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I I I I I I I I I I I I I I I I I I I Memorandum to Mr. Ioannides April 28, 1986 Page 5 MISSISSIPPI AVENUE CHECK DAM Physical Characteristics: Approximate 3 1/2' drop The dam is constructed of sheet piling driven across the river with concrete rubble placed on a 10:1 slope on the downstream face. A boat chute is constructed near the left bank. The chute is con- structed of a concrete cap on the sheet piling, with a notch in the piling and a chute through the concrete rubble. Analysis 1. Navigability. The upstream entrance is very blind, There is no indication of where the chute is unless it is scouted from the bank. There are no signal rocks. The chute is very rough with many protruding rocks and rubble. There is no depth in the chute, particularly at lower flows. It is very easy to damage boats or to get jammed on a rock or rubble. There is no "hole" or "keeper" at the base of this drop. 2. Rescue co~tibilit~ Boat rescue is difficult due to the crete retawing walE on both banks of the river. con- 3. Cost and Construction. Relatively low cost and easy construction using concrete rubble on hand. 4. Ap~arance. The dam and chute are unsightly due to the concrete rub Ie dumped into the river and the linear nature of the dam and chute. 5. Operation and Maintenance. The dam and chute tend to catch debris on the jagged edges of the concrete rubble. 6. Stabili ty. over time. continue. The rubble has been gradually rearranged by the river Since the chute is not grouted, this will probably Other Warning signs have been installed. No portage trail or landing for scouting have been installed. Fish migration is difficult, but possible. Pool - drop sequence is needed.