Jaime Joaquim da Silva Pereira Cabral

Monitoring of soil subsidence in urban and coastal areas due to groundwater overexploitation using GPS

The global positioning system (GPS) is widely used for determining the three-dimensional position of points on earth surface. In the last few years, its use has also been increasingly employed for obtaining vertical geometric coordinates, which associated with the orthometrical altitude of the point can be employed in various civil engineering applications, as has been seen in diverse localities throughout the world. The satisfactory performance of this technology for obtaining excellent precision in vertical coordinates demands some conditions, related to the satellites, such as transmission of signals and, principally, in the case of urbanized areas, the presence of obstructions in the proximity of the equipment, which interferes with the quality and quantity of the information collected. GPS is an efficient technique for the detection of small movements, including the monitoring of soil subsidence. The present article describes adequate forms of the use of GPS in such a way as to guarantee good precision of the resulting vertical coordinates, even under unfavorable situations, such as in coastal areas, where the reference networks for monitoring are implanted in only one of the sides of the point–object region, which makes the situation more difficult and requires careful planning so that the use of GPS reaches the desired precision.

Groundwater management in Recife

In developing countries, the rapid urbanization in the second half of the twentieth century provoked radical changes in the cities with serious water related problems, such as freshwater scarcity, sewage and drainage problems. This growth produced several impacts on groundwater resources such as land impermeabilization and change in groundwater recharge, excessive exploitation and groundwater pollution. These facts have demanded better planning and management, especially in areas with high dense population. In Brazil, water legislation has been approved by parliament, a water agency has been created and technical knowledge of water resources has improved. Management strategies incorporated several issues: planning, legislation, zoning, licensing, concession and controlling. Monitoring, hydrochemical analyses and groundwater modeling have been performed to obtain more information for better management towards sustainability.

Occurrence of Cryptosporidium spp., Giardia spp. and other pathogenic intestinal parasites in the Beberibe River in the State of Pernambuco, Brazil

INTRODUCTION Transmission of pathogenic protozoa and helminths by water is a serious public health problem. In this study, we analyzed the presence of these organisms in the Beberibe River in Pernambuco, Brazil. METHODS Parasite analysis was performed using the Hoffman, Pons, & Janer method followed by centrifugation and preparation of slides by staining with acetic acid and Lugols solution. Protozoan oocysts were isolated by the modified Ziehl Neelsen method. RESULTS Cryptosporidium spp., Giardia spp. and other parasites were found in the Beberibe River. CONCLUSIONS Sanitation companies must assess pathogenic intestinal parasites in water basins providing public water and subsequently develop improved treatment systems for removal of such parasites.

Characterization of the Capibaribe River Dry Bed with Ground Penetrating Radar (GPR)

For an adequate hydrogeological study of alluvial layers in the semi-arid zone, it is important to know well its geometry and its hydraulics characteristics. Alluvial formations are generally constituted by erosion, transport and sedimentation processes, causing considerable heterogeneity in soil hydraulic parameters and water flow. The present research had as objective to perform a geophysical characterization using the Ground Penetrating Radar – GPR in the dry bed of the Capibaribe river. To the extent that depositional layers exhibit changes in water content, granularity, sediment type and layer orientation, the water table as well as sedimentary structures and lithological contacts tend to be identified, making the method effective for hydrogeology research. The study area comprises alluvial dry river bed of upper Capibaribe river in the municipality of Santa Cruz do Capibaribe. The results showed that GPR was efficient in the imaging of the subsurface contributing to the knowledge of the geometry and the stratigraphy of the aquifer of the dry bed of the river. In the dry bed of the river, with 400 MHz antenna the signal reached a depth of 2.65 m, and with the antenna of 200 MHz, the signal reached a depth of 6.00 m. The capillary fringe was identified at a depth of 3.0m with the use of 200MHz and 400MHz antennas.

PROTOCOLO DE AVALIAÇÃO RÁPIDA DO ESTADO DE CONSERVAÇÃO DE UM TRECHO DE MATA CILIAR DO RIO SIRINHAÉM (PE).

The riparian forests that cover the banks of the rivers, tributaries and sub-tributaries, play important roles in maintaining the equilibrium of riparian ecosystems. In the Zona da Mata in the state of Pernambuco these ecosystems were replaced since the installation of the first sugarcane plantations in the beginning of the fifteenth century, however, only at the beginning of the 21st century did the first initiatives of restoration of these riparian zones took place. In this scenario, with the help of a Rapid River Assessment Protocol (RAP), the conservation status of the riparian zone of an 8-km stretch of the Sirinhaem River on the lands of a sugar-alcohol plant in the municipality of Sirinhaem, Pernambuco, was investigated. The results of the RAP pointed out that along both banks of the analyzed section, 7 sub sections were found impacted, 8 possibly altered and only 5 considered natural. The Sub sections that were negatively evaluated reflect the intense economic activity present at the site, such as sugar cane activity and sand extraction. From the ecological point of view, it was observed that Inga edulis, Montrichardia linifera and Mimosa bimucronata provide important ecosystem services to the riparian zone, thus contributing positively to the results of the evaluation of some Sub sections. Therefore, in capturing the positive and negative impacts of the banks of the stream, it is understood that the protocol used has proved to be an important tool in the environmental management of riparian zones.

Multicriteria analysis applied to the management of urban pluvial waters

O processo de urbanizacao altera significativamente os processos de escoamento natural da bacia hidrografica, com o aumento do volume das aguas pluviais escoadas superficialmente, incremento das vazoes de pico dos corpos d’agua, degradacao da qualidade da agua, geracao de sedimentos, entre outros. A gestao das aguas pluviais tem, entao, um papel fundamental em uma area urbana, este processo vem se tornando cada vez mais complexo, envolvendo nao somente aspectos hidrologicos e hidraulicos, como tambem questoes ambientais, sociais e sanitarias, alem dos aspectos tecnicos e de custos usualmente considerados. Esta complexidade leva, cada vez mais, ao uso da analise multicriterio como suporte a decisao. Neste sentido, este trabalho objetiva a aplicacao de uma metodologia de analise multicriterial aplicado a drenagem urbana, com o auxilio do PROMETHEE. Os resultados indicaram que a aplicacao de analise de multicriterio agregado aos cenarios de intervencoes hidraulicas se adequa bem a realidade, pois permite incluir uma gestao participativa.

Compensatory alternatives for flooding control in urban areas with tidal influence in Recife - PE

Este trabalho apresenta um estudo de alternativas compensatorias em drenagem urbana, utilizando o modelo SWMM (Storm Water Management Model), para o ponto critico de alagamento numa area urbana e vulneravel as oscilacoes de mare, situada no Recife. Para isto, utilizaram-se informacoes cadastrais da rede de microdrenagem e definiram-se os parâmetros e variaveis necessarios para a modelagem, tais como: subareas de contribuicao ao sistema de drenagem, indicando o percentual de impermeabilizacao do solo, largura equivalente, declividade e taxa de infiltracao; chuva de projeto; e curva de mare. Com o modelo calibrado, foram simuladas duas condicoes alternativas. A primeira, que trata de uma adequacao da rede de drenagem, apresentou reducoes maximas no volume de alagamento de 37% para os eventos com periodo de retorno de dois anos e de 58% para cinco anos de recorrencia. A segunda, baseada na implantacao de um reservatorio de detencao na rede existente, apresentou resultado satisfatorio para o evento de dois anos e reduziu cerca de 38% para eventos de cinco anos. Os resultados mostraram que houve uma reducao na area de alagamento para as condicoes simuladas. No entanto, a primeira alternativa nao resolveria os problemas de alagamentos locais, apenas atenuaria e aumentaria a sobrecarga dos condutos a jusante do sistema modificado, enquanto que a segunda alternativa poderia resolver o problema dos alagamentos, com a ocorrencia de um evento de dois anos.

Vertical hydraulic gradient research in hyporheic zone of Beberibe river in Pernambuco State (Brazil)

The interaction between groundwater and surface water occurs naturally and is dependent on the dynamics in the hyporheic zone. The hyporheic zone is the interface between the surface water source and the phreatic aquifer and it’s a system that also influences the water quality. An important feature is the ability to flux in this zone. This work aimed to evaluate the vertical hydraulic gradient in the hyporheic zone at two points in Beberibe river, Olinda-PE, to understand the hyporheic environment characteristics and water flow dynamics in experimental area, in addition to identify the existence of hydraulic connection between surface water and groundwater. The experimental phase consisted of infiltration tests in riverbed with cylinder infiltrometer and vertical hydraulic gradients readings with differential piezometer, complemented with grain size information, for an assessment of the water budget between the river and the aquifer. Analyzing the behavior of the interaction over the period of 10 months, it was observed that the Beberibe river (middle course) contributes to the groundwater recharge in most of the time. The average infiltration rate was 1.02 mm/min in point 1 and 0.85 mm/min in point 2. It was concluded that there is a variability in flow direction, which often is top-down, but may undergo change in the stream showing upstream after long periods of rainfall. Another conclusion is that grain size distribution of bed sediment, that is predominantly sandy, influences hydraulic conductivity of hyporheic zone and influences consequently the vertical flow rates.