Lake Whatcom Watershed Total Phosphorus and Bacteria Total Maximum by HC12092913103

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									Linked Watershed-Lake Models
     for the Lake Whatcom
       Phosphorus TMDL


     Paul Pickett and Steve Hood
   Washington Department of Ecology
                      Where?




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                        What?
• Monomictic lake
• Over 100 meters at deepest
• Twenty kilometers long
• Glacial sills -> Three Basins
• Largest basin (96% of volume) average depth
  over 50 meters
• Other basins about 10 meter average depth
• Most development around two smallest
  basins

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                        Problem
• Lake Whatcom fails to meet oxygen criteria
   – Trend: anoxic hypolimnion sets up earlier
   – Criterion: within 0.2 mg/l of natural conditions
   – Phosphorus loading causing oxygen decline
• Just over 10% of watershed developed
   – Developed tributaries have highest nutrient levels




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              Obligatory Flow Chart
                              Tributary
        HSPF
                                Load

                   Loading                                     CE QUAL W2

       Fixed                  Fixed
     Parameters               Loads

                                                                Response


                      N         Meets                           Dissolved
 Revise Rollback                Criteria                         Oxygen
                                   ?                             Results

                                           Y


11 Feb 2009
                                Done                                        5
                   2009 Puget Sound Georgia Basin Conference
                 HSPF input
• Base Scenario: 1992 National Land Cover
  Dataset, with photo update to 2002-2003
• Full Buildout Scenario: development to
  allowable zoning
• Full Rollback Scenario: all watershed
  Mixed Forest or wetlands
• Partial Rollback: Change land cover from
  developed to forest until standards are met

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              Model View of Rollback
• Developed
  area
    – pink/brown
    – Approx 3600
      ac
• Changed to
  Mixed Forest
    – light green


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              Developed Acres vs.
               Tributary Loading




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              The Rollback View


                86%             94%
                Rollback        Rollback




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               CE QUAL W2
• 2 Dimensional
    – Laterally averaged segments
    – Variable depth layers
• Dynamic
    – Time-step selected based on transit times
• Hydrodynamic
    – Simultaneous equations to balance, water,
      temperature, chemistry, growth, death

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                   CE QUAL W2
• Lake Whatcom enhancements
    – 3 algal groups
    – Sediment variable stoichiometry and decay
         • Sediment stoichiometry linked to water column
         • Both 0th order and 1st order sediment decay w/
           different nutrient release rates
    – Looping methodology
         • Rerun model using end conditions of one loop for
           beginning conditions of next loop
         • Allows model to reach equilibrium from loading
           changes (15 year retention in Basin 1)
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         Hillsdale & Silver Beach
                                                        CE QUAL Plan
                                  62               67
                                                         Branch 5
                            63
                                                  66
                                                                                                                                                                           Waterbody 1 =
     Whatcom                                                Academy
                                                                                                                                                                           Branch 1+2+3




                                                                                                 Br
                                             60
     Creek




                                                                                                  ran
                                                             Eagle
     (Outlet) Bloedel




                                                                                                     ch
                                                             Ridge
               Oriental                      59                               Agate




                                                                                                        3
                                                        57
                            Ba                           56
                                                              55
                                                                               Bay                              Carpenter
                               s   in
                                        #1                                                                       Olsen       North Shore




                                                                                                                                                                      Br
                                                                                                                                                                      Br
                                                                                         29
              Donovan                                                           31 30




                                                                                                                                                                      an
                                                                                                                                                                       nc
                                                    Ba
                                 Geneva                                                         28
                                                                                                                            Ba




                                                                                                                                                                        ch
                                                      sin           52




                                                                                                                                                                          h
             Br                          Cable              #2           51
                                                                                    48
                                                                                                                                 sin




                                                                                                                                                                           1
                                                                                                                                                                           1
                                                                               50
                                                                                    49
                anc
                    h                                              Strawberry
                                                                                                                                            #3
                        4
                                                                                                                                                              Smith


                                                                                              Sudden Valley
              Waterbody 2 =
              Branch 4+5                                                                                    Austin




                                                                                                                                                                           Blue
                                                                                                                                                                           Canyon


                                                                                                                     South Bay
               Lake Whatcom                                                                                                                       40


               CE-QUAL-W2                                                                                                                        39
                                                                                                                                                38
                                                                                                                                           37
                                                                                                                                                                                             Middle
               Model Layout                                                                                                            36
                                                                                                                                                                                             Fork
                                                                                                                                                         2
                                                                                                                                                          h

                                                                                                                                      35
                                                                                                                                                       nc



                                                                                                                                 34                                                          Nooksack
                                                                                                                                                    a
                                                                                                                                                 Br




                                                                                                                                                                                             Diversion
                                                                                                                                                                  Brannian
                                                                                                                                                                                          Anderson
                                                                                                                                                                                    Fir
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                      CE QUAL Cross Section
                                       Lake Whatcom Grid

         100


                 80
 Elevation (m)




                 60


                 40


                 20


                 0


           -20
                        15000                10000              5000        0
                                         Distance (meters)

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          CE QUAL results: spring




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              CE QUAL results: fall




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              Cumulative Volume




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                     Bottom Line
• Developed area needs to generate
  phosphorus loading like pre-development
    – Partial Rollback from Base Scenario
         • 86% reduction
    – Partial Rollback from Full Buildout Scenario
         • 94% reduction
• Stormwater storage and infiltration are key
• Better land use practices reduce nutrients
  before they are released
    – Fertilizer, erosion, human and pet waste
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              Lake Whatcom TMDL
Thanks to:
•   WWU – Institute of Watershed Studies
•   City of Bellingham
•   Whatcom County
•   Lake Whatcom Water and Sewer District
•   EPA
•   Portland State University
•   CDM
•   Tetra Tech

Backgrounds courtesy of Gordon Tweit and Anne Kreft
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