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M+Octlmerlt C - SECTION 404(b)(1) EVALUATION Of the Effects of Placing Fill Material into the Waters of the United States Pursuant to the Clean Water Act EMERGENCY RIVERBANK PROTECTION ST. JOSEPH RIVER SOUTH BEND, INDIANA I. PROJECT DESCRIPTION a. Location: The U.S. Army Corps of Engineers, Detroit District, proposes to construct riverbank protection at three sites along the St. Joseph River in the City of South Bend, Indiana. The sites are located within a one -mile reach of the river. They include the east shore of Leeper Park Island, a section along North Shore Drive and the riverbank around a stormwater outfall that formerly was a combined sewer outfall (CSO) as described in the Environmental Assessment to which this evaluation is attached. b. Authoritv: Section 14 of the Federal F1ood.Control Act of 1946 (Public Law 79-526), as amended. c. General Description: The proposed action is to protect all three sites with riprap stone, with the upper bank at North Shore Drive protected with a bio -engineered erosion control turf mat. i. Erosion protection for the North Shore Drive and CSO sites would be provided to the 50 -year recurrence flood elevation (approximately 675 feet). Upper riverbank trees at the North Shore Drive site would be preserved by using a bio -engineered erosion control turf mat instead of riprap above the two-year flood occurrence elevation (approximately 670 feet). At the North Shore and CSO sites the riprap would be finished to a 1 vertical on 2 horizontal slope (about 27) with a 1.5 -foot thick riprap layer over a graded gravel filter. At Leeper Park the riprap would be finished to a 1 vertical to 3 horizontal slope (about 18.5°) with a geo-textile filter under the riprap. ii. Construction of the riprap slopes would require vegetation removal and some fill. aCti �.it" too ro t finished o T7 }. grading and u;� vu ij ;.� .;iJu;v :u iinifG;;;;, sable .in7She:. slop.. The Lill beneath the riprap layer would consist of well -compacted granular material with good drainage characteristics— likely a compacted silty sand, or medium -fine sand soil. Coarse material such as sandy gravel, C- 1