map of the Roughans Point area showing locations of both existing and proposed 

 sources of outflow from the area. 



70. There are two existing storm drainage outlets. The largest drain, 

 a 42-in. diam pipe, runs to the west under Revere Beach Parkway at the 

 southwest corner of Roughans Point. The other outlet is an 18-in. diam 

 flat-gated drain which discharges into the ocean at the south end of Broad 

 Sound Avenue. Two proposed improvements, both located at the existing pumping 

 station, are an improved pump intake and a new gravity drain (42 in. diam) 

 into the ocean through reach E. 



71. Especially for existing conditions, the water levels inside 

 Roughans Point can reach elevations which are higher than the existing wall at 

 reach D (10.5 ft NGVD). Since the inside water level at these times would be 

 higher than the ocean level, water would flow out over this wall section dur- 

 ing peak flooding. This occurs with maximum interior water levels greater 

 than approximately a 40-year return period. Also, at the western edge of the 

 Roughans Point area, there are at least two locations where, at high water 

 levels, water would flow over and under Revere Beach Parkway and into an ad- 

 jacent drainage area. This outflow was modeled using weir equations. 



72. The existing pumping station was built in 1975. The station has 

 three pumps with a combined capacity of 48 cfs. However, with the existing 

 intakes, the capacity is reduced to approximately 38 cfs. As was stated 

 above, proposed improvements to the intakes for the pumping station are 

 planned. The pumping station was inoperative during most of the February 1978 

 storm because of electric power failure. Also, if a severe storm is forecast 

 the pumping station might not be operational after the evacuation of the area. 



73. Loss of water from the interior of Roughans Point will also occur 

 because of infiltration into the ground and seepage through the walls back out 

 into the ocean. The seepage rate should be highest at low tide and when the 

 interior levels are near the top of wall at reach D, where the ground appears 

 especially porous. 



74. Four basic equations (13-16) were used in the flood routing calcu- 

 lations. Equations 13-16 and the accompanying coefficients used to calculate 

 the outflows from the interior of Roughans Point during times of overtopping 

 were supplied by NED and were based upon their knowledge of drainage and 

 hydrologic characteristics of the interior of Roughans Point. Drainage and 

 seepage were calculated by Equation 13. Weir outflow was calculated when the 



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