a long narrow land-filled peninsula but has been subsequently expanded many times to accommodate development. Exiting the tunnel, the sewage was pumped through Squantum Neck and reached holding tanks on Moon Island through another conduit placed under the embankment from Squantum to Moon Island. The sand and gravel needed to complete this project was stripped from Half Moon Island, a crescent-shaped island that was located near the mouth of Black's Creek in Quincy Bay. Four huge cut-granite storage tanks with a capacity were built by the Cape Ann Granite Company to handle the sewage. These vats were formed by digging out the northern section of the hill and cementing and bricking the sides of the excavation. This reservoir was divided into four compartments, each with inlets and four outlets. The tanks were 900 by and deep. The bottoms were seven feet thick and were grooved to ease the removal of sludge. At one end was a gatehouse. The tank outlets were connected with a power pump and a turbine that was used to open the gates of the outflow pipe. The diameter outflow conduit extended into the harbor from the northern end of Moon Island. The Sewage Plant was completed in 1884 at a cost of $6-million. The original operating plan was to collect the raw sewage in the four storage tanks during times of high water and, then, two hours after the start of ebb tide, the sewage would be discharged into the harbor. This allowed approximately four hours until slack water. The total outflow time was three to four hours per cycle or six to eight hours per 24-hour period. Boston Harbor normally has two tide and current cycles each day. The expectation was that the effluent would flow between Long and Rainsford Islands, through a small gut between Gallops and Georges Island, then out through Black Rock Channel and Nantasket Roads. As time passed, the population of Boston expanded and additional communities were added to the system. The discharge of sewage at Moon Island required longer and longer outflow periods. The situation worsened until the incoming tides distributed the unprocessed sewage throughout the sand flats and beaches of Boston Harbor and Quincy Bay. In 1889, The Metropolitan Sewerage District (MSD) was formed to build one of the first regional sewer systems in the United States. The system continued to expand through the early 20th century. The Moon