Determination and redetermination are critical components of a unitization agreement. The negotiation and renegotiation of the share allocation system enable parties to update the agreement as new information or technology appears. Several accepted methods of redetermination have developed in the oil and gas context, but none currently exist for aquifers. Some examples do appear to approach direct and indirect methods of aquifer redetermination. Examples of direct methods would involve the proven availability of groundwater or available rights to storage within the aquifer. Examples of indirect methods include allocations determined by modeling of geologic conditions, pooled reductions in groundwater extraction, or refinements in a management plan that allocates extraction rates.