In the past few decades, freshwater scarcity has become a global threat to the sustainable development of societies, with half of the global population living under conditions of severe water scarcity, at least one month of the year (An et al. 2021). The increasing world population, economic development, changing consumption patterns, and expansion of irrigated agriculture are the main driving factors of the rising global demand for water, thus the pressure on freshwater resources (Liu et al. 2017; Rosa et al. 2021). Climate change is also predicted to aggravate the existing challenges of water scarcity by reducing the availability of water resources and arable lands (Meltzer et al. 2013; Sowers et al. 2011; MDPS 2018; PSA 2018). In regions suffering from physical water scarcity, the state of the economy affects both demand and supply. This is the case of developing resource-rich countries, such as the ones in the Gulf Cooperation Council (GCC), where increasing water consumption is expected with higher standards of living, and water utility providers have the capacity to invest in costly water supply infrastructure, such as desalination (DeFelice and MacDonald Gibson 2013; Oki and Quiocho 2020).
Qatar, a GCC country, is an arid country located in the Arabian Peninsula, with a land area of 11,610 km2, and is characterized by erratic rainfall averaging between 40 and 80 mm/year, and high temperature and humidity (AlMamoon et al. 2014). Due to its geographical location and climatic features, the country suffers from acute freshwater scarcity with renewable freshwater resources of 28 m3/cap/year (2018), which is far below the worldwide average of 6000 m3/cap/year and the water poverty threshold of 1000 m3/cap/year (The World Bank 2022; Alhaj et al. 2017; Alsheyab and Kusch-Brandt 2018). The average domestic water demand in Qatar has been one of the highest in the world, varying between 216 and 238 m3/cap/year in recent years (PSA 2018).
Having experienced a tremendous increase in national wealth and a rapid population growth in the last three decades (Hussein and Lambert 2020), Qatar currently meets domestic water demand using energy-intensive fossil fuel-powered desalination technologies where consumers receive their water needs at a heavily subsidized cost (Baalousha and Ouda 2017). While plans are underway to expand further the desalination plants supply capacity and meet the future water demand of the growing population for at least the next 50 years, this process is far from being environmentally sustainable (Alhaj et al. 2017). In fact, the carbon footprint associated with desalination ranges from 0.3 to 34.7 kg CO2 eq/m3 of water produced with the currently used technologies; and may be reduced to 0.08–4.3 kg CO2 eq/m3 using newer (Reverse Osmosis) technologies (Cornejo et al. 2014; Liu et al. 2015). Furthermore, desalination has negative effects on marine ecosystems due to the discharge of concentrated brine into the sea (Rahman and Zaidi 2018).
As regards agricultural sector, Qatar relies heavily on non-renewable groundwater abstraction for its supply, which resulted in lowering of the water table, deterioration of groundwater quality, and rising salinity over the years (Mohammed and Darwish 2017). In effect, groundwater withdrawals contribute to nearly 25% of total water supply in Qatar which have been estimated at around 250 million cubic meters (MCM)/year throughout the period of 2008–2016, of which 226–230 MCM/year go for agricultural irrigation (Alhaj et al. 2017; PSA 2018). Furthermore, Qatar aims to increase its food self-sufficiency to 40% by 2025, which will put additional pressure on dwindling groundwater resources if no other water resources are utilized (Hussein and Lambert 2020).
To overcome these challenges, Qatar embarked in several initiatives.
-
The Ministry of Environment imposed regulations to limit groundwater withdrawals and use efficient irrigation methods, which resulted in more than 50% reduction in the volume of water used per metric ton (MT) of agricultural produce between 1995 and 2013 (Alhaj et al. 2017; Mohammed and Darwish 2017).
-
Qatar General Electricity and Water Corporation ‘KAHRAMAA’ invested in reducing the leakage of the water distribution network to 4% (Kamal et al. 2021).
-
KAHRAMAA allocated 4 billion dollars in 2018 to build the world’s largest potable water mega-reservoir (Hussein and Lambert 2020).
-
Qatar started incorporating the use of treated sewage effluent (TSE) in different applications, including irrigation of public green spaces (PSA 2018).
Despite these initiatives, desalination provides about 61% of the national water supply, while groundwater accounts to 25% and treated sewage effluent to 14% (PSA 2018) and withdrawals remained many folds higher than the natural recharge rate of groundwater resources (Alhaj et al. 2017; Baalousha et al. 2017).
On the other hand, it must be noted that domestic water is currently sold at a price lower than the actual cost. Qatari nationals are still granted desalinated water for residential use free of charge, and non-nationals pay for water depending on the volume of water consumed past a given threshold (increasing block structure) at a highly subsidized cost (Srouji 2017, KAHRAMAA 2021).
Multiple studies have concluded the need for a more sustainable water management scheme in Qatar, specifically in terms of incorporating non-conventional supply methods, along with efficient demand control policies – beyond only raising public awareness and promoting the use of water conservation devices (Alhaj et al. 2017; Alghool et al. 2019). In this regard, there has been a few studies to model water demand in Qatar for the purpose of informing the decision-making process.
Khalifa et al. (2019) provided a dynamic model to forecast water consumption in Qatar from 2018 to 2030, under different scenarios of population growth and water conservation policies proxied by a reduction of water consumption elasticity to population. The results predicted that residential (villa) and commercial demand accounting for most of the domestic water consumption in Qatar, can be decreased by up to 27%-46%, respectively, if stringent water conservation policies are implemented.
Kamal et al. (2021) used multi-linear regression models to estimate future water consumption in various sectors in Qatar in function of population, gross domestic product (GDP) and average rainfall. The model was applied to assess the long-term impacts of water efficiency policies, under several scenarios including capped groundwater abstraction and reduced water consumption in the household, commercial and industrial sector.
Alshaikhli et al. (2021) performed a multi-linear regression analysis to evaluate the impact of population density and weather parameters (temperature, humidity, rainfall, daylight, and sunshine) on per capita water consumption in Qatar for the year 2017. They concluded that temperature and population density are the determining factors.
In comparison with reported studies, this paper is the first attempt to quantify the impact of combining non-conventional water supply strategies (namely intensive TSE reuse and water recovery form waste) with water demand reduction policies (namely tariff reform and regulated on-site greywater reuse) in Qatar, using a scenario approach. Also, it is the first study to include temperature projections in water demand modelling in Qatar, in addition to developing models to forecast wastewater generation and the growth in residential constructions. This work generated “indicative” water usage figures and patterns that were used by the authors to develop a data-driven recommendation framework.