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330 Land Company, LLC Arroyo Lago 9785.004.001 Design-Level Geotechnical Report Page | 16 April 16, 2024 Latest Revision October 31, 2025 The duration required to achieve the desired degree of settlement based on future loads could vary across the site based on the variability of subsurface conditions. The surcharge should be monitored with settlement plates and surface settlement markers, as further discussed in Section 5.2.1. The surcharge can be removed once sufficient settlement has been achieved, as evaluated by the geotechnical engineer. Surcharge loads should extend a lateral distance of at least 5 feet beyond improvement limits (such as streets and utility corridors) and at least 10 feet beyond building pad limits. Surcharge fills should be sloped no steeper than 1:1 (horizontal:vertical); where this is not feasible, a vertical surcharge can be constructed using the Tensar temporary retaining wall system or a similar wrapped-face, geosynthetic-reinforced wall system. If the surcharge is planned to remain as civil fill after the surcharge program, the fill should be compacted to the specifications described in Section 5.6. 5.2.1 Surcharge Settlement Monitoring Program The surcharge should be monitored with settlement plates and surface settlement markers, at the least. The surcharge can be removed once sufficient settlement has been achieved, as evaluated by the geotechnical engineer. The settlement-monitoring plates should be installed prior to surcharge placement to monitor compression. The number and location of the settlement-monitoring plates should be determined by us once the surcharge staging has been determined. The settlement-monitoring plates should be surveyed to determine elevations at least weekly for the first month and then bi-weekly for the next 5 months, or if we have determined that the desired degree of surcharge-driven pre-compression has been achieved. All readings of settlement shall be tied to benchmarks established well beyond the zone of surcharge influence. Traditional survey techniques should be used to survey the target affixed to the top of each monitoring point . A piezometer may be installed in conjunction with settlement plates to evaluate the pore pressure dissipation of the compressible material and better inform the estimated duration of the program. 5.3 DIFFERENTIAL FILL SLOPE MITIGATION 5.3.1 Busch Pit Lots affected by differential fill slope conditions in Busch Pit are shown in Figure 2C. We present two potential options to mitigate the differential fill slope condition for the site. 5.3.1.1 Option 1: Subexcavation and Recompaction The existing cut-to-fill transition material may be partially subexcavated to minimize the potential for differential movement below building footprints. We recommend that building pads be underlain with a minimum of 5 feet of uniformly graded engineered fill subgrade. This can be accomplished by reworking the upper 4 feet below finished pad grade and processing the fifth foot in place. The fill should be compacted to the specifications described in Section 5.6. The subexcavation should extend at least 5 feet beyond building pad limits. Following subexcavation and recompaction, we estimate differential fill settlement to be less than ½ inch over a span of 50 feet.