Wood River Levee District Relief Wells and Pump Stations Install

The work includes installation of approximately twenty two (22) partially penetrating relief wells, four (4) Pump stations, three (3) Piezometers, a collection ditch, ditch formation and regarding, and riprap erosion control in Madison County, Illinois. The levee system is located along the east bank of the Mississippi River between river miles 195 and 199. The proposed project is located at the south end of the levee district along the right descending bank of the Cahokia Creek Diversion Canal.  The wells are D-type, 10-inch diameter and approximately 65 to 90 feet deep. The wells are to be constructed of stainless steel riser pipe and well screen sections. The well screen shall be of the continuous slot, wire-wound design. The riser pipe roundness, wall thickness, and straightness shall meet ASTM A312 specifications. The screened portion of the well shall be surrounded by a filter pack composed of a washed sand composed of hard, noncarbonated, tough, durable, and uniformly graded particles free from adherent coating. The filter pack shall be placed in a tremie hopper so that filter material will feed freely and equally to two tremie pipes located at 180 degrees on each side of the screen. Following placement of filter pack materials, the relief wells shall be developed and pump tested for a minimum of two hours to determine the efficiency of the new wells. After each new well has been developed and tested, the annular space above the filter pack shall be backfilled by extending the filer pack a minimum of five feet above the top of screen, sealing with a five foot seal of bentonite pellets or chips. The remainder of the space up to the base of the concrete pad shall be backfilled with concrete grout. The work is anticipated to be performed on land adjacent to the levee toe. The four (4) proposed pump stations are located at approximate levee stations of 446+50, 463+75, 505+00, and 530+45 will be soil founded with each station having a discharge range between 19 - 35 CFS.  Additional features include pavement restoration, stone protection, chain link fencing, inlet channels, holding bays, trash racks, sluice gates, power distribution, pump control systems, station lighting, grounding and lightning protection, variable frequency drives, and formed suction inlets.  All existing infrastructure will remain and continue to function as originally intended.