From: Gerald Fisher
Sent: Thu Nov 03 14:50:53 2016
To: Jeff Ring; Mark Strandberg; Jason Clifford; Dan Huff
Subject: FW: Molalla Lagoon Leak Test
Importance: Normal
Attachments: Molall Lagoon Leak Test Report - Rev1.pdf; Folks, Please see attached revised report. DEQ will approve this report and then we can close out the project. Let me know if you have any questions and I will post the revised report on the website. Thanks. Regards, Gerald Fisher, P.E. | Public Works Director City of Molalla 117 N Molalla Ave. | PO Box 248 |Molalla, OR 97038 Office: 503.829.6855 | Direct: 503.759.0218 CONFIDENTIALITY NOTICE: The information contained in this email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient and have received this communication in error, please contact the sender by reply email and destroy all copies of the original message. Thank you. From: R Quigley [mailto:rquigley@dyerpart.com] Sent: Thursday, November 03, 2016 1:58 PM To: Gerald Fisher <gfisher@cityofmolalla.com> (gfisher@cityofmolalla.com) <gfisher@cityofmolalla.com> Subject: Molalla Lagoon Leak Test Gerald, Please find the revised lagoon leak test report attached for your review. The report was revised per phone comments I received from Randy Bailey at Oregon DEQ. Randy found a discrepancy in the lagoon volume used in the report versus the volume he used to check the values in the report. After reviewing the information, I found that the original design drawings for the lagoons noted volumes that did not match the actual properties of the lagoons. I found that using the data from the Tetra Tech data used for the 2008 NPDES application (Appendix B in the report) are more accurate when compared to aerial data for the lagoons. The result of using the 2008 properties is a larger volume (gal/in) for the lagoons, which changes the leak calculations to show that no seepage was detected and that the lagoons gained 0.087 in/day in unaccounted for influent. This value is less than 5% of the measured influent flow (pump station flow meter and precipitation) and is a reasonable variance for the metered system and considering the rainfall that occurred during the test. Please review the report and let me know if you have any questions or see anything that needs to be addressed. If acceptable, please forward to Randy Bailey at Oregon DEQ for his review. Thanks, Ryan Quigley, P.E. The Dyer Partnership Engineers & Planners, Inc. 1165 S. Park St. Lebanon, OR 97355 (541) 405-4520 – Office (541) 451-0089 – Cell