Developing Nutrient Criteria – Divide and Conquer! Dan Obrecht, MU Limnology

How do you set nutrient criteria for ~ 400 lakes that vary in: Size (area and volume) Watershed (size and impacts) Hydrology Use

By dividing them into manageable groups.

Start here ? ? ? ? Group A or Group B Group C Group DGroup EGroup F

Lake/Reservoir data sets 147 waterbodies that MU has monitored for at least four years 457 waterbodies listed as classified

Is it a Big River remnant lake? no yes Set criteria knowing that these lakes are naturally nutrient rich due to their shallow depth and location in the floodplain. Also note that watershed is difficult to define.

Big River lakes account for 12 MU and classified lakes Water Quality Data for the 12 MU Lakes median range Total Phosphorus (μg/L) – 395 Total Nitrogen (μg/L) 1, – 3,291 Chlorophyll (μg/L) Inorg. Susp. Solids (mg/L) Secchi (meters)

Is reservoir greater than 2,000 acres? no yes Set criteria on an individual basis due to the differences among the reservoirs and their complex nature. Set criteria for dam site as well as the individual arms?

Large Reservoirs account for 12 MU and 12 classified lakes (though not the same 12!)

MU list TrumanClassified listTrumanLake OzarksTable RockStocktonMark TwainPomme de TerreWappapelloSmithvilleThomas HillLong Branch TaneycomoBull Shoals ClearwaterSilver Lake - Levee 3 If surface area is lowered to 1,500 acres: MontroseTaneycomo, Clearwater and Duck Creek

Large Reservoirs Water Quality Data for the 12 MU Lakes median range Total Phosphorus (μg/L) – 58 Total Nitrogen (μg/L) – 1,223 Chlorophyll (μg/L) Inorg. Susp. Solids (mg/L) 3 <1 - 9 Secchi (meters) – 3.2

Is reservoir < 20 acres in size? no yes Set criteria realizing that these reservoirs probably have short residence times and possibly internal loading issues.

Small lakes account for 8 MU and 118 classified lakes Water Quality Data for the 8 MU Lakes median range Total Phosphorus (μg/L) – 77 Total Nitrogen (μg/L) – 1,313 Chlorophyll (μg/L) Inorg. Susp. Solids (mg/L) Secchi (meters) Six of the eight MU reservoirs are located in Ozark Region. Mean % forest for all eight is 55%.

Does reservoir have average depth of < 1 meter? no yes Set criteria realizing that these reservoirs probably have short residence times and possibly internal loading issues.

Shallow lakes account for 0 MU and ? classified lakes

Does reservoir have a municipal point source in it’s watershed? no yes Worth noting these reservoirs due to TMDL considerations associated with the point source.

Reservoirs with municipal point sources and permitted point source volume (MGD) Table Rock – Smithville – Truman – Killarney Mark Twain – Long Branch – Stockton – 8.312Clearwater – Lake Ozarks – 6.231Lake St. Louis – Wappapello – 4.553Thomas Hill – Taneycomo – 3.625Springfield – Pomme de Terre – 1.788Rocky Fork – 0.009

Lakes with point sources account for 4 MU and ? classified lakes Water Quality Data for the 4 MU Lakes median range Total Phosphorus (μg/L) – 63 Total Nitrogen (μg/L) – 952 Chlorophyll (μg/L) Inorg. Susp. Solids (mg/L) Secchi (meters)

Does reservoir have an urban watershed (>50%)? no yes These reservoirs will have different nonpoint source impacts than others.

Urban lakes account for 9 MU and ? classified lakes Water Quality Data for the 9 MU Lakes median range Total Phosphorus (μg/L) Total Nitrogen (μg/L) Chlorophyll (μg/L) Inorg. Susp. Solids (mg/L) Secchi (meters)

Urban lakes sampled by MU Longview Waukomis Weatherby Tapawingo Prairie Lee Winnebago Raintree Jacomo Blue Springs

That leaves… 102 MU reservoirs and ~200 – 300 classified lakes

Regional breakdown of MU reservoirs Ozarks (n-37)Plains (n-65)median (range) TP μg/L20 (6 - 64)53 ( ) TN μg/L480 ( )900 ( ) CHL μg/L 5 (1 - 36)16 (3 - 56) ISS mg/L2 (<1 - 4)5 (<1 - 47) Secchi meters1.6 ( )0.7 ( )

Other ways of dividing the reservoirs into groups

Drinking Water Reservoirs MU has monitored 33 in Plains region and 5 in Ozarks median range Total Phosphorus (μg/L) Total Nitrogen (μg/L) Chlorophyll (μg/L) Inorg. Susp. Solids (mg/L) 4 < Secchi (meters)

Drinking water by region median (range) Ozarks (n=5) Plains (n=33) TP μg/L28 ( )50 (21 – 182) TN μg/L483 ( )926 (430 – 2330) CHL μg/L6.2 (4 – 24)14.4 (4 – 41) ISS mg/L1.6 (0.9 – 4.2)4.7 (1.6 – 15) Secchi meters1.2 (0.7 – 2.8)0.7 (0.4 – 1.8)

“Protected Reservoirs” based on 25 th percentiles

“Protected reservoirs” for whole state Sunnen Lower Taum Sauk Goose Creek Wauwanoka Fellows Clearwater Marie* Roby Nehai Tonkeia* Crane Weatherby Lake* Lincoln* Capri Shayne Timberline Council Bluff Carmel Fourche Creek Loggers Table Rock Monsanto Marseilles Noblet Stockton Fox Valley* Turner Miller Community Austin Tishomingo Bismark Pinnacle Taneycomo Westmoreland* Rocky Fork Bowling Green* * Denotes the reservoirs in the Plains region. List based on TP <22 μg/L

Weatherby Lake Nehai Tonkeia Lincoln Forest Marie Bowling Green Viking Spring Waukomis Jacomo Blue Springs Watkins Mill Westmoreland Lotawana Fox Valley Brookfield Hazel Creek Allaman New Milan Longview Marie Nehai Tonkeia Weatherby Lake Lincoln Fox Valley Westmoreland Bowling Green Brookfield Forest Mozingo Waukomis Spring Viking Baring Country Club Hazel Creek Lotawana Jacomo Bethany Tapawingo Longview Nehai Tonkeia Marie Weatherby Lake Forest Lincoln Westmoreland Spring Bowling Green Fox Valley Hazel Creek Brookfield Viking Bethany Amarugia Highlands Longview New Milan Raintree Paho Long Branch Waukomis Thunderhead Plains Region “Protected Reservoirs” based on 25 percentile CHL 11.5 μg/L TN 672 μg/L TP 32 μg/L

Loggers Lower Taum Sauk Noblet Clearwater Fourche Creek Council Bluff Shayne Crane Timberline Sunnen Capri Marseilles Carmel Capri Shayne Timberline Council Bluff Carmel Fourche Creek Loggers Table Rock Monsanto Marseilles Noblet Stockton Sunnen Shayne Capri Timberline Carmel Marseilles Fourche Creek Noblet Council Bluff Monsanto Taneycomo Wauwanoka Loggers Sunnen Roby Ozark Region “Protected Reservoirs” based on 25 percentile TP 12 μg/L TN 332 μg/L CHL 3.0 μg/L

Hydrology and Phosphorus

Multiple Regression Plains Region Log TP = *log flushing index R 2 = 0.51 Log TP = *log flushing index – 0.038*mean depthR 2 = 0.56 Lake Volume, Lake Area and Watershed Area - NS

25 th percentile Phosphorus values at different Flushing Indexes for the Plains Region Flushing IndexResidence Time Target TP (times per year) (months) (μg/L)

Multiple Regression Ozarks Region log TP = 1.46 – 0.032*mean depthR 2 = 0.15 Flushing Index, Lake Volume, Lake Area and Watershed Area - NS

25 th percentile Phosphorus values at different Flushing Indexes for the Ozark Region Flushing IndexResidence Time Target TP (times per year) (months) (μg/L)

Questions?