Guys, if you live in Texas the below link looks like a very valuable resource. It is a topographical map and you click where you want to put a culvert and it will determine the acres of runoff, elevation change and will even calculate the required culvert size. I am sure other states have a similar resource. This could also be very handy when preparing to build a pond and determining the acres of watershed that feeds the pond.

http://tfsfrd.tamu.edu/planmylandoperation/

The below FEMA document also has tips and best practices for Bridges, Culverts and Low Water Crossings.

https://www.fema.gov/media-library-data/20130726-1724-25045-9448/fema_p_778_508compliant.pdf

Last edited by N.TexasHalfAcre; 09/26/19 04:33 PM.
NTHA - North Texas Half Acre
Cattle Ranch Ponds