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Measurements on groundwater level and subsurface drain discharge have been carried in a small field-scale catchment from November 2012 to February 2013 in south-western Norway. The main objective of the measurements has been to study the interaction between the subsurface drainage discharge and groundwater level. Different methods were used to analyse the measurements. One method was to study the variation in groundwater level and drain discharge. The measurements showed there were large day to day variations. However, in addition, there were large diurnal variations in both the groundwater level and drain discharge. Also the recession of groundwater level was studied using a two-exponential decay function. During several months the precipitation largely exceeded the long-term precipitation. The measurements showed that drainage system had the capacity to react fast to precipitation-induced rise in groundwater level, resulting in a fast drawdown. The measurements at the small scale field catchment showed that the drainage system is designed and capable to react to high precipitation amounts like those predicted by climate change scenario studies. [ABSTRACT FROM AUTHOR]

This paper summarises environmental monitoring activities and small plot research in agriculture as practiced in the Heilongjiang province located northeast in China and in Norway. For both countries, there is a need to recommend efficient mitigation measures to farmers and monitor the environmental effect of agricultural systems and management practices. Climate change scenarios predict changes in precipitation which potentially can influence agricultural practices as well as lead to changes in run-off and related to land use as well as the environment losses. As such, cooperation in the further development of monitoring programmes and related techniques will be useful in documenting both present and future, climate change-induced changes, related land use as well as the environmental. [ABSTRACT FROM AUTHOR]

The strategy to mitigate phosphorus (P) losses in areas of arable cropping in Norway has focused on measures to reduce erosion. Risk assessment of erosion has formed the basis for implementation of the measures. The soil P content has increased during recent decades, motivating an evaluation of its effect on P transfer in the landscape. The present study describes the spatial variability of runoff P concentrations from an agricultural dominated catchment (4.5 km2), representative for agriculture in south-eastern Norway. The concentrations of suspended sediments (SS), total P (TP) and dissolved reactive P (DRP) in runoff from 22 subcatchments (0.3–263 ha) during one year (monthly and during runoff-events) were evaluated. Contributions from point sources were 38 kg TP yr-1 compared to a total P loss of 685 kg yr-1 from the whole catchment. During low flow, mean diffuse TP concentration in runoff from subcatchments varied from 28 to 382 µg l-1. The mean low flow TP concentration was 39 µg l-1 from the housing area (only diffuse runoff) and 33 µg l-1 from the forested area. During high flow the highest diffuse TP concentration was measured in an area with high erosion risk and high soil P status. At the subcatchment level the transfer of SS varied from 25 to 175% of the whole catchment SS transfer. Correspondingly for TP, the transfer varied from 50 to 260% of the whole catchment TP transfer. For each of five agricultural subcatchments the slope of the relationship between TP and SS concentrations reflected the mean soil P status of the subcatchment. Erosion risk estimates were closely related to the SS concentration (R2=0.83). The study illustrates that soil P status in addition to soil erosion is an important factor for P transfer. [ABSTRACT FROM AUTHOR]

• Small constructed wetlands (0.05% of catchment area) capture significant amounts of TSS and TP. • Conditions in the catchment are most important for CW performance. • Constructed wetland relative removal efficiency is highest in summer, with low runoff and limited erosion. • The highest loads are captured in autumn (for TSS) and spring (for TP) • Constructed wetlands are a good supplement to best management practices in erosion-prone catchments. Constructed wetlands (CWs) are a widely recognised measure for reducing pollution loads and improving the quality of surface waters. The removal efficiency of CWs varies considerably depending on system type and design as well as residence time, hydraulic load, particles and nutrient loading rates. Therefore, there is a need to closely monitor the efficiency of existing measures, look at their efficiency in practice and be able to foresee potential implications for their efficiency in light of climate change and land management intensification. This study presents 18 years of data from a typical Norwegian small CW established in the Skuterud catchment. The main objective of this study was to look at the impact of hydraulic load, particles and nutrient loads (depending on climatic factors such as temperature and precipitation) on CW effectiveness. The results showed an average of 39 % and 22 % annual removal efficiency for sediment and phosphorus, respectively. It appears that good CW effectiveness coincides with a combination of high sediment or phosphorus loads to the CW and a stable runoff of low to moderate intensity. At the seasonal level, the highest sediment and phosphorus removal efficiency is observed in the summer seasons (47% for sediment and 29% for phosphorus), when the sediment and phosphorus loads and runoff are at their lowest, and the lowest in autumn (23% for sediment) and in winter (4% for phosphorus). The relationship between removal efficiency and loads to the CW is not that straightforward, as other seasonal differences, such as erosion patterns, vegetation development, also become important. The conclusion based on the results presented is that establishing CWs can be a good supplement to best management practice in erosion-prone catchments with sensitive recipients. [ABSTRACT FROM AUTHOR]