This research aimed at evaluating groundwater vulnerability to agrochemical contamination. To that end, we developed an index called Hydric Vulnerability and Agrochemical Contamination Index (HVACI), which integrates a geographic information system and fuzzy logic to measure catchment vulnerability to agrochemical contamination. Our case study investigates two sub-basins, the Baixo Jaguaribe and the Médio Jaguaribe, in the state of Ceará, Brazil. We built a logical relationship matrix involving economic and environmental information as a tool to enhance public managers' decision-making capabilities. Evaluation was based on four categories of vulnerability — high, medium-high, medium-low, and low —, and we found that the joint area of the Baixo Jaguaribe and Médio Jaguaribe sub-basins presented the following levels of risk contamination: 80.3% of the area had low vulnerability, 3.5% had medium-low vulnerability, 3.0% had medium-high vulnerability, and 13.2% had high vulnerability. Geographically, the municipalities with high vulnerability to contamination by pesticides were Aracati, Icapuí, Limoeiro do Norte, Tabuleiro do Norte, and Quixeré. Therefore, HVACI is an important tool for directing environmental management efforts toward areas identified as highly vulnerable to agrochemical contamination.

Resumo Os riscos de extremos hidrológicos para um local ou região estão associados aos modos de variação do clima, em suas diversas escalas temporais. A compreensão da variabilidade de baixa frequência ganha uma elevada importância em regiões onde eventos de seca são frequentes, por estar associada a longos períodos de secas consecutivas. O presente artigo analisou a relação entre a precipitação média da bacia a montante da estação fluviométrica de Iguatu, com os índices PDO e AMO (Pacific Decadal Oscillation e Atlantic Multidecadal Oscillation) através das metodologias de Análise de changepoint, Transformada de Ondeletas (TO), Transformada de Ondeletas Cruzadas (XTC) e Análise da Coerência das Ondeletas (WTC). Essa estação mensura as vazões afluente ao reservatório de Orós, um dos principais do Estado do Ceará (Brasil). A precipitação média da bacia foi obtida a partir de dados de pluviômetros. Os resultados permitiram estabelecer uma relação entre a precipitação da região e os índices PDO e AMO, indicando que um modelo baseado nos índices pode ter alguma capacidade preditiva do comportamento da precipitação local. Nota-se também que períodos com fases simultaneamente positivas (negativas) da PDO e da AMO resultam em um comportamento mais previsível das precipitações da região, com valores abaixo (acima) do normalmente esperado.

This paper presents the IAD-SES-ILT heuristic model built from the combination of the Institutional Analyzes Development (IAD) framework of Elinor Ostrom and the Institutional Legal Theory (ILT). Using the grammatical syntax for the examination of institutional statements, proposed by Crawford and Ostrom, the structure of the Action Situation levels (Constitutional, Collective and Operational Choice) that make up the governance of the Hydrographic Basin of the Metropolitan Region of Fortaleza was analyzed . It was possible to show that the legal view introduced to the IAD-SES by ILT added new values to the institutional approach, allowing an assessment of governance regarding the respect for the principles indicated by the OECD as necessary for good governance of water resources.

RESUMOO artigo avalia a transferência de risco de uma política de alocação de água entre dois setores usuários: abastecimento urbano e irrigação. Para isso, a alocação entre usos foi realizada utilizando dois métodos: rateio linear e rateio com prioridades (adotado em períodos de escassez hídrica). O volume disponível para alocação foi obtido utilizando duas estratégias de operação INTRODUÇÃOA história da apropriação do recurso água pelas diversas sociedades é marcada por crises de ordens econômicas, sociais, políticas, por inovações tecnocientíficas e pela compreensão do tempo-espaço.Para Harvey (2014), o tempo instantâneo e o espaço fluido se constroem e se reconstroem por relações sociais que extrapolam os limites fronteiriços dos lugares e modificam as relações próximo-distante e local-local.

Este estudo explora a construção de um mecanismo de compensação financeira baseado em índices de seca como forma de eliminar o risco moral e a mitigar impactos resultantes de uma alocação de água ineficiente. Para isso, foi analisado um sistema com reservatório de regularização plurianual e múltiplos usos (abastecimento urbano e irrigação). O mecanismo financeiro foi projetado com base no SPI (Standardized Precipitation Index) com escala de tempo de 12 meses e no SRI (Standardized Runoff Index) com 12 e 24 meses. No intuito de obter recursos suficientes para a cobertura das compensações financeiras elaborou-se um fundo de reservas que possui parcelas de arrecadação anual realizadas pelo abastecimento humano e pelo governo. O modelo financeiro permite que as compensações sejam pagas com base unicamente no valor percebido do índice, assim, não há necessidade de estimar a perda real do usuário. As simulações realizadas mostraram que o índice SRI-24 obteve o melhor desempenho para as taxas de juros aplicadas, 0%, 2% e 3%.O instrumento proposto impede que os usuários influenciem no valor do índice e, consequentemente nos valores das compensações e no período de pagamento. Ele consegue compensar a transferência de risco entre setores conflitantes e gerar uma maior equidade ao sistema de recursos hídricos.

This study aimed to understand the perception of drought among farmers, in order to support decision-making in the water allocation process. This study was carried out in the Tabuleiro de Russas irrigated perimeter, in northeast Brazil, over the drought period of 2012–2018. Two analyses were conducted: (i) drought characterization, using the Standardized Precipitation Index (SPI) based on drought duration and frequency criteria; and (ii) analysis of farmers’ perceptions of drought via selection of explanatory variables using the Random Forest (RF) and the Decision Tree (DT) methods. The 2012–2018 drought period was defined as a meteorological phenomenon by local farmers; however, an SPI evaluation indicated that the drought was of a hydrological nature. According to the RF analysis, four of the nine study variables were more statistically important than the others in influencing farmers’ perception of drought: number of cultivated land plots, farmer’s age, years of experience in the agriculture sector, and education level. These results were confirmed using DT analysis. Understanding the relationship between these variables and farmers’ perception of drought could aid in the development of an adaptation strategy to water deficit scenarios. Farmers’ perception can be beneficial in reducing conflicts, adopting proactive management practices, and developing a holistic and efficient early warning drought system.

Proposta de gestão integrada das águas urbanas como estratégia de promoção da segurança hídrica: o caso de Fortaleza Proposal of integrated urban waters management as a strategy to promote water security: the Fortaleza case ABSTRACT The study proposes the use of integrated urban water-management models as a strategy to promote water security and drought preparedness. It was developed in two stages: assessment of water system's vulnerability; proposition of the integrated urban water management model. In the first step, a flow network model was used to simulate the water system. In the second stage, the inductive method was applied after conducting an exploratory research. The assessment of the water vulnerabilities revealed a deficit in Fortaleza's water supply in 2.56% of the simulated period and the complete emptying of Castanhão's reservoir in 6.52% of the months. The integrated urban water management model is based on the management of water supply and water demand. In the first case, it is proposed that Fortaleza's supply system be constituted by conventional water sources (surface waters) and by alternative sources (groundwater, rainwater, desalination of sea water). For the management of demand, it is pointed out the use of water saving plumbing fixtures and financial mechanisms. This model presents a more robust matrix of water supply sources, which increases the water security of urban centers.

This work aims to identify the key sectors of the economic structure, considering their water flows, and estimate each sector’s impact. The goal is to highlight systemic characteristics in the regional economy, establish water use priorities, and assess water security. Based on a regional input-output matrix, we use the following methodologies: the Rasmussen and Hirschman indices for the ‘forward and backward linkages’; simple multipliers of production, job, and income; and the elasticity of water consumption to final water demand. Thirty-two economic sectors and household consumption are analysed. From the elasticity of final water demand, we find that both trade and household consumption put more pressure on water consumption. Furthermore, a joint analysis of the applied methodologies shows that: (a) the trade sector is more relevant for the linkage of water flows, (b) the agriculture sector has the highest direct water consumption, and (c) the public administration sector has the highest intermediate water consumption.