where can I find benchmark locations in Brazoria County, Tx
benchmarks in brazoria county tx
http://www.ngs.noaa.gov/NGSDataExplorer/ is a good place to start.
You could also download DSWORLD and plot all the benchmarks in the county in Google Earth.
http://www.ngs.noaa.gov/PC_PROD/PARTNERS/DSWORLD/DSWorldV307.zip
What order, which class, which adjustment, which agency ?
You can retrieve monuments of all types published by the NGS at: http://www.ngs.noaa.gov/cgi-bin/ds_county.prl
I encourage to read the file ngsdata.txt linke from each datasheet. It explains the contents of the datasheets. It explains, for example, what a VERTCON height versus an ADJUSTED height. Many problems would be resolved if folks took the trouble to understand the contents.
Given the problems with vertical control in eastern coastal Texas, you might want to contact one of the two NGS advisors to Texas. The one in Corpus Christi works directly with the Texas Spatial Reference Center hosted by the University. See: http://www.ngs.noaa.gov/ADVISORS/AllStates.shtml#TX
Wherever you get your data be sure to get details about its characteristics.
Good luck,
DMM
Be aware that whatever you find the published datum will most likely be wrong.
The reasons is subsidence.
The last leveling should be less than a month old to have any chance of accuracy.