Context

Tenerife, Spain, is the biggest island in the Canary chain off the Western coast of Africa. The Canaries’ volcanic origins mean their geography is quite diverse from island to island, but their warm climate, beautiful beaches, and diverse landscapes make them a popular tourist spot (1). However, the very same features that make the islands such coveted vacation destinations also contribute greatly to their water insecurity. With the impacts of climate change expected to exacerbate weather around the world, it comes as no surprise that the Canaries – and Tenerife in particular –  have been experiencing more frequent and extreme droughts in recent years, leading them to draw groundwater more and more (2). While there are many compounding issues contributing to the water crisis on the island of Tenerife, physical scarcity — where “water sources are limited by nature” — is only expected to worsen. Thus, it is of utmost importance that Tenerife strengthens the resilience of their water portfolio as soon as possible (3). 

Geography and Climate 

Due to its volcanic nature, Tenerife is made up of a highly porous surface layer that gives way to an impermeable basal layer, fractured by dykes. The groundwater beneath Tenerife is broken into smaller aquifer “pockets” that are tough to recharge even when occasional heavy rains do occur (4). Precipitation patterns are sparse and inconsistent with a year-to-year average of 207 millimeters (10 inches) of rain per year resulting in slow aquifer recharge rates (5). Additionally, as Tenerife has had to extract increasing amounts of groundwater to match demand, saltwater intrusion has begun to occur in the coastal aquifers, compromising the quality (6). 

Government 

Tenerife’s governing structure is complex – as the Canaries are their own autonomous Spanish community, they possess the right of self-governance, operating with a Parliament and their own President. The island of Tenerife also has its own Council (Cabildo Insular) and President, both of which are responsible for governing the island (7). Further, Tenerife is broken down into 31 different municipalities each governed by elected local councils (ayuntamientos) (8) (9). 

Given this governance structure, when it comes to water management, the island must abide by decisions made at the level of both the autonomous community as well as the whole country of Spain. Specifically on the island of Tenerife, groundwater is a private resource, meaning that water laws have traditionally sought to protect the privatization of water and drilling rights rather than the resource (10). Even though Tenerife has an Island Water Council (CIATF) which oversees most island-specific water management decisions, the privatization of groundwater limits their governing abilities. From municipality to municipality, there are different utilities, subject to different rate structures and limits. 

Tourism

With just under 1 million permanent residents and around 5 million tourists each year,  Tenerife is the island with the biggest population and the most visitors in the whole archipelago (11). Given the large visiting population, it makes sense that Tenerife’s economy is highly reliant on tourism and thus is also highly vulnerable to fluctuations in annual visitors. To accommodate the large tourist population and balance it with local water needs, in the midst of one of its worst droughts ever, the Tenerife government decided to raise water rates for hotels and other forms of accommodation (12). 

Tenerife’s Water Portfolio

Water Portfolio

With no surface water available on the island, Tenerife relies heavily on groundwater–80% of its total supply (12). The remaining 20% of water consumption comes from a combination of desalinated brackish and seawater, recycled wastewater, and imported water from mainland Spain. Desalinated water likely makes up the majority of that 20%, with estimates ranging from 12-16% (13) (14). This high reliance on groundwater makes Tenerife’s current water portfolio high-risk. 

Water Management and Infrastructure

Water management on Tenerife is varied and complex, with little data often available. The Island Water Council (CIATF), a leg of Tenerife’s government, does oversee general water planning for the island, including the development of five-year hydrological plans (15). However, private companies own and operate most water infrastructure, such as desalination plants and wastewater treatment plants. Groundwater is also legally a private resource and CIATF is limited in its ability to legislate about or regulate its use (10).

There is no available data on drinking water treatment plants on the island, though there are private companies that provide drinking water to consumers from groundwater aquifers. Many residents also consume desalinated water, which is treated at five large plants along the coast (16). Wastewater treatment plants were historically sparse on the island–Tenerife has traditionally discharged treated and untreated sewage into the ocean, posing an obvious contamination risk (17). However, CIATF planned for the construction of eight new wastewater treatment plants by this year, bringing the total on the island to 12. This expanded infrastructure is expected to have the capacity to treat 100% of Tenerife’s wastewater (18). 

Rate structures and prices vary by private company. Emmasa, the provider in Santa Cruz de Tenerife, uses an increasing block structure and charges two rates for all water consumption (potable and non-potable) and wastewater. Stormwater is not priced (19). 

Current Interventions

To help solve water scarcity on the island, CIATF has mainly turned to conservation, desalination and wastewater reuse. Reminders to conserve water can be frequently seen throughout the island and in its hotels. Desalination plants are expected to expand in the coming years, with an estimated five or six plants in the planning or construction stages (20). Wastewater reuse is also increasing, though only for agricultural purposes, providing 55% of water needs for the sector (21). At least two of the five operating plants are recycling water for agriculture (22) (23). 

Water Management Challenges

Overview

Tenerife faces an interconnected network of water management challenges. Water quality on the island is a non-constant, but recurring issue, with salinization from seawater intrusion and excessive mineral contamination occasionally posing issues in times of groundwater aquifer over-extraction or natural disasters (4) (24). Managerial scarcity can also exacerbate the issue with a lack of regulation on water quality standards, testing and reporting. This scarcity, in conjunction with local law that protects private groundwater rights, also means that the aquifers can be pumped unlimitedly, draining the water supply. Infrastructure is also an issue, with an estimated 30% of water lost during leaks in pipelines (25). Finally, with desalination increasing at a rate of 16% per year, water is becoming increasingly unaffordable, as the process is highly energy-intensive and expensive (25). 

Physical Scarcity

While these issues are serious concerns for Tenerife, physical water scarcity remains its most pressing water management challenge. Normal desert climate conditions will be compounded in coming years as water demand grows from an increasing resident and tourist population and water supply becomes less reliable as climate change makes precipitation less predictable and drought conditions more likely. Reclamagua aims to tackle this issue with a combination of supply-side and demand-side strategies, making Tenerife’s water supply more resilient.

Policy Details

Reclamagua (a wordplay on the Spanish translation for reclaimed water, agua reclamada) pulls inspiration from the conservation and reuse strategies employed by other countries with physical water scarcity such as Israel and Singapore. Israel in particular has been a leader in water reuse, recycling nearly 90% of their wastewater for agricultural and other non-potable uses (26). This high rate of reuse has allowed the country to boost its resilience and bolster its water security. Singapore similarly has incentivized water reuse, treating enough of its wastewater to meet 40% of its potable water demand and publishing a nationwide educational campaign (27). This education campaign has involved the creation of a mascot, a new beer brand, hosting school tours of facilities, and running ads, all to normalize the consumption of reclaimed water (28). Our proposed water management intervention in Tenerife is a three-pronged reclaimed water policy with the goal of diversifying the island’s water portfolio and increasing its resilience in the face of future climatic changes.  

1. All existing and new Wastewater treatment plants (WWTPs) must develop infrastructure to treat 75% of their water per year for non-potable reuse. 
2. Water utilities must add new piping infrastructure to support pricing differences between potable and non-potable water. 
3. The government must launch a consumer education program to boost the cultural acceptance of using recycled water. 

Timeline and Financing 

This policy would be carried out over fifteen years with benchmarks set for years 5, 10, and 15 of the timeline. 

Given that water utilities in Tenerife are private, we assume they have sufficient funding available to cover a large portion of their infrastructure construction. However, to assist utilities in meeting the upfront costs, the Tenerife island government will have a low-interest loan program that utilities can access. We anticipate that utilities might need to raise consumer water rates to finance major infrastructure costs and thus are also implementing a low-income assistance program. This will provide vouchers to cover the first two blocks of water per billing cycle for households under the poverty line. Finally, to incentivize utilities to treat water for reuse beyond Reclamagua’s minimum, the government will offer a tax credit of 0.5% per percentage point over 75% as illustrated in the table below. 

% water reused	Tax credit
76%	0.5%
85%	5%
90%	7.5%
100%	12.5%

Fig 7: Table demonstrating utility tax credit examples for wastewater reuse percentages over 75%.

Demand-Side Strategies 

To address the cultural side of water reuse, two of Reclamagua’s strategies focus on consumer demand. The first involves separately pricing non-potable and potable drinking water for both domestic and industrial use – a strategy made possible by adding and upgrading piping infrastructure. Non-potable water is to be priced at 30% less than the rate charged for potable water by each utility (taking into account that water rates differ across the island). This pricing schematic will mean that less water will be treated to drinking water standards, thus reducing electricity and financial costs. It will also help consumers begin to understand the differences between potable and non-potable water, which will lead to smarter water use habits. 

The second demand-side strategy involves a diverse island-wide consumer education campaign. This program will aid in the normalization of reclaimed water use amongst Tenerife’s residents to grow support for treating wastewater to non-potable water consumption standards. Importantly, the campaign will stray away from traditional ‘toilet-to-tap’ rhetoric, instead drawing inspiration from Singapore to design culturally relevant products and/or ads promoting reclaimed water use. 

Challenges for Implementation

While there are quite a few challenges for implementation given Tenerife’s complex governance structure, many fall under the umbrella of financial challenges. Given that many of the wastewater treatment plants on Tenerife are still under construction, it seems it would be less expensive to construct reuse technology at this stage in the process, as opposed to completely building new plants. However, as is the case with any large infrastructure project, construction is  expensive, potentially requiring utilities to raise rates and pass the costs onto ratepayers. The potential for higher water bills, despite the low income assistance program, might dissuade Tenerife’s residents from supporting the implementation of this policy. Given that the new pricing schematic will lower the rate of non-potable water, eventually residents will realize that their water bills will actually decrease since they will not be paying to treat all their domestic water to drinking water standards. 

Utilities might also be frustrated by the fact that they need to take on extra responsibility in constructing new reuse technology and piping systems. Large infrastructure projects are slow and expensive, with the benefits usually not realized until far into the future. The short implementation timelines we propose are intended to tackle this challenge, with the positive outcomes expected to begin by Year 10. Additionally, the tax credits and low-interest loans available to utility companies should help them surpass the initial hurdles of funding construction. 

Another pressing challenge is the information deficit of public recordkeeping or reporting of water data on the island. In our research for this project, we had to cobble together information from a myriad of sources to create a full picture of Tenerife’s water landscape. It was often unclear which WWTPs or desalination plants were still under construction, fully in operation, or retired. This was also true for the locations of different reservoirs and other water infrastructure. Since there are quite a few utilities across the island, operating under the policies of their respective municipalities, there is no uniform rate structure for pricing water, making it harder to to make island-wide management decisions. Together the lack of cohesive and comprehensive information across the island poses a challenge for implementation, particularly concerning the construction of the new piping infrastructure required of them by the Reclamagua bill. 

Expected Outcomes and Opportunities for Expansion

Benefits

By increasing recycled water’s share of the water portfolio from less than 8% to 20%, and with additional conservation measures, Reclamagua can reduce Tenerife’s reliance on groundwater from 80% to 45% by completion of the 15-year rollout. This diversified water portfolio will be more resilient in case of disaster or emergency (29). Physical water scarcity, while inevitable due to the region’s climate and geography, will be less of a concern for Tenerife’s residents and businesses. Recycled water will “increase” the supply of water without really increasing it at all–by closing the loop and keeping exiting wastewater in the system, more water will be available for consumption.

In addition to alleviating physical water scarcity, Reclamagua provides other co-benefits. By redirecting wastewater into treatment, the island will be able to significantly reduce the amount of sewage that is released into the ocean. This will help prevent beach closures due to bacterial and fecal matter contamination, which are common on the island and can last weeks or months in popular tourist locations (30) (31) (32). 

A lesser need to extract from the groundwater aquifer will help keep the groundwater quality safe. With a higher water table, seawater intrusion will be less likely, preventing salinization. And more water available will reduce the need for more desalination plants, helping to preserve the picturesque Tenerife landscape, prevent consumer water rates from increasing and save energy. 

Room to Build

If Reclamagua is successful in increasing the supply of clean and safe water, and if it has support from water utilities, government stakeholders and the public, there are opportunities to expand the policy beyond its 15-year plan. New requirements or incentives to treat greater than 75% of wastewater can be rolled out, and reclaimed water use for potable consumption can also be explored. Treated wastewater for drinking water is already an existing practice in other water-scarce areas like Singapore and Israel, and is soon to come to California. These areas treat water to drinking water standards and release the supply into their resources, like reservoirs, surface water or aquifers (33) (34).

Conclusion

Water scarcity is a pressing challenge in Tenerife, given the area’s lack of rainfall and surface water resources. A booming residential and tourist population has increased demand in recent years, and with private pumping rights protected under law, the island’s limited groundwater has been over-extracted. Tenerife turned to desalination as a solution, which has increased and continues to increase water rates. While the island spends money and energy to turn salty water into water suitable for consumption, it has let nearly all of its wastewater be dumped into the ocean. Wastewater reuse has been introduced on the island, but only for agricultural purposes. 

Reclamagua will expand reclaimed water to all non-potable uses and make treated wastewater for reuse a requirement at all 12 wastewater treatment plants. Its mixed approach will use both regulation and incentives, both private and public efforts, and both supply-side and demand-side strategies. In addition to alleviated water scarcity, it offers co-benefits of a diversified and more resilient water portfolio, cleaner oceans and beaches, safer groundwater quality, and energy and cost savings from avoided desalination plant construction. 

Reclamagua is the solution for a safer, smarter and more water resilient Tenerife.

References

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