The project to create a green belt around the city of Ouarzazate was presented to King Mohamed VI during his visit in 2007. Welcomed with enthusiasm, this initiative perfectly meets the kingdom's international commitments and its national policy. It is part of an integrated sustainable development that promotes long-term effects. It also responds to Sustainable Development Goals 6, 13 and 15 (SDGs) defined by the United Nations, particularly with regard to the policies put in place to: Guarantee access for all to managed […] sanitation services sustainably; Take urgent action to combat climate change; Preserve and restore terrestrial ecosystems […] fight against desertification […] put an end to the loss of biodiversity.
The subject of an agreement between the Ministry of the Interior, the Provincial Council and the High Commission for Water and Forests, the general objectives of the project therefore include environmental, climatic and socio-economic issues of vital importance for the inhabitants. from the city. This is to contribute to:protect the city against desertification and strong winds;Create recreational spaces for the population ;Optimizing the use of water for irrigation. The belt area encompasses the outskirts of the city of Ouarzazate, the banks of the Mansour Eddahbi dam lake and some spaces inside the city.
Of the approximately 2000 hectares initially planned, only 635 hectares will finally be retained after three years of the launch of the initiative.
After a series of technical studies and consultations between project stakeholders, a global reframing was approved around two main elements: Decrease in the area of plots dedicated to plantations and gradual introduction of the use of treated wastewater discharged by STEP.
A new irrigation architecture
The memorandum of understanding signed between UNEP, the United Nations Convention to Combat Desertification (UNCCD) and the Forest Service of South Korea called "Partnership for Greening Drylands on Forest Rehabilitation, Conservation Biodiversity and Sustainable Land Management” has as its first pilot project “Biodiversity Conservation and Community Development through Tree Planting”. This pilot project first covers three African countries: Morocco, Tunisia and Ghana for the period 2012-2015. A second phase 2015-2018 will include Benin and Ethiopia. The Forest Service of South Korea provides financial support to the project under the initiative of Changwon.
It will be in this context that Targa integrates the project of realization of the green belt of Ouarzazate by signing a cooperation agreement in 2012 with the UNEP. This involves setting up a solar pumping system for treated wastewater for the irrigation of the green belt.
Favorably received, this initiative initiates a strategic change and gives the project a strongecological added value insofar as the wastewater of an arid city is recovered and purified in compliance with environmental standards to be then reused in the irrigation of the green belt and recreational areas and this by solar pumping only.
In addition to this technical challenge of rethinking the entire irrigation system, there are two other innovative components in the device allowing rational and optimized management of purified water: a modern weather station for data collection and a remote management system via a powerful digital application.
The complete architecture of the irrigation system is reviewed and the necessary resizings are gradually implemented by the Targa teams. They support the realization of this new configuration on a daily basis through the design, installation and management of the solar-powered irrigation system.
At the end of the third phase of the project, some 635 hectares will be irrigated by this new device. In the medium and long term, the effects will be multiplied both on the irrigated area and on the environment and biodiversity of the region. The same applies to the social and economic prospects of the city.
Technical achievements:
·Installation of pumping stations (head station):
The pumping station with a filtration system was initially to consist of two pumping units fulfilling the need for three plots of the project. However, the cost turned out to be high compared to the estimated budget. An intermediate two-phase purchase solution was adopted.
. Installation of the photovoltaic field
The installation work of the photovoltaic field at the level of the Anatim perimeter required earthworks and preparation of the foundations supporting the metal frame and the installation of the tubing for the power cables between the technical room and the field. photovoltaic. As the work progressed, relocations of the panels were carried out according to the needs expressed, the operation of the two pumps and the rotary filter required the installation of 120 photovoltaic panels.
. Installation of a suction tarp
The impurities contained in the recovered water cause malfunctions in the drip system and more particularly in the water valves. The latter are clogged and cause a break in the flow of water to the plants. The installation of a suction cover near the pool was therefore necessary to accommodate a filtration system adapted to this unforeseen situation. It is a room dug into the ground and made watertight.
Casing of the basin of the suction tank.
Casing of the walls of the filtration station.
· Installation of a rotary filter
The suction cover accommodates this filter equipped with a rotating drum. It soaks in the water to be filtered which arrives from the basin. Its wall, covered with a porous layer, traps solid impurities. A blade scrapes the drum at a distance to remove solid residue as it goes, while maintaining effective wall porosity. The water thus filtered is sucked up by the pumps and then sent back to the main pipes and then to the drop by drop.
· Setting up a weather station
Installed at the foot of the STEP, the station allows the measurement of the surrounding climatic parameters every 10 minutes. These parameters include temperature, air humidity, wind speed and direction, rainfall and solar radiation. Through these readings, it is a question of centralizing significant measurements on the meteorological state of the sectors, of integrating consumption forecasts, of taking into account operating constraints, and possible savings in electrical energy consumption to ensure optimal overall management.
It is a fundamental decision-making aid in irrigation planning.
Currently, this device only concerns the so-called Anatim plot. The results of this first experience will depend on its extension to the entire perimeter of the green belt.
Implementation of a remote management system
Thanks to this system, the planning and management of the irrigation of the green belt and recreational areas will be done in appropriate and optimal conditions and according to the climatic data provided by the meteorological station. This system thus enables: (i) optimization the mobilization of water in sufficient quantity (ii)the reductionoperating costs and network maintenance costs (iii)automation irrigation system facilities (iv) mastery irrigation planning by generating reports, statistical data and balance sheets that help decision-making
Installation of a nursery
The establishment of a nursery of forest seedlings near the green belt was taken on the initiative of the Targa team on land near the perimeter of the Anatim plot. This establishment aims to anticipate the lack of plants by immediate reactivity on site but also to develop new forest areas.
. The other perimeters of the right bank of the green belt:
. Perimeter of Oued R'Bat:
Initially, the perimeter of Oued R'Bat was irrigated through diesel pumping (generator), the ambition of the project as well as the cost of diesel pumping a imposed the conversion of diesel pumping to solar pumping
The Targe association has set up a motor pump unit (Q=42.7 m3 /h) to ensure this operation, the operation of this pump is done through 56 photovoltaic panels.
Perimeter of tasserda:
The tasserda perimeter will be irrigated from the Ouad-R'bat perimeter, which required the reinforcement of the PV field at the Ouad R'bat perimeter with 90 panels.
The targa association recently deposited the metal frame of the PV field, in addition it supplied the motor pump unit intended for the irrigation of the tasserda perimeter, pending the installation of the photovoltaic panels very soon.
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.Generalization of the use of wastewater:
The generalization of the use of treated wastewater for all the perimeters of the green belt required the supply of two new motor pump units at the level of the head station.
In addition, several operations have been finalized concerning the installation of the PV field relating to the two motor pump units, more particularly:
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Excavation and foundation preparation for the support of the metal structure of the photovoltaic panels;
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Installation of power cable casings between the technical room and the photovoltaic field;
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Installation of the warning mesh for the protection of the cables;
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Preparation of the metal frame of the photovoltaic panels.
. Other works:
After the laying of the main water supply pipe and the construction of a new technical room at the level of ouad R'bat on the part of the provincial council of the city of Ouarzazate (project partner), the Targa association intervened to ensure the connection of the main pipe with the technical lots of Ouad R'bat and Anatim in order to ensure the pumping of water through the main pipe.
In addition, the association made some modifications to the secondary pipe located inside the old Anatim technical room, in order to guarantee the pumping of water from the suction tank built in the screen.
Field management and monitoring
Targa is responsible for setting up the entire solar pumping system. To do so, it uses external service providers for certain works, in particular earthworks, development and construction. Its missions include, among other things, ensuring:
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The management of the expenditure of the funds dedicated to the device;
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The choice and then the purchase of the appropriate equipment;
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Supervision and monitoring of development works with the service provider;
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Maintenance of pumping equipment, photovoltaic panels, filtration system as well as the remote management system.
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Moving equipment (photovoltaic panels, solar pumps, etc.) as needed;
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Control and supervision of the remote management system provided by the engineer on site;
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The collection of meteorological data through a specific application;
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Training and awareness of users in the operation and maintenance of the irrigation system and the remote management system. A manual is provided to the maintenance company.
Constraints and difficulties of the terrain
Like any pilot project, the implementation of the solar pumping unit faced several difficulties and hazards to which it was necessary to provide answers and find solutions. These obstacles are all lessons to be learned for the rest of the project but also for possible duplications.
Some of the difficulties that have caused slowdowns and delays in implementation include:
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Delays in finalizing calls for service tenders within the implementation deadlines;
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Few and insufficiently qualified human resources: poor maintenance of the irrigation system impacting the availability of water in sufficient quantity for the irrigation of certain plots;
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Absence of regulation of pumping at the outlet of the WWTP: farmers (mainly olive-growing) withdraw large quantities for their needs;
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Slow procedures for obtaining authorizations to lay cabling through private properties.
Results achieved and expected in the short and medium term
Immediate effects
- Solar powered drip irrigation system currently covers Anatim 1 and 2 plots wooded with eucalyptus, tamarix and acacia trees.
- The system has also made it possible to create jobs essential to the maintenance and planting of trees
- New knowledge and skills in the design, installation and management of a drip irrigation system powered by solar energy are acquired.
Short and medium term effects
A third phase in progress in the perimeter of Oued R'bat will cover the water needs of 65 Ha. The system should then cover the planned 30 Ha of recreational spaces in the city, then the perimeters of Talat (153 Ha) and the area adjoining the public dump (100 Ha).
The expected effects of the implementation of the system should allow the consolidation and then the development of the green belt. These effects are measured from 3 main angles:
From an environmental point of view : Effects on greenhouse gases. First of all by reducing their emissions into the atmosphere by adopting solar energy. Then by the retention of these gases by the trees: According to studies, 1 wooded hectare can ensure up to 24 tons of CO2 retained / year; The effects on biodiversity will begin to be felt by the gradual development of a local microclimate (increase in the humidity rate, etc.)
From an economic point of view : The economic benefits are analyzed in terms of potential for the creation of income-generating activities (IGA) around the green belt and recreational areas and its direct effects on families. Other positive economic effects in agricultural terms are envisaged: development of agroforestry, olive growing and other crops compatible with the use of treated wastewater. Finally, thanks to land reclamation, the area should attract more and more small investors.
In social and educational terms: Recreational spaces bring well-being to the inhabitants. The lack of green spaces that can provide shade and coolness in summer in particular has been reduced. Tours of the belt are organized for local pupils and students. Future generations are made aware of the protection of the environment.
Impacts
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Reduction of the impact of strong winds on the city;
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Reduction of greenhouse gas emissions
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Reduction of the energy bill: sustainable renewable energy
