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at a slope steeper than 1:5, the bags must be above the waterline and must not be saturated. In particular, studies have shown that the bags have a stable slope of 1:5. During emergency conditions it is not practical to construct a 1:5 sloped embankment above the waterline due to the influence of waves. An attempt was made by Mr. Pishock to protect his property with sandbags; this attempt failed. Under normal _conditions, a properly designed sandbag structure would project significantly onto the active foreshore area and thus, reduce available recreational beach; this would have a high potential for adverse effects upon the downdrift beach. Rock Revetment: A typical rock revetment would be constructed of: two layers of armor stones (2 tons+) on top of bedding stone and filter cloth at a 2:1 slope. An important element of a properly designed revetment is a properly graded embankment. During emergency conditions, it is impossible to prepare this embankment due to wave conditions. In normal conditions, a rock revetment might be constructed at Mr. Pishock's residence; however, such a revetment would significantly project upon the foreshore area and immediately impact downdrift beaches. Seawall: The most commonly constructed seawall entails steel sheet piles driven into the ground via a vibratory hammer. One of the greatest benefits of a steel sheet pile seawall is the relative speed at which such a wall may be constructed; production rates of 50 feet per day are common. Under emergency conditions, a steel sheet pile wall may be easily constructed whereas upon lifting and positioning a sheet for driving, the weight of the sheet and hammer will resist some wave attack and allow for driving of the sheet. Subsequent sheets may be more easily placed by threading through the, first sheet. Such a steel wall was installed by Mr. Pishock under emergency conditions as the only viable alternative available to Mr. Pishock. Under normal conditions, such a wall may be considered most desirable due to the limited projection of the seawall into the foreshore area — thus, limiting the immediate impact to downdrift beaches. - 1 COASTAL TECH COASTAL. STRUCTURAL, CIVIL ENGINEERING AND PLANNING Director Davis advised that the engineering consultants have determined that they have tried other alternative means, particularly sand renourishment, revetments, and sand bagging, and none have been effective. Based on Mr. Walther's analysis, staff is comfortable that the other alternatives that have been tried simply have not worked in this case. Director Davis felt the main reason they haven't worked is the close proximity of the dwelling to the mealn high waterline and also because the renourishment activity that has occurred in this area has simply washed away due to storm surge. 51�4,1U