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Santorini, Greece

Research Program from May 29 - June 18, 2016
Cistern in Santorini

Rainwater harvesting in Santorini: local wisdom and modern needs

Water is intrinsically linked to all aspects of society, and is a resource that cannot be put at risk. Water is necessary for supporting life, ecosystems, and economic activities. It is used at all levels of society, from the individual to all of society at once, making it a local and global concern. A sustainable water supply is necessary for a social development from a social perspective.

Water Background of Santorini (Thera)

Santorini or else Thera is a small, circular group of volcanic islands located in the Aegean Sea, about 200km south-east from the mainland of Greece. The island was the site of one of the largest volcanic eruptions of the large several thousand years when it erupted about 3,500 years ago. The eruption left a caldera surrounded by ash deposits hundreds of feet deep, and its effects may have indirectly led to the collapse of the Minoan civilization on the island of Crete. Excavations started in 1967 at the site Akrotiri. Except from a large town which was uncovered revealing complexes of multi-level buildings, streets and squares, pipes with running water were also found. The pipes and the water closets found on Santorini islands are the oldest such utilities discovered. The pipes run in twin systems, indicating that the Therans used both hot and cold water supplies. The hot water origin was probably geothermic, given the volcano proximity. This is a great achievement accomplished in the ancient times (1) given the fact that the island, as most Aegean islands, has suffered from water scarcity having no rivers and few springs. The locals were forced to depend almost exclusively on rainwater and to develop extensive collection and storage systems. Rainwater was collected from rainfall on the flat roofs of the buildings and channeled to cisterns using drains, pipes and channels.

Cisterns are found everywhere, equally as often under private and public buildings, but also under temples and theaters. The small to medium size of these cisterns and their large number is an indication that the water was collected more on a micro-scale. Such a method was certainly anticipated because of the huge mechanism for the collection of water in its properly adjusted underground spaces. Cisterns have been used to store both rainfall runoff water and groundwater originating from springs and streams for the purpose of meeting water needs through seasonal variations. It is interesting to underline that the quality of craftsmanship of the cisterns in Santorini is admirable as the Theran soil which is an ingredient in the plaster, gave the plaster a high degree of impermeability making the construction more stable.


The objective of this project is to

  1. Study rainwater harvesting cisterns found in the villages in Santorini, dating from different times, and undertake an assessment on those which could be reinstated and used in the future for water storage and/or rainwater collection.
  2. Increase awareness on rainwater harvesting potential at community level, utilizing cisterns identified in the study; and at individual level, by promoting the use of household cisterns, as well as water saving measures, as cost effective measures for local water security.

Description of the project

A team of 3-4 senior and 1-2 graduate students from Cornell University will be hosted Santorini and work under the guidance of the Global Water Partnership – Mediterranean and in collaboration with the Municipality of Thera, for a period of 4 weeks. The students will come from different backgrounds to cover a broader spectrum of research: Architecture, Civil and Hydraulics Engineering; Agricultural Studies and Social Studies.

Activities to be undertaken include the following: 

Activity 1: Main task of the team is to register the ancient rainwater harvesting cisterns found in the villages of the island focusing mainly on the ones in Pyrgos village and the nearby villages: Ekso Gonia and Mesa Gonia. They will also study two big reservoirs: one found in the Byzantine church of the Episcopate of Thera founded at the end of the 11th century by the Emperor Alexios I Comnenos, close to Mesa Gonia village and one found in Nimborio Village. The second step will be to study the rainwater harvesting reservoirs, from an architectural, hydraulics and social perspective. The study, depending on the students’ background may elaborate on:

  1. Architecture: the type of architecture and material used
  2. Hydraulics: how water was collected and reused, connections, etc.
  3. Technical: size of cisterns,  current condition, needs for reinstatement
  4. Water management: end uses of water and its social and economic impact.

Activity 2: An awareness raising campaign will be developed by GWP-Med with the contribution of the students and with the support of the Municipality and the Water Supply and Sewage Company of Thera, aiming to draw the attention of the locals on rainwater harvesting, how it can be leveraged in modern times and with modern means, as well as raise awareness on water saving, as a critical measure for local water security. The campaign will include:

  1. Awareness raising material: posters, stickers etc. The team will be responsible for distributing the material and raising awareness on water issues in the island.
  2. An event on good practices of Water Management and water saving. This will focus mainly on encouraging locals to use rainwater and other non-conventional water resources for secondary uses. It can be a cultural event, including a concert and a photo exhibition of the work completed by the students in Santorini.

Activity 3 (optional-depending on capacities): Focusing on one area (Pyrgos or other one- to be defined), the team will study the water budget in the area/village, including all water inputs (water supply from network, ground water abstractions, rainwater harvesting and reuse, etc.) versus consumption and will make recommendations to improve water efficiency and management of water resources.


  1. Registry of water cisterns identified, including related data (location, size, photos, use, etc.). Architectural drawing of selected reservoir(s) of special interest, as water monuments.
  2. Social study on the water management and use practices of the past and comparison with the current practices.
  3. Assessment of the condition of the cisterns and recommendations for reinstatement to be used for storage of water or for collection of rainwater, including suggested end uses.
  4. Awareness raising campaign & local event.
  5. Recommendations on how to improve water efficiency in the focus area (or island)
  6. Based on the study, a “Water Walk” can further be designed. This will include a map of water monuments and their descriptions, to be used for cultural visits.

Proposed focus area

Pyrgos where the research will be undertaken has a population of approximately 732 inhabitants and is situated 7km far from the island's capital Fira. Pyrgos is a typical example of medieval architecture with narrow, labyrinthine streets, fortified walls and hidden passages. Nowadays it is one of the villages of Santorini least spoiled by tourism.

Not far from the village of Mesa Gonia, in the foothills of Prophet Elias, lies the Byzantine church of the Episcopate of Thera, founded in the end of the 11th century by the Emperor Alexios I Comnenos. It is an inscribed-cross, four-columned church with dome. Preserved in the interior are wall paintings of excellent quality and a wooden, carved templon (iconostasis), and decorated in the technique of mastic wax.

This was the seat of the Orthodox and, later, the Latin Episcopate. During the Turkish occupation there were disputes between the Orthodox and Latin inhabitants of the island as to who should hold the property and oversee the running of the church. Today the church gathers large crowds on August Fifteenth, the day of its festival.

The water reservoir found in the church is one of the most well preserved reservoirs at the island. The reservoir although it is in good condition, it is not used any longer. For research reasons one can enter the reservoir.


Three partners will be involved in this research:

  • Global Water Partnership – Mediterranean ( Ms. Konstantina Toli, Senior Programme Officer,Coordinator of Non Conventional Water Resources Programme in the Mediterranean

The Global Water Partnership – Mediterranean (GWP-Med, is a Regional Partnership of the Global Water Partnership (GWP). GWP-Med is a multi-stakeholder platform that brings together competent organisations working on water issues in the Mediterranean Region, including Southeaster Europe. 

  • University of CornellSupervisor of the team: Mrs. Gail Holst-Warhaft, Adjunct ProfessorStudents who will participate in the project will come from:        
    • School of Architecture
    • School of Civil Engineering (Specialization in Hydraulics)
    • School of Social Studies
    • School of Agriculture
  • Municipality and the Water Supply and Sewage Company of Thera.

CLICK HERE TO APPLY - Due by March 25


Ancient Cistern

Structure for the collection of a spring water and inner view of an ancient cistern (Source: Duvall, Z.W., 2006)

Map with area of study

Map with area of study.