Newman Lake Total Phosphorus Total Maximum Daily Load Water Quality Improvement Report November 2007 Publication Number 06-10-045 Newman Lake Total Phosphorus Total Maximum Daily Load Water Quality Improvement Report Prepared by: Anthony J. Whiley and Ken Merrill Washington State Department of Ecology Water Quality Program November 2007 Publication Number 06-10-045 You can print or download this document from our Web site at http://www.ecy.wa.gov/biblio/0610045.html For more information contact: Department of Ecology Water Quality Program Watershed Management Section P.O. Box 47600 Olympia, WA 98504-7600 Telephone: 360-407-6404 Headquarters (Lacey) 360-407-6000 Regional Whatcom Pend San Juan Office Oreille location Skagit Okanogan Stevens Island Northwest Central Ferry 425-649-7000 Clallam Snohomish 509-575-2490 Chelan Jefferson Spokane K Douglas i Bellevue Lincoln ts Spokane a Grays p King Eastern Harbor Mason Kittitas Grant 509-329-3400 Pierce Adams Lacey Whitman Thurston Southwest Pacific Lewis 360-407-6300 Yakima Franklin Garfield Wahkiakum Yakima Columbia Walla Cowlitz Benton Asotin Skamania Walla Klickitat Clark Persons with a hearing loss can call 711 for Washington Relay Service. Persons with a speech disability can call 877-833-6341. If you need this publication in an alternate format, please call the Water Quality Program at 360-407-6404. Persons with hearing loss can call 711 for Washington Relay Service. Persons with a speech disability can call 877-833-6341 Table of Contents List of Figures and Tables..............................................................................................................iii Summary....................................................................................................................................... vii Introduction..................................................................................................................................... 1 Overview of the total maximum daily load study process.......................................................... 1 Newman Lake’s inclusion on the 303(d) list.............................................................................. 1 Background..................................................................................................................................... 3 Newman Lake and its watershed ................................................................................................ 3 Applicable Criteria.......................................................................................................................... 7 Target total phosphorus (TP) concentration ............................................................................... 8 Water Quality and Resource Impairments.................................................................................... 13 Stratification - patterns to phosphorus enrichment and circulation .......................................... 13 Effect of oxygenator on lake water quality............................................................................... 14 Seasonal Variation ........................................................................................................................ 17 Lake total phosphorus concentrations....................................................................................... 17 Technical Analysis........................................................................................................................ 21 Inflow........................................................................................................................................ 22 Water budget............................................................................................................................. 27 External TP loads...................................................................................................................... 38 On-site wastewater systems ...................................................................................................... 44 Nutrient Budget......................................................................................................................... 51 Loading Capacity.......................................................................................................................... 55 Establishing the load capacity................................................................................................... 55 Model application for establishing the load capacity ............................................................... 55 Result of load reductions on water quality ............................................................................... 60 Load Allocations........................................................................................................................... 61 Thompson Creek allocation...................................................................................................... 62 Watershed allocation................................................................................................................. 64 On-site wastewater allocation................................................................................................... 65 Margin of Safety ........................................................................................................................... 67 References..................................................................................................................................... 69 Summary Implementation Strategy .............................................................................................. 73 What needs to be done.............................................................................................................. 73 Who needs to participate........................................................................................................... 77 Schedule for achieving water quality standards ....................................................................... 78 Reasonable assurances.............................................................................................................. 78 Monitoring plan ........................................................................................................................ 80 Adaptive management .............................................................................................................. 80 Summary of public involvement methods................................................................................ 80 Newman Lake Phosphorus TMDL Page i Potential funding sources.......................................................................................................... 82 Next steps.................................................................................................................................. 83 Appendix A. Record of Public Participation ............................................................................... 85 Summary of Comments and Responses.................................................................................... 85 List of public meetings ............................................................................................................. 95 Public Outreach and Announcements....................................................................................... 96 Appendix B. Water Quality Data............................................................................................... 105 Appendix C. Water Quality Issues Concerning Oxygenator..................................................... 127 Stratification and phosphorus recycling ................................................................................. 127 Comparison of July temperature profiles................................................................................ 128 Lower water column mixing................................................................................................... 130 Factors influencing oxygenator mixing .................................................................................. 130 Effect of spring inflow on water temperatures ....................................................................... 131 Increased rate of heating......................................................................................................... 135 Effect on dissolved oxygen..................................................................................................... 138 Summary................................................................................................................................. 146 Appendix D. Water Budget........................................................................................................ 149 Page ii Newman Lake Phosphorus TMDL List of Figures and Tables Figures Figure 1. Newman Lake bathymetry along with monitoring locations. ........................................ 4 Figure 2. The Newman Lake watershed along with monitored inlet locations (numbered).......... 5 Figure 3. The relationship between TP and chlorophyll (a) concentrations observed for Newman Lake (1986-1992)......................................................................................................... 11 Figure 4. The relationship between Secchi depth and chlorophyll (a) concentrations observed in Newman Lake (1986-1992). (Circles are from Dillon and Rigler, 1974)................... 12 Figure 5. Median TP concentrations (ug/L) observed at the three monitoring depths