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r • INFORMATION SHEET, ORDER NO. 5-01-251 -7- CITY OF LATHROP AND CROSSROADS CREA LLC WASTEWATER TREATMENT FACILITY NO. 1 (CROSSROADS) SAN JOAQUIN COUNTY Monitoring Requirements Section 13267 of the CWC authorizes the Board to require monitoring and technical reports as necessary to investigate the impact of a waste discharge on waters of the state. In recent years there has been increased emphasis on obtaining all necessary information, assuring the information is timely as well as representative and accurate, and thereby improving accountability of any discharger for meeting the conditions of discharge. Section 13268 of the CWC authorizes assessment civil administrative liability where appropriate. The proposed Order increases the previous Order's influent and effluent monitoring requirements, and includes flow rates,wastewater storage ponds, disposal areas, and groundwater monitoring requirements. In order to adequately characterize its wastewater effluent,the Discharger is required to monitor for settleable solids,BOD, coliform, TDS, nitrogen, sodium, and chloride. Monitoring of additional minerals is required on an annual basis. To ensure that disposal ponds do not create nuisance conditions,the Discharger is required to monitor freeboard available and dissolved oxygen content weekly. The Title 27 zero leakage protection strategy relies heavily on extensive groundwater monitoring to increase a discharger's awareness of, and accountability for, compliance with the prescriptive and performance standards. With a high volume, concentrated, uncontained discharge to land, monitoring takes on even greater importance. The proposed Order includes monitoring of applied waste quality, application rates, and groundwater. Title 27 regulations pertaining to groundwater monitoring and the detection and characterization of waste constituents in groundwater have been in effect and successfully implemented for many years. No regulation currently specifies similar criteria more suitable for a situation where extensive infiltration into groundwater occurs. However,where, as here, such infiltration occurs, it is appropriate that the Title 27 groundwater monitoring procedures be extended and applied on a case-by-case basis under Water Code section 13267. The Discharger must monitor groundwater for constituents present in the discharge and capable of reaching groundwater and violating groundwater limitations if its treatment and control, and any dependency of the process on sustained environmental attenuation,proves inadequate. The Discharger's existing network of groundwater monitoring wells is not adequate to fully characterize background water quality and potential groundwater impacts for the wastewater treatment facility and land application areas. For each constituent where no increase in concentration is authorized over background,the Discharger must, as part of each monitoring event, compare concentrations of constituents found in each monitoring well to the background concentration or to prescribed numerical limitations to determine compliance.