Check out river levels for Colorado at this hot link for stats that really dial you in to what is going on with the river levels for around 280 points at major rivers for Colorado River Rafting and any water hobbies you do on the rivers. You get the full stats from graphs to info on feet of water for every major river.
Real-time data typically are recorded at 15-60 minute intervals, stored onsite, and then transmitted to USGS offices every 1 to 4 hours, depending on the data relay technique used. Recording and transmission times may be more frequent during critical events. Data from real-time sites are relayed to USGS offices via satellite, telephone, and/or radio and are available for viewing within minutes of arrival.