a management framework for the efficient use of surface ... papers... · the peninsula of sithonia...

INTRODUCTIONChalkidiki is one of the 52 prefectures, i.e. themajor administrative entities, in which Greece isdivided (Figure 1). The water resources ofChalkidiki are, in general, characterized by thefact that the current development of their poten-tial hardly meets the total water demand. This ismainly due to the almost complete lack of surfacewater storage facilities. Although plans for theconstruction of two major dams of high storagecapacity in inland catchments have been

approved more than two decades ago, the deci-sion process regarding their implementation isvery slow. Moreover the investment rate for theconstruction of even small-size dams in the regionis practically zero. As a consequence the solewater source for all uses in the prefecture isgroundwater.The geomorphology of the three peninsulas(Kassandra, Sithonia and Mount Athos, shown inFig. 1) results in a large number of small to medi-um-size hydrologic basins within them. It should

Global Nest: the Int. J. Vol 3, No 2, pp 145-152, 2001Copyright© 2001 GLOBAL NEST

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A MANAGEMENT FRAMEWORK FOR THE EFFICIENT USE OF SURFACE WATER RESOURCES IN SITHONIA PENINSULA

(GREECE)

Aristotle University of ThessalonikiSchool of Technology

Faculty of Civil EngineeringGR-540 06 Thessaloniki, Greece

* to whom all correspondence should be addressedfax: +30-310-995 711

e-mail: [email protected]

ABSTRACTThe Peninsula of Sithonia is one of many typical regions in Greece in which overexploitation of localaquifers has led to several serious problems related to quantity and quality degradation of groundwa-ter reserves. In this paper, a management plan is presented that aims at the utilization of the so farunexploited surface water resources of the area in order to restore the degraded aquifers and to sup-plement the groundwater supplies, mostly for domestic use. To this end the total municipal waterdemand and the potential of surface waters are first estimated at both the local and regional levels.Next, four alternative management schemes are examined, each one consisting of a different numberof reservoirs. A preliminary evaluation of these water supply alternatives, that concludes the paper, isbased on both operational and economic factors in order to facilitate a future multi-criterion decision-making analysis.

KEY-WORDS: Water resources management, water supply dams, project analysis

P. LATINOPOULOS *N. THEODOSSIOU

Received: 07/09/01Accepted: 08/11/01

latinopoulos.qxd 1/2/2002 4:33 45

be noted that, due to its religious autonomy, theregion of Mount Athos, that occupies most of thethird peninsula, is excluded from any develop-ment plan of the Prefecture of Chalkidiki, includ-ing the management of water resources. From thebasins of the other two peninsulas mainly thosealong the seacoast have been so far exploited,exclusively by pumping the local alluvial aquifers.In almost all of Chalkidiki groundwater is mainlyused for agricultural or domestic consumption.Particularly along the seacoast of Kassandra andSithonia groundwater storage is not continuouslyavailable for meeting peak demands, especiallyduring the summer period (Latinopoulos andTheodossiou, 1998). During the hot months ofJune, July and August, the increased demand forirrigation water but mainly for municipal water,which largely originates from the touristic devel-opment of the coastal area, is met by overpump-ing the local, mostly coastal, aquifers. The imme-diate consequence of such an overuse is a distinctdecline of groundwater levels, which in turn hascaused two very serious problems: (a) a high riskof aquifer depletion in the very near future, and(b) severe seawater intrusion at specific locations,a fact that adds to the overall losses of the under-ground basins water potential.Within the above framework this paper presents amanagement scheme for the efficient use of sur-face water resources in the Peninsula of Sithoniaaiming at: (a) reducing and hopefully reversing thetwo major adverse effects of groundwater overex-ploitation mentioned above and (b) supplement-ing or even replacing at places the use of ground-

water, as a medium and long-term strategy tomeet the steadily increasing water demand in thearea. This plan is based on the outcome of a pro-ject study that was assigned by the Association forthe Development of Sithonia Communities to aresearch group of the Faculty of Civil Engineeringat the Aristotle University of Thessaloniki(Latinopoulos and Papacharisis, 1997).The proposed management framework intro-duces the construction of a number of storagedams, mainly for water supply, because, asexplained throughout this paper, it is the solemeans of utilizing the surface water resources ofthe Peninsula. Although the decision to build adam � particularly a large one � has been increas-ingly contested in many countries, there are still alot of proponents who point to the social and eco-nomic development demands that dams areintended to meet (World Commission on Dams,2000). Given the present local conditions in thestudy area, it is believed that all other options,including both non-structural measures (which inthe case of domestic water supply are in generallimited) and structural measures (such as desali-nation etc), cannot offer better solutions to thesevere water shortage problem. On the otherhand, it looks like that building these dams willsignificantly advance human development on abasis that aims to be economically viable, sociallyequitable and environmentally sustainable.

ESTIMATION OF WATER DEMANDSithonia is the central of the three peninsulas ofChalkidiki (Figure 1) and covers an area of 544.7

146 LATINOPOULOS and THEODOSSIOU

Figure 1. Location map of Chalkidiki and Sithonia

latinopoulos.qxd 1/2/2002 4:33 Page 146

km2, which corresponds to 18.7% of the total areaof Chalkidiki. Its present population is about13,000 and it is unevenly distributed among sevencommunities (i.e. villages of up to 3,000 inhabi-tants). The scenic beauty of the beaches ofSithonia has attracted many individuals who havebuilt their summer houses, either isolated or with-in settlements, along the coastal area. Tourismaccommodation infrastructure consists of numer-ous family-operated guesthouses or single roomsto let, located mostly in or very close to the vil-lages, with an exception of a large hotel complexnear the village of Neos Marmaras.The present development of tourism in thePeninsula has a positive return from the econom-ic point of view; still undesirable effects are notfew, most of which are related to environmentaldegradation. As far as water is concerned,groundwater mining and saline intrusion incoastal freshwater aquifers are the principal con-sequences of the rapid and irrational touristicdevelopment, especially during the �80s. Due tothe direct cause-effect nature of these phenome-na, the most serious problems appear in the areasof high water demand. Thus in the first part of thestudy, the distribution of municipal water demandis only estimated, as water consumption for irri-gation and industry account for less than 8% ofthe total demand. In this way, the municipal waterdemand is calculated as the sum of public andhousehold water supplies, including those con-cerned with tourist accommodation. By the termmunicipal water, the supplies for public andhousehold uses are referred (tourism accommo-

dation included).As the work presented herein was faced from anengineer�s perspective, some concepts wereadopted according to this specific point of view.The estimation of water demand is a typicalexample of such an approach, as it was made onthe basis of consumption data only, that is withouttaking into account the economist�s concept ofeffective demand (Merrett, 1997), which in thecase of water is inevitably exacerbated by a num-ber of various factors (Easter et al., 1997). Therequirements approach was thus applied in ourstudy by looking particularly at two variables: (a)the total annual consumption, and (b) the season-al (summer) consumption peaks. In estimatingboth variables, official data and locally elicitedinformation were combined. Population figures,which were taken from the archives of theNational Statistical Service of Greece and refer tothe last five published national censuses (in theyears 1961, 1971, 1981, 1991 and 2001), are theonly official population data available and aregiven in Table 1.The absence of valid and reliable data regardingthe summer increase of population in Sithoniawas a crucial factor in the estimation of the peakvalues of water demand. According to a localreport (Union of Chalkidiki Hotel Owners, 1995),figures from the inventory of the Greek TourismOrganization regarding tourism mobility inChalkidiki are rather misleading, and in any casethey underestimate the actual situation. This isdue to the fact that declared licensed accommo-dation (hotels, rooms to let and campings) does

147A MANAGEMENT FRAMEWORK FOR THE EFFICIENT USE OF SURFACE WATER RESOURCES

Table 1. Permanent population of Sithonia (Source: National Statistical Service of Greece)

Village 1961 1971 1981 1991 2001

Agios Nikolaos 2176 2110 2073 2260 2276

Metagitsi 769 676 726 749 737

Metamorphosis 215 188 240 379 710

Neos Marmaras 1587 1706 2407 2598 2893

Nikiti 1805 1786 1871 2454 3048

Sarti 706 678 777 937 1155

Sikia 2740 2489 2357 2933 2871

Sithonia (total) 9998 9633 10451 12310 13690

Chalkidiki (total) 79263 73390 79036 91971 105156


not exceed half of the total number of operatingaccommodation units and also because, evenlegally operating, many owners tend to report butonly a small fraction of their guests.For the above reasons the research group askedfor assistance from the local authorities, whichare largely familiar with the actual situation.Local surveys in the seven communities of thePeninsula were carried out by the means of a, spe-cially designed and suitably organized for theoccasion, questionnaire eliciting issues of waterdemand and availability of water resources(Latinopoulos and Theodossiou, 1997;Latinopoulos et al., 1997). By combining officialdata and elicited information, in order to over-come the previously mentioned problems con-cerning mainly the population variations and theextend to which the currently exploited waterresources meet the respective demands, a finalestimation was made for each of the following: (a)the maximum daily water consumption, whichwas calculated by taking into account the peakpopulation demand over the summer period (esti-mated to as 385 l day-1 per inhabitant), and (b) thetotal annual water consumption, which was esti-mated by considering the population variationover a typical year.The final estimates of the above two water con-sumption variables for each of the seven commu-nities are given in Table 2. In summary, the totalannual demand for municipal water in thePeninsula is in the order of 4×106 m3, while local(community) values vary from about 0.1×106 m3

to 1.2×106 m3. This significant variation is due tothe great disparity in the spatial distribution ofthe permanent population and also to different

rates of touristic development in the areas sur-rounding the communities.

SELECTION CRITERIA OF DAMSIn the second part of this study, the focus was onthe identification of a number of catchments inwhich the construction of storage dams shouldmeet specific feasibility criteria. As mentioned inthe introduction, the geomorphology of theregion is characterized by a large number of smalland medium-size catchments. After a preliminaryidentification of 80 catchments and sub-catch-ments and considering geomorphological onlycriteria, derived from both an extensive in-situinvestigation and a desk analysis, 36 of them wereselected for further assessment.The two histograms of the catchment areas andtheir lowest ground elevations, respectively,shown in Figure 2, are indicative of the local geo-morphology of the 36 catchments: (a) Althoughthe range of catchment areas is from 1 to 23 km2,their average value is only 7.7 km2, as most ofthem (78%) are less than 11 km2. (b) The rathermild topography of the Peninsula (maximumground elevation is 753 m) is reflected upon thedistribution of the lowest ground elevations of thecatchments. The fact that the average value of thelowest ground elevations is 54 m and 60% of themare below 40 m shows that these catchments endin low plains, some of which are very close to theseacoast.Before proceeding to the next stage of evaluatingthe specific characteristics of the catchments, thehydrological budget within each of them wasdrawn up. The calculation, which was based onavailable meteorological data from stations with-


Table 2. Municipal water consumption in Sithonia

Village Peak population Max. consumption (m3 day-1)

Annual consumption (103 m3)

Agios Nikolaos 13000 5000 525

Metagitsi 1300 500 84

Metamorphosis 13000 5000 415

Neos Marmaras 35000 13750 1205

Nikiti 7000 2500 370

Sarti 11000 4250 386

Sikia 10000 3750 476


in and close to the study area, was made on anannual basis, using standard hydrological meth-ods and models (Shaw, 1983). The summary ofthe results for the 36 basins shows that the annu-al catchment values of rainfall vary from 440 to725 mm and of evapotranspiration from 611 to760 mm, while the average annual temperature iswithin the range of 12.3 °C to 16.2 °C. A com-plete absence of streamflow records did not allowfor a more accurate estimation of the yields ofreservoirs; therefore the relevant calculationswere based on the average annual runoff from thecatchments.For each of the 36 catchments several specific cal-culations were next made regarding: (a) the aver-age annual runoff, (b) the design flood peak dis-charge, (c) the height of the dam, and (d) the stor-age capacity of the reservoir. As far as the heightof the dam is concerned, an �optimum� value wasestimated by maximizing the ratio of reservoirstorage over the volume of the dam. As long asthis height meets the safety requirements againstflooding, its selection guaranties economic effi-ciency of the dam-reservoir system.In the present management study of the surfacewater resources of Sithonia the following charac-teristics of each catchment were taken into con-sideration: (a) the yield of the reservoir, using thecatchment�s annual runoff as its surrogate, (b) thevolume of the dam structure, calculated for itsoptimum height value, (c) the actual cost of thedam, (d) the dam�s location, as related to the dis-tances from water supply areas and to the alloca-tion of other proposed reservoirs, and (e) a set ofadditional physical factors and ecological, envi-ronmental and economic considerations.

SURFACE WATER MANAGEMENT SCHEMESThe current water resources management inSithonia, which relies solely on groundwater, isabout to reach an almost irreversibly adverse sta-tus. This is because if groundwater basins aredepleted then users will not only lose the compar-ative advantages of underground water storageand distribution but they will probably sufferenormous financial costs. Under these conditionsthe proposed management framework for theefficient use of the so far unexploited surfacewater resources, that is proposed in our study,aims at two distinct targets: (a) to reduce the rateof groundwater resources degradation, and (b) tomeet additional future water demands, by relax-ing, at the same time, the conflict betweengroundwater mining and tourism development.The main point of the proposed plan is eventual-ly to provide public water resource managers withspecific alternative solutions in order to achievemultiple objectives. The first objective is con-cerned with the protection of the hydrologicalcycle and specifically of its capacity to renew thegroundwater flows and stocks. This particularfield of action is a predominant factor of the sus-tainability principle, as related to water resourcesmanagement (Merrett, 1997). Unfortunately thecomplete lack of valuation studies for the region�sresources does not allow for the necessaryengagements in order to meet also the require-ments of efficiency and precautionary policy prin-ciples. As a result the urgently needed resolutionprocess, regarding the conflict of the economic-environmental values (Turner and Postle, 1994),cannot be implemented but through engineering-based solutions. In conclusion, the construction of


Figure 2. Histograms of (a) catchment areas and (b) their lowest ground elevations

(a) (b)


dams in the area, despite the high costs, will defi-nitely serve the first objective, as the stored sur-face water can be used to: (a) supplement or evenreplace the existing groundwater supplies, revert-ing thus the aquifers to their natural function, and(b) prevent seawater intrusion, by reversinggroundwater gradients, either naturally (as lesswater will be abstracted from coastal aquifer) orartificially (by recharging the coastal aquifers withexcess surface storage). Undoubtedly bothactions will have positive economic effects on thearea regarding the value of groundwaterresources (National Research Council, 1997).The second objective of the proposed plan con-cerns the creation of a water system far more flex-ible than the one currently operating in thePeninsula. That is because a group of surfacewater reservoirs could be further used to supplywater in excess of their average yield by applyinga periodically varying schedule of withdrawalsfrom the reservoir system alone or in conjunctionwith controlled groundwater abstractions.Assuming that the reservoir system will servemost of the area, an efficient market, facilitatingwater transfers and eventually water trades, couldthen be easily created (Easter et al., 1997).The evaluation of surface water managementschemes, which is next presented, is based on eco-nomic and operational factors under some basicassumptions and estimated projections: (a) Currentdemand is not significantly different from the waterconsumption values presented in Table 2. (b) In theworst case of a complete absence of demand man-agement in the near future, water needs willincrease up to 40% of the current values within thenext 20 years. (c) The total groundwater abstractionshould eventually decrease by 40% in order to sat-isfy the first objective above and at the same time tobe adequate for serving the second objective.

With the above in mind the least-cost requirementfor total storage capacity is about 3.4×106 m3, whichis roughly 20% of the estimated aggregate annualrunoff would the 36 catchments be fully exploitedall together. Due to this obvious abundance of sur-face water resources, a careful evaluation of alter-native management schemes was made, based onthe following criteria: (a) the number of damsshould not be greater than seven, i.e. equal to thenumber of communities to be served by them, (b)the total storage capacity should range between theleast-cost value of 3.4×106 m3 and 4×106 m3, a max-imum value required mainly in schemes with asmall number of dams in order to cope with con-veyance losses, and (c) the size of the distributionsystem to be also constructed should be kept mini-mum, which means that each community will beserved only by the nearest reservoir(s).Among many feasible schemes, four of them,which better satisfy the above criteria, are pre-sented in Table 3 and Figure 3 below. Theseschemes were further ranked according to theirdegree of collective responsibility and function.Thus scheme A consists of only two dams whichare operated and utilized collectively by at leastthree communities each, while at the other endscheme D, consisting of seven dams each servingonly one community, is characterized by a com-plete financial and operational autonomy.A preliminary evaluation of the four alternativeschemes resulted in some interesting findings.When fixed costs only are taken into account (asshown in Table 3), the differences in the total costsof the four schemes are rather non-significant. So,at the government level, total investment is not acrucial factor in the decision-making process.Maintenance costs were not calculated but they arein general considered low for the dam structuresand high for the distribution systems. Therefore


Table 3. Total yield and costs of the alternative management schemes

Managementscheme

Number of dams

Estimated yield

(million m3)

Cost of dams

(million )

Cost of distribu-tion systems (million )

Total cost (million )

A 2 4.0 10.6 14.1 24.7

B 3 4.0 14.1 12.9 27.0

C 5 3.4 19.1 7.3 26.4

D 7 3.4 23.2 5.6 28.8


schemes C and D would be more preferable toschemes A and B, specifically by the local authori-ties, which are expected to pay these expenses.From the operational point of view scheme Dwould be more suited to greek conditions, as thelocal authorities should opt for the highest possi-ble operational autonomy provided. Still, from ageneral point of view, such a solution can be con-

sidered a luxury for the specific area. In additionit may cause some adverse environmental effects,which were not examined in the present study. So,taking also into account that in a future develop-ment a number of reservoirs could operate con-junctively, we suggest that schemes like B and Cshould be further examined towards a most effi-cient use of surface water resources.


Figure 3. Allocation of dams for the alternative management schemes (also shown are the initially examined 80

catchments)


A final note should be devoted to negative exter-nalities that would probably add to the total costs ofthe dam projects. Such externalities can be either inthe form of possible impact on the environment(i.e. loss of land, impact on landscape, wildlife etc.)or of a more general type, like negative impact onhousing, productive and service functions, historicaland cultural heritage, agricultural framework etc.The local conditions of all proposed dam locationsare similar; moreover, resources and activities inthese areas are of negligible importance, so that, inpractical terms, none of the above mentioned nega-tive externalities has a significant cost worth to betaken into consideration in the economic analysis ofthe whole management plan.

CONCLUSIONSIn the present study a radical change in the waterresources management in Sithonia Peninsula isproposed. The urgent need to upgrade the dam-aged aquifers in the area and to ensure safe yieldsto meet future demands inevitably leads to theexploitation of the abundant surface waterresources of the area. Despite their costs, the con-struction of a number of dams in the region seemsto be the only solution to the problem at hand.Preliminary guidelines and criteria to enable theselection of an efficient water managementscheme are proposed following a detailed investi-gation of demand and surface water potentialcharacteristics.


REFERENCESEaster, K.W., Becker, N. and Tsur, Y. (1997), Economic mechanisms for managing water resources: Pricing, per-

mits and markets, In: Water Resources: Environmental Planning, Management, and Development, Biswas,A.K. (ed.), Ch. 13, McGraw Hill.

Latinopoulos, P. and Papacharisis, N. (1997), Investigation, exploitation and management of water resources ofSithonia Communities, Aristotle University of Thessaloniki, Final Project Report (in greek).

Latinopoulos, P., Theodossiou, N., Papaharisis, N. and Fotopoulou, E. (1997), Investigation of the water demandin Sithonia Peninsula in Chalkidiki, Procedings of the 7th Conference of the Hellenic HydrotechnicalAssociation, Patras, Greece, 105-112 (in greek).

Latinopoulos, P. and Theodossiou N. (1998), Water resources quantity and quality investigations in ChalkidikiPeninsula, Proceedings of International Conference: Protection and Restoration of the Environment IV,Chalkidiki, Greece, I, 69-75.

Merrett, S. (1997), Introduction to the Economics of Water Resources - An International Perspective, UCL Press.National Research Council (1997), Valuing Ground Water - Economic Concepts and Approaches, National

Academy Press.Shaw, E.M. (1983), Hydrology in Practice, Van Nostrand Reinhold.Turner, R.K. and Postle, M. (1994), Valuing the water environment: An economic perspective, CSERGE

Working Paper WM 94-08, University of East Anglia and University College London.Union of Chalkidiki Hotel Owners (1995), Tourism in Chalkidiki - Policies for Development and Land Planing,

Official Report (in greek).World Commission on Dams (2000), Dams and Development: A New Framework for Decision-Making,

Earthscan Publications.


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