User story: as a water resources manager, I want to know how water availability this year compares to previous years for critical water supplies in my region.

task: code should enable creating site-level stream flow hydrographs for a particular water year with summary statistics for that year, including:

• highest cumulative flow recorded
• lowest cumulative flow recorded
• cumulative flow between daily 25-75 percentiles
• cumulative flow of daily median
• observed cumulative flow

Water Watch example: https://waterwatch.usgs.gov/index.php?id=wwdur_cumflow