Leonard Osté

• Technical assistance to develop the Sediment Discharge Test.

  NL, 2014

  The sediment discharge test is developed in cases that new sediment comes in contact with surface water, due to deepening or widening a surface water body. Deltares supported Rijkswaterstaat to improve the user friendliness, and to introduce the tool to Dutch water managers. Deltares also introduced the tool in a course for Latvian people.

• Design of the restoration measures of Lake Sloterplas

  Amsterdam, The Netherlands, 2013 - present

  Lake Sloterplas is a 35 m deep lake in Amsterdam which is used for recreation. The lake has been suffering from blue green algae for many years. The city has made a restoration plan and asked Deltares to elaborate the P-fixation measure. P-fixation will be realized by the addition of poly aluminium chlorides. Deltares calculated the amount needed, the dosing speed, whether buffering agent was needed, and the costs.

• Technical support to the development of the Dutch soil and sediment decree.

  NL, 2012 - present

  The soil and sediment decree regulates the reuse of soils and sediments in the Netherlands. Current standards for sediments are very much based on the protection of the sediments itself, but should be more related to the aquatic system (water quality and ecology). Therefore, standards for nutrients and newly regulated substances are needed and standards for other substances should be related more to water quality standards. Deltares supports the Ministry in the technical aspects (methods, revised values) of new and revised standards.

• Consequences of revised Dutch standards for putting dredged material on land.

  NL, 2013 - 2014

  A lot of dredging takes place in Dutch ditches and canals and, if it is not too contaminated, the dredged material is directly placed on the adjacent land. Plans to sharpen the standards may result in more disposal of dredged material, which requires a lot of money. Deltares calculated the effects of changed standards based on a large database of sediment quality in the Netherlands.

• Derivation of Dutch Background concentrations. If the WFD standards for heavy metals are exceeded

  NL, 2011 - 2013

  Member States may take into account (a) the natural background concentrations or (b) hardness, pH or other water quality parameters that affect the bioavailability of metals. Deltares derived dissolved background concentrations for 20 elements in Dutch inland surface waters

• Evaluation Sediment remediation Lake Ketel

  NL, 2013

  Lake Ketel is a lake at the end of the Rhine river basin, which had been contaminated around 1960-1980 by river sediments. A large part has been remediated. The question whether the last part of lake needs to be remediation still remains, and will be answered this year.

• BaggerNut

  NL, 2010 - 2012

  The Water Framework Directive innovation project ‘Baggernut’ focuses on Nutrients in sediments. Twelve water boards, two knowledge institutes and 2 consultants participate in this project. Based on a combination of measurements, water system analysis and modelling activities on 24 locations, a method will be developed to quantify the contribution of sediments to eutrophication and measures to reduce the internal eutrophication. Deltares was responsible for the water and nutrient balances and modelling the contribution of the sediment to water quality.

• Capping Lake Bergse Voorplas

  Rotterdam, The Netherlands, 2009 - 2011

  A huge reduction of external P load had been achieved in de Bergse Plassen, but in part of the lake still problems with water quality remained, due to internal P loading by eutrophic sediment. Regional Water Authority Schieland en de Krimpenerwaard capped the sediment. Deltares monitors the cap, and advised on the addition of aluminium hydroxide to the sand to increase de binding capacity for phosphate.

• Dutch guidance for assessment of sediment quality within the Water Framework Directive

  NL, 2008 - 2010

  Sediments are assessed from a water quality perspective. The guidance explains how to quantify the relationship between sediment quality and (ecological) water quality. In January 2011, the guidance was published, including supporting tools, such as an Excel application to calculate prescribed methods.

• Sediments are assessed from a water quality perspective. The guidance explains how to quantify the relationship between sediment quality and (ecological) water quality. In January 2011, the guidance was published, including supporting tools, such as an Excel application to calculate prescribed methods.

  NL, 2009

  The Dutch minister of the Environment asked this committee to answer technical questions about the policy concerning the reuse of contaminated soil and sediment in deep lakes/reservoirs.
  
  

• Monitoring of the sediment and water quality of the capping layer in lake Bergse Voorplas, Rotterdam (in Dutch)

  2013
  Osté, L.A., G.D. Roskam,

• The contribution of sediments to eutrophication of Lake Volkerak-Zoom, the Netherlands.

  2012
  Osté, L.A., J. Klein, G.J. Zwolsman,
  Deltares/KWR-report 1206111.005.

• Inventory of methods to derive natural background concentrations of metals in surface water.

  2012
  Osté, L.A., J. Klein, G.J. Zwolsman, 2012. Deltares/KWR-report 1206111.005.

• Derivation of dissolved background concentrations in Dutch surface water based on a 10-percentile of monitoring data.

  2012
  Osté, L.A., 2012. Deltares-report 1206111.005-2.

• The sediment capped: laboratory research and field application of a phosphate adsorbing capping layer in Lake Bergse Voorplas

  2011
  D.J. Bakker, L.A. Osté, G.D. Roskam, J. De Weert, J. Hemelraad, 2011.. Deltares-report 1201913-000 (in Dutch).

• Guidance Sediment Quality Assessment. Ministry of Infrastructure and Environment, Den Haag, The Netherlands (also available in English)

  2010
  J.A. Hin, L.A. Osté, C.A. Schmidt, 2010

• Application of contaminated soils and sediment to redevelop deep lakes and reservoirs. What is acceptable? (In Dutch).

  2009
  National experts committee, 2009

• Management of dredged sediments: the theory, the model Prospect, and the real life

  2003
  L.A. Osté, J.H. Rienks,. Paper K-02, in: M. Pellei and A. Porta (Eds.), Remediation of Contaminated Sediments—2003. Proceedings of the Second International Conference on Remediation of Contaminated Sediments (Venice, Italy; 30 Sep–3 Oct 2003). ISBN 1-57477-143-4, published by Battelle Press, Columbus, OH, USA.

• In situ immobilization of cadmium and zinc in contaminated soils: fiction or fixation?

  2001
  L.A Oste. PhD thesis, Wageningen University

Activities