Jens Kværner

Senior Research Scientist

(+47) 924 91 309
jens.kvarner@nibio.no

Place
Ås F20

Visiting address
Fredrik A. Dahls vei 20, 1430 Ås

To document

Abstract

The awareness of sediment and nutrient loss from non-point sources are of increasing environmental concern as measures to reduce point source inputs to surface waters have been introduced. Mitigation efforts to reduce loss of particles and nutrients from agriculture in Norway and other countries have mainly focused on surface runoff, whereas sub-surface drainage has received little attention. However, research has shown that the sub-surface field drains are transporting both sediment and nutrients rapidly to the watercourses. Despite these established facts there has been little development of measures to reduce these losses. This article describes how Lightweight Aggregates (LWA), Leca®, can mitigate some of the environmental challenges connected to sub-surface field drains. A field experimental project was performed to assess the effects on drainage water quality hydrological performance and functionality of drainage systems based on Lightweight Aggregates compared to traditional pipe drains. Registrations of the performance of the systems were done in two separate periods, 1992–1993 and 1999–2000. After 2000 no measurement programme has run. The functionality of the drainage systems was registered in connection to ordinary farming activity. In 1999–2000 LWA drains showed particularly good performance with regard to reducing the content of Phosphorus, 40–90 % reduction in Total-P. The drainage water from the LWA drains contained less than half the amount of suspended solids compared to traditional pipe drains. The results from 1993 showed no significant difference between LWA drains and pipe drains with respect to Nitrogen. The results from 1999/2000 showed higher loss of Nitrogen through pipe drains with no envelope compared to all other systems. LWA drains may be particularly useful in reducing particles and nutrient loads from cultivated flat drained areas adjacent to environmentally sensitive and ecologically important water ecosystems. Further investigations are recommended to optimise the design of LWA drains.

To document

Abstract

Assessing the vulnerability of groundwater to adverse effects of human impacts is one of the most important problems in applied hydrogeology. At the same time, many of the widespread vulnerability assessment methods do not provide physically meaningful and operational indicators of vulnerability. Therefore, this review summarizes (i) different methods used for intrinsic vulnerability assessment and (ii) methods for different groundwater systems. It particularly focuses on (iii) timescale methods of water flow as an appropriate tool and (iv) provides a discussion on the challenges in applying these methods. The use of such physically meaningful indices based on timescales is indispensable for groundwater resources management.

To document

Abstract

The study examines the influence of agricultural activities on pesticides in groundwater in an area with fluvial deposits of sand with a top layer of sandy silt and silt, intensive cultivation of potatoes and cereals, and drinking water supplies of households from local groundwater wells. Information about local agricultural practice and washing sites for pesticide spraying equipment, properties of soils and deeper deposits, hydrogeology and groundwater flow, simulations of pesticide leaching, and contents of pesticides and nitrate in groundwater samples from drinking water wells was used to explore extension and reasons of pesticide contamination of groundwater. Pesticides were found in a majority of the sampled wells. Eight different pesticides and metabolites were detected in groundwater samples. The results demonstrate that on fluvial deposits diffuse pollution from spraying of fields with pesticides can result in groundwater contamination in Nordic climate. Higher concentrations of pesticides in some wells can be explained by point source contamination from washing sites. The occurrence of pesticides in drinking water wells touches up the question whether pesticides should be given general approvals, or approvals should include restrictions or recommendations regarding use on areas with high risk of groundwater contamination. Combination of washing sites for pesticide spraying equipment and groundwater wells for drinking water requires attention, proper equipment and practice, and knowledge about pesticides, soil and water to avoid contamination. Samples from wells adjacent to washing sites for pesticide equipment might overestimate average pesticide concentrations in groundwater bodies. In Nordic areas attention should be given to pesticide pollution of shallow groundwater in fluvial deposits. To provide basis for interpretation of results and planning of mitigation measures against pesticide contamination, an integrated approach using information about agronomical practice and point sources, soil properties, hydrogeology and simulations of pesticide leaching is recommended for future surveys and monitoring of pesticides in groundwater.

Abstract

In the traditional EIA procedure environmental vulnerability is only considered to a minor extent in the early stages when project alternatives are worked out. In Norway, an alternative approach to EIA, an integrated vulnerability model (IVM), emphasising environmental vulnerability and alternatives development in the early stages of EIA, has been tried out in a few pilot cases. This paper examines the content and use of the vulnerability concept in the IVM approach, and discusses the concept in an EIA context. The vulnerability concept is best suited to overview analyses and large scale spatial considerations. The concept is particularly useful in the early stages of EIA when alternatives are designed and screened. By introducing analyses of environmental vulnerability at the start of the EIA process, the environment can be a more decisive issue for the creation of project alternatives as well as improving the basis for scoping. Vulnerability and value aspects should be considered as separate dimensions. There is a need to operate with a specification between general and specific vulnerability. The concept of environmental vulnerability has proven useful in a wide range of disciplines. Different disciplines have different lengths of experience regarding vulnerability. In disciplines such as landscape planning and hydrogeology we find elements suitable as cornerstones in the further development of an interdisciplinary methodology. Further development of vulnerability criteria in different disciplines and increased public involvement in the early stages of EIA are recommended.