708Cleaning and Flushing Pipes and Drainage Structures

708.01 Description.

This work consists of cleaning stormwater and drainage assets such as catch basins, drainage manholes, stormwater treatment units (STU), pipes and surface water culverts of all types and sizes as required when applicable for preservation and rehabilitation techniques.

708.02 Materials.

Equipment. Equipment for cleaning drainage assets includes hoses, rodding machines, balls, hydraulic cleaners, root cutters, small clam shell buckets, steel porcupines, pumps, vacuums (trailer and/or truck mounted) or other suitable and approved means. Water. Ensure that the water used for cleaning and flushing drainage pipes is fresh and free of oil, acid, salt, alkali, organic matter, or any other deleterious substances. Provide all water required for the cleaning operation. If the Contractor uses a public water supply, obtain all necessary permissions and approvals from the respective water supply before usage. Provide proof of permission and approval to the Engineer before the start of work via the Shop Drawing process. Vacuum System. Use a truck mounted or trailer mounted system capable of removing sediment and debris from pipes, drainage manholes, catch basins, and stormwater treatment units. Equip the system with sufficient water capacity, lines, hoses, nozzles, tanks and other required equipment to provide for cleaning multiple structures per operation. Ensure that the system can store wastewater until a proper decanting site can be reached and be equipped with a hand -held high-pressure spray nozzle. Qualifications. The Contractor shall be qualified to perform pipeline, catch basin, manholes and stormwater treatment unit cleaning, with a minimum of three active years of experience in performing pipeline cleaning. Provide proof of the qualifications to the Engineer before the start of work via the Shop Drawing process.

708.03 Construction Methods.

Operation of Drainage System During Cleaning. Ensure the proper operation of the storm drainage system during the cleaning operations. During stormwater drainage system cleaning operations, take satisfactory precautions to: • Protect the drainage system pipelines and vertical structures from damage that might be inflicted by the improper or overuse of the cleaning equipment

Part 700 — Drainage and Selected Utility Accessories August 2025

700-26 SECTION 708 — CLEANING AND FLUSHING PIPES AND DRAINAGE STRUCTURES • Prevent water build up in the system to cause back flow, contamination, water damage, injury, and/or flooding to persons or public or private property • Protect any environmentally sensitive areas from impacts of the operation; ensure that all cleaning operations conform to the Project SWPPP and/or SESC Cleaning Methods. Clean and flush all drainage assets as required by use of pressure hoses, suction pumps, and/or any other methods required to perform the work. Perform c leaning by mechanical means, vacuum, and/or high velocity hydraulic jet cleaning equipment. Select equipment based on field conditions such as physical accessibility, condition, asset size, type of asset, and type of debris to be removed. Ensure that the pipes and other drainage assets that will be rehabilitated (lined or cured in place) meet the cleaning requirements of the rehabilitation treatment selected. Equip the hydraulic jet cleaning equipment with the appropriate nozzles for cleaning the various pipe sizes and material types identified in the Contract. Construct a suitable weir or dam in the nearest downstream manhole or catch basin so that debris material will be trapped. Do not allow the material to pass on from one section to the next. Clean each manhole or catch basin independently of other portions of the storm drainage system. Submit daily worksheets indicating the location and quantity of pipes, catch basins, and manholes cleaned. Reclean any pipe as needed to obtain satisfactory results at no additional cost to the Department. Cleaning and Flushing Pipes. Ensure that the equipment and methods selected do not cause damage to the pipe. Use a high velocity hydraulic jet cleaning nozzle based on the conditions of the pipe at the time the work commences. Use equipment for cleaning that can remove soil, rocks, sand, other deleterious materials, and obstructions from the assets. Proceed so as to prevent the migration of debris or sediment to previously cleaned segments or assets , and do not allow debris or sediment to be discharged from the outfall. Provide suitable screening and containment of waste and wash water in the downstream manhole or catch basin to prevent wash water and waste material from passing downstream into previously cleaned pipe, environmentally sensitive areas, or other parts of the system. Ensure that the pipe is cleaned sufficiently to provide full access to a CCTV inspection system. Root Removal. Remove all invasive roots and vegetation in all sections of pipes as identified in the Contract. Use a method of chemical root treatment with an EPA approved herbicide in conjunction with mechanical root removal to aid in root removal and to mitigate future root growth. Ensure that the handling and application of the herbicide complies with the manufacturer’s instructions and applicable certification and application regulations to ensure safety and to preclude any damage to surrounding vegetation. Replace any damage to surrounding vegetation at no additional cost to the Department. Submit the proposed method(s) and material(s) in advance via the Shop Drawing process.

Part 700 — Drainage and Selected Utility Accessories August 2025

SECTION 708 — CLEANING AND FLUSHING PIPES AND DRAINAGE STRUCTURES 700-27 Cleaning and Flushing Vertical Structures. Clean vertical structures such as catch basins, drainage manholes, and stormwater treatment units of debris using a vacuum system. Clamshell excavating equipment may be used for initial cleaning, if it can be done without damaging the structure; however, a vacuum system is required for compliance with cleaning specifications and payment. Use a vacuum system that can remove debris to the bottom of the sump or outfall apron. After vacuum removal of debris, clean the structure by pressure washing the frame or cover, grate, and inside surface of the structure from top to bottom. Vacuum the water and debris resulting from the high- pressure spraying from the structure using appropriately sized hoses and nozzles, including on all sides of weirs, hoods, or baffles. Clean the area around the structure to be free from materials that may have been ejected by the cleaning process. Reset all sound grates and covers into the existing frame. Replace any cracked or broken frames, grates , or covers at the direction Engineer , which will be paid for separately or under another item of the Contract. Disposal of Debris Collected. Properly dispose of all material displaced and removed by the cleaning operation, including grit, sediment, dirt, sand, rock, grease, roots, vegetation, organic mass, or solid material contained therein. Test in accordance with PART 200 and properly dispose of any waste material removed from the drainage according to State and Federal requirements. Testing of the material will be at the Contractor’s expense. Submit all test results to the Engineer. Notify the Engineer of the proposed disposal location and requirements of that facility to allow disposal of the waste material. Store waste material until all testing requirements including that of the proposed facility have been met. Ensure that t emporary storage and handling facilities, including stockpiles and decanting areas, conform to the Project SWPPP and/or SESC.

Part 700 — Drainage and Selected Utility Accessories August 2025

700-28 SECTION 708 — CLEANING AND FLUSHING PIPES AND DRAINAGE STRUCTURES Pay Item Pay Unit Cleaning and Flushing Pipe LF Root Removal LF Cleaning and Flushing Vertical Structure EA The Contract prices constitute full compensation for all labor, materials, and equipment required to conduct the operation by normal methods and for all incidentals required to finish the work , complete and accepted.