Level loop 6 was eliminated. The value of benchmark IV-24 was determined in Loop 10 was used in Loop 23. Level loops were begun in April 1998 and completed in May 1998. The value of benchmark V-36 as determined in Loop 10 was used in Loop 22. The value Loop 22 was readjusted resulting in the value of benchmark IV-43 changing.
Elevations are subject to change over time due to earth subsidence, construction activity, etc.