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Plans for augmentation
An augmentation plan is a court-approved way to keep diverting when you are out of priority, by putting replacement water back into the stream. You calculate what your diversion takes from the river, when and where it takes it, and then deliver an equivalent amount so no senior right notices the difference. C.R.S. § 37-92-103(9)
In over-appropriated basins — most of the South Platte and Arkansas — augmentation is not an exotic option. It is the ordinary price of new water use, and often the largest single cost of developing rural property.
The problem augmentation solves
On a fully appropriated stream, every drop is already spoken for by older rights. A new well or a new diversion is therefore always out of priority in a dry year, and prior appropriation says it must shut down when a call comes on. That is unworkable for a house, a subdivision, or a gravel pit, none of which can switch off for six weeks in August.
Augmentation resolves it. Rather than curtailing your diversion, you replace the water it removes, at the time and place the senior needs it. The senior is made whole; you keep pumping.
The statutory definition is deliberately open-ended
"Plan for augmentation" means a detailed program, which may be either temporary or perpetual in duration, to increase the supply of water available for beneficial use in a division or portion thereof by the development of new or alternate means or points of diversion, by a pooling of water resources, by water exchange projects, by providing substitute supplies of water, by the development of new sources of water, or by any other appropriate means.
"By any other appropriate means" is doing real work there — Colorado engineers have built augmentation plans out of purchased ditch shares, reservoir releases, recharge ponds, leased water, retired irrigation, and treated effluent.
The same definition carves out two things that look like new water but are not:
"Plan for augmentation" does not include the salvage of tributary waters by the eradication of phreatophytes, nor does it include the use of tributary water collected from land surfaces that have been made impermeable, thereby increasing the runoff but not adding to the existing supply of tributary water.
Both exclusions rest on the same logic: rearranging water that was already in the system does not create any. Killing the willows along a creek, or paving a parking lot so more runs off, changes timing, not supply.
What a plan has to prove
The test is the ordinary water-court test, and it is the only one:
A change of water right, implementation of a rotational crop management contract, or plan for augmentation, including water exchange project, shall be approved if such change, contract, or plan will not injuriously affect the owner of or persons entitled to use water under a vested water right or a decreed conditional water right.
Proving no injury takes four pieces of engineering, and this is where the money goes:
- Depletions. How much water your use actually removes from the stream — not how much you divert. A house on a septic system returns most of its indoor water to the ground; lawn irrigation returns very little.
- Timing and location. Pumping in July may not reach the river until the following spring. The model has to say when and where the depletion arrives.
- Replacement supply. Water you own and can deliver, of the right amount, at the right time, at the right place — usually shares, storage, or a recharge credit.
- Accounting. How you will measure and report it, forever. Decrees come with accounting obligations that outlive the people who negotiated them.
Where to get the replacement water
Most people do not build a plan from scratch. The common routes are:
- Join an augmentation association or water district plan. Many over-appropriated areas have umbrella plans that individual well owners buy into annually. Far cheaper than a private decree.
- Buy ditch shares and change them. Purchase an agricultural right, run a change case, and dedicate its historical consumptive use to augmentation.
- Contract for stored water from a reservoir or provider.
- Recharge. Deliver water to a recharge pond so it returns to the alluvium on a timed schedule that matches your depletions.
Substitute water supply plans: the interim option
Water court takes time, and some uses cannot wait. The State Engineer may approve a substitute water supply plan — a temporary administrative approval that lets replacement operate while a court application is pending, or for short-term needs C.R.S. § 37-92-308. It is an interim measure, not a permanent substitute for a decree, and it is administered by DWR rather than the court. DWR · augmentation plans
Filing one
An augmentation plan is applied for in water court like any other water matter, on a verified application to the water clerk C.R.S. § 37-92-302(1)(a) — and the filing fee is doubled, the same as for a change of water right C.R.S. § 37-92-302(1)(d)(I). Expect opposition from downstream seniors and from the division engineer as a matter of course; that is the system working, and it usually ends in negotiated decree conditions rather than a trial. How adjudication works covers the sequence, and the rest of the legal section covers the surrounding machinery.
Common questions
What is a plan for augmentation in Colorado?
It is a court-approved program that replaces the water an out-of-priority diversion depletes from the stream, so senior rights are not injured. C.R.S. § 37-92-103(9) defines it broadly — new or alternate points of diversion, pooling, exchanges, substitute supplies, new sources, or any other appropriate means.
Do I need an augmentation plan for my well?
Not if the well is an exempt well permitted under C.R.S. § 37-92-602 — those sit outside priority administration. Any non-exempt well in an over-appropriated basin generally does need one, either its own decreed plan or membership in an augmentation association's plan, because its depletions must be replaced.
What does an augmentation plan cost?
The cost is dominated by the replacement water itself, which must be owned permanently, plus consulting engineering and water court work. It commonly exceeds the cost of drilling the well. Joining an existing augmentation association plan is usually far cheaper than obtaining a private decree.
What is a substitute water supply plan?
A temporary approval by the State Engineer under C.R.S. § 37-92-308 that allows replacement water to operate while a water court application is pending or for short-term needs. It is administered by the Division of Water Resources rather than the water court and does not replace a decreed plan.
Can I augment by clearing vegetation or paving?
No. C.R.S. § 37-92-103(9) expressly excludes both salvage of tributary water by eradicating phreatophytes and the use of runoff from surfaces made impermeable, on the basis that neither adds to the existing supply of tributary water.
Primary sources
- C.R.S. § 37-92-103(9) — definition of plan for augmentation (Title 37, official text) C.R.S. 2025 edition
- C.R.S. § 37-92-305(3) — no-injury standard (Title 37, official text) C.R.S. 2025 edition
- C.R.S. § 37-92-308 — substitute water supply plans (Title 37, official text) C.R.S. 2025 edition
- Colorado Division of Water Resources — augmentation plans read July 22, 2026