Ilile River, near Norton, Massachusetts (drainage area = 1^2 ,1; square 

 miles). A 6-hour \mit hydrograph at State Farm was developed from 

 the August and October 1955 floods and routed to the mouth. The 

 observed October 1955 flood was used for the Wading River at Norton, 

 doubled, lagged four hours, and assumed to represent the runoff 

 from the Three I-Iile River at its nouth. The 6-hour i:!nit graph ob- 

 tained from this flood was routed to the mouth of the Taunton 

 River, xcLth a lag of three hours. By using a straight drainage 

 area relationship, the unit graph for the 185-square-mile uncon- 

 trolled drainage area was computed from the ujtiit graph at State 

 Farm, The components of the three computed hydrographs were 

 added together and adjusted. The same residual rainfall excess 

 that was used for the Pawt-uxet River was applied to the Ta\anton 

 River unit graph (see Table 0-k) • 



C-9, DESIGN STREAII FLOJ 



The design stream flows obtained from the studies of the 

 transposed September 1938 storm are discussed in the following 

 paragraphs for the Fox Point and Lower Bay Barrier sites, 



a. Fox Point Barrier , The peak fresh water inflow at 

 this location is 9,200 cubic feet per seond, of which 5>350 cubic 

 feet per second is contributed by the Woonas qua tucket River, 3^700 

 cubic feet per second by the Iloshassuck River and 100 cubic feet 

 per second by the area below the confluence of these two rivers 

 in Providence (see Plate G-5 and Table G-lj.) , This latter area 

 has a maximum discharge of 600 cubic feet per second, but the 

 discharge reaches its peak approximately nine hours before the 

 total inflow. Some local flooding will occur on the Woonas- 

 quatucket River above Eagle Street near such places as the 

 U, S, Rubber Company, the Queen iJying Company, and in the 

 vicinity of the business area of Olneyville for discharges 

 in excess of 1,500 cubic feet per second. However, below this 

 point the flood flows will return to the confines of the river 

 before reaching the downtown business area of Providence, For 

 the Iloshassuck River, some flooding will occur above Randall 

 Street (about 0,8 mile above its mouth) for flows greater than 

 1,200 c.f.s. Considerable flooding will be experienced for dis- 

 charges in excess of 3,600 c,f,s, above Smith Street (0,3 mile 

 above the mouth) , 



The total volume of runoff at Fox Point is about 21,000 

 acre-feet, or 5.1 inches of runoff from the 77 square miles of 

 drainage area. The storage available above the barrier is less 

 than 950 aCre-feet at elevation 6,5 m,s,l, (approximate elevation 



0-9 



