A framework for addressing the information needs of catchment water quality management

The process of catchment water quality management must be built on sound philosophies and appropriate information. Over the last few years, the Department of Water Affairs and Forestry in South Africa has been reviewing and developing the philosophical support for catchment water quality management and has initiated a number of catchment plans. The translation of these philosophies into management information needs, which is supported by appropriate assessment of data obtained by monitoring the physical catchment, requires concomitant development. This paper provides a framework to anchor the scientific-technical support to catchment water quality management. The first part of the framework deals with the classification of the physical system, providing the conceptual 'platform' for monitoring, assessment and management. This is based on the definition of four physical process elements representing the components of water quality management, namely production, delivery, transport and use. The second part of the framework involves the definition of an assessment 'super-structure', building on these elements. This provides the link between the physical system and management in formation needs, through monitoring and assessment. The paper ends by providing an integrated framework, which indicates possible types of assessment associated with the different phases of the catchment water quality management process.Articl

Variação espacial e temporal dos fatores limnológicos em riachos da microbacia do rio São Francisco Verdadeiro Spatial and temporal variation i of limnological factors in streams of the micro-basin of the São Francisco Verdadeiro river

Com objetivo de caracterizar espacial e temporalmente os riachos da microbacia do rio São Francisco Verdadeiro, Marechal Cândido Rondon - PR, em função de fatores limnológicos, foram estabelecidas seis estações de coleta em três riachos (Curvado, Ajuricaba e Arroio Fundo), sendo uma estação na foz e outra na nascente. As coletas de água foram obtidas entre junho de 2005 e maio de 2006, totalizando 72 amostras. Foram analisadas as seguintes variáveis: temperatura, pH, condutividade elétrica, oxigênio dissolvido, turbidez, material em suspensão, fósforo total dissolvido, ortofosfato, nitrogênio total e nitrogênio amoniacal. De acordo com a análise de variância, houve baixa variabilidade entre as estações de coleta, porém a variação temporal demonstrou a influência do ciclo hidrológico. A análise de componentes principais (ACP) discriminou o sistema com base nos maiores valores registrados para as variáveis limnológicas, ficando separados os períodos influenciados pelas secas e pelas chuvas. A maior parte das variáveis está associada com o período de chuvas, no entanto há concentrações esporádicas de nutrientes na seca e menores valores de oxigênio dissolvido, demonstrando a dificuldade de diluição nesse período, causada pela diminuição da chuva e, consequentemente, do volume de água dos riachos.<br>In order to characterize spatially and temporarily streams of the São Francisco Verdadeiro river micro-basin in Marechal Cândido Rondon, State of Paraná, Brazil, according to limnological factors, six sampling stations were established in three streams (Curvado, Ajuricaba and Arroio Fundo) - one station at the mouth of the river and other at the spring of the streams. Water samples were collected between June 2005 and May 2006, totalizing 72 samples. The following variables were analyzed: temperature, pH, electric conductivity, dissolved oxygen, turbidity, suspended matter, total dissolved phosphorus, orthophosphate, total nitrogen and amoniacal nitrogen. According to ANOVA (variance analysis) it was observed low variability among the sampling stations however the temporal variation demonstrated the influence of the hydrologic cycle. The Principal Components Analysis (PCA) discriminated the system based on the largest values registered for the limnological variables separating the periods influenced by droughts and rains. Most of the variables are associated with the rain period; however, sporadic concentration of nutrients in the drought and smaller dissolved oxygen values indicates a dilution difficulty in this period, caused by decrease of rain and consequently decrease of water volume in the streams