PB 22 10 Altera 769 LLC Filed Application with Exhibits Final Site Plan Phase 2

s valuable data on the condition of the stormwater management facilities. Review of this information will also help to establish more efficient and beneficial maintenance procedures and practices. All recorded information should be directed to the owner of the facility for review and subsequent follow-up on recommendations. Inspection and maintenance checklists and logs are included in the Appendix of this manual. Altera Development Company, LLC -8- Revised August 2022 DECPC #2530-99-006

2. Corrective Maintenance Procedures Corrective Maintenance is required on an emergency or non-routine basis to correct problems or malfunctions and to restore the intended operation and safe condition of the basin. Bioretention: a) Removal of Debris and Sediment Sediment, debris and trash which threaten the discharge capacity of the basin should be removed immediately and properly disposed. As noted previously, it is recommended that all water be evacuated from the basin with a pump before any significant amount of sediment, settled debris or trash is removed from the basin. The lack of an available disposal site should not delay the removal of trash, debris and sediment. Temporary disposal sites should be utilized if necessary. b) Structural Repairs Structural damage to outlet and inlet structures, trash racks, access hatches, roadways and headwalls as a result of vandalism, flood events, settlement or other causes must be repaired promptly. The urgency of the repairs will depend upon the nature of the damage and its effects on the safety and operation of the facility. The analysis of structural damage and the design and performance of structural repairs should only be undertaken by the consulting Professional Engineer. c) Embankment and Slope Repairs Damage to embankments, and side slopes must be repaired promptly. This damage can be the result of rain or flood events, vandalism, animals, vehicles or neglect. Typical problems include settlement, scouring, cracking, sloughing, seepage and rutting. The urgency of the repairs will depend upon the nature of the damage and its effect on the safety and operation of the facility. The analysis of the damage and the design and performance of geotechnical repairs should only be undertaken by qualified personnel and under the direction of a consulting Professional Engineer. All

and performance of geotechnical repairs should only be undertaken by qualified personnel and under the direction of a consulting Professional Engineer. All basin embankments shall be inspected quarterly and after each significant storm greater than one (1) inch of rainfall. Any damage or indication of erosion shall be immediately inspected by a professional engineer. d) Dewatering It may be necessary to remove ponded water from within a malfunctioning basin. This ponding may be the result of a blocked principal outlet or poor bottom drainage. Altera Development Company, LLC -9- Revised August 2022 DECPC #2530-99-006

Portable pumps may be necessary to remove the ponded water temporarily until a permanent solution can be implemented. e) Weed Harvesting It may be necessary to remove congested weeds from the basin. Companies with specialized harvesters should be contacted to perform these operations. Note that such work may require the approval of various regulatory agencies. f) Extermination of Mosquitoes If neglected, the basin can become an ideal mosquito breeding area. The extermination of mosquitoes will usually require the services of the County Mosquito Commission. If mosquito control in the facility becomes necessary, the preventative maintenance program should be re-evaluated, and more emphasis should be placed on control of mosquito breeding habitats. g) Erosion Repair Vegetative cover or other protective measures are necessary to prevent the loss of soil due to the forces of wind and water. Where a re-seeding program has not been effective in maintaining a non-erosive vegetative cover, or other factors have exposed soils to erosion, corrective steps should be initiated to prevent further loss of soil that may result in danger to the stability of the facility. Soil loss can be controlled by a variety of materials and methods, including rip-rap, gabion lining, geotextile fabrics, sod, seeding, concrete lining and re-grading. h) Elimination of Trees, Brush, Roots and Animal Burrows The stability of embankments can be impaired by large roots and animal burrows. Additionally, burrows can present a safety hazard for maintenance personnel. Trees and brush with extensive, woody root systems should be completely removed to prevent destabilization and the creation of seepage routes. Roots should also be completely removed to prevent decomposition within the embankment. Root voids and burrows should be filled with material

seepage routes. Roots should also be completely removed to prevent decomposition within the embankment. Root voids and burrows should be filled with material similar to the existing material, and capped just below grade with stone, concrete or other material. If the filling of the burrows does not discourage the animals from returning, further measures should be taken to either move the animal population or to make critical areas of the facility unattractive to them. Altera Development Company, LLC - 10 - Revised August 2022 DECPC #2530-99-006

i) Snow and Ice Removal Accumulations of snow and ice can threaten the functioning of the inlets, outlets and emergency spillways. Provision of the equipment, material and personnel to monitor and remove snow and ice from critical areas will assure the function of the facility during the winter months. j) Basin Drain Time As mentioned above, two basins are infiltration basins. In accordance with the Drainage Report, the amount of time for the water quality storm volume to drain and reach the bottom elevation is approximately 24 hours. If the basin fails to drain in the above-mentioned time, the basin should be dewatered down to the soil bed elevation and the soil bed shall be replaced partially or completely depending on field inspection result. This task is to be followed by re- grading and leveling of the soil bed. The thickness of the sand layer should be checked to ensure that a minimum of 18” is maintained throughout the basin bottom area to ensure that the infiltration basin water quality treatment feature operates correctly. The soil bed material to be utilized shall consist of the following, by volume: 85-95% sand, with no more than 25% of the sand as fine or very fine sands; no more than 15% silt and clay with a 2-5% clay content. Pre-mixed soil must be certified to consistent with the requirement above for use in a bioretention basin by either the vendor or a professional engineer. The contact of any soil mixed on-site must be certified by professional engineer who must be present while its being mixed. A maximum permeability rate of 10 inches per hour. Any disturbed vegetated area should be re-vegetated immediately to prevent erosion. 3. Summary of Maintenance Procedures Preventative Maintenance -Bioretention basin a) Grass Cutting b) Grass Maintenance c) Vegetative Cover

Summary of Maintenance Procedures Preventative Maintenance -Bioretention basin a) Grass Cutting b) Grass Maintenance c) Vegetative Cover d) Removal and Disposal of Trash and Debris e) Sediment Removal and Disposal f) Mechanical Components g) Elimination of Mosquito Breeding Habitats h) Parking Lot Maintenance i) Observation After Rainfall Altera Development Company, LLC - 11 - Revised August 2022 DECPC #2530-99-006

j) Inspection of the Soil Bed k) Vegetation Maintenance l) Inspection and Reporting Corrective Maintenance – Bioretention basin a) Removal of Debris and Sediment b) Structural Repairs c) Embankment and Slope Repairs d) Dewatering e) Weed Harvesting f) Extermination of Mosquitoes g) Erosion Repair h) Elimination of Trees, Brush, Roots, and Animal Burrows i) Snow and Ice Removal j) Basin Drain Time Aesthetic Maintenance a. Grass Trimming/Landscape Maintenance b. Control of Weeds Altera Development Company, LLC - 12 - Revised August 2022 DECPC #2530-99-006

B. Checklists and Logs The Appendix of this report contains sample checklists and logs regarding various aspects of the basin maintenance and inspection. A brief description of the use of each form is listed below: 1. “Grading, Drainage & Utility Plan” – a plan identifying stormwater management facilities on- site. 2. “Estimated Maintenance Costs” – an estimate of the approximate cost to maintain the proposed stormwater management system on an annual basis. 3. “Maintenance Equipment and Materials” – a comprehensive list of equipment and materials typically required for stormwater management facility maintenance. 4. “Maintenance Work Order and Checklist” – a comprehensive form outlining both required and completed maintenance work. 5. “Maintenance Log” – a summary table for recording of all maintenance work at the site. 6. “Inspection Checklist” – a comprehensive checklist of the items to be inspected. 7. “Inspection Log” – a summary table for recording the results of all inspections. Altera Development Company, LLC - 13 - Revised August 2022 DECPC #2530-99-006

APPENDIX