Quinte Conservation has…

Quinte Conservation has reviewed the Picton Terminals Lower Dock Stormwater Management Report prepared by Josselyn Engineering Incorporated and dated August 23, 2017. The purpose of the report is to determine appropriate stormwater management measures to control the transport of suspended solids offsite. The report does not discuss the mobilization, transport and treatment of industrial materials. Quinte Conservation’s review is limited to the removal of inert suspended solids. Our review does not include the mobilization, transport and treatment of industrial materials. As a member of the Bay of Quinte Remedial Action Plan, Quinte Conservation is concerned that the treatment of industrial materials, such as salt, has not been properly addressed for the current ECA application. Quinte Conservation recommends that the Ministry of Environment and Climate Change review the industrial land use and methods to limit pollution from migrating off the subject lands to receiving water bodies, adjacent properties and the atmosphere. Conveyance It is proposed to regrade the site to direct stormwater to a series of ditch inlet catchbasins and storm sewer network which drain to an oil grit separator which then outlets to Picton Bay. The east portion of the property sheet flows to a 2 metre wide flat bottom swale which is drained by a ditch inlet catchbasin. The Dock Access Road is steep and the runoff will have a high velocity from the road to the south. No calculations have been provided to demonstrate that the flat bottom swale and the storm sewers have the capacity to convey the stormwater runoff. The flat bottom swale may be difficult to construct in bedrock with no slope and may experience ponding of untreated stormwater runoff if not constructed correctly. Quantity Control Quantity control was not a requirement for this development as per the report. Quality Control Enhanced quality control is required for properties draining to the Bay of Quinte as per the March 2006 Bay of Quinte Remedial Action Plan Stormwater Management Guidelines. Stormwater quality controls are proposed through the flat bottomed swale and the oil-grit-separator. No calculations or cross-section details have been provided for the flat bottomed swale to design the swale for quality control. The swale should be designed as per the Ministry of Enviroment’s 2003 Stormwater Management Planning and Design Guidelines. No information has been provided on how the groundwater would be protected from any ponded, untreated stormwater in the flat bottomed swale. The oil-grit-separator was designed for 3.1 hectares of contributing drainage area, using the Kingston rainfall station and FINE sand particle size distribution. It appears from the proposed grading on the drawings that the land being developed and draining to the oil-grit-separator is larger than 3.1 hectares. The area draining to the oil-grit-separator should be delineated so that it can be clearly identified. A larger oil-grit-separator may be necessary to achieve enhanced stormwater quality treatment if the development and associated drainage area is larger than that used for sizing the oil-grit-separator. Sediment and Erosion Control Sediment and erosion control drawings have not been provided. These drawings are important to ensure that the proper sediment and erosion controls are installed and maintained correctly and in the right location. The sediment and erosion control plan should also detail the construction sequencing. Drawings The review was difficult to complete because there was overlapping information provided on the drawings.