape and Planning Consultants: Moriyama & Teshima Planners Ltd., Canada
Engineering Consultant: Buro Happold, United Kingdom
Wastewater Consultant: Nelson Environmental Inc., Canada
Construction Firm: Badan Agricultural and Contracting Company, Saudi Arabia
Role of the Landscape Architect
The landscape architect served as the primary liaison with the client and coordinated all phases of the development plan and its first phase of implementation. Particular emphasis was given to the environmental appraisal of the watershed and to the development of the rationale supporting an integrated approach for environmental restoration, urban wastewater bioremediation, and the provision of public space. Responsibilities also included the site design of all parks, parklands, and facilities, contract documentation, supervision of implementation (including overseeing the creation of a local environmental restoration infrastructure), and the development of operation and maintenance manuals.