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From Bryant St. to Stat~on 10+00, a grasslined channel with 3,1 side slopes is planned. Acquisition of several structures will be necessary through this reach. From Station 10+00 to Decatur St., the master plan calls for a vertical walled, concrete lined channel between two manufacturing buildings. Draw~ng No. W-3 At Hooker St., two additional conduits are proposed, ing the existing inlet conduit to Barnum Reservoir. bined capacities of the three conduits is sufficient the 10 year runoff. parallel- The com- to carry At the Decatur St. crossing, a bridge is proposed in the master plan which would pass the 100 year storm without overtopping. From Hooker St. to Knox Court, the channel flows through a very congested area with deep side slopes, numerous bends, and scat- tered portions of public ownership. The proposed improvements consist of raising the channel invert 4 to 6 feet above the exist- ing flow line to enable the construction of a grasslined channel ~n most locations. Certain portions of the area are so narrow that 3,1 and 1,1 channel side slopes are recommended as sho..'n on the drawing. The steeper side slOpe should be protected with gabion mats or concrete slope paving. It is recommended that an underdrain be placed below this section of Channel to elim- inate the possibility of raising the ground water table in the area. The underdrain may also be necessary to intercept under- drains from sanitary sewers in the area. A short section of concrete lined channel extends above Decatur St. and then the channel opens out into a wide grasslined channel with 3,1 side slopes. Two structures must be acquired in the area just west of Decatur St. The existing conduit, extending under Federal Blvd. and 8th Ave., may be utilized if the improvements recommended for the Federal Blvd. detention area are completed. The existing conduit will pass 1600 cfs with a head water at the elevation of Federal Blvd. Drawing No. W-2 The area between Federal Blvd. and West 6th Ave. is OCCUpied by the proposed site of the Federal Blvd. detention area. The pro- posed ponding area would require the excavation of approximately 200,000 cubic yards of earth to create sufficient storage to allow the 10 year storm runoff to pass beneath Federal Blvd. in the existing conduit. Numerous dead-end alleys and dead-end streets exist through this reach channel. Recommendations are presented on methods of re- locating alleys and cu1-de-sacing streets to allow for better traffic movement after construction of the channel. The improvements to the ~edcral Blvd. detention area could grad- ually be undertaken over a period of time, as uses for fill mater- ial became available. The reservoir is only economical if excava- tion could be disposed of for a cost of less than $1.00 per cubic yard. Construction of a smaller ponding area would simply mean that th~ frAquency of ov~rtoppin~ F~ner~l Blvd. would he incr~~s~rl. A new bridge is proposed for K~~x Court. Due to the elevation of Knox Court, this bridge will be capable of passing the 100 year storm without flooding from adjacent areas. The existing conduit beneath 6th Ave. may be developed into an adequate outlet for Barnum Lake with the installation of a taper- ed entrance section on the upstream 100 feet of the conduit. The entrance structure must be designed to develop the conduit's Cdpac- ity to 2,600 cfs. A concrete chute and formal energy dissipator nust be constructed on the downstream end of the culvert due to the exceedingly high velocities developed in the culverts. West of Knox Court, the channel presently flows through ~ culvert around a real estate office. The recommended improvements consist of acquiring this property and continuing the open channel from Knox Court to King St. Acquisition of two ~dditional r~sid~n~~~ near King St. will be necessary. A new bridge is recommended for the King St. crossing. The bridge will pass the 10 year storm without inundating the surrounding area, although the 100 year storm will cause local flooding. From King St. to Lowell Blvd. an open channel is again proposed. A long box culvert is necessary from Lowell Blvd. The proposed culvert will pass the 10 year storm without inundation of adjac- ent ~rc~~ ~~t will c~u~c floodi~g of the local area during major storm occurrences. The improvc~cr.tc for B~r~~~ Reservoir cor.sist of raising the enb~nk- ment along the north and east sides to an elevation sufficient to store the 100 year storm runoff. Construction of a spillway at the northeast corner of the reservoir is still necessary to allow greater storm occurrences to flow out of the reservoir without breaching the dike. From Lowell Blvd. to Meade St.,an open channel is proposed with one sidcana3:1 slope and the other side on a 1,1 slOpe with gabion slope protection recommended for the steeper side slope. A bridge is proposed for Meade St, c<lpable of passing the 10 year storm runoff. -104- -105-