vi. In the UST excavation zone, the site mustshall be assessed to ensure compliance with the requirements in Clauses A.5.b.i-iv of this Section and to establish the number and positioning of monitoring wells that will detect releases within the excavation zone from any portion of the tank that routinely contains product. vii. Monitoring wells mustshall be clearly marked and secured to avoid unauthorized access and tampering. c. Liquid Monitoring. Testing or monitoring for liquids on the water table must shall meet the following requirements. i. The regulated substance stored mustshall be immiscible in water and have a specific gravity of less than one. ii. When an RDD is installed in the tank hold backfill, there shall be water present in the RDD during measurement at least once every 30 days in order to use liquid monitoring. When an RDD is installed in native soil, the dDistance to the water table mustshall never be more than 20 feet from the ground surface and shall be present in the RDD during measurement at least once every 30 days, and the hydraulic conductivity of the soil(s) between the UST system and the RDDs mustshall not be less than 0.01 centimeters per second (e.g., the soil should consist of gravels, coarse-to-medium sands, coarse silts, or other permeable materials) in order to use liquid monitoring. iii. The slotted portion of the RDD mustshall be designed to prevent migration of soils or the filter pack into the RDD and to allow entry of the regulated substance on the water table into the RDD under both high and low groundwater conditions.
vi. In the UST excavation zone, the site mustshall be assessed to ensure compliance with the requirements in Clauses A.5.b.i-iv of this Section and to establish the number and positioning of monitoring wells that will detect releases within the excavation zone from any portion of the tank that routinely contains product. vii. Monitoring wells mustshall be clearly marked and secured to avoid unauthorized access and tampering. c. Liquid Monitoring. Testing or monitoring for liquids on the water table must shall meet the following requirements. i. The regulated substance stored mustshall be immiscible in water and have a specific gravity of less than one. ii. When an RDD is installed in the tank hold backfill, there shall be water present in the RDD during measurement at least once every 30 days in order to use liquid monitoring. When an RDD is installed in native soil, the dDistance to the water table mustshall never be more than 20 feet from the ground surface and shall be present in the RDD during measurement at least once every 30 days, and the hydraulic conductivity of the soil(s) between the UST system and the RDDs mustshall not be less than 0.01 centimeters per second (e.g., the soil should consist of gravels, coarse-to-medium sands, coarse silts, or other permeable materials) in order to use liquid monitoring. iii. The slotted portion of the RDD mustshall be designed to prevent migration of soils or the filter pack into the RDD and to allow entry of the regulated substance on the water table into the RDD under both high and low groundwater conditions.
UT018fin.docx