Romac Pipe OD charthttp://www.romac.net/PUBLICATIONS/BROCHURES/ROMAC-OD-WALL-CHART.pdf
Friction loss chart
https://www.rainbird.com/professionals/friction-loss-charts
pvc pipe pressure ratings
http://www.heritageplastics.com/pvc-water-plumbing-pipe-west/
evapotranspiration info
https://www.usbr.gov/pn/agrimet/etsummary.html?station=hoxo&year=2020
USDA crop prices
https://www.nass.usda.gov/Charts_and_Maps/Agricultural_Prices/index.php