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Behind the Scenes of Palm Jumeirah Island


Driving through the world-renowned Palm Jumeirah Island, with its lush landscape designs, five star resorts and the most expensive residential real estate in Dubai, you wouldn`t think of the struggle UAE has with water resources` limitations in both quantity and quality. Dubai Municipality treats wastewater and has implemented Reclaimed Water (RW) distribution systems for irrigation purposes to curb the water resources` limitation. This allows the government to eliminate the consumption of potable water for irrigation, as potable water is produced through a highly costly and energy intensive process of seawater desalination.



The challenge of implementing RW for irrigation purpose is its high content of Nitrogen and Phosphate concentration, even though very beneficial for plants and greenery due to its nutrition factor, its negative side effect is the contamination of runoff stormwater with the pollutant causing algal bloom and deterioration of seawater quality when washed into the sea. Tremendous efforts are made by government to address this concern; as a result, Dubai`s coastal area water is closely monitored to ensure quality due to its critical role in tourism and the fact that it is the water supply for the desalination plant, hence ensuring the health of the public.

 

Spearheading research conducted by Dr. Kianmehr, Assistant Professor of Civil Engineering, addresses the assessment methodology through a set of numerical measurement analysis to identify potential pollutants in stormwater. The quality of RW was examined from chemical concentrations such as Ammonia, TKN, Chlorine, Zinc, Nitrogen, Nitrate and Phosphate to considering the soil`s nutrient content as a time-dependent parameter with concentration variation dependent on locations. Other factors such as type of foliage, distance between soil and irrigation point, and land slope effects were taken into consideration. Two sets of experiments were conducted to assess the amount and rate of nutrients release in runoff at different slopes and soils. The results show that eutrophication (algal bloom) could indeed be a valid concern where using RW for irrigation. It is evident that total Nitrogen and Phosphate are the governing nutrients when it comes to complying with standards for stormwater quality.   
Dr. Peiman Kianmehr
Assistant Professor of Civil Engineering



The findings reassured Dr. Peiman research to implement guidelines for future sustainable coastal area developments using RW irrigation, some of which are already addressed by land survey requirements, while the irrigation and landscaping part of it is yet to be implemented. The proposed guidelines would further the requirements from land to building ratio, into entire land division including landscaping to curtail the challenge of RW contaminants seeping into seawater through stormwater. The guidelines identify the following key parameters: 6.8% of development land allocated to building, 4.8% allocated to roads, 20% allocated to grass, 17.2% allocated to trees, 21.2% allocated to other irrigated soil, 30% allocated to non-irrigated landscaping (pools, stones, walkways, etc.). To this effect, the runoff from non-irrigated areas (buildings, roads, landscaping) with respect to irrigated areas (greenery), 41.6% to 58.4% respectively, is sufficient to dilute the final concentration of nutrients and meet the recommended criteria set by the Environment Protection Agency (EPA). This ensures the reduction of pollutants in stormwater runoff and maintains a clean source of water for the desalination plant.



Identifying and implementing such guidelines in the preliminary stages of coastal developments design is crucial for a sustainable RW irrigation system implementation. It should be noted that using different types of vegetation, including trees and grass, could affect the level of nutrient accumulation in the soil accumulated and accordingly the extent of water pollution. Additional investigation regarding the impact of vegetation types can potentially introduce more sustainable results for such projects and can be implemented when stricter stormwater quality standard is targeted.


 

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