From Water Balance to Action
Purpose
This page defines bankability to Great Salt Lake and explains how a proposed conservation, dedication, delivery, operational change, or reduction in depletion can be evaluated for its measurable physical effect at the lake. Its purpose is to distinguish the amount of water reported or claimed by an action from the amount that actually reaches or remains within the defined lake system.
The Great Salt Lake water ledger provides the physical foundation for that evaluation. It describes how measured and estimated inputs, losses, and storage changes reconcile under the canonical annual identity:
Ending Storage = Beginning Storage + Net Inflow + Lake Precipitation − Lake Evaporation − Mineral Depletions
Once that balance is established, a second question follows: if an action is intended to benefit Great Salt Lake, how much additional water will actually reach or remain in the lake, when will that benefit occur, and how durable will it be?
The difference between a reported or claimed water benefit and its measurable physical effect at the lake is the central constraint on policy, planning, and investment decisions. This framework refers to that relationship as bankability.
Bankability is the portion of a claimed, conserved, dedicated, protected, or delivered water benefit that produces measurable and durable physical lake accretion. Depending on the action, that benefit may take the form of additional Net Inflow, water retained in lake storage, or a reduction in terminal-system depletion. Its magnitude depends on the action’s effect on depletion, return flow, downstream reuse, interception, storage, routing, timing, delivery, and measurement.
As used by Great Salt Lake Accounting, water bankability is a physical accounting concept: the share of a claimed water saving, transfer, donation, or operational change that produces measurable, durable additional water in Great Salt Lake. It is distinct from water banking under the Utah Water Banking Act, which provides a legal and administrative mechanism for temporarily leasing water rights. It is also distinct from the financial use of “bankability,” which concerns whether a water infrastructure project can attract investment. A water action may be legally eligible for a water bank or financially viable without its full stated volume being bankable to Great Salt Lake; physical bankability depends on depletion avoided, return flows, location, timing, routing, and delivery to the lake.
Bankability in Water Accounting
The lake does not respond to reported savings or legal classification alone. It responds to the physical water that reaches or remains within the defined lake system. Bankability therefore evaluates the connection between an action and its resulting lake benefit while distinguishing documented physical accounting from analytical inference and policy judgment.
Bankability is an accounting and policy-evaluation concept, not a formal hydrologic classification or legal determination. It does not establish water rights, regulatory standing, or entitlement to delivery.
It is also distinct from dedicated water. Dedicated water is the legal quantity credited to Great Salt Lake through the State’s Distribution Accounting Tool (DAT). Bankability is the estimated physical lake accretion resulting from that dedication under representative operating conditions. The Dedicated Water Reconciliation page provides the order-by-order accounting between the legal quantity and the estimated physical outcome.
The Menu of Potential Water Actions
The principal controllable component of the water ledger is human depletion, but depletion reduction is not the only action capable of producing lake benefit. Potential actions also include protecting existing flow from diversion, importing water, releasing stored water, changing system operations, improving delivery, and reducing terminal-system losses.
The depletion inventory remains the appropriate starting point because it shows where water is currently consumed or removed from the system and where reductions might create additional water physically capable of reaching or remaining in Great Salt Lake. It should not be interpreted as a menu of automatically bankable quantities. Each category must still be evaluated for return flow, downstream reuse, routing, timing, control, measurement, and durability.
The table below combines 2020–2024 five-year depletion estimates from the Utah Water Budget Model, Great Salt Lake Strike Team reporting, and basin-level allocation assumptions used within this framework. These values are approximate and are presented to illustrate the location, scale, and routing characteristics of recent depletion—not to establish regulatory totals or replace the canonical 30-year accounting periods used elsewhere in the water ledger.
The basin totals follow the full Great Salt Lake Basin convention and include the Idaho and Wyoming portions of the Bear River Basin. The baseline Water Ledger uses a Utah-only convention. Direct comparison between the table and that ledger therefore requires adjustment for differences in geographic boundary, accounting period, and category definition. The Frequently Asked Questions page provides the corresponding reconciliation.
The table shows where recent estimated depletion occurs and, by extension, the pathways through which any reduction would have to move before producing lake benefit. The listed quantities are depletion estimates at their respective accounting locations, not estimates of water that could automatically be delivered to Great Salt Lake.
Municipal and industrial depletion is concentrated in the Jordan Basin, which is physically close to the lake but relies on a combination of imported surface water, groundwater, primary municipal supply, and secondary outdoor irrigation. Those sources have different return-flow pathways and accounting consequences. Outdoor use is generally more consumptive than indoor use, but the bankability of any reduction still depends on its source, location, wastewater or return-flow destination, and connection to terminal inflow.
Agricultural depletion is larger in aggregate and is heavily concentrated within the Bear River system, including areas above the Idaho–Utah state line. A reduction in upstream depletion may increase water physically available downstream, but that water must pass through intervening diversions, return-flow systems, reservoirs, wetlands, state boundaries, and operating constraints before reaching the lake. Downstream reuse, interception, storage effects, and changes in return flow may therefore reduce or delay the resulting lake benefit.
These differences reflect more than geographic distance. The Bear River can move substantial water under a range of conditions, but it also contains large upstream uses, storage operations, wetlands, and multistate governance. The Jordan system is closer to the lake but is affected by channel capacity, flood-control functions, wastewater and urban-drainage systems, Utah Lake operations, and imported-water accounting. Proximity can improve bankability, but it does not establish bankability by itself.
Accounting boundaries are consequently important. Different geographic boundaries, time periods, and category definitions may produce different depletion totals while describing overlapping portions of the same physical system. Those totals must be reconciled before they are used to estimate lake benefit.
Mineral depletion is located at or near the terminal lake system and is not subject to the same upstream routing and reuse pathways. A reduction can therefore have a direct relationship to water remaining in lake storage. Its total scale is limited relative to major upstream depletion categories, however, and the allocation between mineral-related depletion and the broader evaporation residual is approximate rather than independently measured with complete precision.
Taken together, the table illustrates why depletion volume alone does not determine lake benefit. Bankability depends on where the action occurs, what would happen to the water without the action, how the resulting water moves through the system, and what portion ultimately reaches or remains in Great Salt Lake.
Bankability Within the Water Ledger
Bankability is evaluated within the same physical accounting structure as the Great Salt Lake water ledger. An action must produce a documented change in one or more terms of the canonical storage identity and must avoid counting the same water benefit in multiple categories.
The relevant physical sequence is:
Precipitation → Basin Yield → Available Supply → Diversions and Depletions → Return and Instream Flows → Net Inflow → Lake Storage and Losses
Each proposed action enters this sequence at a particular location. An upstream action may change depletion, return flow, downstream reuse, or the timing and location of water moving through the system. A delivery or operational action may protect existing flow, alter storage or routing, or change whether water crosses the defined terminal accounting boundary. An action within the terminal lake system may affect storage directly or reduce a lake-loss term.
Bankability is determined by comparing two internally consistent cases:
- the expected physical outcome without the action; and
- the expected physical outcome with the action.
The difference between those cases is the estimated lake benefit. That comparison must use consistent boundaries, time periods, assumptions, and measurement methods.
Actions located near the terminal system often have fewer opportunities for downstream interception, reuse, or delay. Their effects may therefore be easier to trace and measure. Proximity alone, however, does not guarantee bankability. A near-lake action may still be constrained by source, return flow, infrastructure, wetland storage, operating rules, measurement uncertainty, or the absence of durable control.
Conversely, an upstream action is not inherently non-bankable. Its outcome simply depends on more intervening processes and therefore requires a longer and more carefully documented chain of physical accounting from the action to the lake.
What Determines Bankability
Bankability is governed by four principal constraints: proximity, timing, control, and measurement. Durability is the cross-cutting test of whether the resulting benefit can be sustained over time. These factors are not measures of an action’s popularity or policy importance; they describe the physical, operational, and evidentiary conditions connecting an action to Great Salt Lake.
Proximity
Proximity describes the number and character of the processes between an action and the lake—not simply its straight-line distance from the shoreline. Water originating upstream may encounter additional diversion, reuse, storage, groundwater interaction, wetlands, and operating constraints before reaching the terminal system.
This framework distinguishes two accounting zones:
- Zone 1 consists of the contributing river systems upstream of the framework’s defined terminal stream gages.
- Zone 2 is the transition between those terminal gages and the open lake, including wetlands, managed impoundments, bays, groundwater interaction, storage, and other terminal-system processes.
Crossing a Zone 1 terminal gage does not necessarily mean that the same quantity will immediately reach open-lake storage. Zone 2 can absorb, delay, release, or redirect water depending on hydrologic conditions and system operations. Proximity can reduce the number of intervening processes, but it does not eliminate the need to trace them.
Timing
Timing determines whether water moves through the system under conditions that allow the intended lake benefit to occur. Diffuse, early-season, or slowly moving water may be absorbed into soil moisture, wetlands, shallow groundwater, storage, or downstream use. Concentrated or directly routed water may be more likely to cross the terminal accounting boundary, but its outcome still depends on channel conditions, storage state, operating rules, and seasonal demand.
Timing must therefore be evaluated against the period in which the action occurs, the lag between the action and lake delivery, and the duration of the resulting benefit.
Control
Control determines whether water made available by an action remains protected through the delivery pathway. Under prior appropriation, water not used at one location may remain legally or operationally available for diversion elsewhere. Downstream users may also rely on return flows produced by existing uses.
A reduction in diversion does not necessarily create additional lake inflow. For a conservation action, the relevant quantity is generally the reduction in depletion after accounting for changes in return flow and downstream recovery. Other actions—such as imports, storage releases, protected instream delivery, or reduced terminal loss—must be evaluated according to the physical term they change and the controls that keep the resulting water available to the lake.
Shepherding is the administrative protection and routing of water through the river system toward Great Salt Lake. It can improve bankability by limiting intervening diversion, but it does not by itself establish the physical quantity delivered. The outcome still depends on the source of the water, the gages used to measure delivery, travel time, channel and reservoir operations, and conditions within Zone 2.
Measurement
Measurement determines whether the difference between the without-action and with-action cases can be observed, estimated, and independently reviewed. A bankability claim should identify:
- the quantity and location of the original depletion, flow, or loss;
- the physical change caused by the action;
- the return-flow and downstream-use response;
- the delivery pathway and applicable measurement points;
- the timing and duration of the expected lake benefit; and
- the uncertainty associated with each estimated or inferred term.
Measurement does not require every component to be directly observed. It does require observed, derived, estimated, and residual quantities to be identified accurately and supported by documented methods.
Durability
A lake benefit is durable when it persists or can be repeated across the period for which it is claimed. A one-time delivery may increase storage temporarily, but it does not establish a continuing operating condition. Likewise, a benefit that occurs only under a narrow set of hydrologic or operational circumstances should not be represented as certain across all years.
Durability therefore describes both the persistence of the action and the repeatability of its physical effect at the lake.
From Depletion to Lake Response
A reported reduction at the point of use is not the same as a resulting increase in lake inflow or storage. Bankability analysis follows the physical consequences of an action from its accounting location through return flow, downstream reuse, interception, storage, routing, timing, and terminal-system processes.
The first step is to establish the without-action condition: what portion of the water is currently depleted, what portion returns to the system, where those returns occur, and what would otherwise happen to them downstream. The second step is to evaluate how the proposed action changes that condition. Only the difference that reaches or remains within the defined lake system constitutes the estimated bankable benefit.
Large reported savings may produce comparatively small lake effects when they reduce return flow, are recovered by downstream users, or are absorbed elsewhere in the system. Conversely, a smaller action with a direct, controlled, and measurable connection to Net Inflow or lake storage may produce a more readily demonstrable lake benefit.
This does not make upstream conservation unimportant or unsuccessful. It means that conservation volume, depletion reduction, and lake accretion are different accounting quantities. Bankability analysis identifies the relationship among them and reports the uncertainty in translating one into another.
Bankability by Source
Different water-use and depletion categories have different bankability characteristics, but no category has a single bankability value that applies in every location or circumstance. The following descriptions identify typical considerations; individual actions must be evaluated against their actual source, baseline condition, return flow, routing, control, measurement, and duration.
Agricultural Use
Agricultural depletion represents the largest estimated human-depletion category in the Great Salt Lake Basin. It is also widely distributed and closely connected to return flow and downstream reuse.
A reduction in agricultural diversion is not necessarily a reduction in depletion. Changes in crop consumptive use, irrigation efficiency, irrigated acreage, water source, and return-flow timing may produce different downstream results even when the reported diversion reduction is the same.
Lower-basin agricultural actions may have shorter delivery pathways, while upstream actions may encounter additional reuse, storage, and routing processes. Agricultural bankability is therefore highly location-specific and must be evaluated from the reduction in depletion—not simply the reduction in diversion—through the resulting effect at the lake.
Municipal and Industrial Outdoor Use
Outdoor municipal and industrial use is often substantially consumptive, but its bankability depends on the source and location of the water being reduced. Surface water, groundwater, imported water, and secondary irrigation supplies may have different effects on streamflow, aquifer storage, wastewater returns, and terminal inflow.
Outdoor conservation may produce moderate or high bankability where the depletion reduction has a direct, controlled, and measurable connection to the terminal system. It may produce a smaller or delayed lake benefit where groundwater response, downstream recovery, or changes in return flow intervene.
Municipal and Industrial Indoor Use
Indoor municipal use is often less consumptive at the system level because much of the water is collected, treated, and returned through wastewater systems. Reducing indoor use may therefore reduce wastewater return flow as well as the original withdrawal.
Its bankability depends on the original water source, the location and timing of the wastewater discharge, treatment losses, reuse, and whether the returned water would otherwise contribute to Great Salt Lake. Indoor conservation commonly has low direct lake bankability, but that conclusion should be demonstrated rather than assumed for every system.
Mineral and Other Terminal-System Depletions
Mineral production and other terminal-system uses occur at or near Great Salt Lake. A reduction in water permanently removed by those activities can have a direct relationship to water remaining in lake storage because it is not subject to the same upstream routing and reuse pathways.
The total opportunity is limited relative to major upstream depletion categories, and the allocation between mineral-related depletion and the broader evaporation residual is approximate. Bankability may be high in physical proximity and control while the estimated quantity remains subject to measurement uncertainty.
Wetlands and Terminal-System Management
Wetlands, managed impoundments, and terminal-system operations occupy an intermediate position. They are physically close to the lake, but water moving through them may support habitat, enter storage, evaporate, return to the river or lake, or be released at a different time.
An operational change may improve delivery to open-lake storage while affecting habitat or other system objectives. Its bankability depends on the without-action condition, the change in storage and evaporation, the timing and location of releases, and whether the resulting lake benefit can be measured without counting the same water twice.
Bankability Matrix
The matrix below summarizes typical bankability characteristics. It is an analytical starting point, not a predetermined score for every project. The bankability of a specific action may differ materially from the general tendency shown here.
The matrix describes how readily different types of actions may translate into measurable physical lake benefit. It does not rank actions by social importance, legal priority, cost-effectiveness, ecological value, or total potential volume.
A category identified as having a high typical tendency still requires an action-specific baseline, physical pathway, measurement method, and durability assessment. Likewise, an action in a lower or more variable category may produce bankable water if its source, location, control, routing, and measurement establish a defensible connection to Great Salt Lake.
Bankability is therefore an evaluated outcome—not an attribute assigned permanently to an action type.
Supporting a Durable Operating Floor
The water ledger shows that Great Salt Lake elevation reflects the balance among Net Inflow, direct lake precipitation, evaporation, mineral depletion, and changes in storage. Climate strongly influences the lake’s long-term operating range, while human depletion and water-management decisions influence where the lake operates within that range.
Bankable water is the portion of a proposed action that can be demonstrated to improve that physical balance. It may increase Net Inflow, retain water in storage, or reduce a terminal-system loss. A bankable action can therefore contribute to or support a higher operating condition.
No individual action establishes a durable operating floor merely because it is classified as bankable. A durable floor requires sufficient aggregate water, sustained over time, to refill any storage deficit and maintain the intended elevation under the applicable climate and evaporation regime. The amount required may change with lake area, climate, timing, and the persistence of the contributing actions.
Actions with lower or uncertain direct lake bankability may still provide important economic, ecological, operational, water-supply, or social benefits. Those benefits should be described on their own terms rather than represented automatically as measurable lake inflow.
Bankability identifies the portion of an action that can defensibly be connected to the Great Salt Lake water balance. It does not determine whether the action is worthwhile, how it should be prioritized, or what combination of actions is sufficient to achieve a policy target.
Practical Application
The Great Salt Lake Factsheet evaluates proposed water actions through four questions. The same sequence applies here to municipal and industrial conservation, agricultural optimization, leasing, donations, operational changes, and other proposed lake benefits.
1. Source
Where is the water coming from?
Identify the water source, location, existing use, and accounting category affected by the action. Distinguish diversion, depletion, return flow, protected delivery, Net Inflow, lake storage, and terminal-system loss. The quantity reported by the action should not be assumed to equal its lake benefit.
2. Pathway
What would happen to this water without the action?
Establish the without-action condition, including depletion, return flow, downstream reuse, storage, groundwater interaction, routing, and terminal-system effects. Then identify how the proposed action changes that pathway and how the resulting water remains protected from intervening diversion, interception, or reassignment.
3. Timing
Does the action produce water in dry years, wet years, or both?
Identify when the physical effect occurs, how long delivery takes, and whether the benefit is one-time, seasonal, condition-dependent, or repeatable. An action that performs differently under wet and dry conditions should report those outcomes separately rather than presenting a single quantity as universally available.
4. Bankability
What portion is likely to reach or remain in Great Salt Lake?
Estimate the physical lake accretion separately from the action’s gross diversion reduction, reported savings, legal dedication, or released quantity. Identify how the benefit will be measured, the period for which it is claimed, and the uncertainty associated with the calculation.
Legality and bankability are related but distinct. Legal analysis asks whether an action can be implemented and protected within the water-rights system. Bankability asks whether it produces a measurable and durable physical effect at Great Salt Lake. Strong proposals must address both.
Key Takeaway
Bankable water can help establish and support a durable operating floor for Great Salt Lake. The relevant question is not only how much water an action conserves, dedicates, or releases. It is how much additional water reaches or remains in the lake, when that benefit occurs, whether it can be measured, and whether it can be sustained.
That documented difference between the stated action and its physical lake benefit is bankability.
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© 2026 GSL Accounting · Version 1.1 (August 2026). Content may be shared or cited with attribution. Built by humans with AI assistance for data validation and drafting, and grounded in public data; analytical judgments and conclusions are the authors’ own. See the Changelog for revision history and archived change notes.