GARY, IN -- BORMAN PARK
OWNER: Indiana-American Water Company
LOCATION: Gary, IN
VALUE: $40,409,328.00
Construction of 15, 817 feet of 11-6 inch diameter hard rock tunnel from the main water treatment facility in Gary to a point 5,000 feet offshore in Lake Michigan to provide a new water intake to the City of Gary and surrounding communities
Kenny acquired a new 11’-6” Robbins hard rock TBM in order to meet the completion date of a very tight schedule.
The main shaft was constructed with a thirty- foot diameter concrete drop caisson in order to overcome the wet sands and super-soft clays encountered at the site. After sinking the caisson to rock at 123 feet deep, the lower section of the future pump station was blasted to over 225 feet deep and expanded to allow the installation of the TBM and trailing gear. This shaft was finished and plumbed to include six main feed pumps to the adjacent water treatment facility.
The main tunnel drive encountered difficult ground conditions and high water inflows requiring extensive rock bolting and shotcrete support. Kenny forces successfully completed the drive within inches of alignment to connect to the lake shaft one mile out under Lake Michigan. A high speed tunnel concrete lining operation then proceeded to advance 210 lineal feet of lining per day in order to make up valuable schedule.
The Pump Station was constructed on the surface while the tunnel completion occurred simultaneously as Kenny forces installed the required piping, main feed pumps, chemical application lines and prepared final connections to the Pump Station and Lake Shaft. The pump station was finished with 5 turbine pumps with preparations to add a 6th at a later date. Three pumps rated at 13,900 gpm and two pumps rated at 8,300 gpm. There is provision for a fourth large pump. The total installed capacity is currently 58,300 gpm or 83,952,000 gpd.
The Lake Michigan Intake Structure and Crib was drilled from both floating equipment and a fixed platform established in 60 feet of water one mile offshore. The shaft required drilling in both overburden and rock to the 225 foot tunnel level with grouting to secure the shaft prior to the arrival of the TBM. The large wooden crib intake structure is 60 feet by 60 feet to secure the safety and lake flow around the shaft. Miners removed the bottom plug and divers removing the Lake Shaft top bulkhead with tunnel flooding occurring in May, 2003. Full operation of the Borman Park Pump Station in commercial operation was May 30, 2003.