City of Sunnydale – PWS# 41XXXXX
Stage 2 DBPR Compliance Monitoring Plan (CMP)
The City of Sunnydale is required to monitor quarterly. As described in our IDSE report, Stage 2 DBPR compliance monitoring will begin the third week of November 2013, and then approximately every 90 days thereafter. We will be taking two dual sample sets per quarter; one sample for TTHM's and one sample for HAA5's at sample point SM-3 (1555 NE Willow St) and one sample for HAA5's and one sample for TTHM's at sample point SM-1 (221 W Xander Ct) per quarter.
Each quarter we will calculate a locational running annual average (LRAA) for TTHM and HAA5 at each monitoring location, beginning in the fourth quarter of 2013. Compliance calculations will start at the end of the third quarter of 2014. Compliance will be achieved if the TTHM and HAA5 LRAA at each monitoring location for the four most recent quarters is less than or equal to 0.080 mg/L for TTHM and less than or equal to 0.060 mg/L for HAA5. The LRAA will be calculated prior to the fourth quarter of data if fewer than four quarters of data would cause the MCL to be exceeded, regardless of the monitoring results in subsequent quarters.
Compliance is calculated for each LRAA as: (Q1 + Q2 + Q3 + Q4)/4 < MCL for each location.
If, after 4 quarters of monitoring and the city has an LRAA calculation of equal to or less than .040 mg/L for TTHM and .030 mg/L for HAA5 and an annual average TOC of less than 4.0 mg/L the city will request to be qualified for reduced monitoring. If the city is approved for reduced monitoring we would collect two dual sample sets per year: one from the location and during the quarter with the highest TTHM single measurement, and one from the location and during the quarter of the highest HAA5 single measurement. They may occur in different quarters. We will then continue to monitor at the reduced frequency until we have any sample (TTHM or HAA5) that exceeds the maximum MCL at any sample location, our LRAA calculation exceeds .040 mg/L for TTHM or .030 mg/L for HAA5 at any location, our annual average TOC exceeds 4.0 mg/L, or we are otherwise instructed to return to routine sampling. Routine sampling would be returning to two dual samples quarterly.