WEREC has during 2012-2013 constructed ten Phosphorus retention dams of different sizes, from 0,25 to 1,4 hectares. Often in combination with Calcium filter beds providing a total Phosphorus removal of 65%. In the dams a significant part of the particulate Phosphorus is removed by sedimentation, while the Calcium filter beds remove a considerable part of the dissolved Phosphorus fraction.
We offer to assume responsibility for the entire process, from consultations and design to construction and operation. We contribute to improved knowledge on design and removal capacity through research cooperation with SLU, the Swedish University of Agricultural Sciences.
Assessment of the need for actions
If the existing information for the upstream sub-basin is inconclusive regarding the cost-effectiveness for a Phosphorus retention dam, we offer characterization of the basin. In some cases it is recommendable to conduct water sampling at high flow, medium flow and low flow episodes. The sampling is often coordinated with sampling at other alternative locations.
Design
Also for Phosphorus dams we are happy to conduct the full design process, including:
- Consultation of authorities
- Registrations and permits
- Geodetic measurements, design and construction plan
- Plan for the construction work
- Establish agreements and contracts
Installation
We generally conduct part of the construction with in-house staff and machinery but often also engage contractors. We then carry out the procurement process and generally also control and inspection routines. We procure all the material required for the installation.
Operation and evaluation
WEREC plans and conducts water monitoring programs for control and evaluation of the function of the dam. Monitoring also includes sedimentation analyses. We offer assistance in applying for funding of operation and management of the dams, and also conduct the operation tasks.