and . If the water level measured represents a static level, this field is blank Description Water level was affected by atmospheric pressure Water level was affected by tide stage. For a more complex query, use readNWISdata, including an argument service="gwlevels". If the nwis parameter site_no is supplied, it will overwrite the site parameter. List of parameter code names, and help finding a code. 2 KB xlsx) - Turbidity parameter codes and methods codes (May 2012) Turbidty Codes January 2007 (69. The code is written in C++ and is a formulation and expansion of the algorithms included in PEST, a widely used parameter estimation code written in Fortran.