A method for classifying interrelation between sectoral regulatory laws and the ‘water-energy-agriculture nexus concept’ in Brazil

We propose a method to classify the level of interrelation between the water, energy and agriculture sectoral regulatory laws and selected main characteristics of the nexus concept. This method was created to be applied with sectoral regulatory laws so a study case was conducted in Brazil. The results show that all analysed legislations have low to medium interrelation with the criteria intrinsic to the nexus concept; the policies that stood out the most, regarding the number of criteria present in their scopes, were the national irrigation policy and the desertification policy; and in order to operationalize the nexus concept in management models in the Brazilian context, adjustments and a restructuring of regulatory laws are necessary. The proposed method was able to investigate the interrelation between regulatory legislations with the characteristics of the nexus concept as well as their strengths and weaknesses.

For Huckleberry & Potts (), the nexus concept has emerged as a powerful approach to address the social and environmental challenges created by land-use and climate change. Hoff () sees the nexus concept as an analytical approach to derive strategic resource management solutions with an emphasis on integrated system efficiency rather than isolated sector productivity. There is no consensus on the nexus concept, it is interpreted as processes that integrates ideas and actions from different stakeholders present in different sectors in pursuit of a common goal to achieve sustainable development (Endo et al. ).
Because the nexus concept is perceived as integrated management, this terminology is often associated with integrated water resources management (Abdullaev & Rakhmatullaev ; Roidt & Avellán ), integrated environmental policy management (Venghaus & Hake ), and more recently integrated solid waste management (Garcia et al. ; Roidt & Avellán ). Due to the aforementioned concepts' previous existence, some authors question the nexus concept's innovation in conceptual terms and its lack of coherence in more practical terms (Biggs et  Despite these criticisms, there is one feature that strongly defines the nexus concept and makes it an innovative approach, which is the shift from a single sector-centric perspective or a single resource to a multi-centred and multilevel perspective (Bazilian et al. ; Bréthaut et al. ).
Dealing with water-energy-food nexus interrelations in a sustainable way has become one of humanity's great global challenges (Endo et al. ). Besides that, existing integrating concept applications have shown that the transformation required to implement these concepts requires a framework that explicitly explains interdependencies not only between resources but also between their policies (Venghaus & Hake ). The analysis of the coherence of sectoral policies and institutional arrangements through the nexus concept represents the essential aspects of achieving their operationalization. (IV) in some cases does not require a radical overhaul of the regulatory frameworks and governance system, as some regulations may be structured to address the implications of nexus analysis, requiring merely revisions and better articulation (Larcom & Gevelt ).
Furthermore, to our knowledge, no study addressing the nexus concept has developed a method for classifying the level of integration of sectoral policies concerning the main features surrounding the concept. Research directed at these aspects tends to help identify the limitations and challenges surrounding the implementation of the nexus concept in management models. By recognizing this knowledge gap and challenges, this article's key questions are: (I) What is the level of interrelation between sectoral regulatory laws and the main characteristics present in the nexus concept? and (II) What are the main strengths and weaknesses of sectoral regulatory laws upon the nexus concept?
To investigate the key questions raised, this study aims to propose a method to classify the level of interrelation between the water, energy and agriculture sectoral regulatory laws and selected main characteristics of the nexus concept.

PROPOSED METHOD
This section presents the method proposal for the classifi- Step II: Definition of alternatives (Regulatory Legislation); (III) Step III: Evaluation and Classification of the interrelation between criteria and alternatives.
In order to test the proposed method minimum requirements were designed for each step of the application and a study case was conducted. The country selected for this application was Brazil. The country characterization and the minimum requirements are going to be described in more detail in the following sections.

Characterization of the case study: Brazil
Brazil is a country with continental dimensions (8,510,295.914 km 2 ), located in South America. The country stands out in the agricultural sector, being one of the main suppliers of raw materials to the world economy. In terms of energy, the country also excels in hydraulic generation and bioenergy production, it has a diversified matrix with a high share of renewables.
Despite the advances mentioned, in recent years, Brazil has been going through great uncertainties due to the water crises that have advanced in several regions, in addition to the consecutive political and economic conflicts at the national level with repercussions in the whole society.
Water crises and, its conflicts were a motivation to the first nexus concept studies in the country back in 2015.
These studies were developed in order to propose solutions to the water crisis between two brazlian largest metropolises, In the water sector, the Federal Constitution defines as the domain of the Union 'lakes, rivers and any body of water in lands that belong to its domain, or that bathe more than one State, serve as limits with other countries, or extend to foreign territory or from it, as well as marginal lands and river beaches' (Brazil ). technical documents) were used to propose 18 criteria for each sector that represent the main characteristics of the nexus concept for this study. In total there were 18 criteria (6 for water, 6 for energy and 6 for agriculture sectors).

Definition of alternativesregulatory legislation (step II)
The alternatives are represented by the federal regulatory laws for the water, energy, and agriculture sectors. This The application of the method in regulatory legislation of national scale was chosen because the Federal laws have precedence, that is, priority over State and Municipal laws according to the Federal Constitution of 1988 (Section 2.1.1). Therefore, the first changes that must be made in legislative terms must be at the Federal level, so as to guide the changes at lower levels. Evaluation and classification of the interrelation between criteria and alternatives (step III) The evaluation step consisted of identifying whether the criteria are included in the scope of the alternatives (legislation). To identify the criteria in the scope of the legislation, a matrix must be filled out as a minimum requirement to move forward. The matrix contains two numerical codes, 1 to indicate presence of the criterion and 0 its absence, the outcome of this first matrix is a checklist.
After this process, the sum of all the criteria present in the alternatives analysed by the type of segment (water, energy, and agriculture) is performed. For example, in Legislation 1, x criteria of the water segment, x criteria of the energy segment and x criteria of the agriculture segment were found. The results of the sums for each segment corresponding to a weight scale as shown in Table 1.
The weight scale was built considering a total of six criteria per segment, totalling 18 criteria. There is no requirement for the number of criteria that one can use on its studies when applying this method, but if the criteria number changes a new scale may have to be adapted.
With the filling of the matrix by the weights shown in Table 1 (classification by segment) the joint classification is performed. This classification is performed considering the comparison between the sum of the weights of all the criteria fulfilled in the matrix with the classes determined in Table 2. The classes were defined symmetrically, both with the same amplitude, totaling six classes due to the maximum limit of the class being 18 (corresponding to the total number of criteria).

Main composition characteristics of the nexus concept
Based on the 194 technicalscientific documents, eighteen (18) criteria were established as the main characteristics of the nexus concept for this study, with six representing the water, energy and agriculture segment (Table 3). Overall the criteria were based on two aspects: the occurrence of the terms in the analyzed technicalscientific documents and their level of relevance (essential aspects of the nexus concept). For this study, all the selected criteria have the same relevance in the evaluations of regulatory legislation, therefore no weight system was used to differentiate their relevance. All criteria are used to evaluate and classify all alternatives individually.

Identification and characterization of the main regulatory laws in Brazil
In Brazil, ten federal regulatory laws were identified, as shown in Table 4. It can be seen that the laws were formulated in different time periods. Some of these laws have been updated over time, while other laws remain with the same scope.
The water sector in Brazil is governed by the National Water Resources Policy (Law n 9433/1997), which brings water management as decentralized, participatory   Water security (C1) Energy security (C7) Food security (C13) Conservation and rational use (efficient) of water (C2) Conservation and rational use of energy (C8) Encourage the use of unconventional water sources, promoting reuse (C14) Integrated relationship between surface water and groundwater (C3)

Mitigation of greenhouse gas emissions (C9) The incentive to increase alternative energy sources (bioenergy, wind and solar) in agricultural systems (C15)
Water resources without dissociation between quantity and quality (C4) The incentive to increase renewable energy sources in the energy matrix (C10) The incentive for more sustainable production by reducing greenhouse gas emissions (C16) Encourage the generation and transfer of technologies related to the efficient use of water (technological efficiency associated with water efficiency) (C5) Foster the generation and transfer of technologies related to energy efficiency (technology efficiency associated with energy efficiency) (C11)

Case study application
Based on the defined criteria and the selected legislation for each sector, the application of the proposed method was conducted. Table 5 contains the filling matrix with the results of the checklist carried out in the documents of the sectoral regulatory legislation. In this case, the weight scale presented in Table 1 was applied, which corresponds to the individual assessment of alternatives through the criteria for each segment. Within the scope of the analyzed legislation, it was possible to notice the lack of integration between them.
Each legislation tends to focus only on its sector and does not cover direct communication with other laws.
The lack of integration between the laws and the low number of criteria shows that, in order to operationalize the proposed nexus concept, regulatory laws must be restructured, and along with them their institutional arrangements. This restructuring can be carried out through changes in current laws, it may not always require the creation of new laws. For example, the national sanitation legal framework was recently updated instead of being replaced by a new law. Its update included changes in its scope and the restructuring of its related institutions.
Through these proposed changes, there is a chance that actions of the water resources sector will become closer to the actions of the sanitation sector, which are both interconnected by the same regulatory agency.
ii. Climate variability decreasing environmental resources (e.g. water security problems): for example, another   factor that has been occurring in Brazil that has a direct impact on sectoral interrelations refers to water scarcity.
The country experienced a severe water scarcity crisis; among those, one hit its two biggest cities ( It should be noted that water is a link that connects all other sectors that make up a nation's economy and survival.
Therefore, the lack of this resource brings the need for reflection on the current management model. In this scenario, legislation starts to be validated, discussed and reformulated, new regulations and government programs are structured, and a closer relationship between sectors that have joint demands and share risks tends to occur to contain conflicts.
Complementing the assessment of legislation by segment, Table 6 shows the results found from the final classification of regulatory legislation. As can be seen, the policies evaluated presented similar classifications, from low to very low interrelations with the criteria for characterizing the concept of nexus, except for the Irrigation Policy (L9), which obtained the highest score, being classified as average interrelationship.
No analysed legislation scored above nine criteria. In other words, no policy was rated as high or excellent interrelation.
In a hierarchical manner, the laws of greatest interrelation with the characteristics of the nexus concept for the least interrelation are: (I) Irrigation Policy (L9); (II) National Policy to Combat Desertification and Mitigate the Effects of Drought (L3);  As for the integration between regulatory laws, it was possible to notice that the irrigation law, referring to the agricultural sector, was the only one that presented integration with more than two regulatory legislations, energy, water resources, sanitation, and environmental law.
For L1 (National Water Resources Policy), no associations were identified with energy policy and agricultural policy. It is important to note that agricultural activity and energy generation, in the water resources policy, are considered as users of water, as well as mining activities, industry, among others. Therefore, any mention of these activities is described in the context of 'users', as can be seen in its article 3, item IV: 'General guidelines for action for the implementation of the National Water Resources Policy are the articulation of water resources planning with that of user sectors and with regional, state and national planning' (Brazil ).
By making a comparative analysis of water resources policies and other sectoral regulatory policies, it was possible to notice that for the water sector, the desertification policy (L3) obtained a greater correlation with the proposed criteria than the water policy itself (L1) and sanitation (L2).
As in the agricultural sector, the irrigation law (

FUTURE TRENDS
Once the method is applied into the Federal Regulatory Laws, the next step should be to study a smaller scale; for example, state and municipal laws of water, energy

CONCLUSION
The nexus concept still represents a paradigm for public management of natural resources. Traditional models of natural resource management no longer respond to today's complex social and economic problems, so new strategies need to be considered. The nexus concept could be part of this new strategy. In this paper, a new method was proposed for the classification of sectoral regulatory laws based on the corresponding main characteristics of the nexus concept for this study. With the results achieved, the following can be concluded: • All analysed legislations have low to medium interrelation with the criteria that represent the main characteristics of the nexus concept for this study. The policies that stood out the most, regarding the number of criteria present in their scopes, were the national irrigation policy and the policy to combat desertification.
• The analyzed laws must contain points of interconnectivity (water reuse and unconventional water sources in agricultural and energy policy; use of renewable energy sources in agricultural and water policy, among others) and its guidelines must advocate efficient and safe resources.
• Older laws need to be reviewed and updated in order to achieve higher interrelation between themselves and be more efficient and synergistic.
• The strengths identified in the laws must be strengthened with interconnected public policies aiming at greater efficiency in actions and the weaknesses must be carefully investigated so that they are eradicated.
• Current regulatory laws in the agricultural sector in Brazil need to consider water, energy, and technological efficiency as a prerequisite for releasing investment in sector projects and programs.
• The Brazilian energy sector needs to be tightly integrated with water and agricultural legislations, especially when referring to the biofuels and biodiesel policies that have a strong association with the agricultural sector. Some examples that characterize advances in the more intense approximation between the sectors under study in Brazil arose from the need to solve problems present in situations of a scarcity of a certain natural resource in common between them. In other words, because they share the water, energy, and agricultural risks and insecurities, they have tended, due to circumstances, to a greater recognition of the existence of interrelations and interdependencies between them, which has fostered some joint actions. This represents management in a crisis; however, the nexus proposal is to make this interconnected management continuous throughout the process.
In order to achieve an efficient and synergistic intersectoral and shared management, changes in the medium to long term must be initiated by its institutional and legislative base. The proposed method represents an important factor in the change process; however, its individual application alone is not sufficient to achieve more ambitious goals in terms of operationalizing the main characteristics of the nexus concept proposed for this study. It should be noted that investigations about the practical effectiveness of the regulatory laws analyzed as well as their interference in society were not considered in this study. For this, it is recommended to structure research with this objective through the application of questionnaires, interviews, development of a focus group, or other methods that help to gather information about the applicability of these laws.