CONSTRUCTING A NUTRIENT MASS

BALANCE FOR

POST‐ERUPTION SPIRIT LAKE

UW Tacoma, Environmental ScienceLaura Alskog, Danielle Dahlquist, Erika Klein, Katie Royer

Advisors: Jim Gawel, Mindy Roberts, Matt Kelley 

BATHYMETRY PRE‐ERUPTION POST‐ERUPTION

INTRODUCTION

• Post‐eruption:– Elevation raised almost 60 meters

– Surface area increased

– Shallower

(Dale et al. 2005)

Surface water(Streams)

Groundwater 

Tunnel

Plants

Phytoplankton

Zooplankton

Insects

Sediments

Water Column

Amphibians

Fish

WHAT ARE WE DOING?Atm Deposition

Logs

METHODS

• Stream flow was measured using Swoffer Velocity Meter and measuring tape

• Well head depths were recorded

• Water samples were collected from streams and wells

• Measured for nitrogen and phosphorus concentrations

SAMPLED STREAMS

• The 5 streams along the southern shoreline and Harmony Falls were sampled and measured every outing

• Due to the floating log mat, the other sampled streams were  not sampled regularly

(Butcher 2010)

CALIBRATION CURVE AND SURFACEWATER INPUT

y = 3.3523E‐08xR² = 8.2368E‐01

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.0E+00 2.0E+06 4.0E+06 6.0E+06 8.0E+06

Point D

ischarge

 Rate (m

3 /s)

Drainage Area (m2)

Stream #Basin Area 

(m2)Flow (m3/s)

Annual Flow Estimate  (m3/yr)

1 7199654 0.2185 6891697

2 179321 0.0271 854949

3 1688218 0.1031 3252819

4 1835528 0.0871 2745956

5 919126 0.0090 284174

6 2325294 0.1016 3205122

Remaining Watershed 23560194 0.7898 24907397

Total Inflow 42142114

AVERAGE FLOW OF STREAMS VS. BASIN AREA

ALL HYDROLOGY

Tunnel Outflow

161,278,279 m3/year

Groundwater Inflow

119,136,165 m3/year

Surface Water Inflow

42,142,114 m3/year

‐

=

NUTRIENT LOAD IN SURFACE WATER

Total Nitrogen (mg/L) in Streams

DateStream 

1Stream 

2Stream 

3Stream 

4Stream 

5Stream 

66/24 0.0373 0.0474 0.0552 0.1027 0.1183

7/7 ‐ 7/8 0.2241 0.0609 0.0585 0.1194 0.15957/19 ‐ 7/23 0.1497 0.1870 0.0584 0.2454 0.1503 0.4173

8/3 0.0832 0.0777 0.0491 0.1268 0.1389 0.34588/17 ‐ 8/18 0.1099 0.1057 0.1712 0.2769 0.31239/14 ‐ 9/15 0.0135 0.0571 0.0411 0.0982 0.0136

10/1 0.1054 0.0507 0.2112 0.2618 0.0899Average 0.1546

Total Phosphorus (mg/L) in Streams

DateStream 

1Stream 

2Stream 

3Stream 

4Stream 

5Stream 

66/24 0.0999 0.0759 0.0346 0.0688 0.1156

7/7 ‐ 7/8 0.3602 0.0784 0.0520 0.0760 0.1298 0.01717/19 ‐ 7/23 0.1138 0.0825 0.0305 0.0941 0.1185 0.0131

8/3 0.1608 0.0815 0.0353 0.2189 0.12708/17 ‐ 8/18 0.0488 0.0527 0.0311 0.0099 0.09239/14 ‐ 9/15 0.1105 0.0734 0.0360 0.0538 0.1237

10/1 0.0516 0.0715 0.0297 0.0395 0.1335Average 0.0726

• Nutrient concentrations  from all streams and all sampling dates were averaged together 

• The result was multiplied by the Surface Water Inflow to find annual load

NUTRIENT LOAD IN GROUNDWATER AND TUNNEL

• Nutrient concentrations  were averaged and multiplied by the Groundwater Inflow to find annual loadTotal Nitrogen (mg/L) in Wells

Date Well 1 Well 2 Well 3 Well 4 Well 5 Well 6

7/8 0.1747 0.4001 0.1274 0.2205 1.2055 0.4279

7/19 0.1167 0.2444 0.7829 0.2519 0.2650 0.2612

8/3 0.0652 0.1159 0.2689 0.1305 0.2442 1.2545

8/17 0.0749 0.1245 0.0932 0.2612 0.3189 0.1573

9/15 0.3602 0.2066 0.3028 0.2624 0.4438 0.1883

10/1 0.1091 0.1243 0.3250 0.2037 0.4943 0.1145

Average 0.2978

Total Phosphorus (mg/L) in WellsDate Well 1 Well 2 Well 3 Well 4 Well 5 Well 6

7/8 0.0000 0.0080 0.0423 0.0000 0.0277 0.0152

7/19 0.0000 0.0000 0.0643 0.1802 0.0178 0.0000

8/3 0.0181 0.0201 0.0160 0.0324 0.0897 0.0046

8/17 0.0342 0.0408 0.0194 0.2483 0.0490 0.0063

9/15 0.1882 0.0451 0.0110 0.0544 0.0372 0.0247

10/1 0.0221 0.1043 0.0100 0.0268 0.0169 0.0161Average 0.0414

• Tunnel Outflow Nutrient Load is found by multiplying epilimnion nutrient concentrations and Tunnel Outflow 

Total Nitrogen (mg/L)

Epilimnetic Average 0.1095

Streams Average 0.1546

Wells Average 0.2978

Total Phosphorus (mg/L)

Epilimnetic Average 0.0041

Streams Average 0.0726

Wells Average 0.0414

StreamsTN: 6,517 kg/yearTP: 654 kg/year

GroundwaterTN: 35,483 kg/yearTP: 4,936 kg/year 

TunnelTN: 17,656 kg/yearTP: 654 kg/year

Plants

Phytoplankton

Zooplankton

Insects

Sediments

Water Column

Amphibians

Fish

Atm Deposition

Logs

NUTRIENT FLUXES kg N/yr kg P/yr

Tunnel Outflow 17656.07 654.17

Surface Inflow 6517.19 3060.29

Groundwater Inflow 35483.92 4935.71

NUTRIENT MODEL

DISCUSSION• Hydrology Assumptions

– Average summer surface water flows and nutrient concentrations are a good representation of yearly flow

• Nutrient Concentration Assumptions– Measured nutrient concentrations are similar throughout the year even though they were only measured in summer

FUTURE WORK IN STREAMS AND WELLS

• Collect a more complete set of surface water flows

• Apply annualized flow rates to streams

• Insert wells in more locations

• Find source of N and P that enters into streams and wells

WATER COLUMN

METHODS

• Water sampling – Secchi disk, water transparency. 

– Hydrolab Quanta, temperature, DO, specific conductivity, and pH at 2m depth intervals.

– Nutrients, chlorophyll, phytoplankton, zooplankton, and alkalinity were collected at depths of 5, 15, and 25 meters 

– Nutrient samples• filtered for dissolved nutrients 

• unfiltered for total nutrient concentrations. 

METHODS

• Nutrient Analysis– Stored on ice for transport, frozen prior to analysis

– Westco SmartChem 200 Discrete Analyzer

– Filtered samples:• Ammonia  SM 4500 G

• Nitrate  EPA 353.2

• Orthophosphorus SM 4500 P‐E

– Digestion of unfiltered samples  SM 4500 P‐J • Nitrate & orthophosphorus above methods

http://em‐1.stanford.edu/Schedule/DAnalyzer/Index.htm

SPIRIT LAKE TEMPERATURE AND DO

SPIRIT LAKE AMMONIA FINAL CONCENTRATION

Date 7/20 8/4 8/17 10/2 Average

Epilimnion 0.1891 0.1548 0.1843 0.2063 0.1836

Hypolimnion 0.2079 0.1858 0.1969 0.2231 0.2034

TOTAL NITROGEN AND PHOSPHORUS INSPIRIT LAKE

Kg NTOT Kg PTOTEpilimnion 8,691 322

Hypolimnion 19809 1374

Total 28500 1696

WATER COLUMN FUTURE STUDIES

• Nutrient Collection– Continue sampling into winter season

– Apply N & P to the plankton data

– Apply log mat

SEDIMENT SAMPLING

METHODSSediment Trap• Two traps were constructed out of PVC pipe 40 cm in length and 15 cm diameter. 

• Funnels were adhered to the bottom of the pipes and 60 mL Nalgene bottles were attached to the funnels for collection of sediment. 

• Traps were positioned three meters above the lake floor with buoys suspended ten feet below the lake surface to avoid log mat damage. 

• Traps were placed in the East and West arms of Spirit Lake over a ten week period

Dredge• A 6” X 6” Petersons Dredge was used to collect surface sediment samples. 

• Dredge collects about the top ten cm of sediment per grab

• Fourteen samples were collected

Sediment Core• A Wildco Instruments  gravity corer was used to collect a short sediment core

• The core was cut into 2 cm increments

Total Nutrient in SedimentsAvg N in lake  (%) Total Area (m2) Sediment Depth Grams dry sed/cm3 Grams N Total Kg N Total Kg N/year

0.0640 10331457 0.10 0.90 595290457 595290 19843

Avg P in lake mg/kg Total Area (m2) Sediment Depth Grams dry sed/cm3 Grams P Total Kg P Total Kg P/year

0.0682 10331457 0.10 0.90 633820866 633821 21127

0.0025 10331457 0.10 0.90 22921843 22922 764

About 625,000 Kg of Carbon

is deposited into the sediment per year

Avg C in Lake (%)

Total Area (m2)

Depth of Sediment (m)

Grams dry sed/cm3

Grams C Total Kg C Total Kg C/year

2.018 10331457 0.10 0.90 18761831674 18761832 625394

• Plant data collected by PSU using sonar

• Ground truthing done by Bellarmine High School

• Plant height data converted to plant mass

• Plant mass converted to nutrient biomass

Total Nutrients in Plants in Photic Zone

Nitrogen

Avg Height (m) Area (m2) Avg Plant N (mg/m3) Total N in Plants (mg) Total N (kg)

0.2377 4205794 2446 24456000012 2446

Phosphorus

Avg Height (m) Area (m2) Avg Plant P (mg/m3) Total P in Plants (mg) Total P (kg)

0.2377 4205794 364 363807981 364

SEDIMENT FUTURE WORK

• More sampling locations in the East Arm for dredge samples

• More sediment deposition data by adding more traps 

INSECT SAMPLING

METHODS

• Emergence Collection– Amphibious Emergence Trap II, BugDorm

– 1 to 4 m of water, southeast corner of lake

– Insecticidal kill strip, drop into 500 mL bottles

– Stored on ice for transport, stored in freezer

METHODS

• Emergence Analysis– Weighed for total biomass

– Sorted by order and weighed

– Nutrients calculated using nutrient values from 2009 Spirit Lake insect samples

METHODS

• Deposition Collection– Homemade traps

– Filtered, stored in 70% ethanol

• Deposition Analysis– Samples filtered, dried, and weighed

– Nutrients not calculated due to very small amount collected

0

20

40

60

80

100

120

Average kg/day

Sampling Date

Coleoptera

Diptera

Emphemeroptera

Hemiptera

Hymenoptera

Lepidoptera

Odonata

Tricoptera

AVERAGE KILOGRAMS OF INSECTS EMERGING

FROM SPIRIT LAKE DAILY BY ORDERFROM JULY TO SEPTEMBER, 2010

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

% In

sect Emergence (M

ass)

Sampling Date

Tricoptera

Odonata

Lepidoptera

Hymenoptera

Hemiptera

Ephemeroptera

Diptera

Coleoptera

PERCENT BY ORDER OF INSECT EMERGENCE

TOTAL MASSFROM JULY TO SEPTEMBER 2010

0

10

20

30

40

Average kg N/day

0.00.51.01.52.02.53.03.5

Average kg P/da

y

Sampling Date

AVERAGE NUTRIENTS LEAVING SPIRIT LAKE THROUGH

INSECT EMERGENCE DAILY

Total N/year: 1,607 Kg

Total P/year:  139 Kg

INSECT FUTURE STUDIES

• Insect Emergence and Deposition– Test assumption that insects only leave lake from photic zone

– Study deposition of insects through fish gut contents

Streams 6,517

Groundwater 35,484

Tunnel 17,656

Plants 2,446

Phytoplankton

Zooplankton

Insects 1,607

Sediments 19,843

Water Column 28,500

Amphibians

Fish

NITROGEN NUTRIENT FLUX PER YEAR (KG)Atm Deposition

Logs

Streams 3,060

Groundwater 4,936

Tunnel 654

Plants 364

Phytoplankton

Zooplankton

Insects 139

Sediments 764/21,127

Water Column 1,696

Amphibians

Fish

PHOSPHORUS NUTRIENT FLUX PER YEAR (KG)Atm Deposition

Logs

THANK YOU TO JACOB ASPLUND, JESSICA ASPLUND, LIA WETZSTEIN, HEATHER JENNINGS, NICOLE BUTHER, BRIDGET MASON, MINDY ROBERTS, 

TIFFANY WAX AND JIM GAWEL

THANK YOU FOR LISTENING!