Comparison of impacts of human activities and climate change on water quantity and quality in Finnish agricultural catchments

Abstract

Context We studied the influence of human activities and climate change on water quantity and quality. Human activities included methods of agricultural policy, i.e. land use and management practices. Objectives Finland started to follow EU's agricultural policy in 1995. In this study our main objective was to find out whether the original targets of the Finnish Agri-Environmental Programme (FAEP) were achieved. Methods We analyzed trends in discharge, water quality and climate parameters in 37 years long timeseries in two catchments. We focused on the suspended sediment and phosphorus concentrations and loads, the main interests to FAEP. Results We found an increasing trend in mean annual temperature, especially in spring and late summer-early autumn. There was no statistical significant change in annual runoff. Increasing winter runoff in the other catchment could be explained by the increased number of days when temperature was above zero degrees making snowmelt possible. In this area high potential sediment delivery occurred in early winter. FAEP succeeded in decreasing the suspended sediment load by reduced tillage and wintertime vegetation cover. In controlling the phosphorus loads FAEP succeeded only in the catchment with erosion sensitive soils. In the catchment where soils were less sensitive for erosion increase in the dissolved reactive phosphorus load exceeded the benefits of the reduced particulate phosphorus load. Conclusions Climate change may increase the suspended sediment load by increasing winter runoff. Even then, instead of decreasing the suspended sediment loads FAEP should rather focus on dissolved nutrients as they cause eutrophication in receiving waters.

Total, Dissolved and Particulate N:P Stoichiometry in Canadian Prairie Streams in Relation to Land Cover and Hydrologic Variability

“…This study was conducted in the RRV of southern Manitoba (Figure 1). Seven sub-watersheds were selected [6] to span a gradient in nutrient-producing human activities resulting primarily from livestock density and crop cover ( Table 1). A detailed description of the methods of calculation of human activity intensity (livestock and crop) is given by [16].…”

“…For example, a three-year study of seasonality of nutrient export from 11 Canadian prairie streams showed that total P and total N concentrations and loads both peaked during the snowmelt season [5]. Similarly, in selected Finnish catchments, total P and total suspended solids concentrations tracked changes in seasonal discharge, with highest values in April during snowmelt [6]. This flush of nutrients associated with snowmelt in cold regions is caused by the combined effect of intense runoff (which is dependent upon antecedent moisture conditions such as snow depth as well as the rate of warming [7]), frozen soils which restrict infiltration of snowmelt [7], and the presence of nutrients in the form of residual inorganic fertilizer or organic matter residue (crop, pasture or riparian material; [8]).…”

Changing climate and nutrient transfers: Evidence from high temporal resolution concentration-flow dynamics in headwater catchments

“…The pressures are further exacerbated by the effect of a changing climate, which is predicted to bring more frequent extreme events (Kendon et al, 2014;Murphy et al, 2009), resulting in the likelihood of more winter runoff and longer periods of low flow Wilby et al, 2006), although still with much uncertainty (Arnell, 2011;Kay and Jones, 2012;Prudhomme et al, 2012). In conjunction with projected climatic changes, previous studies have indicated likely increases in sediment and nutrient loads (Crossman et al, 2014;El-Khoury et al, 2015;Jeppesen et al, 2009;Jeppesen et al, 2011;Macleod et al, 2012;Rankinen et al, 2015;Whitehead et al, 2009).…”

Cattle Production for Exports in Water-Abundant Areas: The Case of Finland

“…Despite the vast freshwater resources, Finland is already facing the challenge of eutrophication in the rivers and lakes that are close to agricultural production, in particular through nitrogen and phosphorus loadings [85,86]. In addition, the entire Baltic Sea is already affected by eutrophication, due to the intensive use of the sea itself and anthropogenic activities [87,88].…”