250 R.I. Code R. 250-RICR-150-10-8.16

Current through November 21, 2024

Section 250-RICR-150-10-8.16 - Minimum Standard 10: Construction Activity Soil Erosion, Runoff, Sedimentation, and Pollution Prevention Control Measure Requirements

A. Soil Erosion and sedimentation control measures must be utilized during the construction phase as well as during any land disturbing activities.

B. All soil erosion, runoff, sedimentation, and construction activity pollution prevention control measures must be designed and implemented in accordance with the SESC Plan requirements outlined in the Performance Criteria in § 8.16(D) of this Part. The Rhode Island Soil Erosion and Sediment Control Handbook provides the recommended and primary means to achieve the performance criteria. The component of the Stormwater Management Plan that addresses this standard is referred to as a SESC Plan.

C. For all land disturbance activities that require a permit from the RI DEM or the CRMC, a qualified SESC Plan preparer shall be a Rhode Island Registered Professional Engineer, a Certified Professional in Erosion and Sediment Control, a Certified Professional in Storm Water Quality, or a Rhode Island Registered Landscape Architect who certifies that the SESC Plan meets the Performance Criteria in § 8.16(D) of this Part. The Preparer shall have the specific credentials and experience needed to select the appropriate practices for the application. If the project involves significant land grading or requires an engineered site design, then the SESC Plan must be prepared by a Professional Engineer licensed in the State of RI.

D. SESC measures must be utilized during the construction phase as well as during any land disturbing activities. Owners and operators must design, install, and maintain effective soil erosion, runoff, and sediment controls. SESC plans must document how the proposed activities are consistent with the following Performance Criteria:

1. Avoid and Protect Sensitive Areas and Natural Features: Areas of existing and remaining vegetation and areas that are to be protected during construction must be clearly marked on the plans. Throughout planning, design, and construction the Applicant must demonstrate that the activities are consistent with § 8.7 of this Part (Minimum Standard 1, Low Impact Development Site Planning and Design Strategies).

2. Minimize Area of Disturbance:

a. Limits of Disturbance (LOD) shall be clearly marked on all SESC plans. The SESC Plan must identify how the Applicant has minimized the area of disturbance by locating sites in less sensitive areas in accordance with § 8.7 of this Part (Minimum Standard 1, Low Impact Development Site Planning and Design Strategies).

b. Construction activity shall be phased to minimize the amount of area that is being actively disturbed. Activities disturbing greater than five acres must include phasing in combination with other controls.

c. Adequate temporary controls must be installed on previous phases prior to initiating the land disturbance in subsequent phases until final site stabilization is achieved and post-construction control measures are brought on-line.

3. Minimize the Disturbance of Steep Slopes: Construction activities should be avoided on steep slopes to the Maximum Extent Practicable to comply with § 8.7 of this Part.

4. Preserve Topsoil: Site owners and operators must preserve existing topsoil on the construction site to the maximum extent feasible and as necessary to support healthy vegetation. If it is determined that preserving native topsoil is infeasible, the reasons why this was determined must be addressed in the SESC Plan.

5. Stabilize Soils: Stabilization of disturbed areas must, at a minimum, be initiated immediately whenever any clearing, grading, excavating or other earth disturbance activities have permanently ceased on any portion of the site, or temporarily ceased on any portion of the site and will not resume for a period exceeding 14 calendar days. Stabilization must be completed using vegetative stabilization measures or using alternative measures whenever vegetative measures are deemed impracticable or during periods of drought. All disturbed soils exposed prior to October 15th shall be seeded by that date. Any such areas which do not have adequate vegetative stabilization by November 15th must be stabilized through the use of non-vegetative erosion control measures. If work continues within any of these areas during the period from October 15th through April 15th, care must be taken to ensure that only the area required for that day's work is exposed, and all erodible soil must be restabilized within 5 working days. In limited circumstances, stabilization may not be required if the intended function of a specific area of the site necessitates that it remain disturbed.

6. Protect Storm Drain Inlets: If there is a stormwater discharge from the construction site to a storm drain inlet under the project's control, the site owner and operator must install inlet protection measures that remove sediment from discharge prior to entry into the storm drain inlet. The operator must clean, or remove and replace, the protection measures as sediment accumulates, the filter becomes clogged, and/or performance is compromised. Accumulated sediment adjacent to the inlet protection measures must be removed by the end of the same work day in which it is found or by the end of the following work day if removal by the same work day is not feasible.

7. Protect Storm Drain Outlets: Outfall protection must be used to prevent scour and erosion at discharge points through the protection of the soil surface, reduction of discharge velocity, and the promotion of infiltration.

8. Establish Temporary Controls for the Protection of Post-Construction Stormwater Control Measures: Temporary measures shall be installed to protect permanent or long-term stormwater control and treatment measures as they are installed and throughout the construction phase of the project so that they will function properly when they are brought online. The plan shall identify areas where infiltration measures are proposed and provide measures to restrict construction activity to prevent compaction of the area. In cases where this is not possible to avoid the area the Plan must include methods to restore the infiltration capacity of the soils.

9. Establish Sediment Barriers: Sediment control measures must be installed along the perimeter areas of the site that will receive stormwater from earth disturbing activities. The Rhode Island Soil Erosion and Sediment Control Handbook provided the recommended and primary means to achieve this performance criteria.

10. Divert or Manage Run-on from Up-gradient Areas: Structural control measures must be used to limit stormwater flow from coming onto the project area, and to divert and slow on-site stormwater flow from exposed soils to limit erosion, runoff, and the discharge of pollutants from the site.

11. Properly Design Constructed Stormwater Conveyance Channels: Temporary conveyance practices must be sized to handle the peak flow from the 10-year, 24-hour Type III design storm. Temporary conveyance measures may be required to be sized to handle the peak flow from larger design storms as determined on a case-by-case basis.

12. Retain Sediment On-Site

a. The SESC Plan shall contain a combination of practices that control erosion, control run-off, and control sediment. The combination of practices must be designed to prevent discharges of sediment. All plans shall include inlet protection, construction entrances, and containment of stockpiled materials.

b. For Disturbed Areas <1 Acre: Those areas with a common drainage location that serves an area with less than 1 acre disturbed at one time, a combination of phasing, stabilization and conveyances that provide run-off control will be sufficient.

c. For Disturbed Areas 1 to 5 Acres: Those areas with a common drainage location that serves an area between 1 and 5 acres disturbed at one time, a temporary sediment trap must be provided where attainable and where the sediment trap is only intended to be used for a period of 6 months or less. For longer term projects with a common drainage location that serves between 1 and 5 acres disturbed at one time, a temporary sediment basin must be provided where attainable. Temporary sediment trapping practices must be sized to have a total storage volume capable of storing 1 inch of runoff from the contributing area or 134 cubic yards per acre of drainage area. A minimum of 50% of the total volume shall be storage below the outlet (wet storage). The Rhode Island Soil Erosion and Sediment Control Handbook provides the recommended and primary means to achieve this performance criteria.

d. For Disturbed Areas > 5 Acres: Those areas with a common drainage location that serves an area with greater than 5 acres disturbed at one time, a temporary (or permanent) sediment basin must be provided where attainable until final stabilization of the site is complete. The Rhode Island Soil Erosion and Sediment Control Handbook provides the recommended and primary means to achieve this performance criteria. The volume of wet storage shall be at least twice the sediment storage volume and shall have a minimum depth of 2 feet. Sediment storage volume must accommodate a minimum of 1 year of predicted sediment load. See the sediment volume formula in the Rhode Island Soil Erosion and Sediment Control Handbook as the recommended and primary means to achieve this performance criteria. In addition to sediment storage volume and wet storage volume, the sediment basin shall provide adequate residence storage volume to provide a minimum 10 hours residence time for a 10 -year frequency, 24 hour duration, Type III distribution storm. To the maximum extent practicable, outlet structures must be utilized that withdraw water from the surface of temporary sedimentation basins, if required or specified by the designer, for the purpose of minimizing the discharge of pollutants. Exceptions may include periods of extended cold weather, where alternative outlets are required during frozen periods. If such a device is infeasible for portions of or the entire construction period justification must be made in the SESC Plan.

13. Control Temporary Increases in Stormwater Velocity, Volume, and Peak Flows:

a. The Plan must identify all discharge points and propose a combination of practices to ensure control of both peak flow rates and total runoff volume to minimize flooding, channel erosion, and stream bank erosion in the immediate vicinity of discharge points. The plan must identify if discharge points from the site discharge directly to a surface water or to an off-site conveyance. The designer must ensure that the proposed combination of practices are adequate to protect the receiving waters and downstream conveyances from the excessive velocities that would cause scouring or channel erosion.

b. In most cases, the combination of practices that control erosion, control run-off, and control sediment used to retain sediment on-site will be adequate to control temporary increases in volume and peak flows. However, the designer must evaluate if conditions warrant the use of additional retention/detention practices beyond those required to address § 8.16(D)(12) of this Part. The evaluation must include a description of site conditions and proposed on-site controls and conveyances for all discharge points. For those projects proposing a common drainage location that serves an area with greater than 5 acres disturbed at one time, the approving agency may require peak flow control on a case-by-case basis.

14. Construction Activity Pollution Prevention Control Measures: The SESC Plan must describe the pollution prevention measures that will be implemented to control pollutants in stormwater. The owner and operator must design, install, implement, and maintain effective pollution prevention measures to minimize the discharge of pollutants. The Rhode Island Soil Erosion and Sediment Control Handbook provides the recommended and primary means to achieve this performance criteria.

15. Control Measure Installation, Inspections, Maintenance, and Corrective Actions:

a. The installation of temporary erosion, runoff, sediment, and pollution prevention control measures must be completed by the time each phase of earth-disturbance has begun.

b. Construction sites must be inspected by or under the supervision of the owner and operator at least once every 7 calendar days and within 24 hours after any storm event which generates at least 0.25 inches of rainfall per 24 hour period and/or after a significant amount of runoff.

c. If an inspection reveals a problem, the operator must initiate work to fix the problem immediately after discovering the problem, and complete such work by the close of the next work day, if the problem does not require significant repair or replacement, or if the problem can be corrected through routine maintenance.

d. When installation of a new control or a significant repair is needed, site owners and operators must ensure that the new or modified control measure is installed and made operational by no later than 7 calendar days from the time of discovery where feasible. If it is infeasible to complete the installation or repair within 7 calendar days, the reasons why it is infeasible must be documented in the SESC Plan along with the schedule for installing the stormwater control measure(s) and making it operational as soon as practicable after the 7-day timeframe.

e. If corrective actions are required, the site owner and operator must ensure that all corrective actions are documented on the inspection report in which the problem was first discovered. Corrective actions shall be documented, signed, and dated by the site operator once all necessary repairs have been completed.

250 R.I. Code R. 250-RICR-150-10-8.16

Amended effective 11/13/2018