25C - AGMT - CATCH BASIN PROJ - Laserfiche WebLink

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Performance Effectiveness Targeted Pollutants This product has demonstrated both in the field and in the laboratory to be an effective structural treatment control BMP for capturing trash, sediment, gross solids, oil and grease, and total metals. Recent testing of the DrainPacTm was conducted by California Polytechnic State University San Luis Obispo resulted in 83% to 91% removal efficiency of fine suspended solids with the best removal observed at lower flow rates, and oil and grease removal efficiency varied from 40% to 80% under the test conditions. Higher rates of oil and grease removal can be achieved by adding an absorbent sock around the periphery of the products frame (optional). See attached Filter Testing Report for additional information. Trash Capture & Storage Capacity A DrainPacTm has a trash capture and storage capacity equivalent to the area of each unit. For drop inlets the product will cover the entire length and width of the drain inlet point and standard filter depths are 12" yet can/will be fabricated shallower to prevent the device from obstructing the outlet pipe of the catch basin. For curb inlets the product will be fabricated to the length of the curb inlet opening with 12" wide by 12' deep standard dimensions. Wider and/or shallower devices will be fabricated if/as required based on catch basin configuration. Overflow or Bypass Flow Capacity Drop inlet configurations of the DrainPacTm are designed with a center overflow bypass port to prevent flooding in the event that a unit is full of trash and is no longer filtering. Curb inlet configurations of this product do not require any type of special overflow bypass feature. If a unit is full of trash and Is no longer filtering water entering the catch basin will merely flow over the 12" wide device into the catch basin. Maximum Overflow or Bypass Flow Capacity The overflow bypass features of the DrainPacT'" described have been proven in the field to withstand a 10-year storm event without causing flooding. Siting, Operational & Maintenance Installation Process Before the start of installation United's Project Manager will coordinate with the County's Project Manager to discuss the proposed installation schedule by service zones. For work performed in areas that encroach on traffic right-of-way, an encroachment permit will be obtained from the appropriate entity and United will develop a written and approved traffic plan. When proposed work zones have been accepted United will install DrainPacsT"' in the designated storm drains. Devices installed in drop inlets will be gravity held in place and will rest on the existing catch basin grate shelf. For this configuration Installation will require United's Service Staff to remove the traffic grate using a 'traffic grate puller" tool and will require approximately five minutes to install each device. Devices installed in curb inlets will be mounted to the forward wall of the catch basin approximately 4' below the flow line or as required based on catch basin design and/or other Storm Water Devices that may be installed in the same catch basin. This configuration will require drilling of the interior of the catch basin and Installation of support/mounting brackets (see attached Technical Drawing) and will require approximately fifteen minutes to install each device. Site Specific Measurements The County would have to provide United with storm drain maps, inlet location where the product is proposed for installation, and approximate lengths and widths of drop inlet openings and lengths of curb inlet openings in order to provide Entities with cost estimates. Devices would thereafter be custom made to fit each respective storm drain based on measurements taken by United's Service Staff. This device could be used in conjunction with a CleanScreen"m ARS and/or CPS for added effectiveness based on the level of trash and debris that commonly p. 4 25C-11