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I I I I . I I I I I I I I I I I . I I -8- due to the limited capacity of the culverts, with the two houses upstream of Eagle Street being inundated. Between the two streets, the culverts have little effect on flood elevations and the flood is, for the most part, confined to the deep channel. No property damage will occur in this area, however, erosion to the banks of the channel should be anticipated. In the reach from Eagle Street Ditch is generally undefined. and the only street culvert is pipe under Montview Boulevard. to Montview Boulevard, Sable This area is low density residential a 36-inch corrugated metal Because street elevations are From Helena Street to Jasper Street. Sable Ditch runs through an industrial area with' two 60-inch concrete culverts under Helena Street and 17th Avenue and a 36-inch by 48-inch metal pipe under both Batavia Drive and Jasper Street. The warehouses in this area encroach up to the edge of the small channel, which will only contain 50 percent of the 100-year storm runoff. Because of the relatively flat terrain, this area is inundated by the 100-year flood with depths ranging from one to four feet. low, only the roads are flooded and minimal property damage will occur north of 22nd Avenue. The houses just up and downstream from Montview Boulevard are subject to flooding due to the constriction at Montview Boulevard and the properties along the west side of Fraser Street south of 22nd Avenue could also suffer some damage. In the reach from Jasper Street to the upper limits of the study, the area is relatively undeveloped with one corner of one building encroaching upon the 100-year flood plain. Granby Ditch - The flood plain limits and flood profiles for Granby Ditch are shown on the Flood Hazard Area Delineation maps, Sheets 6 through 12. In the reach from Montview Boulevard to Helena Street, Sable Ditch is again poorly defined with the exception of the deep confining channel immediately downstream from Chambers Road and Helena Street. In this reach, the ditch goes under Chambers Road through two 36-inch pipes that convey about eight percent, 70 cfs, of the 100-year flow. This condition will result in extensive flooding and property damage both upstream and downstream from Chambers Road. The three houses downstream of Chambers Road on the south side of the ditch are inundated by the water spilling over Chambers Road and the houses just upstream of Chambers Road on the south side of the channel are also inundated because of the backwater caused by Chambers Road. All buildings located north of the ditch are out of the 100-year flood plain. In the reach from the confluence with Sable Ditch to Montview Boulevard, the flood plain is divided and encompasses the open space east of the apartment buildings with about 90 percent of the discharge conveyed in this area and in the manmade channel east of the apartment buildings. About 10 percent of the flow is conveyed west of the apartment buildings, encompassing Billings Street and the ditch along 1-225. There is very little property damage in this reach because the apart- ment buildings and houses sit on relatively high ground and the manmade channel carries a large percentage of the flow. The one house closest to the confluence of Sable and Granby Ditch is in the flood plain because of the low capacity of the culverts under Billings Street and because the house is on relatively low ground. Also, one apartment building next to Montview Boulevard is inundated by the 100-year flood.