Hydrohistorian
Lesson E3 · Changing a Right · transfers & change cases
Augmentation plans
AugmentationReplacing water depleted out of priority -- usually by a well -- with water from another source, under a court-approved plan. is prior appropriation’s pressure valve: a court-approved plan under which a junior keeps diverting out of priority by replacing the water it takes, so seniors are made whole. No concept better separates people who have read about Colorado water from people who work in it.
The deal, and why it is hard
The junior must replace its depletions — not what it diverts, what the stream actually loses, net of returns — in the right amount, at the right place, at the right time. Time is the hard part: a well’s depletions arrive on a lagged schedule (lesson D3), so the plan must deliver replacement water on that schedule, drought years included. Replacement supplies are themselves water rights — storage releases, changed senior rights, reusable effluent, leases — which is why augmentation demand is a standing engine of change cases (lesson E2).
The decree that approves a plan fixes its accounting forever after: measurement, reporting, and what happens when replacement runs short. In wide swaths of the South Platte basin, a well without a plan (or membership in one, like GASP’s successors) simply does not pump lawfully during the call season — the 1969 settlement (lesson D1) working exactly as designed.
Where you see it in the data
Augmentation appears throughout the record once you know its signature: AUG among a right’s decreed uses, structures diverting steadily through standing calls, and case after case in a structure’s court history amending someone’s plan. Our pages report those facts; whether a given diversion was covered by a plan on a given day is DWR’s accounting, not ours.
What this does not let you conclude
Plan terms live in decrees we do not parse: this site can show that a structure holds augmentation uses or shares plan-related cases, but never whether today’s diversion was in or out of compliance with a plan’s accounting. Advisory reading aid on public data — never an administrative or legal conclusion, and never a substitute for DWR administration or an engineer’s analysis. Our methodology has not yet had outside expert review: how this is built.