ABSTRACT
It is not surprising that conjunctive management is practiced in Arizona, California, and Colorado. All three states have the necessary physical components of groundwater basins that can be combined with surface water impoundment and conveyance facilities. In all three states, growing populations and intensive agriculture have strained the existing and erratic water supplies that depend on annual precipitation and runoff, furthering the search for drought-resistant water management alternatives. Especially in an era when more big dams are widely understood to be as unlikely as they are undesirable, implementing conjunctive management seems to be an obvious step for these three states. What is not as obvious is why conjunctive management practices have followed such divergent paths from California to Arizona to Colorado. As each state’s conjunctive management experience was detailed in Part 2, differences in the purposes, methods, organizational structures, and magnitude of conjunctive management emerged despite their relatively similar water resources and problems. Some key elements of conjunctive management in the three states, which we discuss throughout the chapter, are captured in Table 7-1. Comparison of Conjunctive Management Institutions, Purposes, and Organizations https://www.niso.org/standards/z39-96/ns/oasis-exchange/table">
California
Arizona
Colorado
Conjunctive management purposes
Conjunctive management is used to enhance stream flows
X
Conjunctive management is used for seasonal storage
X
X
X
Conjunctive management is used for long-term storage
X
X
Conjunctive management is used for recovery of groundwater overdraft
X
X
Conjunctive management methods
Groundwater users store water to recharge streams and offset pumping effects
X
In-lieu recharge—incentives offered to use surface water when plentiful, allowing groundwater storage to increase
X
X
Direct recharge—surplus surface water sunk or injected underground for later capture
X
X
Water-rights systems
Integrated ground and surface water rights
X
State law quantifies groundwater rights
X
X
State defines rights to recharge and recover stored groundwater
X
X
State permits local-level institutions to define rights to groundwater
X
Organizational arrangements
State agencies approve locally organized conjunctive management projects
X
X
State agencies operate conjunctive management projects
X
Private organizations and individuals participate in conjunctive management projects
Rarely
X
X
Substate governments, including municipalities, counties participate in conjunctive management
X
X
Rarely
Organizations providing conjunctive management coordinate around basin boundaries
X
