Traditional irrigation systems are spatial units with a remarkable cultural and heritage value, which in turn generate water landscapes. They are part of hydraulic heritage, which includes material, ideational and symbolic assets. However, the assets related to historical irrigation systems and their landscape units have been poorly studied and evaluated. This paper develops a methodological system for the assessment of hydraulic heritage which combines basic and multi-criteria quantitative techniques. The authors conducted an evaluation of water heritage assets and their associated systems for the purpose of establishing a hierarchy for devising appropriate heritage management actions.
In the last decades of the twentieth century, a growing concern about the need to protect and properly manage cultural and natural heritage became manifest. There are some conceptual and methodological precedents for heritage assessment (Australia Icomos 1979; Kalman 1980; Lipe 1984). Since the mid-1990s, interest in the conservation and evaluation of heritage has been increasing, and this has led to the development of several assessment methodologies. The methods related to the assessment of cultural (Throsby 2001; De la Torre 2002; O'Connor 2011), architectural (Lee 1997; Bishop-Greene 2011), and geological heritage (Kim et al. 2009; Pereira & Pereira 2010; Rocha et al. 2014) are generally the oldest ones, and also those for which the greatest volume of proposals currently exists. However, other systems have been developed as well, related to landscape (Otero et al. 2007), paleontological (Endere & Prado 2015), hydrological (Cruz et al. 2014), touristic, immaterial, archaeological or even bibliographical heritage assessment.
The authors are not aware of the existence of any precedent for a heritage assessment system in the field of hydraulic heritage, except for the methodological systems developed by the ESTEPA (Heritage, Landscape and Land Studies) group for projects on historical irrigation systems (Hermosilla & Peña 2010) and on drainage tunnels or qanats (Hermosilla & Iranzo 2014b).
JUSTIFICATION AND OBJECTIVE
The various elements that make up historical irrigation systems are, along with their respective cultivated areas, an extraordinary cultural heritage. Traditional irrigation systems are not just productive spaces, but also places with a social and cultural meaning and particular environmental values, which are sometimes perceived as spaces for leisure and recreation. These irrigation systems are part of hydraulic heritage and generate valuable and valued landscapes. They are familiar spaces close to us, characterized by a remarkable symbolic value and an ingrained sense of identity (Hermosilla & Iranzo 2014a).
Historical irrigation systems are part of hydraulic heritage, a type of heritage characterized by its diversity. One of the qualities that characterize water heritage is universality, as it is present almost everywhere. The water resource can be found in numerous landscapes, as a perceived morphological element; as a primary functional component of the landscape system; as a resource determining the configuration and appearance of the landscape; and even, through art, as a symbolic image. Additionally, irrigation requires mastering complex techniques for using water resources properly.
Traditional irrigation systems are therefore spatial units with high heritage and landscape value. In order to enhance hydraulic heritage assets and their associated landscapes, it is necessary to identify, characterize and evaluate them. In the current crisis of traditional agriculture, actions aimed at the conservation and management of water heritage are of great significance. The development of a methodological assessment system facilitates the prioritization of hydraulic works and ensembles according to their heritage interest. Such information is essential for prioritizing the measures and strategies for the protection, management and enhancement of historical irrigation systems (Iranzo et al. 2010). In a context like the current one, in which local resources are increasingly appreciated, developing a tool for classifying heritage assets according to their value and importance is fully justified. Moreover, it is necessary to establish methods of assessment that are uniform, consensual and standardized. Institutionalizing assessment systems is thus essential so that they can be implemented as useful and effective decision-making instruments.
The aim of this paper is to propose a methodological system for the multi-criteria assessment of water heritage –a system which can be applied to the different types of hydraulic assets and territories. The nature of this system's indicators facilitates ranking assets according to the value that this method has assigned them, which in turn makes it possible to devise consistent conservation, management and – where appropriate – enhancement or restoration measures. Proposals for action must not consider hydraulic devices as isolated assets – such devices should be enhanced by relating them to the irrigation system associated with them and to the landscape which they have generated.
This method is intended to become a tool that can be recognized and used by institutions for heritage management. It is a methodological system based on consensus, and aimed, firstly, at acknowledging the complexity of hydraulic heritage, and secondly, at achieving practicality and simplicity in the application of the criteria and variables used. It is also based on objective, and sometimes quantifiable, parameters. Additionally, it may incorporate complementary actions based on the participation of social agents. It is currently advisable for evaluation methods to ensure the incorporation of local actors. Society's opinion and assessment is a source of vital and necessary information.
This assessment methodology has been designed to be used as a tool for addressing the tasks involved in cultural heritage management, in the case of hydraulic assets and their irrigation systems. Those tasks are: (1) research: cataloguing and inventory; (2) conservation; (3) promotion and dissemination; (4) restoration and enhancement.
The research project on which this paper is based consisted of four consecutive stages.
Stage 1: analysis and evaluation of the existing documentation
In this stage we searched for methodologies and criteria for heritage assessment, both nationally and internationally, and subjected them to bibliographical analysis. We found 50 conceptual and methodological works for the various types of cultural and natural heritage. Table 1 shows the distribution of references according to the types of assets analysed, and it also indicates those applied practically. It highlights studies related to the evaluation of architectural heritage, with 14 works (28%), followed by cultural and geological–geomorphological heritage, with 11 publications each (22%). These three types represent 72% of the works consulted. From the studies analysed, 29 (58%) make a theoretical and descriptive analysis, without a quantitative development. The remaining documents have practical applications of the developed contents, in order to express numerically the value of the assets and reduce the subjectivity of the process.
|.||Theoretical references .||Applied references .||Total references|
|.||(No.) .||(No.) .||(No.) .||(%) .|
|Geological and geomorphological heritage||3||8||11||22|
|.||Theoretical references .||Applied references .||Total references|
|.||(No.) .||(No.) .||(No.) .||(%) .|
|Geological and geomorphological heritage||3||8||11||22|
We conducted a detailed analysis of the reference works found, in order to identify their main characteristics and those areas which could be improved. The processing of documents consisted of three main tasks:
(a) Studying their general aspects, and analyzing their common traits and characteristics. We detailed issues such as the documents' type and subject matter, the aims and structures of the indicators used in them, and their level of intelligibility.
(b) Going more deeply into the assessment criteria proposed in each reference work. We analyzed the evolution and the similarities of the indicators employed according to the type of heritage being assessed in each case.
(c) Analyzing those heritage assessment methodologies when applied practically. We studied aspects such as the scoring system used in each procedure, their method for obtaining the heritage value, and the degree of complexity involved in applying them.
Stage 2: methodological proposal
The previous methodology for quantitative assessment of the elements of hydraulic heritage (Hermosilla & Peña 2010) took into account ten criteria of evaluation and 30 variables, with a single total score. The reading and analysis of bibliographic references consulted regarding asset valuation, and the experience of the research unit ESTEPA in studies of historical irrigation, have enabled the revision and improvement of the methodology. The new system is structured in 12 criteria that define the cultural heritage, each criterion with three variables. The most significant contributions consist of the grouping of evaluation criteria by categories, the introduction of different participatory techniques of social partners, and the creation of bonus indicators for each type of hydraulic element.
The criteria included are potentiality and vulnerability as they contemplate important aspects of the hydraulic heritage related to the enhancement of the asset to be preserved. These criteria are part of numerous references, such as Bruschi (2007), the National Plan of Cultural Landscape (Ministry of Education Culture and Sport of the Government of Spain 2012) and Rocha et al. (2014). The dozen criteria are grouped into homogeneous sets of general categories (intrinsic, heritage, and potential and feasibility values) allowing, therefore, their classification based on their common characteristics or qualities, as reflected in the National Industrial Heritage Plan (Ministry of Education Culture and Sport of the Government of Spain 2011). This enables an individual assessment of each category, so you can compare the importance of each of them separately. The incorporation of bonus indicators for each type of hydraulic element assessed occurs by the existence of rare but extremely valuable traits. They have their origin in the assessment methodology of Neale (2011). In this methodology a series of complementary actions is introduced based on the participation of social partners, techniques that have proven remarkably useful in recent years, as seen in Mata et al. (2009) and Fitri et al. (2015). Surveys and interviews allow the incorporation of a final numerical grade, with the qualitative and quantitative information collected through these procedures.
Stage 3: participation
A panel of experts in heritage and traditional irrigation was consulted in two stages. Those specialists provided various ideas and suggestions for improving and optimizing the proposed methodology. Applying this procedure is essential for achieving validation and consensus for the method, since the training and experience of experts facilitate achieving an objective and rigorous analysis of the proposed evaluation criteria and procedures.
Between the two consultation stages, we checked the applicability of the methodological system in the Amadorio river basin, located in the province of Alicante, in south-eastern Spain. Sixty-two hydraulic heritage assets or ensembles were evaluated in situ. Additionally, in one of the municipalities in the study area we implemented complementary actions based on the participation of social agents, by taking a poll among the local population and forming a panel of experts. We processed the results and designed a geo-referenced data base, managed through geographic information system (GIS) tools.
Stage 4: final document
In this document we collected and detailed the categories, criteria and variables that make up the methodological system of hydraulic heritage assessment and the results of its practical application.
RESULTS: THE ASSESSMENT SYSTEM
The proposed methodology facilitates implementing complementary actions based on the participation of social agents. Such actions are grounded on polls taken among the local population and the formation of a panel of experts in the relevant field of study.
Intrinsic values, heritage values, and potential and feasibility values
The 12 criteria and 36 variables that make up the categories of intrinsic values, heritage values, and potential and feasibility values are based on the general principles that define and evaluate cultural heritage. The criteria used in this assessment system are based on those included in the National Industrial Heritage Plan (Ministry of Education Culture and Sport of the Government of Spain 2011), since there are several conceptual and functional similarities between industrial heritage and hydraulic buildings. The proposed indicators are defined below.
These make a comparative analysis of the asset. The attributes of the artifact and its importance relative to other assets of the same type are considered.
Representativeness. This shows whether the hydraulic asset has common features with other like assets located in the study area. The proposed variables indicate representativeness regarding the asset's construction features and functionality, as well as the type of system in which it is integrated.
Authenticity. This refers to the degree of fidelity of a given hydraulic asset with respect to its original structure as a whole. It evaluates the asset's fidelity to its original appearance, the nature of the interventions or restorations that may have occurred, and the natural or anthropogenic changes that may have contributed to the deterioration of the system.
Integrity. This considers the condition that the hydraulic device is in nowadays, and also its current use. It takes into account the degree of conservation and functionality of the asset and of the system in which it is integrated.
These focus on the descriptive analysis of the heritage asset. They take into account the cultural and environmental characteristics that influence and enrich the asset's intrinsic values.
Water culture. This indicates the relationship of the hydraulic asset or ensemble to water culture manifestations at a local level. It assesses the traditional use of water in the locality, and also the importance of the irrigation system and the asset itself in relation to assets of the same type. The assets related to customs, social norms, worship, festivals, etc. are considered in this criterion.
Historical and social value. This refers to the historical and social component of the hydraulic work. It considers aspects such as the asset's recognition by local society, the availability of written, cartographic and/or photographic documentation, and the age of the asset. Of particular interest is the regulation related to the management and use of water, both as contained in the Ordinances and Statutes of the communities of irrigators, and as detailed in the Concordias, which facilitate the resolution of conflicts between municipalities.
Technology. This analyzes the value of the technological component of the asset and the system in which it is integrated. It considers the ingenuity of the technique used, the innovations and improvements that have been made through history, and the levelling techniques associated with the type of gradient of the irrigation system.
Artistic value. This considers the artistic value of water assets by assessing their aesthetic and architectural qualities. It takes into account whether or not the asset possesses an image that identifies it with the architecture of water, i.e., with constructive features associated with the knowledge of its time. Figures or actions of the Public Administrations are included, aimed at the official protection of the original design of the hydraulic heritage elements.
Territorial value. This indicates the interaction between the hydraulic asset and the environment in which it is situated. It is appreciated that the hydraulic element and its associated system are located in a scenic area of interest and/or of official recognition (LIC, SPAs, National Park…), which makes it possible to limit the presence of activities that could damage the sustainability of the territory. It also takes into account the visibility of the asset and its system, and also the harmony between the cultural asset and the environment where it has traditionally been located.
Hydraulic value. This is evaluated based on the hydraulic characteristics of the heritage asset of a given territory: whether or not it is part of a benchmark traditional irrigation system, is connected to an irrigation system of significant importance, or is larger than most assets of the same type.
Potential and feasibility values
These consider issues related to the enhancement of the asset to be preserved. They focus on the asset's potential and future prospects.
Awareness of social agents. This assesses the degree of involvement and commitment of social agents in the protection, conservation and enhancement of hydraulic heritage assets. The proposed variables include public or public–private investment in the asset, its inclusion in cultural tourism routes or circuits, and the existence of material for the promotion of the asset.
Potentiality. These actions are aimed at the enhancement and rehabilitation of the hydraulic asset and its system. They also take into account the socio-economic development that would follow from carrying out these actions (increase of agricultural, craft, industrial, commercial or tourism activities). In this sense it assumes particular importance for the existence of public–private management institutions to lead potential projects of revaluation, restoration and valuation of the assets.
Vulnerability. This indicates the existence of external natural and/or anthropic hazards, and the capacity of the hydraulic device and its system to withstand their possible impacts. It also considers the inherent vulnerability of the asset itself, i.e., the propensity for degradation that the asset itself has because of its intrinsic characteristics.
A quantification proposal
The 36 variables that make up the sets of intrinsic values, heritage values, and potential and viability values are assessed for each of the hydraulic assets evaluated. If a given quality is present, the corresponding variable is assigned the value ‘1’; otherwise it is assigned the value ‘0’. The possibility of an indicator's assessment influencing that of others has been ruled out. Each criterion and each category are evaluated separately, so that three types of qualifications for each asset are obtained: scores by criterion (12), scores by category (3) and an overall score. Thus, in total we have 16 individualized scores.
The assessment of each criterion is established by the sum of the scores given to the variables that it comprises. A numeric indicator is assigned to each record (0–3), referring to whether the proposed variables are present or not. Hydraulic assets are thus divided into four assessment levels according to their heritage interest: high (3), medium (2), low (1) and very low (0).
The score for each category is obtained through the sum of the scores of its criteria. Once more, four assessment levels are proposed. The intervals vary depending on the number of variables that make up the category in question. For intrinsic values and potential and feasibility values, the levels are: high (8–9), medium (5–7), low (2–4) and very low (0–1). For heritage values, they are: high (15–18), medium (9–14), low (3–8) and very low (0–2).
Finally, an overall assessment is established as a result of adding the scores assigned to the three categories – the maximum value of the system is therefore 36 points. The final rating is expressed on a decimal scale (0–10 points). Six levels of assessment are proposed, according to the asset's heritage interest: very high (8.6–10), high (7.2–8.5), medium (5.8–7.1), low (4.4–5.7), very low (3–4.3), and uninteresting (0–2.9).
These evaluate the presence of certain particular attributes for each type of hydraulic asset – namely, unusual aspects or features that contribute to the importance of the heritage site. Such singularities provide additional significance to the asset, which is why their absence does not detract from the final score (Neale 2011).
Regardless of the type of hydraulic asset being assessed, two types of bonus indicators are taken into account. First, a bonus is assigned to those assets dating back to earlier than the 19th century, following a criterion which is commonly used by some technical disciplines. The second indicator evaluates the grouping of various significant assets in one system, so that they make up a significant heritage ensemble.
For each water management function, we show the indicators proposed for some of its associated hydraulic assets. In some cases, several bonus indicators may refer to the same type of asset. For example, in weirs or dams we value the existence of water-screening structures for filtering dirt and other impurities, a length over 100 metres, the building of a specific ramp for trout to overcome the obstacle, and the construction of drains for letting off accumulated silt. In aqueducts, we consider whether they have more than one level of arches, their dual function as a bridge and an aqueduct, and the presence of more than three arches. Fortified water splitters located inside a building and mobile water splitters are given special consideration. In the case of ponds we appreciate their having buttresses. Troughs have several bonus indicators, such as keeping the ring where draft animals are held, having spaces or slabs for recharging jars and other containers, and having separate compartments for watering livestock.
Participation of social agents
The proposed methodological assessment system includes implementing complementary actions based on the participation of social agents. Such actions are of two types: taking polls among the local population and forming a panel of experts consisting of specialists. Both procedures are structured based on the indicators that make up the methodology, which facilitates a detailed analysis of the results by categories, criteria and variables. Applying those actions is relevant for finding out the social agents' opinion on the hydraulic heritage of the study area.
Polls among the local population
The aim of these is to quantify the degree of knowledge that local society has about its hydraulic heritage, and its appreciation thereof. We have developed a standard questionnaire for assessing listed hydraulic assets, which is composed of 12 dichotomous closed questions, with the answers yes, no and don't know. At the start of the poll there are also five questions for identification or affiliation, related to the responding subject's characteristics: their age, sex, educational level, and occupation, and the associations to which they belong.
The 12 questions that form the questionnaire have been prepared based on the criteria that structure the methodological system. Each respondent must answer only questions on those hydraulic assets which they recognize, which will allow us to quantify the degree to which each heritage site is known. Global assessment and assessment by indicators are obtained for each asset by establishing the ratio between the number of responses favourable to the asset and the sum total of responses, not counting the don't know/no answer category. The result is expressed on a decimal scale, according to the six levels of heritage interest proposed in the methodological system.
Panel of experts
This allows us to find out the opinion and the views of several specialists on the historical irrigation system of the study area. It consists of about a dozen experts who know the subject in depth, including both public administration technicians and specialists in certain disciplines. The application of this process comprises two phases, as follows:
Phase 1: the experts respond to a technical questionnaire for assessing the hydraulic assets listed in a particular locality. To prepare this questionnaire we used the Likert scale, which is a type of additive scale corresponding to a level of ordinal measurement (Padua 1979). Each of the experts shows their degree of agreement or disagreement with a series of 36 items, which have been prepared in relation to each of the variables that make up the methodological system. Experts respond to each statement according to a scale of five graduated levels of intensity: strongly agree (2 points), agree (1 point), indifferent or undecided (0 points), disagree (-1 point) and strongly disagree (-2 points). Approximately half of the items are positions favourable to the asset while the other half are unfavourable, for the purpose of avoiding response biases. Each specialist's score is the result of the sum of their responses to each item. The use of equally spaced intervals depending on the result obtained is not correct, since the processed data are ordinal. The Likert scale indicates that subjects who have a more favourable attitude or opinion obtain the highest scores.
In order to obtain the ratings for each hydraulic asset, we combine the response levels in two categories: favourable (strongly agree and agree levels) and unfavourable (strongly disagree and disagree). The evaluation of each asset is calculated by establishing the ratio between the number of favourable responses and the sum total of responses, not counting the indifferent or undecided category. Thus, the results are comparable with the ratings obtained in the rest of the methodological system. Ratings are adapted to a decimal scale, and the six levels of heritage interest used in the technical assessment and the polls taken among local people are also employed.
Phase 2: we hold a round table with the local specialists. This facilitates obtaining qualitative information of considerable interest on the hydraulic heritage of the study area. Experts expound their assessments and opinions, and the existing problems are put together. A moderator directs the debate and controls the time. The most important aspects are noted down and treated later. In addition, specialists review the proposed methodological assessment system for the purpose of optimizing the assessment criteria and variables. The participation of the community is essential for improving heritage assessment indicators (Fitri et al. 2015).
REFLECTION AND DISCUSSION
For the assessment of the various kinds of hydraulic heritage assets, we have used a quantitative assessment multi-criteria-type methodology based on the general principles for determining and evaluating cultural heritage. We grouped the dozen criteria used in the proposed system into homogeneous groups in relation to three categories of values (i.e., intrinsic, heritage, and potential and feasibility values). Each criterion and category is assessed individually, and in this way we obtain 15 scores (12 criteria and three categories) and an overall score. Using general categories facilitates classifying criteria based on their common characteristics or qualities. Thus we get more operational indicators, and we can point out the most significant sets of values for the evaluated assets and make a comparison with their various characteristics.
The fact that the 36 variables are given scores of ‘0’ and ‘1’ does not have a strict numerical significance, since it is not easy to define a mathematical relationship between some cultural or environmental parameters. Variables can only receive two values, ‘1’ and ‘0’, without weighting and without ranking some criteria over others. We consider scoring criteria equitably as a valid, even an appropriate, option, since the assignment of values is usually quite subjective, and is not always the result of a systematic analysis of the importance of the various factors involved.
In the methodology we choose to give an additional significance to each type of asset evaluated. This is why we propose adding bonus variables which assess the presence in hydraulic assets of certain unique characteristics. We also establish two other bonus indicators regardless of the type of asset in question; these indicators refer to the asset's age and to the existence of a noteworthy heritage ensemble, combining several significant hydraulic assets into one system. We believe that these attributes should give those assets that have them a bonus allowing them to receive specific treatment for their conservation, promotion and enhancement. Many hydraulic heritage experts regard the inclusion of such variables as indispensable, as they facilitate greater effectiveness in the protection and management of certain assets whose conservation should be regarded as imperative by decision makers.
The design and application of the heritage assessment methodology presented in this paper have been based on objective criteria, even though the variables and the scoring system might be questioned and improved. Assessing and integrating the various heritage values require a highly complex nomenclature of standard values. Still, we consider that the application of the chosen criteria and variables results in a useful system with a high degree of applicability, which may become a tool or instrument for heritage assessment that can be used in tasks of heritage conservation and enhancement. The procedure that we use in this methodology facilitates reaching reproducible, objective results, and provides a common standard for comparison, which can be applied to any asset and to any territory.