After the severe drought of 2016, which resulted in what is still the poorest water quality we have recorded in 11 years of monitoring at Island Park Dam—as well as the lowest reservoir drawdown since 2007—HFF started laying the scientific foundation for what we would eventually call “precision water management.” In its first seven years, that collaborative program has decreased drawdown of Island Park Reservoir by an average of 23,941 ac-ft and increased winter flow by an average of 100 cfs. See blog posts summarizing water year 2024 and the winter of 2025.
One of the centerpieces of the precision water management program is the daily water report, which I first issued to a small group of water managers and water users in early 2017. The daily email distribution list has grown to over 370 subscribers, which include water users, water managers, anglers, fishing outfitters and guides, local journalists, scientists, nonprofit colleagues, weather enthusiasts and others.
Every day, we run a set of computer code that automatically downloads and compiles around 220 pieces of daily climate and water data from a variety of sources, including our own stream gages. In the summer, we download and compile an additional 60+ data points from HFF’s water-quality network. Many of the daily data values come to us as 15-minute observations, meaning that 96 individual observations are summarized to produce a single daily value. No matter how you count it, we automatically download and process many thousands of data points each day, amounting to millions each year. While HFF staff have written every one of the thousands of lines of computer code that do this, we are greatly reliant on state and federal agencies that collect most of that data and make it available for free to anyone who has an internet connection.
Here are the primary sources of that data, including links to the agency websites and portals. Full disclosure—our computer code primarily uses backdoor pathways provided specifically for automated download by the agencies, although we do access some of the data directly through internet address strings that can be built and accessed through the links below.
In addition to numerical data that form the core of the water report, we also rely on a variety of weather and climate products, most provided by the National Oceanic and Atmospheric Administration (NOAA). We also rely heavily on the U.S. Drought Monitor, a collaborative project of the University of Nebraska and several federal agencies. Real-time data from local weather stations, including HFF’s, are also used to downscale these broader-scale products to provide accurate watershed-specific forecasts.
The 220 pieces of raw daily water and climate data generate well over 400 pieces of daily output that range from simple measures such as the mean daily streamflow at Island Park Dam to complex drought indicators such as the one-year accumulated difference between precipitation and evapotranspiration. Whether you just missed today’s report or aren’t on the email list, you can access, view and download all of this information at the online version of the water report and at HFF’s water quantity dashboard. From either of those locations, you can access the rest of HFF’s online data websites and modeling tools.
The content and narrative text of the water report varies from season to season and across days of the week. If you are a long-time reader, you know the drill. If not, here’s a brief guide to daily and seasonal content.
Download the full water report data guide and disclaimer here.
As it is the afternoon of December 31, I am closing the year with my annual fish-of-the-month blog, this one at the end of my 11th year of catching a fish in my home waters in each month of the year. To spare you the math, that’s 132 consecutive months of catching a wild trout or whitefish (and in some years I’ve fair-caught suckers and shiners, too) within a three-hour drive of my home in
In this blog post, we 1) present our turbidity and suspended sediment data, 2) explain our suspended load calculations, and 3) provide some additional information justifying why we think that a substantial amount of bed load was transported into the Henry’s Fork in addition to the suspended load. Since first observing high turbidity in Thurmon Creek and the Henry’s Fork downstream associated with the Silver Lake drawdown in November 2025, HFF’s Science and Technology team
Written by Doris Squeri Tom and I met on our first day of grad school back in 1982. We were both broke and stressed, and we both loved the outdoors, so I decided that an affordable way to relieve some of that stress might be to learn how to fly-fish. We had learned to fish with our dads when we were very small, but it was bait fishing, and we wanted to try something new.
The Henry’s Fork Drought Management Planning Committee (DMPC) met on Monday, November 24 to set this winter’s outflow and reservoir-fill strategy for Island Park Reservoir—an annual decision with implications for winter trout habitat in Box Canyon and the Ranch. Winter Outflow: What’s Coming on December 1 Beginning December 1, outflow from Island Park Dam will increase, bringing winter streamflow through Box Canyon to ~380 cfs from December through February*. That equates to 76% of Box
