Temporary Concrete Traffic Barriers (TCTBs) are essential in order to protect the traveling public and highway construction crews from accidents due to driver misfortune or negligence. In order for TCTBs to be installed, however, they must be successfully crash tested. Barrier height and drainage open space are key characteristics that influence this crash test rating. This is because an increase in height will insure that a vehicle will not over-top the barrier and a decrease in drainage open space will result in greater barrier mass, which will in turn resist larger impact forces. The factors that increase the crash worthiness of a barrier, however, lead to poor hydraulic performance. This then becomes a concern if barriers are placed in areas where they may adversely impact the local floodplain elevation. The objective of this research is the development of a hydraulic rating curve that describes the relationship between upstream energy head and the flow rate passing the barrier. To accomplish this objective, a three parameter model with three unknown coefficient terms was utilized. The model was then fit to experimentally obtained data, and a rating curve was developed. In addition, the effects of downstream submergence and clogging of the drainage opening, with respect to the rating curve, was also analyzed. Finally, a method for using this information in the hydraulic modeling software HEC-RAS was developed. / text