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COMPREHENSIVE STORMWATER MANAGEMENT PLAN CITY OF HUGO WSB PROJECT NO. 1904-610 PAGE 4 PROPOSED REGIONAL BEST MANAGEMENT PRACTICES: CREDIT SUPPLY A. Credit Generation and Verification RCWD rules currently require that each BMP undergo three years of monitoring for credit verification. Prior to the monitoring period, an irrigation rate of 0.5 inches per week over the 26- week growing season may be credited. Additional water quality treatment capacity beyond the 0.5 inches per week may be recognized based on a three-year average of monitoring records of volume irrigated. This document allows the City to receive credit for the projects in this report as well as any future projects under the following monitoring schedule. 1. Project Completion Upon substantial completion (project construction completion, the irrigation surface has been graded, and seeding placed and the irrigation system is functional), the City will receive all allowable credits. The City may then use the credits towards public or private developments as it sees fit. The credits received at this time are irrevocable. 2. Additional Credits & Monitoring If the City decides that it desires more credits than the RCWD allowable volume on any given project, it may undergo additional monitoring. The City will notify RCWD that monitoring of the system is being done and at least three years of irrigation volume records will be required. The annual volume pulled from the reuse pond for irrigation would be divided by the number of weeks the system was running and the area irrigated to get a weekly rate (in/wk) of irrigation. This would be done for the three or more years of irrigation monitoring data available. The updated number of credits for the reuse system would be the average irrigation rate over the average length of time the system was being used for irrigation. Wet periods that exceed the recent statistical average may reduce the need for irrigation during the monitoring period. The City can request an extension of the monitoring period if the initial monitoring period is characterized by significantly above or below average precipitation. B. Project Tracking Process The estimated volume reduction for each irrigation project is calculated using the total irrigated area and applying RCWD’s allowable irrigation depth of 0.5 inches applied weekly for a 26-week irrigation season. Allowable irrigation volumes will be verified in accordance with RCWD rules by preparing the Metropolitan Council Stormwater Reuse Guide “Water Balance Tool – Irrigation Constant Demand” spreadsheet to ensure designs have sufficient drainage area, storage and demand over the growing season. Some of the projects involve infiltration galleries. These galleries will likely vary in size, but their treatment capacity will be based on the Minimum Impact Design Standards (MIDS) calculator developed by the MPCA. The estimates of total volume reduction are given for each project in Section III.C below and are summarized in Table 2, Appendix B. As projects enter into the design phase or are put on-line, the credit tracking table will be updated with the actual volume reductions. The City will be responsible for notifying RCWD that the project is functioning and available for compliance use and will include the ROC (or ROCs) of the project is in and the volume reduction achieved at that time.