mr. aaron salzberg. before i turn it over to ms. castle, let me ask the chairman if he'd like to make any remarks at the start. >> i really didn't have any opening statement. i'm glad to be here to learn what i can from these witnesses. i think it's an important issue. one we need to understand much better. so thank you for having the hearing. >> thank you. ms. castle. >> thank you. thank you for inviting me to be here today to talk to you about the department of the interior's undertakings and accomplishments with respect to what are scarcity domestically and globally. i will be talking about the two agencies i work with. while it is states that allocate water supplies and control administration of use, the federal government has a very important role to play in leading the way to stainability of water resources and providing the tools that we need to get there. the usgs is best known in the world of water for the over 7,000 stream gauges that they operate deployed all across the country. those stream gauges provide with realtime i