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crushed gravel, and crushed concrete is more desirable for backfill below the water line because it requires less compaction to attain the required density. Once the slopes are cut and backfilled, the respective filter layer (gravel or geo-textile) would be placed in preparation of placing the riprap protection. d. Description of Fill Material: Only clean stone and granular material from active commercial sources would be placed in the water as part of the bank protection. Site preparation for all three sites includes excavation of approximately 2600 cubic yards (cy) of material, about 1,100 cy of which would be from below the water line. Approximately 1,200 cy of backfill would be placed into the riverbanks of the three sites, about 500 cy of which would be below the water line, in preparing the slope for the bank protection. Bank protection, both in -water and above the water line, includes 1,800 tons of gravel filter stone and 5,900 tons of riprap stone. e. Description of Discharge Site: Leeper Park Island contains two municipal wells. The island is protected by a 5 -foot -high (minimum), 1,400 -foot -long stone wall that surrounds the entire island. Erosion has undermined the wall and about 250 feet of wall has been destroyed, resulting in severe erosion in these areas. The North Shore Drive site extends approximately 1,500 feet between along a steep, severely eroding riverbank (approaching lvertical on 1 horizontal or 45° in some locations) immediately adjacent to North Shore Drive. This erosion also jeopardizes two drainage outfalls and several utility lines. The CSO site also is on a steep riverbank (up to 1 vertical on 2 horizontal or 27° in some locations), across the river from the North Shore Drive site. The CSO site is about 100 feet long and includes a retired 90 -inch diameter CSO that currently is serving as a stormwater overflow, but is.being undermined by erosion. f. Description of proposed discharge method: Construction may be from on land or from the river. Land-based access must be achieved with minimal disruption of trees and other habitat that is to remain in place. Water-based construction access may be by floating plant or, if water levels are too low, by rubber -tired equipment in the riverbed. Any equipment operation or travel on the riverbed outside the excavation area shall be limited to a single path to limit the area directly disturbed. Riverbed travel shall be limited to that necessary for construction. The contractor must protect the city water intakes and must control sediment transport into the river during construction. 11. FACTUAL DETERMINATIONS a. Phvsical Substrate Determinations: The fill sites currently are subject to erosion, which is undermining trees and structures and causing turbidity and siltation. The eroded areas and adjacent river bottom areas would be affected by excavation and construction activities. Eroded areas and adjacent river bottom and riverbank areas would be replaced by riprap which is not expected to extend more than 3% into the river channel over the existing channel conditions. C.-9