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Indian River County File No. 06-5699 4.2 Groundwater Control -5- The groundwater level was measured in the boreholes on the date drilled after stabilization of the downhole water level. As shown on Figure 5, the measured groundwater level in the auger borings was at approximate depths ranging from 2.5 to 5.2 feet. Fluctuations in groundwater levels should be anticipated throughout the year primarily due to seasonal variations in rainfall and other factors that may vary from the time the borings were conducted. Some form of groundwater control (dewatering) will likely be required during construction, particularly for utility construction and roadway construction during the wet season. Means and methods of groundwater and surface water control should be the responsibility of the contractor. We suggest that the contractor be made aware of the presence of clayey and hardpan soils present through portions of the project corridor. Such material may influence the dewatering methods used during the project. 4.3 Typical Seasonal High Water Table The normal seasonal high groundwater level each year is the level in the August -September period at the end of the rainy season during a year of normal (average) rainfall. The water table elevations associated with a flood level would be much higher than the normal seasonal high groundwater level. The normal high water levels would more approximate the normal seasonal high groundwater levels. The seasonal high groundwater level is affected by a number of factors. The drainage characteristics of the soils, the land surface elevation, relief points such as drainage ditches, lakes, rivers, swamp areas, etc., and distance to relief points are some of the more important factors influencing the seasonal high groundwater level. Based on our interpretation of the site conditions using the boring logs and the soil survey, we preliminarily estimate the normal seasonal high groundwater level at the site to be approximately 1 foot above the groundwater levels measured in the boreholes at the time of our field exploration. The estimated normal seasonal high groundwater table levels are shown on the boring profiles on Figure 5. We recommend additional explorations be conducted during design to further evaluate the normal seasonal high groundwater table estimate. If requested, Ardaman can verify the plotting of the estimated seasonal high groundwater levels on the cross sections. Also, we can verify that the bottom of the proposed base material elevation has proper separation from the seasonal high groundwater elevation, or make recommendations for special base treatment in deficient areas. We note that water will likely "perch" temporarily atop the shallow clayey and hardpan soils at the site, at depths shallower than the estimated normal seasonal high groundwater level, during periods of heavy or prolonged rainfall.