**4. Program Evolution**

The MWQI program was established as a flexible and pro-active collaboration between CDWR and participating water agencies to address new concerns as they arise [25]. Accordingly, the program has evolved in response to regulatory drivers, technology innovations, and an ever-increasing knowledge base. Here, we chronicle the evolution of the MWQI program by distilling the past 30 years into three eras: the early years (1990–1995), the CALFED years (1996–2005), and the RTDF years (2006–present). The CALFED Bay-Delta Program, a cooperative state-federal planning effort created as part of the 1994 Bay-Delta Accord [8,16], was tasked with developing a 30-year plan that addressed key problem areas in the Delta, including water quality. Although this goal was not achieved under the expired CALFED program, the Delta Stewardship Council (a state agency stemming from the CALFED program and created under the 2009 Delta Reform Act) developed a plan for the long-term management of the Delta's water and environmental resources [4].
