CORRESPONDENCE_4/7/22 [REV] APPENDICES W/FIRE PERMIT

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Forward Resource Recovery Facility WDR Technical Report HDR Engineering, Inc. 7 October 2021 Groundwater Flow Direction and Depth Based on data collected between 2003 and 2017, groundwater generally flows in a north to northeasterly direction. The facility’s First Quarter 2020 Water Quality Monitoring Report indicated that groundwater flowed to the northeast at an average hydraulic gradient of approximately 0.001 to 0.002 ft/ft. The depth to groundwater across the site ranges from 50 to 70 feet below the ground surface, with seasonal variations in groundwater depth up to 10 feet. Typically, the highest groundwater elevations are observed during the winter/spring and the lowest levels are observed in the summer/fall. The groundwater flow velocity ranges from 0.001 to 0.003 ft/ft. Slug tests performed in four wells at Forward Landfill indicated hydraulic conductivity values of 0.02 to 0.002 cm/s for the uppermost aquifer beneath the landfill. Based on the maximum hydraulic conductivity and hydraulic gradient and an estimated effective porosity of 0.2, the maximum groundwater velocity beneath the facility is estimated to be approximately 0.85 ft/day. 2.4 Water Supply Wells There are two water supply wells located at the Forward Resource Recovery Facility. The water supply well used for dust control and process water is located south in the southeast corner of the facility along Austin Road. The water supply well used for irrigation purposes (e.g., frontage landscaping) is located just south of the facility entrance. These are shown in Appendix D. 2.5 Flood Plain The operation is located within a Special Flood Hazard Area (SFHA) and immediately adjacent to a regulatory floodway based on the Federal Emergency Management Agency’s (FEMA) designation. This information can be found on flood map numbers 06077C0630F and 06077C0635F in FEMA’s Flood Map Service Center and is included in Appendix E. The distances to the nearest 100-year floodplains are approximately 1 mile east, 0.6 miles west, and 0.7 miles north of the facility. 2.6 Nearby Water Bodies The nearest water body to the facility is the south fork of South Littlejohn’s Creek, which runs through the Forward Landfill and directly north of the Forward Inc. Compost Facility. An off-site unnamed drainage ditch runs on the south side of the compost facility and meets the south fork of South Littlejohn’s Creek on the west side of the site. Surface water from the site flows west and ultimately discharges into Littlejohn’s Creek approximately 2.5 miles northwest of the facility. See Appendix F for a map of the nearby surface water bodies.