The City of Lake Oswego's obligations toward our stormwater permit ("municipal separate storm sewer" or MS4) and related water quality ("total maximum daily load" or TMDL) are outlined in a number of plans and progress reports, provided as Supporting Documents. These Supporting Documents are prepared by the City in response to the MS4 permit and TMDL analyses. The Permit and TMDLs are prepared by the Oregon Department of Environmental Quality and available through the web links at the bottom of this page.
Each year, the City prepares and submits the MS4/TMDL Annual Report to DEQ, describing efforts to manage water quality in the City for the prior fiscal year.
In addition to the normal reporting on TMDL activities in Appendix D of the annual reports, the City has made minor revisions to the TMDL Implementation Plan at DEQs request for their review and approval. These revisions consisted of changing the TMDL Implementation Plan period of performance to 2014-2019 (rather than 2015-2020) and additional clarification of implementation milestones (see revised Table E-1). A complete version of the revised plan will be posted here after March 1, 2017.