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A GIS FOR IRRIGATION NETWORKS IN SOUTHERN ITALY1

P. NINO, A. FAIS

INEA- Italian Institute for Agricultural Economics, Roma, ItaliaE-mail: nino@inea.it; fais@inea.it

ABSTRACT

INEA, as part of the EU Operative Programme “Water resources”, has developed aGeographic Information System (GIS) on the whole irrigation network of Southern ItalyRegions. The GIS is implemented with several cartographic layers (land use, soil, watersources, climate) and is related, thanks to a Relational Data Base Management Systems(RDBMS), to a data base on technical and functional characteristics of each cartographicelement of the network. The system is integrated with analysis, evaluation and simulationmodelling to support the decision makers in water resources management.

WORK PURPOSES AND SHORT DESCRIPTION OF THE PROJECT

Irrigated agricultural productions represent about 72 % of total agriculture’s GDP (GrossDomestic Product) of Southern Italy Regions. The total area covered by irrigated crops isabout 1.600.00 hectares. But water networks and irrigation utilities have a low degree ofefficiency, with significant losses of water (differences between sources water availability andwater availability in irrigation areas) from sources to field. The full utilisation of water meansthe possibility of enlarging the irrigated areas and reducing the environmental impact of wateruse. Therefore water use optimisation in agriculture is a key factor in rural development andagri-environmental management. Also for this reason EU has financed, inside Reg (CEE) n.2081/93 – QCS 1994/99, the Operative Programme (P.O.) “ Water Resource, in Objective 1Italian Regions”. The research on water use in agriculture realised by INEA, part of P.O., hasseveral objectives (economic value and potential markets of irrigated agricultural productions,monitoring of irrigated areas and efficiency in water use, support the local water managingstructure, etc.) and is finalised to the realisation of an integrated information and decisionsupport system. This paper analyses the factors affecting the development of the geographicdata base on irrigation networks and related possible benefits in water resources management.

STUDY AREAS

The work concerns all the irrigated areas of Objective 1 Italian Regions. Data were collectedand organised at “Consorzi di Bonifica” (Italian administrative structures for irrigation watermanagement) and regional (NUTS II) level (in South Italy, 65 “Consorzi” manage an area of8.358.165 hectares). To detect all the irrigated surfaces (about 1.600.000 hectares, inside andoutside “Consorzi”), a land use map has been realised, using remote sensing technology onthree different Landsat TM images (thematic accuracy 1:50.000 scale) of three different yearsand three different season (autumn, spring and summer) and digital ortophotos (grey scalewith pixel of 1 m – geometric and geographic base of the whole system) for geometricaccuracy (1:25.000 scale). The study’s area (about 6.500.000 hectares – Fig. 1) waspreviously mapped, thanks to the superposition of different cartographic layer (DTM,CORINE, irrigated areas). 1 This paper was realised in co-operation with Guido Bonati (P.O. co-ordinator), Mauro Bianchi (dB Accessbuilder and query): INEA; Alessandro Piscicelli (Oracle dB builder and query, Internet application developer)Guglielmo Raimondi (Oracle designer and arc – node topology construction builder): consultants.

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MATERIALS AND METHODS

Starting from the state of the art in GIS applications on irrigation network and agriculture,GIS architecture and procedures were designed taking into account the following aspects:1. Data to needs (cartographic and alphanumeric) related to the irrigation topics

(administrative boundaries of “consorzi, comprensori and distretti», land use, soil, typeand characteristics of the irrigation network, climate, Digital Terrain Model, etc.);

2. Logical and physical design of database;3. Spatial data, raster (topography, orthophotos, etc.) and vector (thematic layer), format;4. Hardware requirement;5. Tools (based on GIS technology), to manage spatial data in terms of:

Topographic aspect, to correctly describe the exact position of network’s objects; Topological aspect, (with analysis of contiguity and connection inside the network).

In the first part of the project (collection of information about the availability of spatial andalphanumeric data) numerous cartographic data were founded (very few in digital format andmostly in different co-ordinate system and realised with different methodology. In particular,data on irrigated networks are not updated and not homogeneous between “Consorzi”).

FIGURE 1. Irrigated and not irrigated areas in Objective 1 Italian Regions.

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DATA BASE DESIGN

The physical structure of data base was designed on the basis of the (following) typologies ofcartographic object and related attributes necessary to implement the system:

Polygon: define administrative boundaries of “consorzi, comprensori and distretti»; Point: represent a node in irrigation network, where node is an hydraulic change (e.g.

source, tub accumulation, heave installation etc.), or a change of the arc characteristics(e.g. diameter, constructive material, type of network: primary, secondary or distribution);

Line; represent an arc (conjunction between two nodes).

The logical structure of data base (concerning the relation between the different component ofthe network) is organised in arc - node topological relation, type of topology “connection”(nodes must correspond to the intersection between arcs, only water sources and distributionnodes have one arc). Distribution node is the end point of the irrigation network and ispositioned inside the “distretto” polygon that is the place where water is used.

DATA ACQUISITION

The GIS (SIGRIA: Water Resources Management Information System in Agriculture) and therelated alphanumeric database (MS Access) for each “Consorzio” were developed, with thefollowing steps:1. Field and photographic surveys to collect data on hydraulic scheme2 [at differentcartographic scale: from 2.000 to 25.000 using topographies maps as basis and, in same cases(data not available), with ground survey, using orthophotos as bracket];2. Integration of all MS Access database in a single database, with also territorial utilities(Oracle), linked to related cartographic data base, and development of an Internet application(with both cartographic and alphanumeric data), accessible to different level of planning andmanagement of the water resources in agriculture (U.E. Commission, Italian Minister ofAgriculture, Italian Minister of Publics Works, Consorzi di Bonifica, etc.);3. Arcs of hydraulic scheme are georeferenced, digitised in the same projection system usingARC/INFO software to guarantee the correct topology and then organised in ArcWiewshapefile (the software choose to visualise and querying data) with storage of connecting keysto the central database [(Figure 2 - Hydraulic scheme and irrigated areas (general view)];4. Quality control (thematic and geometric precision). Thematic accuracy is defined inaccording with the technicians of the “Consorzi di Bonifica”, while geometric accuracy isassured using greyscale digital orthophotos. To improve the time of the work an appropriatemosaic of digital orthophotos was realised using the Image compressor “EnhancedCompression Wavelet (ECW)” an ER MAPPER product. That allows to mosaic and balance agreat number of orthophotos and give access to high resolution imagery roaming and zoomingin real time. With this bracket the arcs of hydraulic scheme (acquired in raster mode) arephotointerpreted and digitised with high geometric accuracy (normally 1:5.000 scale) (Fig. 4).Irrigation network (blank lines) is acquired from the existing cartography of “Consorzi”,using a transparent film, acquired (with a scanner) in raster format and then georeferenced.Arc elements of irrigation network are digitised with high level of geometric accuracy (black– grey lines), thanks to the overlaid of raster image with the digital orthophotos.5. Arc – node topology construction, using “Avenue”, the programming language ofArcWiew, integrated whit a Visual Basic application, to automatically generate the nodes,with their correct keys, used to connect cartographic objects to the central database (Figure 4).

2 Hydraulic scheme describe “ensemble of structural elements, that from a source bring the water at the place ofuse”

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ArcWiew version 3.1 was select as GIS interface. ArcWiew has a good potentiality in dataintegration and development tools (Avenue and Visual Basic). A Graphical User Interface(GUI) is still in development phase. The GUI has different level of data accessibility,depending on the different typology and authorised target level of end users [Ministry level,Regional level, local (“Consorzi”) level]. The interface allows to display basic map,orthophotos and to query interactively SIGRIA (e.g.: what happens if an open canal, issubstituted with another type of irrigated network, such as pressure pipeline, in terms of watereconomise?), selecting and processing data for analysis, in a given area of interest.These applications are possible only if a great number of alphanumeric data (related tocartography) are available and stored in a data base management system. To develop theSIGRIA (with architecture client server for different users) was selected ORACLE 8.1.5.version. Server can work either isolated or in combination with ArcWiew.

FIGURE 2. Quality control and arcs network digitisation.

RESULTS

Data on irrigation networks in South Italy were collected and organised, to support decisionmakers at national, regional and locale level on irrigation water management andoptimisation. To allow these actors to an integrated and geographic use of data, aninformation system has been developed. with the following properties:1. Homogeneity and good quality of the data in whole study areas;2. Same projection system (UTM 33, except for Sardinia UTM 32);3. Possibility to query the system (Fig. 4) to obtain information about the maintenance state

of the networks and their constructive and functional characteristics;4. Possibility to develop new information, from the integrated use of land use and soil

cartography with irrigation networks cartography and related alphanumeric data, todevelop models capable of evaluating the better location of new irrigated areas.

5. Possibility of up-dating the central database at local level (“Consorzi di Bonifica”) withInternet communications procedures.

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FIGURE 3. Hydraulic scheme and irrigated areas (general view).In figure 5 is showedhow, using differentcartographic layers,with information onirrigation schemes, ispossible to defineareas suitable (irriga-tion soil suitabilityevaluation is calcu-lated on the basis ofF.A.O. standard) or notsuitable to be irrigated,according with theirterritorial characteris-tics. In particular areasnot suitable have a lowdegree in Land Capa-bility(derived from soilmap and land usemap).

FIGURE 4. Particular of an arc and his related alphanumeric information

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FIGURE 5. A model to evaluate the better location of new irrigated areas.

Digital cartography Alphanumeric data

CONCLUSION

Since now, Southern Italy decision makers and irrigation water managers had very few and nostructured information to evaluate the efficiency and convenience of water use in agricultureand to develop project quality indicators (in terms of optimisation of water use), through theimplementation of the existing network and the enlargement of irrigated areas. In this part ofEurope the full utilisation of the available water and the optimisation of water use in agricultureis a key factor in social-rural development and agri-environmental management. The realisationof an integrated information and decision support system, based on GIS technology3, could bethe first step to a better and more efficient water resources management.

REFERENCES

G. Bonati, A. Fais, D. Michelini, P. Nino (1998). Il SIGRIA – Sistema informativo per lagestione delle risorse idriche in agricoltura – Regioni obiettivo 1, Atti della secondaconferenza ASITA Vol. 1 Bolzano.

G. Bonati, A. Fais, P. Nino e G. Raimondi (2000). Il SIGRIA - Sistema Informativo per laGestione delle Risorse Idriche in Agricoltura, MondoGIS n° 23, Roma

C.Caroppo, S.Altieri (1988). Esperienze di mapping agricolo per un Consorzio di Bonificadell’Italia meridionale , Atti della seconda conferenza ASITA Vol. 1 Bolzano.

A. Fais (1996). The project "Numeric Soil Cartography" in the Objective 1 Italy Regions:results and methodological innovations in e GIS agricultural applications, Proceedingsof 1st Congress of AITICA '96, Rome.

A. Fais et AAVV. (1996). GIS applications to extension services: an experience in Calabria,Proceedings of ICCTA '96, Wageningen.

E. Orlandi (2000). La tecnologia GIS per le reti tecnologiche, MondoGIS n° 7, Rome.

L. Tosini, G. Mantovani (2000). Il progetto GIS del Consorzio di Bonifica Delta Po Adige,MondoGIS n° 7, Roma.

G. Morin et AAVV (1993). La gestione della risorsa idrica nella pianificazione territoriale,Atti della VI Conferenza Nazionale Italiana AM/FM, Roma.

3 GIS technology give the opportunity (with spatial operation, such as intersecting and buffering differentthematic layers) to derive the parameters effecting the planning of investment for enlarge irrigated areas.

Land use

Soil

Water

Irrigation Irrigation Land

Water availability

Climate Data

Areas with not good suitability fori i i

Areas with good suitability fori i i