The crest of a standard, USBR 90°V-notch weir is 3 feet above the bottom of an irrigation channel. It is used to measure 25.6 cfs of flow to a customer. At this flow rate, the depth of water upstream of the weir is at the channel capacity. If the customer needs to increase the flow rate to 33.3 cfs, what is the required crest length of a standard, contracted horizontal weir (with the same crest height) that will accommodate the new demand without flooding the upstream channel?