b, WoonasQUP-tucket and Iloshassuck jtiivers . The 3 -hour unit 

 hydrographs that were developed for these rivers were converted to 6- 

 hour unit graphs and comtined. The residual rainfall of 13.0 inches 

 was a-Dplied to this, then added to the runoff from the area above the 

 Woonasquatucket Reservoir » The resulting hydrograph had a peak dis- 

 charge of 7,800 cubic feet per second and a volume of S.U inches of 

 runoff (see Table C-U) . 



£, Pavjtujcet River . Thic river, which is fonri.ed bj the 

 junction of the North and South Branches (drainage areas 106 and 73 

 square miles, respectively) in West 'iarwick, Rhode Island, has a 

 total watershed area of 230 square niles. The runoff from the North 

 Branch is controlled by the Scituate Reservoir, the water supply for 

 the City of Providence, The runoff frori the South Branch is partially 

 controlled by the ITLat River Reservoir. Two U.S. Geolot;ical Survey 

 gaging stations are located in the basin, one on the South Branch at 

 Washington, Rhode Island (drainage area = 63. £ square miles), and the 

 other at Cranston, Rhode Island (drainage area = 200 square miles,) 

 on the main river, A 6-hour unit hydrograph for the Pawtuxet River 

 at Cranston x-ras developed from the September 195U and October 1955 

 floods, and from the discharge records obtained from the Scituate 

 and Flat River Reser\'-oirE, The 6-hour imit hydrograph at the mouth 

 of the Pawtuxet River was- obtained fro:~i. the oranston "onit graph by 

 increasing the volume to give one inch of runoff from tlie total 

 drainage area. No lag was used for the [,,5 mile reach between the 

 gage and the mouth as it was assumed that it would be offset by the 

 local runoff. The rainfall distribution for the transposed Sep- 

 tember 1938 flood, using the Corps of Engineers' design criteria, 

 was the residual rainfall depending on the location at which the 

 total runoff was desired, i,e., at Conimicut Point, or for the Middle 

 or Lower Bay, In each case, the storm was considered to be centered 

 over the Blackstone River Basin, For Coniinicut Point, therefore, the 

 residual rainfall (13,5 inches occurring in a 72 -hour period) was 

 applied to the drainage areas with a combined area of 370 square miles. 

 For the Iliddle and Lower Bay sites, the accumulative rainfall amounted 

 to 13,0 inches over an area of 1,250 square miles. The rainfall excess 

 was applied to the unit hydrograph after deducting the infiltration at 

 a rate of 0,1 inch per hour (see Table G-U). 



d, Taunton River . This river, with a drainage area of 550 

 square miles, including Watuppa Pond, flows in a general southerly 

 direction into floiont Hope Bay op-oosite Fall River, Massachusetts , 

 Its principal tributary is the Three Ilile River, wlxLch drains 85,5 

 square miles. There is a U, S, Geological Survey gaging station on 

 the main river at State Farm, Massachusetts (drainage area = 260 

 square miles), and on the VJading River, a tributary of the Three 



