Example of type B-l specifications (dewatering and pressure relief)

a. Scope. This section covers furnishing, installa­tion, operation, maintenance, and removal of the jet- eductor wellpoint and pressure relief well systems, as subsequently specified in this section; control of any seepage from the soils above the bottom of the excava­tion not intercepted by the jet-eductor wellpoint sys­tem deemed necessary by the Contractor to permit in­stallation of the sheeting shown to grade as specified; pumping of surface water or seepage through the sheeting during excavation or after the jet-eductor de­watering system is turned off or removed; and install­ing any additional pressure relief wells, pumps, and appurtenances, if necessary, to maintain the hydro­static water level in the clayey silty sand and sandy silt (semipervious) stratum (about el 235± 1 foot) beneath the excavation at all times.

b. Responsibility. The Contractor shall be fully re­sponsible for furnishing, installing, operating, main­taining, and removing all wellpoint, pressure relief, and seepage or surface water control systems. How­ever, any pressure relief wells, pumps, piping, and electrical wiring and controls required to lower and maintain the hydrostatic water level in the semiper­vious stratum below the bottom of the excavation, oth­er than the pressure relief system specified, will be paid for as an extra.

(1) The Contractor shall be responsible for:

(a) Installing and testing the wellpoint and pres­sure relief systems as specified.

(b) Dewatering or controlling any seepage from the soils above the bottom of the excavation so that the sheeting may be installed without any significant sloughing of earth during excavation and placement of sheeting and pea gravel backpack.

(c) Maintaining the hydrostatic water level in the semipervious stratum below elevation 250.0 feet at all times.

(d) Maintaining the bottom of the excavation free of all seepage or surface water until the structural mat has been placed and the waterproofing installed up to the top of the mat.

(e) Operating, maintaining, and monitoring the wellpoint and pressure relief well systems. System maintenance shall include but not be limited to at least daily supervision by someone skilled in the operation, maintenance, and replacement of system components; at least one spare submersible pump and controls and one pressure pump of the same capacity as specified; and any other work required by the Contracting Offi­cer to maintain the excavation in a dewatered and hydrostatically relieved condition. Dewatering and pressure relief shall be a continuous operation and in­terruptions due to power outages, or any other reason, shall not be permitted. Some responsible person shall also monitor the dewatering sump pumping, and pumping the relief wells continuously until the suc­ceeding contractor assumes the responsibility for such, and the Contractor has received a written instructive that he or she is no longer responsible for this oper­ation.

(2) The Contractor shall also be fully responsible for any failure of any component of the systems. The Contractor shall be responsible for all damages to work in the excavation area and for damages to any other area caused by failure to maintain and operate the dewatering and pressure relief systems as speci­fied.