RT Journal Article T1 Estudio de la calidad de las aguas superficiales en los espacios naturales del sur de las provincias de Salamanca y Avila. Aplicaciones del índice ISQA T1 Study of fresh waters quality in the natural site of the southern Salamanca and Ávila provinces (Spain). Application of the ISQA index A1 Bustamante, I. de A1 Sanz, J. M. A1 Goy, José L. A1 González Hernández, F. M. A1 Encabo, J. L. A1 Mateos, J. AB The aim of this paper deals with the study of the surface waters quality in the northwestern "Sistema Central" Range (Spain), in two different periods, spring and summer. The area is characterized by the existence of natural environments of great interest (western area of the Regional Park of "Sierra de Credos", Natural Parks of "Las Batuecas" and "Candelario" and the Protected Landscape of "El Rebollar"). The quality of the surface waters has been determined using the simplified index of water quality (ISQA). An hydrological mapping has been carried out having into account the ISQA values for these two seasons. The observed seasonal variability is mainly due to the variation of flows and the concentration of the chemical species in the water PB Sociedad Geilógica de España YR 2001 FD 2001 LK http://hdl.handle.net/10272/9483 UL http://hdl.handle.net/10272/9483 LA spa DS Repositorio Institucional de la Universidad de Huelva RD 14 jul 2026