Sustainability and Environmental Impact of the Tourism Sector: Analysis Applied to Swimming Pools in the Hotel Industry on the Costa Brava

The aim of this research is to critically evaluate the environmental implications of public pools in Costa Brava hotels, with a focus on their impact in terms of energy, water, and carbon footprint. The methodology employed hinges on the characterization of the stock of pools installed in the hotels of the region. Following this characterization, calculations were undertaken regarding water and energy consumption, in addition to the computation of the equivalent carbon footprint for the entirety of the pools combined. The findings of the study reveal an annual energy consumption of 1,850.2 MWh/year and an annual water evaporation consumption of 50,105 m3/year. As a result, the carbon footprint corresponding to these consumptions is 481.8 tCO2 eq./year. Identified areas of improvement within the facilities encompassed the modernization of equipment towards more contemporary models with higher efficiencies, the adoption of holistic management approaches for pools, and the utilization of emerging modelling trends to enhance facility efficiency. Conclusions drawn from the research suggest that enhancing the sustainability of pools within the Costa Brava hospitality sector holds significant societal relevance, especially when considering the heightened water stress in Mediterranean climate zones during the peak tourist season. Improving the energy efficiency of these facilities not only contributes to environmental sustainability, but also cuts operational costs, allowing establishments to have more room to channel more resources towards their main hospitality tasks. Tourism is vital in global, Spanish, Catalan GDP and an environmental impact key. Costa Brava hotel pools use 1,850 MWh/year, 50,105 m3 water/year, emit 482 tCO2/year. Modern equipment, management, and modelling trends enhance pool sustainability. Efficient pools cut costs, aid environment, free resources for hospitality. Tourism's future relies on holistic sustainability; efforts and policies are vital. Tourism is vital in global, Spanish, Catalan GDP and an environmental impact key. Costa Brava hotel pools use 1,850 MWh/year, 50,105 m3 water/year, emit 482 tCO2/year. Modern equipment, management, and modelling trends enhance pool sustainability. Efficient pools cut costs, aid environment, free resources for hospitality. Tourism's future relies on holistic sustainability; efforts and policies are vital.


Introduction
Tourism is a strategic sector for the Spanish economy, which has contributed with 154,487 million euros in 2019, a 12.4% of the Spanish GDP; but in 2020 with the pandemic, this percentage dropped by almost 7 points to a 5.5% of the GDP or 61,406 million euros, an approximate decrease of 60% (Instituto Nacional de Estadistica 2021).Catalonia also presents similar figures, with a GDP of 12% in 2019 and a 14% of employment rate.
The pandemic caused a global loss of 78.5% of international tourists, a fall that was already partially recovered in 2021.Projections for 2022 are very optimistic, with a global increase of 182% from January to July compared to the same period in 2021, a recovery led by Europe (+ 280%) and America.Despite these optimistic strides, the numbers are still lower than the record year of 2019, particularly in Europe, where the figures for January-July 2022 are still 26% lower than in 2019 (World Tourism Organisation (UNWTO) 2022), as detailed in Table 1.
On the other hand, the tourism sector is directly related to sustainability and environmental considerations (Iraldo and Nucci 2016;Della Volpi and Paulino 2018).It engenders an array of environmental ramifications, among which the impacts from hotel swimming pools on water and energy resources are significant (Iraldo and Nucci 2016;Della Volpi and Paulino 2018;Yoon et al. 2022).
The central objective of this research is to critically assess the environmental repercussions of public swimming pools within hotel infrastructures located along the Costa Brava, focusing on their energy, water, and carbon footprint implications.
The Costa Brava, the coastal area of Girona, from the municipality of Blanes to the French border, includes 24 municipalities covering Alt Empordà, Baix Empordà and the seaside localities of La Selva.After the city of Barcelona, is the second most visited tourist area in Catalonia, capturing 20% of visitors to the region.Given this influx, the tourism industry plays an important role, with the different hotel establishments equipped with swimming pools.Figure 1 and Table 2 provide a comprehensive depiction of the distribution of these hotels along the Costa Brava's shoreline, categorized by municipality.
Catalonia, and more specifically the Costa Brava, have a Mediterranean climate, with normal dry periods, especially in the summer.This, in conjunction with the region's rich cultural offerings and pristine coastline, positions it as a prime tourist destination.In this sense, swimming pools are one of the main assets of the hotel industry, serving as significant attractions for potential guests.The inherent seasonality of these coastal tourist spots means that during peak summer months, certain municipalities witness a population surge, sometimes increasing up to fivefold.This amplification brings with it heightened energy and water consumption, increased mobility, and a spike in waste production, all of which invariably leave a profound environmental impact (Sun and Gao 2012).In addition, the hotel sector, especially the coastal establishments, have important environmental impacts in the broader framework of climate change.Ensuring a more sustainable future for tourism mandates the meticulous monitoring and management of the sector's carbon footprint (Puig et al. 2017).There is an imperative need to adopt strategies to reinforce the resilience of the tourism sector, given the mounting environmental challenges (Torres-Bagur et al. 2019).
It is essential to underscore the significant role of hotel swimming pools which are important assets for the attraction of tourism, especially in the seaside area.A substantial number of hotels are outfitted with pools (Mendoza et al. 2023), a fact prominently highlighted in their promotional material and websites.As these pools cater to the general public, they invariably fall under a strict regulatory framework.This encompasses stringent technical and sanitary controls, including the maintenance of optimal water and air quality standards, especially for indoor pools.Adherence to these health guidelines ensures the safety and well-being of all patrons.
Data regarding hotel establishments and their swimming pools in the Costa Brava region were sourced from the Institute of Statistics of Catalonia (Idescat) and the Spanish Land Registration Office (Catastro de España) website.These resources were instrumental in facilitating the research detailed in this study.
The research methodology is based on an exploratory analysis.Data was primarily sourced from the Spanish Land Registration Office's website (Catastro (Spanish Land Registry)-Ministerio de Hacienda y Función Pública de España 2023).This entailed downloading and scrutinizing the cadastral records of properties within the municipalities of Costa Brava, with an emphasis on identifying and examining the swimming pools of the hotel establishments.Following the collation of this data, additional resources were  2. Climate Change: Investigates the effects of climate change on the tourism and hotel sectors.3. Energy: Focuses on sustainable energy management practices within the hotel sector. 4. Environmental Impact: Addresses the wider environmental repercussions of tourism and the hotel industry and strategies to enhance sustainability.5. Hotel Industry Sustainability: Central to these is the approach towards sustainable management of the hotel industry.6. Sustainable Tourism: Research here delves into sustainable tourism practices and their alignment with the hotel sector. 7. Water: Places emphasis on crucial water management practices for the tourism and hotel industries.8. Hotel Sustainability Reporting: Highlights transparency and methods behind hotels' sustainability reporting, emphasizing non-financial indicators.
The tourism sector has an impact on the environment (Deyà Tortella and Tirado 2011; Gössling et al. 2012;Iraldo and Nucci 2016;Della Volpi and Paulino 2018) and ensuring a more sustainable tourism is imperative (Hunter 2002;Puig et al. 2017).Effective water management within hotel operations is decisive in enhancing environmental sustainability for a more sustainable tourism industry (Torregrosa et al. 2010;Pešić and Jakovljević 2020).This is particularly important for coastal destinations characterized by pronounced seasonal fluctuations and significant water stress (Rico-Amoros et al. 2013;Gabarda-Mallorquí et al. 2017, 2018;Vila et al. 2018;Kiper et al. 2022;Yoon et al. 2022;Mendoza et al. 2023).
Recent studies suggest that large hotels can take advantage of economies of scale in water management (Gabarda-Mallorquí et al. 2017;Cruz-Pérez et al. 2022;Mendoza et al. 2023).Nevertheless, there have been no specific studies of the Costa Brava on non-financial indicators and, specifically, on environmental indicators related to water and energy.In contrast to prior research in the region, which predominantly revolved around financial indicators, drawing correlations between user perceptions of quality and respective financial metrics (Aznar et al. 2016).
Consequently, there's a pressing need to examine the hotel industry in coastal regions, focusing on the non-financial indicators that significantly contribute to environmental impacts in the context of climate change, with the goal of propelling a more sustainable tourism model (Puig et al. 2017;Torres-Bagur et al. 2019).Among these indicators, water consumption stands out, especially in coastal areas facing water scarcity (Deyà Tortella and Tirado 2011;Gabarda-Mallorquí et al. 2017;Cruz-Pérez et al. 2022;Kiper et al. 2022).Certainly, tourism's prominent contribution to national and global GDP cannot be understated.Equally significant is its influence on the carbon footprint, emphasizing the sector's intricate relationship with environmental sustainability (Lenzen et al. 2018).However, it is a sector that has a particular impact on water resources, due to the significant water demand generated by tourism, especially in the hotel sector.Initiatives centered on water conservation and energy-saving measures are indispensable in tempering the effects of climate change (Scott et al. 2012;Rosselló-Nadal 2014;Styles et al. 2015;Mak and Chang 2019).
Given its Mediterranean climate, the Costa Brava is vulnerable to intense environmental stress due to the influx of international tourists flocking to its municipalities annually.Consequently, scholarly pursuits have delved into projecting the sustainability of both the Spanish landscape and the broader Mediterranean region over the next half-century, informed by various climate models and potential scenarios (Hein et al. 2009).Several researchers have also explored the intricate relationship between tourism and its consequent environmental ramifications (Scott et al. 2012).The adoption of the carbon footprint as a metric to quantify climate change implications has gained traction in academia (Rosselló-Nadal 2014;Puig et al. 2017;Lenzen et al. 2018), and its application extends to assessing the environmental footprint of hotel swimming pools (Rico et al. 2019;Sun et al. 2020).The tourism sector is constantly improving and the innovation in this sector is correlated with sustainability (Smerecnik and Andersen 2011).
Swimming pools contribute to approximately 15-25% of a hotel's water consumption (Gössling 2001;Antakyah et al. 2008), underscoring their significance in water management strategies within the hospitality sector.Given its substantial water consumption, the sector faces the challenge of making more efficient use of water resources (Page et al. 2014;Gössling 2015;Yoon et al. 2022;Mendoza et al. 2023).An area of particular concern is the urban water intake of hotel swimming pools, especially in the semi-arid coastal regions of the Mediterranean (Morote et al. 2017;Yoon et al. 2022;Mendoza et al. 2023).To truly achieve sustainable development in this context, it is imperative to understand and subsequently address this consumption.
In addition, there are several relationships between tourism and sustainability; one of the hottest is that derived from extensive water consumption.Recent studies promote to investigate the balance between tourism activities and their environmental repercussions, particularly related to water consumption (Torregrosa et al. 2010;Rico-Amoros et al. 2013;Pan et al. 2018;Kiper et al. 2022).
Unraveling the water footprint of swimming pools (Gallion et al. 2014;Mendoza et al. 2023) and knowing the chemical, water and energy consumption of swimming pools would allow to identify their environmental impact (Forrest and Williams 2010;Sun et al. 2020;Rana et al. 2020).Furthermore, the carbon footprint of swimming pools highlights the imperative to reduce emissions, as concluded in related environmental studies (Rico et al. 2019;Sun et al. 2020), for a more sustainable water management and survival of the sector (Hof and Schmitt 2011;Page et al. 2014).
Regarding the environmental impact of water in swimming pools of hotels, it is important to know the calculation of the equivalent carbon footprint, especially in coastal areas, because of the effect on climate change (Gössling et al. 2002;Tao and Huang 2014;Puig et al. 2017).Such knowledge does not just serve academia; it is invaluable for those stakeholders in the tourism sector who, with a sustainability-first approach, endeavour to align their practices with the evolving expectations of environmentally-conscious travellers (Schaltegger et al. 2019).
On the one hand, studies highlight the crisis in the quality and quantity of water supply and the impact on tourism and hotels (Kasim et al. 2014;Kiper et al. 2022).More specifically, water stress is a major environmental challenge for many hotels, and good water management practices are imperative (Rico-Amoros et al. 2013;Styles et al. 2015;Kiper et al. 2022).
However, the intensification of droughts, which are becoming more frequent due to climate change, is also causing concern in the tourism sector and, in response to this reality, the tourism sector in Catalonia is promoting technological and behavioural changes in this direction.These shifts are not born from a void; they resonate with governmental directives aimed at mollifying the fallout from recurrent drought episodes (Dinarès and Saurí 2015).
In addition to the swimming pools, the equivalent carbon footprint of water in the tourism sector has also been analysed in coastal areas as a reference indicator to assess the environmental impact (Diaz Perez et al. 2018Perez et al. , 2019)).Water consumption according to hotel typology has also been investigated in areas of the Mediterranean coast, given the importance of water at an environmental level (Gabarda-Mallorquí et al. 2017;Rico et al. 2020).Other research analyses socially and environmentally responsible water practices according to hotel typology (Stylos and Vassiliadis 2015).
Thus, the academic literature includes studies that resonate with the interplay between water and energy consumption in the tourism sector, particularly in relation to its carbon footprint (Diaz Perez et al. 2018;Yoon et al. 2022).Across the tourism industry, there is concern about green innovation of the sector (Song and Yu 2018;Ricaurte and Jagarajan 2021).
Several tourism destinations are implementing measures to improve water management and minimise their environmental impact to highlight this sector, and the Costa Brava is not an exception.The region is part of this transformative journey, with studies underlining its green initiatives (Gabarda-Mallorquí et al. 2017;Vila et al. 2018;Mendoza et al. 2023).
The tourism industry is not just a conglomerate of luxury hotels and picturesque landscapes; it is a pivotal economic mainstay for numerous countries.This recognition comes with the onus of acknowledging and addressing its environmental imprint, especially in the context of climate change.Several academic discourses elaborate on the multifaceted challenges the tourism sector grapples with vis-à-vis climate change (Scott et al. 2012;Mak and Chang 2019).
The COVID-19 pandemic brutally reminded the sector of its vulnerabilities, catalysing conversations around sustainability.The seismic shifts induced by the pandemic were not merely economic; they were ecological as well, accentuating the need for more sustainable tourism (Gössling et al. 2020;Hall et al. 2020).Moreover, to cope with the pandemic, the stringent regulations imposed on hotel and pool facilities did not merely aim at curbing the pandemic's spread.These regulations pushed the sector and hotel facilities towards sustainable tourism, aligning with broader global objectives encapsulated in the UN Agenda 2030 (Romano Spica et al. 2020).
Ultimately, studies from the most recent period analysed identify a new trend in optimizing the efficient operation of swimming pools through consumption forecasting to achieve savings (Delgado Marín et al. 2019).Similarly, there are studies, as in earlier instances, that employ computational methods and the analysis of mathematical and neural models to enhance the energy cycle of swimming pools (Calise et al. 2018;Limane et al. 2018;Lau et al. 2020;Marin and Garcia-Cuscales 2020;Smedegård et al. 2021).Another significant theme in the latest research is the adoption of renewable energy sources, notably solar energy, for pool heating (Pop and Pop 2018;Zhao et al. 2018;Delgado Marín et al. 2019;Lugo et al. 2019;Singh et al. 2020;Wache et al. 2020;Ilgaz and Yumrutas 2022;Pérez-Carramiñana et al. 2022).

Methodology and Results
The hotel offer of establishments on the Costa Brava is made up of 397 hotels, constituting 19.7% of the total offering of hotel establishments and 14.7% of the accommodations available in 2020 in Catalonia (Statistical Institute of Catalonia (Idescat-Generalitat de Catalunya) 2023).As illustrated in Fig. 1, these establishments are distributed throughout the region.And, 6 municipalities, out of the total of 22 towns with hotel establishments, account for a significant 65.5% of the total inventory (Fig. 2 and Table 3).Among them,  the municipality with the largest quantity of establishments is Lloret de Mar with 25.2% of the total number of hotel establishments.When examining this offer by category of establishment, it becomes evident that hotels rated 3 and 4 star are the most represented in the hotel offer in the area, representing 64% of the total (Fig. 3).
In order to analyse the inventory of installed swimming pools in the hotel establishments of the Costa Brava, public data from the Spanish Land Registry (Catastro (Spanish Land Registry)-Ministerio de Hacienda y Función Pública de España 2023) were used.
Among the data of the Catastro (Spanish Land Registry), the following data are used to describe the number and details of swimming pools installed in hotel establishments on the Costa Brava, analysing hotel establishments rated from 1 to 5 stars, with the following data: • Municipality where the establishment is located • Star rating (category) of the establishment • Year of construction and age of the pool • Whether the pool is indoor or outdoor • Surface area of the swimming pool water surface in m. 2 • Whether the land is classified urban or rural A total quantity of 175 swimming pools are recorded in the Spanish Land Registry within hotel establishments in the municipalities of the Costa Brava. Figure 4 illustrates the geographical distribution of hotel swimming pools across Costa Brava.Mirroring the concentration of hotel establishments, the municipality of Lloret de Mar is the town with the highest number of registered swimming pools (81), which represents 46.3% of the overall count.
In contrast to the distribution of the hotel inventory, where 3 and 4 star hotels accounted for 64%, the distribution of swimming pools across these establishments also includes pools in 2 star accommodations, as depicted in Table 4.
In the data sourced from the Spanish Land Register (Catastro de España) website, the pool water surface area for each pool is provided.Using this information, Table 5 The average area (m 2 ) of the total installed pool inventory is 130.7 m 2 , and the total surface area across all the swimming pools is 22,879 m 2 .
In order to estimate the total volume of water in the installed swimming pools stock of the Costa Brava's accommodation facilities, we refer to the sectoral study conducted by ASOFAP (i.e., the Association of Professionals in the Spanish Swimming Pool Sector) in 2017 (Asociación Española de Profesionales del Sector Piscinas (ASOFAP) 2023).This study analyses the number of swimming pools designated for public and collective uses in Spain.Focusing on the segment pertaining to hotel swimming pools, the following conclusions are reached: • Number of swimming pools in hotels in Spain: 13,836 • Total area of the water surface of all the pools: 2,066,130 m. 2 • Total water volume: 3,140,495 m. 3  Drawing from the data of the ASOFAP sectorial study, we can deduce the average depth of hotel swimming pools in Spain stands at 1.52 m.This can be mathematically represented as: Now with the average depth data, it is possible to infer the total volume of water in the swimming pools of the hotels on the Costa Brava: As highlighted earlier in this text, public swimming pools are regulated in both Catalonia and Spain.The aim of these regulations is to establish the foundational technical and sanitary standards for water and air quality, especially in indoor facilities.The primary objective is to safeguard the health of users against possible physical, chemical, or microbiological hazards linked with the use of these pools.Concurrently, these regulations delineate the responsibilities borne by the Administration, owners and users of public swimming pools.The legislation applicable in this area in Catalonia is summarised below: In addition to these regulations, municipal ordinances exist which regulate some other more specific aspects, and these can vary from one city to another.
In all this legislation, it is mandatory to have a continuous water recirculation system that allows for the uniform recirculation of the entire water surface.Moreover, it is also mandatory for this water recirculation system to be operational whenever the pool is open to the public.
The Generalitat de Catalunya (Catalonia Regional Government) has also published a technical guide (Swimming Pools-Public Health Agency of Catalonia (ASPCAT) (Generalitat de Catalunya) 2013).This manual primarily targets the swimming pool engineers for drafting reports on the projects and the necessary sanitary control of public swimming pools.Furthermore, it serves as a guide for managers, maintenance personnel, and operators of public swimming pools.
In this guide released by the Generalitat de Catalunya, which consolidates various legislations and best practices in the sector, it is recommended that the recirculation of the entire volume of water be carried out in a specific time depending on the depth of the pool.In this sense, the recommendations for recirculation time in hours are, depending on the pool's purpose and depth, as follows: 1.For vessels intended for children: 1 h 2. For pools designated for recreational, competition, or sports activities: • 2 h per pool or part of a vessel, up to 1.3 m depth • 4 h per vessel or part of a vessel for higher depths Typically, a recirculation duration of 4 h is considered standard for circulating the entire water volume of the pool.
Given the aforementioned data, the total recirculated flow rate can be calculated as: Based on industry standards within the pool sector, the typical working pressure (manometric head) for public swimming pools is set at 12 m.w.c.(metres of water column).To determine the hydraulic power needed to circulate this volume of water, the following formula for hydraulic pumps is employed: where: P b is the hydraulic power of the pump in W; γ is the specific weight of the fluid (9,800 N/m 3 for water); Q is the recirculated flow rate in m 3 /s; h b is the manometric head (pressure) at which the pump works in m.w.c.(meters of water column).
By utilizing this formula and the provided data, one can ascertain the power required to facilitate the circulation of the entire water volume in the swimming pools: An electric pump integrates two primary mechanical components: the hydraulic pump and an electric motor.To ascertain the necessary electrical power, the efficiency of each component must be factored in: where: P 1 =P input is the input power from the electricity mains in kW; P b is the hydraulic power in kW; η b is the pump efficiency; η m is the motor efficiency, Based on data from Europump (European Pump Manufacturers Association) and the preparatory study for Lot 29 of the Ecodesign Directive 2009/125/EC (European Parliament 2009; Europump 2013Europump , 2014;;Schofield 2016), pool pumps with power ratings above 2.2kW have an estimated minimum efficiency of 65% and a maximum efficiency of 76%, the average being 72%.
In terms of the electric motor, the average value of motor per pool is estimated to be 2.2kW.Referring to the European Commission Regulation (EU) 2019/1781 (European Union 2019), which sets and regulates the Ecodesign requirements for electric motors and variable speed drives in accordance with the Ecodesign Directive 2009/125/EC, the mandatory minimum efficiencies are as follows: • 83.2% for IE2 efficiency level • 85.9% for IE3 level • 88.0% for IE4 level For IE1 motors, the efficiency level is 79.7%.Conversely, data from the Catastro de España reveal that the pools have an average age of 34 years.Considering that pumps typically have a lifespan of approximately 25 years, the 19-year average value reported in the 2017 ASOFAP sectoral study on Spain's public and collective pool inventory will be adopted as the representative figure.
Acknowledging this 19-year timeframe, one can deduce that the prevalent motor efficiencies during that period were either IE1 (79.7%) or IE2.The mandatory adoption of motors with superior efficiency indices is not yet in effect, suggesting a hydraulic efficiency potentially as low as 65%.
Using the aforementioned data, the calculation of the projected total electrical input power: Tourism along the Costa Brava exhibits a pronounced seasonality.By examining multiple sources, such as hotel reservation platforms and scholarly publications (Saló et al. 2012), a clear pattern emerges: most hotels operate primarily between May and October.This span has consequently be adopted as the foundational period for subsequent computations.
Furthermore, as per the data provided by Europump (European Pump Manufacturers Association) and the preparatory analysis for Lot 29 of the Ecodesign Directive 2009/125/ EC (European Parliament 2009;Europump 2013Europump , 2014;;Schofield 2016), pool pumps possessing a power exceeding 2.2 kW -those typically employed in communal swimming pools -boast a forecasted annual operational duration surpassing 3,375 h.This estimate aligns well with the seasonal utilization patterns of Costa Brava hotel swimming facilities; hence, it has been selected as the metric to determine the energy requisite for filtration across all pool installations within these establishments.
By extrapolating from the provided data, the annual electrical energy consumption dedicated to the recirculation of water in all hotel swimming pools throughout the Costa Brava is projected to be approximately 1,850.2MWh, as computed below: A secondary aim of this research is to quantify the water losses associated with the swimming pools installed in the hotels of the Costa Brava.Water losses are usually due to different causes, the most common are a total replacement of water in the pools, as well as partial replacement to compensate for water losses due to evaporation.Furthermore, routine maintenance and cleaning of filtration systems, coupled with potential leakage, also contribute to these losses.
In contemporary times, most pools remain filled throughout the year, rendering the traditional practice of seasonal draining and refilling obsolete.As a result, the water consumption estimations in this study are approached conservatively.This approach does not factor in potential water losses stemming from filtration system maintenance, leaks, and other pool-related activities such as emptying or water extraction by pool owners or users.The nuances and prevalence of these practices are challenging to gauge, making it a fertile ground for future research endeavors.Evaporation can be, especially in warmer climates, one of the main reasons for water loss in swimming pools.Various studies have been conducted to compute evaporation rates, with notable methods including the ASHRAE (American Society of Heating and Air-Conditioning Engineers) formula and the method developed in the article "Methods for Calculation of Evaporation from Swimming Pools and Other Water Surfaces" (Shah 2018(Shah , 2022(Shah , 2023)).
The evaporation of water from swimming pools depends on several factors.These include the surface area of the pool and the number of people using the pool, with the number of people using the pool increasing the evaporation rate, and the transfer of water associated with bathers.Environmental parameters such as water temperature and air temperature, relative humidity and water vapor pressure further modulate this rate.Existing academic literature and industry insights from the Mediterranean region suggest average evaporation values between 5 to 8 L/m 2 /day.
For the purposes of this research, considering the amplified temperatures attributed to climate change, an evaporation rate of 6 L/m 2 /day was adopted (Hof and Schmitt 2011).The calculation covers the entire year and not only the peak season.This is due to the prevalent industry practice in the off-season and winter months to keep pools filled.This measure conserves water by minimizing recirculation and using just enough chemical treatment to ensure water quality.Thus, referring to the 175 swimming pools present in the hotel establishments across Costa Brava, Table 5 delineates the average surface areas classified by municipality and hotel star rating.Cumulatively, these pools span a total surface area of 22,879 m 2 .Based on the evaporation rate mentioned, the annual evaporation amounts to 50,105 m 3 .This translates to an annual evaporation of 2.19 m 3 /m 2 of pool surface.
The total volume of swimming pools in the establishments is 34,776 m 3 , considering an average depth of 1.52 m, according to the sectoral study carried out in 2017 by the Spanish swimming pool sector employers' association ASOFAP (Asociación Española de Profesionales del Sector Piscinas (ASOFAP) 2023), with this, evaporation would be almost equivalent to filling all swimming pools 1.4 times a year.
Finally, to determine the annual equivalent carbon footprint stemming from the aforementioned energy and water consumptions, reference is made to the Greenhouse Gas Emissions Calculation Guide (GHG emissions) issued by the Generalitat de Catalunya in 2021 (Generalitat de Catalunya 2021).Pertaining to Catalonia for the year 2020, the guide specifies: • The GHG emission factor for energy for general electricity mix of the grid is 0.25 kg CO 2 /kWh.
• The GHG emission factor for water is 0.385 kg CO 2 /kWh and covers: • The stages of: water withdrawal, treatment to make it potable, high and low water distribution, sewage system, wastewater treatment and return of treated water to the environment and re-use.The equivalent carbon footprint GHG emissions of swimming pools in the hotel establishments on the Costa Brava is quantified at 481.8 tCO 2 eq./year.In conclusion, Table 6 encapsulates the principal results of this research.
Considering these findings, there is an unequivocal need to curtail the equivalent carbon footprint and enhance the sustainability of swimming pools, a pivotal asset in the hotel industry.The relatively advanced age of pool construction, spanning between 19 and 34 years (Asociación Española de Profesionales del Sector Piscinas (ASO-FAP) 2023), underscores significant opportunities for enhancements.Moreover, synergizing efficiency improvements with cost-saving measures in pool management can yield tangible benefits (Delgado Marín et al. 2019).
Several contemporary market solutions advocate for enhanced pool management efficiency (Cruz-Pérez et al. 2022;Yoon et al. 2022;Mendoza et al. 2023).Notably, transitioning to modern pumps with superior hydraulic efficiency stands out.Advances in design and manufacturing technologies have ushered in noteworthy improvements, including the integration of IE3 or IE4 motors, refinements in the pool hydraulic systems, and the incorporation of variable speed in water recirculation.A more holistic approach involves conceptualizing the entire pool as an interconnected system, where individual enhancements collectively contribute to overarching efficiency and energy consumption reductions.The hotel industry is very sensitive to improving its environmental impact, and many establishments and hotel groups already apply strategies to assess and reduce their environmental impact.Tourism, particularly in the Catalan economy, is intrinsically tied to sustainability and the environment, as evidenced by previous studies (Iraldo and Nucci 2016;Della Volpi and Paulino 2018).The industry engenders a multitude of environmental impacts, including those stemming from pools due to their associated water and energy needs.The Costa Brava, representing 20% of all Catalonian tourist visits, is laden with 397 hotel establishments across 22 municipalities.Swimming pools, bolstered by the region's favourable climate and rich cultural offerings, emerge as pivotal attractions for guests.However, the 175 pools registered within the Costa Brava's hotel establishments exhibit a significant age, indicating a vast scope for modernization and environmental impact reduction.Moreover, with most pools ranging in age from 19 to 34 years, a substantial opportunity exists for enhancements.These potential enhancements cannot only boost efficiency but can also streamline operational costs associated with pool management (Gabarda-Mallorquí et al. 2017;Mendoza et al. 2023).
Swimming pools contribute to approximately 15-25% of a hotel's water consumption (Gössling 2001;Antakyah et al. 2008), underscoring their significance in water management strategies within the hospitality sector.
Given the profound environmental implications of hotel pool water, especially in densely populated coastal regions, assessing its carbon footprint is crucial.Stakeholders across the tourism sector have manifestly demonstrated their commitment to sustainability (Schaltegger et al. 2019).Notably, evaporation, accounting for about 15% of water loss in pools (Styles et al. 2015), can be curtailed by up to 90% through the adoption of industryendorsed pool covers.
Modern market solutions for increasing pool efficiency include the adoption of contemporary pumps with superior hydraulic performance.Advancements in design and manufacturing technologies have further augmented outcomes, particularly with the introduction of IE3 and IE4 motors, enhancements in pool hydraulic systems, and the integration of variable speed in water recirculation.A holistic approach, viewing the pool as an interconnected system, can ensure that any upgrade positively impacts overall efficiency and energy consumption.
Tourism accounts for an estimated 8% of global carbon emissions (Lenzen et al. 2018).The hospitality sector is increasingly exhibiting a laudable commitment to reducing its environmental imprint.Numerous hotel chains and establishments have proactively embraced measures to assess and lessen their ecological impact.
In the hospitality industry, there is an escalating prioritization of environmental sustainability.Global touristic destinations, especially those with Mediterranean climates such as Costa Brava, are grappling with amplified water stress challenges.Consequently, there is an urgent demand for pioneering strategies and scholarly research to address these significant concerns, especially in areas with dense tourist activity.This research thus posits that it is incumbent upon the hotel sector, being the foremost stakeholder, to lead rigorous evaluations and improvements of swimming pool conditions, with the aim of bolstering energy efficiency and mitigating associated environmental consequences.
The overarching consensus among hoteliers and industry stakeholders is clear: the future trajectory of tourism hinges upon holistic sustainability-social, economic, and environmental.Concerted efforts, research, and policies are thus imperative to minimize the sector's impact, while simultaneously maximizing long-term benefits for the collective good.
The contemporary global narrative places an intensified focus on sustainability and environmental ramifications, compelling governmental interventions across different echelons.This paradigm shift is propelled by evolving corporate adversities and a heightened acknowledgment of associated risks by stakeholders.The landmark adoption of the 2030 Agenda by the UN in 2015, alongside the European Commission's ambitious Green Deal in 2019 targeting net-zero emissions by 2050, exemplify pivotal moments in this trajectory.Furthermore, 2022 signified a seminal phase in Europe's pursuit of an integrated sustainability framework, underscored by the ratification of the CSRD (Corporate Sustainability Reporting Directive).
The limitations of this research arise from reliance on indirect data and a conservative methodology employed in estimating water consumption.Assessing the intricacies and prevalence of these practices presents inherent challenges, positioning the topic as a promising avenue for subsequent scholarly pursuits.To address these limitations, forthcoming research trajectories are envisioned, involving the acquisition of direct data from hotels via structured surveys.
Additionally, emerging trends in enhancing swimming pool operational efficiency by leveraging computational methodologies and exploring both mathematical and neural modelling to refine the energy dynamics of swimming pools are noteworthy.Embracing renewable energy modalities, particularly solar energy for pool heating, also stands as a prospective avenue for future investigations.

Fig. 3
Fig. 3 Number of hotels by category of establishment (Statistical Institute of Catalonia (Idescat-Generalitat de Catalunya) 2023)

Table 2
Distribution of hotel establishments along the Costa Brava by municipality and hotel category (Statistical Institute of Catalonia (Idescat-Generalitat de Catalunya) 2023)

Table 3
Offer of hotel establishments per municipality by municipality and hotel category (Statistical Institute of Catalonia (Idescat-Generalitat de Catalunya) 2023)

Table 4
Number of pools by hotel category (Catastro (Spanish Land Registry)-Ministerio de Hacienda y Función Pública de España 2023) • CO 2 , CH 4 and N 2 O emissions, are expressed in CO 2 eq.It is considered that the stages of the water cycle do not generate emissions of fluorinated gases.