The impact of agricultural land use on stream chemistry and inputs to an inland reservoir: case of the Sauce Grande River, Argentina

Abstract

Water quality in the Paso Piedras Reservoir has deteriorated, primarily due to periodic blue-green algal blooms, making it temporarily unfit for human consumption. This phenomenon results from the eutrophication of waters of the watershed, and nutrients are considered to be the primary contributors to degradation of freshwater quality. In order to reduce the levels of nitrogen and, most of all, phosphorus, entering the Paso Piedras Reservoir, it is necessary to understand the incidence of diffuse transfers of nutrients from agricultural soils. The nitrogen composition, soluble reactive phosphorus (SRP) and other physico-chemical parameters of the water were analysed in various different parts of the watershed in order to characterize water input to the reservoir from areas with different anthropogenic activity. The upper Sauce Grande basin was divided into three areas with different edaphic characteristics. The physico-chemical parameters measured in sampling surveys included: SRP, ammonium and nitrate, pH, conductivity, turbidity, and total solids. The results showed that the water of the Sauce Grande (areas 1 and 2) was not strongly contaminated, but in El Divisorio (Area 3, which is a sub-watershed whose stream flows directly into the Paso Piedras Reservoir), the levels of conductivity, total suspended sediments and SRP were so high that its contribution to the reservoir accounts for nearly 50% of the total SRP input. The main characteristics of El Divisorio watershed that make it a diffuse source of SRP were not only that its soils, under agriculturallivestock production, have significant slopes, so that water and wind erosion are faster, but also that human intervention had caused the destruction of aggregates. The results showed the influence of the soil characteristics, production systems and the micro-environment developed in the reservoir on the characteristics of waters flowing out of the reservoir. The two villages located in Area 2 had no significant influence on the concentration of nitrogen compounds and SRP found downstream.

Water quality analysis based on phytoplankton and metal indices: A case study in the Sauce Grande River Basin (Argentina)

“…The increasing TSI values might indicate that the river is becoming eutrophic downstream. The oligotrophic conditions found in the upper basin agree with the data previously recorded by Orioli et al (2008). Chla presented a gradual increase along the river, down to the Sauce Grande shallow lake (73.6 µg L − 1 at S10).…”

“…Anthropogenic activities, such as agricultural activities and domestic dumping, might also contribute to an increase in the seston and OM concentrations. The differences in land use between sites could be responsible for the spatial changes (Orioli et al 2008), as observed here. These results are similar to those found in a river basin in Vietnam (Strady et al 2017) with untreated wastewater combined with industrial water.…”

The effects of turbidity and an invasive species on foraging success of rosyside dace (Clinostomus funduloides)

“…In conclusion, increased turbidity is a major problem for lotic systems worldwide (Mol & Ouboter, 2004;Li et al, 2008;Orioli et al, 2008), yet little is known about its direct effects on foraging success and biotic interactions in stream organisms. We have demonstrated that increases in turbidity and velocity along with increased competition significantly reduce the foraging success of rosyside dace and the invasive yellowfin shiner.…”

“…It is likely that the most frequent cause of habitat degradation in streams is increased fine sediment loads, and these increases have been linked to changes in native aquatic communities in both the northern (Berkman & Rabeni, 1987) and southern hemispheres (Quinn et al, 1992;Richardson & Jowett (2002); Rowe et al, 2003;Townsend et al, 2004). Although ecosystems and species differ with geography, the anthropogenic causes of increased sedimentation in stream sediment are similar worldwide (Harding et al, 1999;Li et al, 2008; Correspondence: Gary D. Grossman, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, U.S.A. E-mail: grossman@uga.edu Freshwater Biology (2009) 54, 1977-1989doi:10.1111/j.1365-2427.02248.x Ó 2009 Blackwell Publishing Ltd Orioli et al, 2008), including inappropriate agricultural, mining and forestry practices and urbanisation (Brasington & Richards, 2000;Mol & Ouboter, 2004;Bonnet, Ferreira & Lobo, 2008). Fine sediments may negatively affect stream biota through a variety of mechanisms, including (i) interference with migration behaviour (Richardson, Rowe & Smith, 2001), (ii) reduction of reproductive success (Burkhead & Jelks, 2001), (iii) increased vulnerability to predation (Miner & Stein, 1996), (iv) direct physiological damage (Berkman & Rabeni, 1987;Sutherland & Meyer, 2007), (v) reduced foraging success (Berkman & Rabeni, 1987;Rowe & Dean, 1998;Suttle et al, 2004) and (vi) reduced prey availability (Stuart-Smith, Richardson & White, 2004;Rabeni, Doisy & Zweig, 2005;White & Harvey, 2007).…”

Spatial patterns of surface water quality in the Cértima River basin, central Portugal

“…Amongst the most evident anthropogenic pollution sources are the discharges of agricultural, industrial and urban wastewaters as well as the diffuse run-off of agri-chemicals from agricultural lands. [1][2][3][4] As a result, eutrophication (the biological response to the excess input of nutrients into a water-body) which was originally a natural slow process have been greatly enhanced by human activities. 5 Eutrophic aquatic ecosystems are typically characterised by, besides high nutrients loads, the recurrent occurrence of algal blooms and the associated strong depletion of dissolved oxygen which, in turn, strongly affects the other biological communities (aquatic ecosystems presenting low nutrients loads and low algal biomass are classified as oligotrophic, while mesotrophic aquatic ecosystems have intermediate characteristics).…”