On December 19, 1995, a Task Force, composed of approximately 20 water, wastewater, and groundwater agencies in the Santa Ana Watershed, was formed to evaluate the impact of total inorganic nitrogen (TIN) and total dissolved solids (TDS) on water resources in the Santa Ana River Watershed. At that time, the Task Force established agreements between SAWPA and two consultants, Risk Sciences and Wildermuth Environmental Inc., to perform the consulting services for the Study . A separate agreement was formed between SAWPA and the State Water Resources Control Board (SWRCB) to obtain the Santa Ana Region RWQCB staff support in an advisory role.
The task force work was divided into a series of phases. Phase 1A focused on the defining the watershed hydrology more precisely and the reaching consensus on TDS and nitrate thresholds for Beneficial Use Impairment. As part of the threshold development, the Task Force reached agreements on the interpretation of beneficial use impairment terms. The results of Phase 1A were presented in the Draft Reclamation Guidance Document (prepared by Risk Sciences, Inc.- Tim Moore). In mid-June 1997, Phase 1B of the Nitrogen TDS Study was commenced. Phase 1B covers tasks to describe analytical methodologies to investigate watershed hydrology and tasks to define the legal, scientific and economic implications of methodologies. In March 1998, Phase 2A, the major technical effort of this study, commenced with the objective of developing a nitrogen loss rater for surface water recharge, developing a new monitoring plan, developing an updated boundary maps for management zone, to estimate TDS and nitrate in groundwater and to computer new groundwater objectives for TDS and nitrate. The results of this major technical effort were incorporated into the Tim Moore’s Reclamation Guidance Document.