06-096-570 Me. Code R. § 6
As part of the Master Plan, a program for continued monitoring of CSO discharges must be submitted to the department for approval. The licensee must conduct block testing and flow monitoring according to the approved Compliance Monitoring Plan. This monitoring information must consist of precipitation from storm events or snow melt flows that cause CSOs, overflow volumes and overflow events for the period of January 1 to December 31 of each year. The department shall use this information and yearly progress reports to measure the effectiveness of the CSO abatement program. The information must be submitted on a form entitled "CSO Volumes and Activity", supplied by the department (or a similar format), and must be part of the annual CSO progress report (see Section 7) . Annual flow volumes for the previous year from all CSO locations must be determined by actual flow monitoring, or by estimation using a model such as EPA's Storm Water Management Model (SWMM). CSO control projects that have been completed must be monitored for volume and frequency of overflow to determine the effectiveness of the project toward CSO abatement. This requirement does not apply to those areas where complete separation has been completed and CSO outfalls have been eliminated. Based on the results of monitoring and experiences gained from implementation of abatement projects, the licensee shall periodically (every three to five years) review and update the Master Plan (see Section 3(C) ).
06-096 C.M.R. ch. 570, § 6