ANAVALOS, Karst formations groundwater discharges in marine environment: Development methods

As world population and human activities rise, demand for water is growing while its quality deteriorates. In many cases rational coverage of real needs do not correspond to water resources management (W.R.M.) schemes. Consequently, an optimum development of new physical resources is still needed. Nevertheless, consumption wastage and environmental impacts have to be the principal concerns. Consumption rules and limits accompanied by a new water culture shall define the essential measures and actions of a sustainable W.R.M. plan.

During second half of 20th century, migration currents took out from mainland to coastal areas. Focusing on many of those, non privileged in water resources, coastal areas, it’s quite often assessed that traditional agriculture, dry or semi-irrigated, cannot be converted to a more extended and  productive irrigated agriculture, while, urban, tourist and industrial development plans are subjected to water supply constraints. When a lack of proper surface runoff management is the main negative factor, the issue of development of groundwater resources is becoming critical. Nevertheless, the exhaustion of non-renewable deep aquifers, and the over pumping from coastal shallow aquifers, causing their salinity by salt water intrusion, requires the research of alternative solutions.

Among these solutions, desalination of sea water, based on promising – until recently- technology of desalination plants, has been given a prominent place.

However, that technology is not a panacea for dry or semi-dry coastal areas. In many cases, for different  reasons, such as high energy cost, quality parameters and significant environmental impacts, that ”marine” water supply technology is proved inappropriate.

Research Object

For the above mentioned reasons, the idea of fresh water development of coastal groundwater submarine resurgences is becoming very challenging. That idea was successfully implemented in Greece 37 years ago, due to an innovative system grasped and designed by the German geologist Dr. Staender.

Built in Kiveri, that intake system made possible the exploitation of the groundwater submarine outflows which radically changed the appearance of Argos vast plain.  European Union has published a very positive evaluation reports for this project, which is still the only successful on a global scale. By constructing the intake system of Anavalos, discharge of 600.000m3/day approximately was gained. 1

However, the intake structures in Kiveri are technological products belonging to previous generations, dispossessed of technical flexibility, adaptability and investment cost alleviation. That was, among other factors, the reason for the non propagation of such projects.

Meanwhile, the  lack of intake system’s function follow up with applied research as well as the negligence in carrying out  modernizing actions contributed to the downgrading of the remarkable structure, which, however, is still supplying the lands  of Argos by approximately 300.000m3/day of good quality water. 2

Plan View of Kiveri’s Dam

Kiveri’ s Dam and Pumping station









Technological progress in recent decades, founded on new paradigms, leads to innovative intake system’s design, by using new generation flexible structure materials and intelligent automation. Within that research context, a innovative concept have been developed by Dr. Ion Argyriadis, member of the research team

At this research stage, both, negative and positive experiences contribute in processing important problems. Researchers in Hydraulics, as well as researchers in related branches, know the difficulties of solving turbulent flow problems in natural milieu. There are also well known difficulties in modeling outflows of finite velocity from a natural source to a natural reservoir of infinitely small or zero velocity. These difficulties are increasing when the liquids are of different viscosity. Besides, Karst Hydrogeology proves that groundwater flow modeling is limited by indefinability and discontinuity of Karst systems.

Project Concept

Karst is a specific geological structure characterized by special landforms, surface and particularly underground drainage networks, simultaneously interrelated and relatively autonomous. Underground water circulation occurs through faults, cavities, galleries and channels within the limestone formations. Drainage network geometry and spatial distribution are mathematically random, therefore, its spatial -and not only- parameters could not be reliable simulated.3 Consequently, drilling in karst is generally unsuccessful, rarely effective and usually financially costly and environmentally detrimental (harmful).

Fundamental hypothesis of this project is that the intake system should not be searched along the coastal underground drainage system but at the outlet. That means, avoidance of any “violent” intervention in the karst hydrosystem’s body, which could cause, among other impacts, salt water intrusion and/or critical changes of flow regime (creating or increasing turbulences), focusing on its area of free discharge. That hypothesis leads to the study of an intake structure which respects the hydraulic equilibrium of the upstream drainage network, while ensuring the designed, by the project, fine adjustments of flow conditions and characteristics.

Beyond the above mentioned hydraulic problems, related with flow regime, another type of problems concern the mixing process of different density, viscosity and osmotic pressure liquids. It is proved that under laminar flow regime, the mixing process does not occur. Contrary, mixing process occurs under turbulent flow regime. That phenomenon is not only produced in laboratory experimental conditions, but is also clearly observed in some groundwater outflows in sea environment. The case of Kiveri Anavalos is a proof of that phenomenon in nature.

Experiences in similar underwater springs in the sea indicate that lower (than sea water) density of fresh water rises constantly to sea level if flow remains laminar. Laminarity can be ensured when turbulences are eliminated at the karst porous level (outlet) and along fresh water trajectory to the sea level. That requires constrain of waves and sea current effects. A type of stilling basin of adequate geometry and volume may respond to the above required hydraulic conditions

Therefore, the problem of decreasing salinity by implementing that kind of intake structures is related to the problem of elimination of turbulent flow. However, the general theory of turbulence is still far from being fully developed.

In relation to the above theoretical problem, it has to be considered that the main field of turbulences is generated at the outlet of the karst underground drainage network in the sea. At that point groundwater flows from a channel simulated as a pipe of a finite diameter to a water reservoir, simulated as a pipe of infinite diameter. Thus, the problem is the reduction, if not the disappearance, of the principal cause of turbulences, which is the sudden decrease of kinetic energy.

Since main factors (dynamic and morphologic) determining velocity could not be directly regulated in those complex natural hydraulic systems, velocity regulation (to lower levels) can be achieved by controlling the hydraulic charge difference between discharge channel and sea level. The possibility of that regulation has been proved in Kiveri Anavalos by raising smoothly the water level inside the intake structure defined by the barrier.


The study of Kiveri Anavalos case. Outlet characteristics -very important discharge, close to coastline, 8meters depth- and intake system form –water basin delimited by an arched concrete barrier and the coastline- could allow generalization on different types of submarine resurgences only under certain conditions. Last three years two different types of such resurgences have been investigated. The first type concerns an important resurgence inEretriacoastal area (EvoikosGulf) at a distance of one mile from the seashore, at35 metersdepth. The second type of resurgence is a small one in Leonidio (100Km south of Kiveri) very close to coastline (like Kiveri Anavalos) at shallow waters, but in open sea.

During last three years Water Resources Management laboratory of Technological Institute of Athens is carrying out measurements on the above mentioned three resurgences. More specifically, at Eretria Anavalos bottom topography measurements, water quality sampling according to a predefined spatial distribution and outlet video recording took place.

Shallow Resurgence (15m) in Stoupa Messinias (near the coast)

Deep resurgence (35m) in Eretria (1 mile from the coast)









The proposed research is structured and is being developed on three distinguished theoretical and empirical fields although has been initially conceived as a wholeness. The first field is referred to the upstream karst hydrosystem which will be configured and analysed through a data base with spatial reference (GIS). The second field is referred to the outlet sea area and the third to the outlet simulation in laboratory. For that purpose, a model representing the flow from a pipe to a reservoir will be constructed. Nevertheless, karst system outlet function in nature cannot be simulated in laboratory if is based on causal relations. While linear or even stratified causality paradigms can not explain karst reservoir reality, they can help in solving intermediate problems. The whole project will be structured in six work packages (WP), each one comprising research units (in total eighteen) covering both in situ and in laboratory empirical tasks. The whole project is also founded on theoretical elements and processes covering interrelated scientific topics of geology-karstology, geomorphology, hydrology, hydrogeology and hydraulics.

Research Milestones

WP 1

General methodology issues, assessment on available project resources, organization and planning, installation of a network for systematic measurements of Kiveri hydrosystem parameters (RU1).

Kiveri’s intake system survey, hydrographic study of surrounding area, underwater photogrammetrical survey of the spring, diving and video recording, use of underwater Remotely Operated Vehicle-ROV (RU2).

ROV monitoring in Eretria Anavalos

Chief Diver Mr Garras. Preparation for diving.








Design of a data base where quantitative and qualitative information are recorded. Existing condition assessment of pumping station, basic instruments and automations (RU3).

WP 2

Geological and hydrogeological preliminary study of the larger area. Elaboration and analysis of existing hydrological and hydrogeological information. Investigation of karst capacity for water storage and definition of the karstification depth Understanding of Kiveri Anavalos karst system (RU4).

4 Examining interrelation effects between karst reservoir and alluvial zone. Time series of underwater hydrological data, collected from a selected sample of wells, will be analyzed, in order to define continuity and discontinuity of the hydrosystem. First approach to define the zones of influence of Kiveri resurgent discharge (RU5).

WP 3

Water level measurements and qualitative analysis of water parameters inside Kiveri intake water basin. Analysis of existing data and available information from recent drillings. Study of the flow at the low karst zone close to the coastline. Time and space data analysis using tracers tests (RU6).

Creation of an appropriate Geographical Information System (GIS) of high and low density of information (RU7).

Intermediate internal evaluation of the research (RU8).

WP 4

Installation of a reservoir of adequate dimensions and material in order to permit visual observation and photographic recording and interpretation of the diffusion process. Theoretical examination and laboratory experiments (RU9).

Liquid diffusion of different viscosity and weight density liquid from defined diameter pore to reservoir. Liquids mixing process study. Spatial distribution of factors and parameters. Sequential and factorial experiments interrelating velocities of the injected (regulated inflow) liquid in the reservoir at a) the end section of the conduit, b) the pore (outlet point) and c) after the outlet point along the flow lines of the injected liquid. (RU10).

Repetition of the experiments after installing on top the pore structures of variable geometry. Direct and indirect observation of turbulences. Sampling for liquid mixing analysis according to the spatial distribution scheme. Spectrographic analysis. Direct or indirect measurements by digital acoustic doppler and/or ultrasonic systems as well as through depiction of beam diffraction technology (RU11).

WP 5

Procedures and measurements, among those mentioned in RE1, RE2, RE3 and RE4, for a preliminary stage study of two different type of resurgences a) in Leonidio and Andros (RU12) and b) in Eretria (RU13).

Investigation of alternative intake methods. Concept analysis of two alternative types (arched and circular) of floating flexible barriers forming dam structures (RU14).

Study of stresses and pressure distribution. Study of water level regulating devices, hydraulic gates of variable forms and automations. Simulation, demonstration and development possibility (RU15).

Specifications and prescriptions for a pilot project in small coastal resurgences, in open sea, will be proposed (RU16).

WP 6

Analysis of the findings and partial conclusions of the research in three stages: a) the macro-scale stage, concerning the Kiveri Anavalos hydrosystem, the Eretria and the Leonidio-Andros resurgences, b) the micro-scale stage, concerning the Kiveri resurgence function and its existing intake structure and c) the experimental in laboratory stage. Final conclusions, innovative proposals and fields for further research (RU17).

Internal evaluation of the project by the research team with the contribution of beneficiaries (RU18).

Progress beyond the state of the art

Progress beyond the state of the art is expected following successful achievement of the project considered as a whole process, although, innovative results will be produced during its distinguished phases, in form of work packages or research entities.

Consequently, innovation concerns:

I) The  integrated   product of the research, amounting to  a  case study of a karst reservoir, its ground water discharge regime and an innovative  fresh water  intake system in marine environment.

II) The intermediate innovative results, concerning its R & D function, dealing with particular theoretical or experimental objects of the project.

Innovative result related to the integrated product of the research aim at the description of a creative conceptual  frame and methodology.

Innovative results related to work steps, methods, technical aids, during distinguished phases of the project (WP and RU) and more specifically, those related to the components of the intake system and their functional characteristics, aim at the creation of new objects (methods, structures and systems).  Among them:

a) Measurement methods and patterns in the coastline karst zone, both in land and sea
b) Monitoring methods and patterns surveying the resurgence outlet and surrounding area.
c) Theorems corroboration or enfeeblement through experimental proofs or contradictions/beliedings
d) Devices which regulates turbulences at the end section of conduits and the pores (variable dimensions and geometry), following sequential and factorial experiments interrelating velocities or viscosities or weight densities.
e) Flexible structure on the top of the pore eliminating external factors influence (i.e. modelling waves and currents effects) as well as regulating the hydraulic charge. Form and construction materials
f) Automation instruments or devices regulating hydraulic gates function.

Research and Development (R&D) Lines and Functions, concerning most of the above topics, are still far from being studied at an advanced level.

Management structures and procedures

During the kick off meeting a project plan and a project organization document will be presented in order to be approved. The project plan will introduce -beyond description and expected effects definition- the project network plan, an activities follow up document, activity description, project cost estimate and cost budget. Moreover, project plan will include the process to be performed and the project control process.

Project organization document will specify the project management group, the organizational units in relation with sub-projects (work packages) identification- their functions and areas of responsibilities. As already described, the project amounts to 6 Work packages (WP) consisting of 18 research units (RU) in total. Communication channels will also be decided.

A responsible researcher will be assign for each RU. Research Unit responsible researchers and the Principal Investigator will constitute the coordinating group of each WP.

Meetings will be hold regularly every six months. Three of those, the kick of meeting, the interim meeting at the end of the first year, synchronized with the first internal evaluation and the final meeting also synchronized with the final internal evaluation, require presence of all project researchers. The other meetings could be hold in form of teleconferences in order to facilitate the participation of project researchers from abroad.

Conclusions of those meetings will be included in the progress reports which will be published every six months. Progress reports will be complementary to eighteen research reports, each one of them covering a RU, and two evaluation reports. Above mentioned reports are deliverables.

Two seminars, one at the end of the first year and the other at the end of the project, will ensure the dissemination of project findings and innovative results.

Expected results

Work steps, methodological and experimental results produced in each research unit (RU), will be integrated to work packages (WP) according to the above described Project Plan. Consequently, each work package could be considered as an integrated result created during an integrated process. Integrated processes correspond to sub-project entities.

Expected integrated results at sub-project level refer to the project process as a research and development (R&D) activity and to the project product as an outcome covering specific real social demand.

As it concerns research and development (R&D) activity, results are related to creation and spread of new knowledge in the academic (research centers) and educational (universities) institutions.

As it concerns the project product as an outcome covering social demand, innovative intake system, developing groundwater submarine resurgences, can be expected.

Moreover, conceiving the research on two levels -technological and scientific-also elaborating an coherent  method of dividing the work in numerous distinct work packages and research units, involving researchers, postgraduate, graduate and undergraduate students, has, beyond advantages and disadvantages, its pedagogic value.

Implementation possibilities

Strong demand has been expressed last years specifically from cities and agricultural perimeters located in coastal zones. That demand becomes stronger in arid, semi-arid areas. A number of local and regional authorities of those areas addressed to us in order to investigate groundwater submarine resurgences. Among them:

  1. the Federation of Argolida municipalities, neighbouring to Kiveri Anavalos, authorized officially the TEI Athens – Water Resources Management Laboratory, directed by Professor Pissias, for the follow up of the existing intake system, for regular sampling from the reservoir and for water salinity control.
  2. the Federation of Evia island municipalities, in cooperation with the  neighbouring west coastal area of Attica and Biotia municipalities, authorized officially the TEI Athens – Water Resources Management Laboratory and Professor Argyriadis to continue the investigations of Eretria Anavalos.
  3. The prefecture of Cyclades islands contracted with TEI Athens – Water Resources Management Laboratory, a research project aiming at water development in Andros island. Among project objects is that of a coastal water resurgence investigation.

Expected benefits in local and international level.

The proposed project generates a fruitful and inventive research topos in which senior researchers from abroad and from Greek national research center will meet senior and junior researchers as well as students and project management personnel of Greek universities and Technological Institutions.

Project Research and development (R&D) function, creates and spreads new knowledge among researchers and students involved in the process. That knowledge produced thought theoretical and experimental interactive activities improves the academic potential.

Project also creates new methods and products promising innovative effects on groundwater resources development systems. Concerning karst groundwater marine resurgences two important aspects have to be considered.  At first, these unexploited –until nowadays- resources constitute a huge stock of fresh water which could cover crucial needs of arid – semi arid areas. Secondly, development of those groundwater resources has a specific comparative advantage since it does not disturb the equilibrium of hydrosystems. Therefore, ecosystems remain unharmed.

Aegean Greek islands and Cyprus as well as other Mediterranean areas suffering from water stress, could be favoured by using the gained project knowledge and its expected innovative results.

It is quite interesting and very encouraging that during last years investigations local societies unanimously expressed their warm interest.

Uphold the National Legislation and the European Environmental Directives.

  • Respect to the DIRECTIVE 2000/60/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 23 October 2000 “establishing a framework for Community action in the field of water policy”
  • Respect to the DIRECTIVE 2006/118/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 12 December 2006 “on the protection of groundwater against pollution and deterioration”
  • Respect to the Greek Law 3199/2003 concerning the protection and the management of water resources
  • Respect to the Greek Directive 51/2007 definition of procedures for the protection and the management of water resources.
  • Respect to the Decision  (Tanger’s  Report 3/12/2008) of South Forum for theMediterranean, organized from representatives of Mediterranean parliaments (reference to the Kiveri’s structure)
  1. Volume about the half of the daily consumption of fresh water in Athens metropolitan area, supplied by Mornos-Evinos big dams system, located 250Km faraway.
  2. That water is characterized by its low degree of salinity (ranging from 250 to 500 ppm) without any treatment
  3. Karst drainage network could be divergent in contrast to surface hydrographic network which is almost exclusively convergent.
  4. Additional information from the more than 2.000 wells operating in wider Kiveri area. However most of them are located in the lowland alluvial zone.


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