Study Site

The Upper River Cinca

MorphSed will be developed in the active gravel-bedded River Cinca (NE Spain), taking as a representative reach for most mountainous large rivers in the Southern Pyrenees. The Upper River Cinca (upstream of the Mediano-Grado Dam Complex, Figure 1) has experienced gravel mining activities in the active channel and floodplain since the middle of the last century. MorphSed study site is presented in the following video.

Figure 1 shows the main rivers in the Upper Cinca, together with the mined volumes (gravels) since 1990. To assess the volumes extracted in this part of the catchment we have only considered the main Upper Cinca and the River Ara (principal tributary, see Figure 1). We have omitted those extractions prior to 1990 and all of these located in floodplains. According to the available data, on average, 0.2 x10^6 tons of sediment are extracted annually from channels in Upper Cinca and Ara (see the spatial distribution of the extracted volumes in Figure 1). The histogram and the accumulated frequency distribution presented in figure 1, reveal that virtually all years experienced gravel mining activities. Maximum volumes were extracted in 2003, when 18% of the total volume for the period 1990-2011 was mined. These data point out the representativity of mining activities in terms of world-wide extracted volumes and also the constant frequency of these activities in this river.

Figure 1. (A) The Upper River Cinca where total volumes extracted from the alluvial channels of the Cinca and Ara have been represented. (B) Historical aerial photo of the confluence between these rivers where most of the mining activities are concentrated. (C) Hystogram of % mining per year; and (D) accumulative frequency of the total volume extracted there between 1990 and 2011 (data source: Ebro Water Authorities).

Monitoring and Sampling Sites

A total of 3 monitoring sites and 5 sampling sites have been set up. Flow, suspended sediment transport, water temperature and timelapse images are being obteianed at 15 minutes intervals in each of the monitor sites. Macroinvertebrate samples, flow hydraulics and bathymetric and grain size data are being obtained in the sampling sites. Data is obtained at the flood scale. Additionally, close range aerials are obtained at the same temporal scale in order to acquire point clouds by means of automatic digital photogrametry (Structure from Motion). See the surface modelling workflow in the outcomes section.

Figure 2. MorphSed study reach, sampling and monitoring sites (source of the aerials: IGN).

Figure 3. Monitoring stations in the Upper River Cinca.