FINAL REPORT APPENDIX C Dispersion Modeling of Discharged Brine Smart Solutions for Engineering, Science and Computing Numerical Brine Dispersion Modeling in the Shubenacadie River Martec Technical Report # TR-07-12 March 2007 Management System Certified to: I SO 9001:200 Smart Solutions for Engineering, Science & Computing Martec Limited tel. 902.425.5101 1888 Brunswick Street, Suite 400 fax. 902.421.1923 Halifax, Nova Scotia B3J 3J8 Canada email.
[email protected] www.martec.com 1.0 Numerical Brine Dispersion Modeling in the Shubenacadie River The numerical modeling of brine dispersion in receiving waters of the Shubenacadie River is based on the USEPA supported Cormix Modeling System (Jirka et. al., 1996) for near-field mixing predictions, and a detailed RMA 10/11 finite element hydrodynamic/water quality river model (United States Waterways Experimental Station Coastal and Hydraulics Laboratory) to quantify far-field dispersion. Various outfall configurations were considered as potential designs for brine discharge in the Shubenacadie River. These included the following: Option # 1 Submerged Outfall at mid-channel and shore-attached. Option # 2 Submerged Diffuser positioned across the river width (perpendicular diffuser) and along the riverbank (parallel diffuser). In addition, multi- staged diffuser configurations were considered where ports operate only under specific ambient and discharge conditions. Option # 3 Shore-attached discharge from pre-mixing pond. A mid-channel single outfall as well as the perpendicular diffuser were not considered feasible options due to the potential problems associated with sedimentation covering the outfall or ports, erosion, potential damage to the pipe from ice flows, difficulties associated with laying or directional drilling of the pipe or diffuser across the river and the required annual maintenance.