25 11.4 1.6 David Lubin Memorial Library
Total Page:16
File Type:pdf, Size:1020Kb
COPY FROM MICROFICHE RECORD OF DOCUMENTARY UNIT NO. : COPIE OE LA MICROriCHE DE L'UNITE DOCUMENTAIRE NO. : 3tn COPIA Did LA MICROFICHA DE LA UNITAO DOCUMENTAL NO. : — |'-8 • ' mmsÊBuJ x / ,25 11.4 1.6 FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS ORGANISATION DES NATIONS UNIES POUR L'ALIMENTATION ET L'AGRICULTURE ORGANIZACIÓN DE LAS NACIONES UNIDAS PARA LA AGRICULTURA Y LA ALIMENTACIÓN DAVID LUBIN MEMORIAL LIBRARY F AO • VU ¿ella Terme di'Caraealla - 00100 ROME. Italy We regret that„some of thé pages in the microfiche copy of this.report may not be up to the proper^'. ' legibility standards,even though the best possible-.: copy was used for preparing the master fiche. - r ¿6 frtkïL F AO- r AG:DP/GRE/77/023 ) l/\ j, )>>-/ Technical Report, Vol. I I v WATER RESOURCES DEVELOPMENT IN THE MOLAI AREA GREECE TECHNICAL REPORT Volume I: TEXT ftgfiß UNITED NATIONS DEVELOPMENT PROGRAMME FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS ROME, 1081 0 FAO - AGiDP/GRE/77/023 Technical Report WATER RESOURCES DEVELOPMENT IN THE MOLAI AREA GREECE TECHNICAL REPORT VOLUME I! TEXT Report prepared for the Government of Greece by the Food and Agriculture Organization of the United Nations acting as executing agency for the United Nations Development Programme UNITED NATIONS DEVELOPMENT PROGRAMME FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 1981 Iii FAO. Water Resources Development in the Molai Area, Greece. Rome, 198T! 3 volb., 56 lip.iire«, ?¿ mnps. AG:DP/GRK/77/023, Technical Report. A BrTRACT The report describes the work carried out by the Government of Greece, with the assistance of I'KDP and FAO, to assess the availability of ground water Cor the irrigation of up to 6 000 ha tin the Molai plain, Lakónia. The project area is located in the southern Péloponnèse and consist", of karstic limestone hills up to 1 200 m above sen level and a structural valley (the Molai plain) filled vith marls and c'..i"s with coarser intercalations sloping from 100 m above sea level '."vatcts the coast. The climate is typically Acf.ean, a cool and wind*, variety of the Mediterranean climate; even in the plain «hört r.-tiodH of frost ore not uncommon in winter. The geology of the area is extremely complex and is still the subject of research. The Tripolitza scries consisting of Mesozoic carbonates on j top of semi-metnmorphic tipper Paleozoic schists hns been overthrustc on top of the flysch ami Mesozoic carbonates ci the Ionian Bcries, which consequently have been metamorphosed into phyllitt'b and marbles. Subsequently the area was blockfaulted, resulting in the formation of the graben which, after filling with Neogene sediments, became the Molai plain. From observations of 16 raingauges and one climatologiçal station, évapotranspiration and crop water requirements were determined. Stiram- flow measurements and spring flow measurements were analysed, resulting in water balances from which the groundwater recharge was determined. Groundwater accumulations in the karatic limestone and the Neop.ine deposits are independert of each other except that the Neogene aquifpr loses some of its water into the limestone reservoir whore they are in contact. The limestone reservoir is restricted to the area (10 km2) between the steeply rising hills and the fault »eparating the limestone from the Neogeno filled graben. Its groundwater is of rather poor quality (EC more than "2.0 mmho/cm and increasing with depth) and it has a low head (3-7 m above sea level, which is 77-150 m below land surface). Trunsmissivity is good nnd wells yield easily 100 m^/hour without more than 50 m drawdown. Recharge is by local rainfall and discharge is to the sea. The coastal springB of Glyfada according to isotope data discharge water infiltratinR nt the highest part of the catchment area. The Neo&cne aquifer is subdivided by low transmissivity fault zones into three segments resulting in distinct ground-later levels in each compartment. The aquifer is fed by local rainfall and discharges by subsurface flow mainly into the sea and into a subwurface groundwater sink connected with a fault zone. A water balance is presented which has been confirmed on a groundwater model. ilic Irtish v.itpr of the limestone nquifer is characterized by the ..¿.;.lxUuc uf n variable an.uunt. of sea-watei. It can still be used for irrigation purposes on well drained soils and with adequate leaching. The water of the Neogenc aquifer is of much better quality, although over-exploitation causes an increase in groundwater salinity in the southern part of the plain. Data cn land and water use, demography and agricultural output give a base for the development proposals. Combining the available water roHOurcc:;, including water transfer from the lower Evrotas plain, the irrigated area in the Molai plain can be tripled to cover half the net irrigable area. Estimates have been made of the water costs, the investment requirements, and the output of a modified cropping pattern adapted to the use of the poor quality water of the limestone reservoir. The economic feasibility of such a project has been studied. Recommendations include proposals and suggestions for a reduced oata collection network, field trials on the use of the poor quality water from the limestone reservoir for irrigation, development of two pilot projects using water from the limestone aquifer, water transfer from the lower Evrotas plain and a water management plan for the over-exploited southern part of the Molai plain. V TABLE OF CONTENTS VOLUME I l'ngü .LIST Or ABBREVIATION'S xiii Chapter 1 INTRODUCTION 1 1.1 Background 1 1.2 Purpose and scope 1 1.3 Previous studies 4 1.4 Project execution 4 Chapter 2 SUMMARY OF FINDINGS, CONCLUSIONS AST RECOMMENDATIONS 6 2.1 Summary of findings 6 2.2 Conclusions 19 2.3 Recommendations 22 Chapter 3 DESCRIPTION OF THE AREA 27 3.1 Location and extent 27 3.2 Physiography 27 3.3 Climatological characteristics 31 3.4 Drainage 32 3.5 Historical note of the area 33 Chapter 4 GEOLOGY 36 4.1 Introduction 36 4.2 Regional setting 37 4.3 Geomorphology 41 4.4 Stratigraphy 47 4.5 Structure 52 Chapter 5 CLIMATOLOGY 57 5.1 Introduction 57 5.2 Climatological observations 57 5.3 Climatological characteristics 58 5.4 Precipitation • 59 5.5 Air temperatures . 63 5.6 Evaporation) évapotranspiration and crop water requirements 65 5.7 Other climatological elements 66 Chapter 6 HYDROLOGY 67 6.1 Introduction 67 6.2 Surface flow 68 6.3 Spring flow 74 6.4 Surface water balances 81 vi Page Chapter 7 GROUNDWATER CONDITIONS 83 7.1 Introduction 83 7.2 Geological structure 84 7.3 Two aquifer system 85 7.4 Limestone reservoir 91 7.5 Neogcne aquifer 98 Chapter 8 WATER QUALITY 109 8.1 Introduction 109 8.2 Gcochemical properties of water 110 8.3 Relationship to use 134 8.4 Pollution of water resources 149 8.5 Conclusions and recommendations 155 Chapter 9 LAND AND WATER USE > 159 9.1 Introduction 159 9.2 Project area lr3 9.3 Soil resources 163 9.4 Land classification 167 9.5 Land use 168 9.6 Present and future water demand 176 Chapter 10 DEVELOPMENT PROPOSAL 182 10.1 Introduction 182 10.2 Description and scope of the development proposal 182 10.3 Other development options 185 10.4 Project costs 186 10.5 Project benefits 196 10.6 Economic evaluation 206 10.7 Project implementation 207 REFERENCES " 210 vii LIST OF TABLES Zas» 2.1 Average surface water balança 10 2.2 Surface water balance with a return period of five yearo 10 3.1 Average rainfall dibtribution 32 5.1 Clinatological network 59 5.2 Precipitation characteristics for Kolai 62 5.3 Maximum duration of temperatures below indicated lévela 65 5.4 ETo and pan evaporation in mm/day at Aosopos 65 6.1 Monthly river flow at the Potamia recorder station 69 6.2 Monthly river flow in Cholorema river 70 6.3 Monthly flow in Taakona Wad i 71 6.4 Monthly flow in Monoporo Wadi "i 6.5 Monthly river flow in Asaopoa river 73 6.6 Monthly river flow in Molai river (1979/80) 74 6.7 Monthly flow into the sinkhole (1979/80) 75 6.8 Subregional water balances, average values 82 6.9 Subregional water balanças, return period five years 82 7.1 Groundwater balance 108 £.1 Chemical analyses of wells I -33 and 2-2 130 8.2 Interpretation of water quality for irrigation 145 8.3 Crop tolerance tabla 146 9.1 Community population for the years 1961-71 and 1979 162 9.2 Area of soil series and soil types 166 9.3 Land classification summary 166 9.4 Communities of the Molai orea 169 9.5 Community data, Molai area 169 9.6 Molai plain community land use in 1966 169 9.7 Crops in Molai area, 19Ó6 171 9.8 Irrigated area, 1966 171 9.9 Present land use and agricultural production 172 9.10 Estimated present crop production 173 9.11 Number of animals 174 9.12 Breakdown of aninal production 174 10.1 Capital investment requirements for 400 ha 187 10.2 Capital requirements to bring water from Lower Evrotas plain 188 10.3 Total project coats 189 10.4 Life expectancy and annual maintenance costs 190 10.5 Estimates of unit costs of.on-farm irrigation equipment 193 10.6 Establishment costs 194 10.7 Estimated water costs 196 10.8 Proposed cropping pattern 198 10.9 Accounting prices for economic evaluation 199 10.10 Economic analysis by crop 200 10.11 Gross and net benefits of the project 202 10.12 Monthly labour requirements 204 10.13 Project benefits summary table 205 10.14 Economic indicators 206 10.15 Sensitivity tests 207 viil LIST OF FIGURES 1.1 Location nap 3.1 Generalized topographic map of the Molai area 3.2 Project area with community boundaries 4.1 Sketch map of the geotectonic zones 4.2 Kremasti normal contact between phyllites and dolomites 4.3 Major structural units 4.4 Tectonic line.air.ants in the southeast Feloponnese 5.1 Monthly averages of characteristic temperatures 6.1 Glyfada spring area 6.2 Glyfada shore springs i 1 Schematic cross-section over the 'catchment' area 7.2 Grour.iiv.i-.