Document: NRC Regulatory Guide
Document ID: a094549d-8685-4dad-b90f-c28c7d279a53
Document Type: regulatory_guide
Title: Geologic and Geotechnical Site Characterization Investigations for Nuclear Power Plants + HISTORY – HISTORY 08/2021 – DG-1392 , Proposed Revision 3 07/2014 – Periodic Review of Revision 2 – Reviewed with no issues identified 02/2001 – DG-1101 , Proposed Revision 2 (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2119/ML21194A176.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.132
CFR Part: 
CFR Title: 

Content:
provides guidance on the design and installation of ground water monitoring wells. Types of piezometers, construction details, and sounding devices are described in EM 1110-2-1908, “Instrumentation of Embankment Dams and Levees,” issued 1995 (Ref. 28). Ground water conditions should be observed during site investigations, and water level measurements should be taken in exploratory borings. Ground water or drilling mud level should be measured at the start of each workday for borings in progress, at the completion of drilling, and when water levels in the borings have stabilized. Ground water observation wells should be installed in as many locations as needed to adequately define the ground water environment. Pumping tests are preferred for evaluating local permeability and conductivity parameters and the level of confinement between aquifers. These parameters are input into calculations for assessing dewatering requirements for construction and operation of the plant. For major excavations where construction dewatering is required, piezometers or observation wells should be used during construction to monitor the ground water surface and pore pressures beneath the excavation and in the adjacent ground. This guide does not cover ground water monitoring during construction of plants that are designed with permanent dewatering systems. DG-1392, Page 22 In areas where perched ground water tables or artesian aquifer systems are expected, piezometers should be installed in each ground water element so that the piezometric level can be determined for the particular aquifer or ground water unit. Care should be taken in the design and installation of piezometers to prevent hydraulic communication between aquifers. The occurrence of artesian pressure in borings should be noted on boring logs, and the artesian heads should be measured and logged. 6. Construction Mapping It is necessary to confirm that in situ conditions revealed in excavations for safety-related