Kim duToit announces, correctly, that attrit and surveil are not words. They are sawed-off verbs made from Pentagonese nouns. I have been observed using the former, just last Wednesday in fact, but I have resolutely refused to use the latter.
I would direct your attention, however, to the usage based on. The word based in this case is a past participle. Without feverishly rifling through Strunk and White, I don't think one can cast a sentence with two participles in a row, one modifying the next.
" . . . our procedures must be modified based on the current situation"is not acceptable, and causes the listener to grit one's teeth. How about "modified on the basis of"?