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

events will be infiltrated and collected via under drains and larger runoff events will be discharged at a controlled rate via proposed outlet control structures. Stormwater runoff that is detained below the lowest outlet is infiltrated and shall drain from the basin in under 72 hours via the proposed underdrains. If significant increases or decreases in this drain time are observed, a qualified licensed Professional Engineer shall be contacted to evaluate possible corrective measures that may be required. Altera Development Company, LLC -3- Revised August 2022 DECPC #2530-99-006

PART II: INSPECTION AND MAINTENANCE A. Routine Inspection and Maintenance of the Stormwater Management Facilities: The stormwater management basin has been designed to control stormwater and reduce downstream impact. Without proper routine inspection and maintenance, the basin may lose some or all of its capability to function to its full capacity. Lack of adequate maintenance at this facility could lead to system failures. A consulting Professional Engineer should perform regularly scheduled maintenance inspections of the stormwater facilities at least (4) times each year. The primary purpose of these inspections is to ascertain the operational condition and safety of the facilities, particularly the condition of outlet structures and other safety-related aspects. Inspections will also provide information on the effectiveness of regularly scheduled Preventative Maintenance Procedures, and will help to identify where changes in the extent and scheduling of the procedures are warranted. Finally, the facility inspections should also be used to determine the need for and timing of Corrective Maintenance procedures. Routine Functional Maintenance is required to insure the safe and effective operation of the storm water management facility and is further broken down into two (2) categories: Preventative and Corrective. It is important to note that a successful Functional Maintenance program will emphasize regularly scheduled Preventative Maintenance over emergency-based Corrective Maintenance. Listed below are the Preventative and Corrective Maintenance Procedures to be performed on a routine basis: 1. Preventative Maintenance Procedures The purpose of Preventative Maintenance is to assure that the basin remains operational and safe at all times, while minimizing the need for emergency or corrective maintenance. These procedures are as follows: Bioretention: a) Grass Cutting A regularly scheduled program of mowing and trimming of grass at and surrounding the basin during the growing season will help to maintain a tightly knit turf, and will

ed program of mowing and trimming of grass at and surrounding the basin during the growing season will help to maintain a tightly knit turf, and will also help to prevent diseases, pests and the intrusion of weeds. The actual mowing requirements of an area should be tailored to the specific site conditions, grass type, and seasonal variations in the climate. In general, lawn areas should me mowed at Altera Development Company, LLC -4- Revised August 2022 DECPC #2530-99-006

least once a month during the growing season and grass should not be allowed to grow more than 1 to 2 inches between cuttings. Allowing the grass to grow more than this amount prior to cutting it may result in damage to the grass’ growing points and limit its continued healthy growth. b) Grass Maintenance Grassed areas require periodic fertilizing, de-thatching and soil conditioning in order to maintain healthy growth and to provide bank stabilization. Additionally, provisions should be made to re-seed and re-establish grass cover in areas damaged by sediment accumulation, stormwater flow, or other causes. These tasks should be performed, or at least evaluated, on a quarterly basis. c) Vegetative Cover Trees, shrubs, and ground cover require periodic maintenance, including fertilizing, pruning, and pest control in order to maintain healthy growth. Vegetated areas must be inspected at least annually for erosion and scour as well as unwanted growth, which should be removed with minimum disruption to the remaining vegetation. The basin should be evaluated regularly to determine whether excessive plant growth is evident. A correction in the application of fertilizers can often solve these problems. Weeds, which have become a problem, can be cleared through harvesting by professional maintenance technicians. Note: All use of fertilizers, mechanical treatments, pesticides and other means to ensure optimum vegetation health must not compromise the intended purpose of the storm water management facility. All vegetation deficiencies should be addressed without the use of fertilizers and pesticides whenever possible. d) Removal and Disposal of Trash and Debris All storm water management components expected to receive and/or trap debris and sediment must be inspected for clogging and excessive debris and sediment accumulation at least

nagement components expected to receive and/or trap debris and sediment must be inspected for clogging and excessive debris and sediment accumulation at least four times annually as well as after every storm exceeding one inch of rainfall. Such components may include the basin, stormwater conveyance network (piping and inlet), flared end sections, bottoms, riprap or gabion aprons, trash racks and inflow points. All components expected to receive and/or trap debris and sediment must be inspected for clogging and excessive debris and sediment accumulation at least four times annually as well as after every storm exceeding 1 inch of rainfall. Such Altera Development Company, LLC -5- Revised August 2022 DECPC #2530-99-006

components may include inlets and diversion structures, fore bays, sand beds, and overflows. Removal of trash and debris will prevent possible damage to trash racks and outlets, vegetated areas and eliminate potential mosquito breeding habitats. Disposal of debris and trash must comply with all local, county, state, and federal waste flow control regulations. Only suitable disposal and recycling sites should be utilized. e) Sediment Removal and Disposal The basin should also be evaluated for excessive deposition of sediment. Accumulated sediment should be removed before it threatens the storage volume of the basin. Before de-sedimentation activities are performed, consideration should be given to evacuating all standing water from the basin. This may be accomplished by clearing any blocked openings of the outlet structure or by mechanical means such as pumping. If stable soil conditions exist on-site, sediment deposition should not be an excessive maintenance issue. Should a recurrent stabilization situation develop, the inspector should identify the upstream sources of sediment and recommend required stabilization measures. Sediment removal should take place when all runoff has drained from the sand bed and the sand is reasonably dry. In addition, runoff should be drained or pumped from fore bays with permanent pools before removing sediment. Disposal of debris, trash, sediment, and other waste material should be done at suitable disposal/recycling sites and in compliance with all applicable local, state, and federal waste regulations. f) Mechanical Components Mechanical components such as valves, sluice gates, pumps, fence gates, locks, and access hatches, should remain functional at all times. Regularly scheduled maintenance should be performed in accordance with the manufactures’ recommendations.

cess hatches, should remain functional at all times. Regularly scheduled maintenance should be performed in accordance with the manufactures’ recommendations. Additionally, all mechanical components should be operated at least once every three months to assure their continued performance. g) Elimination of Potential Mosquito Breeding Habitats The most effective mosquito control program is one that eliminates potential breeding habitats. Almost any stagnant pool of water can be attractive to mosquitoes, and may become the source of a large mosquito population. A maintenance program dedicated to eliminating potential breeding areas is preferable Altera Development Company, LLC -6- Revised August 2022 DECPC #2530-99-006

to chemical means of controlling mosquitoes. The most important maintenance function is removal of all obstructions to natural flow patterns before stagnant water conditions can develop. h) Parking Lot Maintenance This management measure involves employing pavement cleaning practices, such as parking lot sweeping on a regular basis, to minimize pollutant export to the stormwater conveyance system/detention basins and eventually the receiving waters. These cleaning practices are designed to remove sediment, debris, and other pollutants from access drive and parking lot surfaces that are a potential source of pollution impacting urban waterways. Mechanical machines that use vacuum assisted dry sweeping to remove particulate matter shall be utilized as these have the ability to remove finer sediment particles. Parking lots and access drives shall be swept/vacuumed at least once a month. The disposal of the swept material must be properly hauled off the site and transferred to an approved disposal site. Other parking lot maintenance features include the use of on-site trash receptacle. These receptacles should be located in strategic areas where the majority of the pedestrian traffic occurs. These receptacles should be emptied daily. The disposal of the solid waste must be properly hauled off the site and transferred to an approved disposal site. i) Observation After Rainfall This management measure involves monitoring the amount of time the detention basin takes to drain to ensure the basin is working properly. The detention basin should drain to the bottom in less than 72 hours. If significant increases or decreases are observed in the drawdown time, a qualified licensed Professional Engineer shall be contacted to evaluate the basin’s bottom surface, subsoil and both groundwater and tailwater elevations to determine what corrective measures may

eer shall be contacted to evaluate the basin’s bottom surface, subsoil and both groundwater and tailwater elevations to determine what corrective measures may need to be implemented. The management measure involves monitoring the amount of time it would normally take to drain the maximum design storm runoff volume below the top of the filter’s sand bed. This normal drain or drawdown time should then be used to evaluate the filter’s actual performance. If significant increases or decreases in the normal drain time are observed, a qualified licensed Professional Engineer shall be contacted to evaluate the filter’s sand bed, underdrain system, and tailwater levels to determine what corrective measures may need to be implemented to maintain the proper functioning of the filter. Altera Development Company, LLC -7- Revised August 2022 DECPC #2530-99-006

j) Inspection of the Soil Bed The soil bed should be inspected at least twice annually. The infiltration rate of the soil bed material may also be retested. If the water fails to infiltrate 72 hours after the end of the stormwater quality design storm, corrective measures must be taken. k) Vegetation Maintenance All landscaped areas within the aboveground basin shall be periodically inspected a minimum of once per month and every two weeks during growing season or after each mowing session. In general, mowing should occur at least once a month during the growing season. Clippings from the mowing operations shall be removed and disposed of in accordance with all local, state and federal regulations. Reseeding, if required, shall occur within spring or early fall. Summer and fall seeding can be successful with a light mulching of weed-free straw to conserve moisture. All landscaped areas shall be inspected for invasive plant species. Invasive species should be removed immediately and properly disposed of at an approved disposal site. l) Inspection and Reporting: Regularly scheduled inspections of the facility should be performed by a consulting Professional Engineer. The primary purpose of the inspections is to ascertain the operational condition and safety of the facility. Inspections will also provide information on the effectiveness of regularly scheduled Preventative and Aesthetic Maintenance procedures. It should be noted that, in addition to regularly scheduled inspections, an informal inspection should be performed during every visit to stormwater management facilities by maintenance or supervisory personnel. The recording of all maintenance work and inspections provides valuable data on the condition of the stormwater management facilities. Review of this information will also help to establish more efficient and beneficial