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would not leak into any subsurface hydraulic conduits such as joints, fracture sets, or other high permeability zones. Brierley visited the site in 2013, installed several drill holes and observed the water conditions within these drill holes. BA-4 and BA-6 were revisited in 2019. The readings are tabulated below. Table 1 -Ralston Quarry Groundwater Data Water Level Readings Date 06/21/13 07/19/13 08/23/13 05/03/19 -- ------------------- Boring Elev. Water Level Water Level Water Level Water Level .......... bgs elev ft bgs elev ft bgs elev ft bgs elev BA-3 6200 Surface 6200 Surface 6200 Surface 6200 BA-4 6175 Surface- 6175 Surface- 6175 Surface- 6175 Surface- 6175 Artesian Artesian Artesian Artesian BA-5 6200 Dry n/a Dry n/a Dry n/a BA-6 6110 7.7 6102.3 9.1 6100.9 10.2 6099.8 2.3 6107.7 BA-7 6125 8.8 6116.2 11 6114 12.4 6112.6 BA-7A 6125 N/M n/a 4 6121 4.9 6120.1 BA-8 6200 6 6194 9.9 6190.1 9.5 6190.5 BA48A 6200 9 6191 10.5 6189.5 12.6 6187.4 I BA-8B 6185 7.4 6177.6 6.6 6178.4 6.8 6178.2 ----------- Brierley observed that in one drill hole(BA-5),closest to the lowest point of the quarry,no water was found. This hole reached a depth of roughly 100 feet from the surface. The remining borings showed water. Surface water is likely to be the source of all the water observed in the drill holes. Surface water most likely flows into the boreholes via fractures in the basalt. The presence of a higher quantity of fractures is expected near the surface of any rock structure (natural weathering) and in particular in a quarry where blasting is regularly conducted. Indeed,except for BA-5,the borings drilled in 2013 were drilled from higher elevations representing the near- surface fractured characteristics of the basalt. Therefore,water observed in the Brierley drill holes (except for BA-5) is from surface flows through near-surface cracks. This conclusion is corroborated by Brierley's observations that the occurrence of fractures reduces with depth as observed in rock core recovered from these borings and in exploratory borings conducted by Asphalt Paving. Also,packer tests determined a very low hydraulic conductivity range for the basalt(9.3 x 10 -7 cm/sec to 2.4 x 10-5 cm/sec). The findings from BA-5 support this conclusion,as it was drilled from the lowest elevation of all the borings within the quarry and despite surface water ponding in the immediate vicinity, it was dry for its full 100-ft depth. In addition to the detailed hydrogeology work conducted by Brierley, a number of observable site factors provide strong evidence that the Ralston Quarry is hydrogeologically isolated. During precipitation events,water gathers in the lowest points of the quarry. This water does not drain naturally. It either evaporates over time or must be pumped out. Pumping conducted in spring Ralston Quarry GW 2 (;,m Ia wki and Associates.NA A'