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The Delta climate provides good boating conditions <br /> year-round except for periods of fog or high winds. <br /> During the period between May and October climate <br /> conditions are the most conducive for the many types <br /> of boating that occurs in the Delta. <br /> 5. Soils: <br /> The soil of Roberts Island is Staten Peaty Muck. <br /> The rich organic soil is ideal for intensive farming. <br /> On the other hand, the physical and chemical prop- <br /> erties of peat soils -- their susceptibility to <br /> erosion, subsio-ence, flammability, and liquefaction <br /> during earthquakes -- have created costs and hazards <br /> which threaten continued use of the area. <br /> Peat soils resulted from the incomplete decomposition <br /> of vegetable matter by bacteria under water. Their <br /> development, unlike other soils, was dependent upon <br /> both climate and moisutre, which created an environ- <br /> ment in which bacteria could function on the accumu- <br /> lating organic matter. The peat in the Delta in- <br /> creased in thickness as the result of a slow rise <br /> in the sea level following Pleistocene glaciation <br /> some 11,000 years ago. As the sea withdrew, peat <br /> deposits accumulated to their present thickness -- <br /> up to 50 or 60 feet deep in some places. <br /> Erosion is a problem in dry peat soils. <br /> When drained and farmed, the original fiberous brown <br /> peat breaks down into a finely-divided, black powdery <br /> mulch. Soil in this condition is highly susceptible <br /> to both wind and water erosion. The peat dust clouds <br /> often seen in the Delta create a health and safety <br /> hazard, and contribute measurably to the loss of <br /> productive soil and the lowering of the Delta islands. <br /> 6. Seismic Hazards : <br /> Three major active faults could have potential <br /> effects in the Delta -- the San Andreas, Hayward <br /> and Calaveras. These faults are located in the <br /> coastal region approximately 40-50 miles east of <br /> the site. The history of past earthquakes and the <br /> continuing surface movements of these faults indicate <br /> that another major earthquake will occur. The effect <br /> in the Delta is not precisely known. However, be- <br /> cause the magnitude of an earthquake on any one of <br /> these faults could be great, substantial damage to the <br /> Delta is likely. <br /> _ g _ <br />