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Geotechnical Investigations In late December 2015/early January 2016, the County directly hired one of the local geotechnical firms under its continuing services contract. Keller, Schleicher & MacWilliam Engineering and Testing, Inc. (KSM) perform a preliminary subsurface investigation that consisted of five (5) soil borings and five (5) permeability tests. The geotechnical report was furnished to CDM Smith for evaluation in determining if the excavated soils could be used as road underlayment, if the material could be used for the construction of the necessary berm, and ultimately, if the soils underneath the surface would have adequate allowable bearing capacity to support the weight of the berm and reservoir system. The KSM summary report is included in the CDM Smith report under Appendix B. KSM performed five (5) Standard Penetration Tests (SPT) at locations throughout the site where the reservoir would be situated. The types of soils consists of medium to fine-grained, slightly silty sand. From land surface to a depth of 50 feet below land surface (bls), no organic soils (highly compressible) or other unsuitable material was found at the SPT boring locations except for the typical surface vegetation. The soil density was classified as loose to medium dense, and according to KSM, the soils found at the location could support the structures associated with the project. According to the U.S. Department of Agriculture Soil Survey Map of Indian River County, the primary soils found at the site are Eau Gallie fine sand (3) and Pomello sand, 0 to 5 percent slopes (21), with some Myakka-Myakka fine sands, 0 to 2 percent slopes (5). The water table was found to vary from 40 to 80 inches below existing land surface, and based on the types of soils classified at the site, KSM estimated that the normal seasonal high water table could be anywhere between 4 to 30 inches. The normal seasonal low water table was estimated to be 50 to 80 inches below land surface. KSM also performed five (5) Usual Open Hole permeability tests at the boring locations. This type of, test was developed to determine how quickly or slowly water travels through a given soil type and density over a specified amount of time. The results of the test, known as permeability (hydraulic conductivity), indicate if a soil drains well or poorly., Table 4-1 show the results of the KSM permeability tests. Table 4-1 Hydraulic Conductivity Test Results VLZM. P-1 3.7 x 10' 32 P-2 3.0 x 101 26 P-3 1.5 x 104 13 P-4 1.7 x 101 15 P-5 1.9 x 10' 16 -3uurce: n3rva rrenminary �ouosurrace Investigation, January zulb. 1 See Figure 4-1 for permeability test locations Based on the results of the geotechnical investigations, it appears that the soils on the subject property are moderate to high permeability, thus allowing water to travel through the pores J:\Utilities\UTILITY - Engineering\WATER\Alternative Water Supply\Portofino Preserve aka Blackstone 83 acre site\Due Diligence Report for BCC 02_16_2016\Agenda - Due Diligence Report and OPC for 83 acre site for BCC meeting 02_16_2016 v2 cmc.docx Page 7 of 14 105