WEEKI WACHEE RIVER MONITORING SUMMARY

WEEKI WACHEE RIVER

MONITORING SUMMARY

January 2019 - December 2019

PREPARED FOR

FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION,

DIVISION OF PARKS AND RECREATION

Photo By Tessa Skiles

Weeki Wachee River Ecosystem Monitoring Project

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Table of Contents Figures ……………………………………………………………………………………………ii

Tables ……………………………………………………………………………………………ii

Acknowledgments ...................................................................................................................iii

Section 1.0 Introduction ..................................................................................................... 1

1.1 Monitoring Stations ................................................................................................................... 1

Section 2.0 Methods ........................................................................................................... 2

2.1 Sampling Events ......................................................................................................................... 2

2.2 Water Quality ............................................................................................................................. 3

2.3 Light Measurements .................................................................................................................. 3

2.4 Fish Survey .................................................................................................................................. 4

2.5 Vegetation ................................................................................................................................... 4

Section 3.0 Results ............................................................................................................. 4

3.1 Water Quality ............................................................................................................................. 4

3.1.1 Florida SPRINGSWATCH Weeki Wachee River Water Quality ................................ 4

3.1.2 Secchi Disk Visibility ......................................................................................................... 7

3.1.3 Florida SPRINGSWATCH Weeki Wachee River Light Measurements ..................... 8

3.2 Fish Survey .................................................................................................................................. 9

3.3 Aquatic Vegetation Survey ..................................................................................................... 10

3.3.1 Florida SPRINGSWATCH Weeki Wachee River Vegetation Survey ....................... 10

Section 4.0 References ......................................................................................................11


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Table of Exhibits

Figures

Figure 1. Weeki Wachee River SPRINGSWATCH monitoring stations ............................................ 1

Figure 2. Image of a LI-COR PAR Meter ................................................................................................ 3

Figure 3. Florida SPRINGSWATCH Program Weeki Wachee River Dissolved Oxygen Measurements (mg/L) (January 2019-December 2019). ....................................................................... 5

Figure 4. Florida SPRINGSWATCH Program Weeki Wachee River Dissolved Oxygen Percent Saturation (DO %) Measurements (January 2019-December 2019). ................................................... 5

Figure 5. Florida SPRINGSWATCH Program Weeki Wachee River Temperature Measurements (°C) (January 2019-December 2019) ......................................................................................................... 6

Figure 6. Florida SPRINGSWATCH Program Weeki Wachee River Specific Conductance Measurements (uS/cm) (January 2019-December 2019) ...................................................................... 6

Figure 7. Florida SPRINGSWATCH program Weeki Wachee River Secchi Disk Measurements (m) (January 2019-December 2019) .......................................................................................................... 7

Figure 8. Florida SPRINGSWATCH program Weeki Wachee River Attenuation Coefficient (k) and Percent Transmittance Measurements (January 2019 - December 2019) .................................... 8

Figure 9. Average Percent Cover of Vegetation at Florida SPRINGSWATCH Weeki Wachee River Stations (January 2019 to December 2019) ............................................................................................ 11

Tables Table 1. Table 1Weeki Wachee River sampling events (January 2019 – December 2019) ............... 2

Table 2. Horizontal secchi measurements in the Weeki Wachee River. ............................................. 7

Table 3. Summary of Fish Survey Results from stations WW-2 to WW-3 (January 2019 – December 2019) ............................................................................................................................................................. 9

Table 4. Average Percent Cover of Vegetation at Florida SPRINGSWATCH Weeki Wachee River Stations (January 2019 to December 2019) ............................................................................................ 10


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Acknowledgments This report was prepared by the Howard T. Odum Florida Springs Institute (FSI). Ecological monitoring was conducted by FSI and the Florida SPRINGSWATCH volunteers under the Florida Department of Environmental Protection (FDEP) Division of Recreation and Parks Research / Collection Permit Number 04261910.

Our Weeki Wachee SpringsWatch program would not be possible without the hard work of our team leader, Jill Lingard. We would also like to acknowledge the contribution and dedication of our volunteers: Scott Jantz, Julie Flynt, Carla Wilson, Kathryn Herring, Alex Figueroa, John Klawitter, Joan Landis, Irina Marvel, and Savannah Vrana.


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Section 1.0 Introduction The Weeki Wachee Spring and Spring Run System (Weeki Wachee River) is located in western Hernando County and is a focal point for outdoor recreation in the area. Rainbow, Crystal River/Kings Bay, Homosassa, Chassahowitzka, and Weeki Wachee make up what is known as the Springs Coast. The headspring that feeds the Weeki Wachee River is in Weeki Wachee Springs State Park. The Weeki Wachee River flows approximately 7.5 miles from its headspring to the Gulf of Mexico. Through citizen science conducted via the SPRINGSWATCH volunteer program, FSI is able to enhance monitoring of the Weeki Wachee River and Springs system. The resulting data will be used to more accurately assess springs and river health to further educate the public.

This report was prepared by the Howard T. Odum Florida Springs Institute (FSI) and is focused on ecological monitoring currently being conducted along the length of the Weeki Wachee River.

1.1 Monitoring Stations

Data was collected by Florida SPRINGSWATCH volunteers at a total of 15 stations: 5 stations in the Weeki Wachee Springs State Park and 10 stations along the Weeki Wachee River (Figure 1).

Figure 1. Weeki Wachee River SPRINGSWATCH monitoring stations


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Section 2.0 Methods Ecological monitoring was conducted on the Weeki Wachee River from January 2019 to December 2019. Data collection included water quality field parameters, light measurements, aquatic vegetation survey, and fish counts.

2.1 Sampling Events

Table 1 summarizes the sampling events along the upper and lower sections of the Weeki Wachee River. Monitoring in the upper and the lower river was conducted by the Florida SPRINGSWATCH Program volunteers with assistance from FSI.

Weeki Wachee monitoring events included the following:

• Water quality field parameters (temperature, dissolved oxygen, and conductivity) • Vertical light attenuation • Horizontal secchi disk measurements • Aquatic vegetation survey • Visual fish counts

Table 1. Weeki Wachee River sampling events (January 2019 – December 2019)

Jan-19 X X X X X

Feb-19 X X X X X

Mar-19 X X X X X

Apr-19 X X X X X

May-19 X X X X X

Aug-19 X X X X X

Sep-19 X X X X X

Oct-19 X X X X X

Nov-19 X X X X X

Dec-19 X X X X X

SecchiMonth - Year Water Quality PAR Vegetation Fish


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2.2 Water Quality

Surface water data were collected monthly at each station along the Weeki Wachee River with YSI water quality meters. Handheld YSI ProODO and YSI EcoSense EC300A meters were used at each of the 15 monitoring stations to collect measurements of temperature/dissolved oxygen, and specific conductance respectively. Horizontal Secchi disk readings were also taken monthly at each station to measure water clarity. Calibration and maintenance of water quality meters was conducted according to factory instructions. Instruments were calibrated before and after each sampling event.

2.3 Light Measurements

Photosynthetically Active Radiation (PAR) underwater light transmission and attenuation coefficients were measured monthly at the 15 monitoring sites during comprehensive ecological assessments. Data were collected using a LI-COR brand LI-192 underwater quantum sensor to measure PAR energy reaching the water surface and at 1-foot intervals from the surface to a depth of 2 feet in the water column. Figure 2 provides a typical light senor installation. Light extinction (attenuation) coefficients were calculated from these data using the Lambert-Beer equation (Wetzel 2001):

Iz = Io(e-kz)

Where:

Iz = PAR at depth z

Io = PAR at the water surface

k = diffuse attenuation coefficient, m-1

z = water depth, m

Figure 2. Image of a LI-COR PAR Meter


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2.4 Fish Survey

Visual fish counts were conducted between stations WW-2 and WW-3 in the Weeki Wachee River (Figure 1). Fish were counted and identified to the lowest taxonomic group by multiple observers with a mask and snorkel. Average lengths were estimated for each observed fish species by the underwater observers following each survey. Estimates of fish live-weight biomass were made based on published length-to-weight relationships for each fish species (Froese & Pauly, 2000). Some of the observed fish species did not have length-to-weight parameters available; in these instances, published length-to-weight relationships for physically similar fish species were used for biomass estimates.

2.5 Vegetation

Vegetation was monitored monthly at all 15 stations (Figure 1). Two photographs were taken at each station in two different locations which were sent to FSI for vegetation identification and percent coverage estimations. The average between the two photographs was used to provide the overall average percent plant coverage at each station.

Section 3.0 Results This section summarizes field data collected as part of the ecosystem monitoring conducted along the Weeki Wachee River from January 2019 - December 2019. Data collected by Florida SPRINGSWATCH volunteers included water quality field parameters, light measurements, horizontal secchi disk measurements, aquatic vegetation surveys, and visual fish counts. These data provide a quantitative record of existing conditions in the river and will be useful for comparison to future evaluations of the ecological health of the Weeki Wachee River.

3.1 Water Quality

3.1.1 Florida SPRINGSWATCH Weeki Wachee River Water Quality

Figure 3 through Figure 6 present field parameter results collected from the 15 stations along the Weeki Wachee River as part of the Florida SPRINGSWATCH program from January 2019 to December 2019. Figure 3 represents dissolved oxygen (DO) results measured in milligrams per liter (mg/L), or parts per million (ppm), and Figure 4 presents DO results measured in percent saturation (%). Groundwater typically exhibits a lower DO saturation, depending on the duration of time the water has spent underground before emerging from a spring vent. Moving downstream from the spring vent, WW-1 to WW-15, there is a steady increase in DO saturation (figure 3, figure 4) as the water accumulates more free oxygen from photosynthesizing SAV and the atmosphere.

Figure 5 presents data for temperature (°C) field measurements. Temperature in the Weeki Wachee River remains constant year-round since it is primarily fed by spring water (typically 22°C).


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Figure 6 demonstrates the results for Specific Conductance field measurements. Specific conductance levels can be influenced by naturally occurring ions present in spring water but also from ions present due higher levels of nitrate/nitrite, phosphorous, saltwater, and other compounds. Higher specific conductance values suggest a higher concentration of these ions in the water. Figure 6 demonstrates a drastic increase in Specific Conductance at stations WW-14 and WW-15. This could suggest increased influence of saltwater (increasing salinity) as the river approaches the Gulf of Mexico.

2

3

4

5

6

7

8

9

10

WW-1 WW-2 WW-3 WW-4 WW-5 WW-6 WW-7 WW-8 WW-9 WW-10 WW-11 WW-12 WW-13 WW-14 WW-15

DO

(m

g/

L)

P-95

P-75

AVG

P-50

P-25

P-5

20

30

40

50

60

70

80

90

100


DO

(%

)

P-95

P-75

AVG

P-50

P-25

P-5

Figure 3. Florida SPRINGSWATCH Program Weeki Wachee River Dissolved Oxygen Measurements (mg/L) (January 2019-December 2019)

Figure 4. Florida SPRINGSWATCH Program Weeki Wachee River Dissolved Oxygen Percent Saturation (DO %) Measurements (January 2019-December 2019)


6

21

21.5

22

22.5

23

23.5

24

24.5

25

25.5

26


Wa

ter

Te

mp

era

ture

(C

)

P-95

P-75

AVG

P-50

P-25

P-5

200

400

600

800

1000

1200

1400

1600

1800


Sp

. C

on

du

cta

nce

(u

S/

cm)

P-95

P-75

AVG

P-50

P-25

P-5

Figure 5. Florida SPRINGSWATCH Program Weeki Wachee River Temperature Measurements (°C) (January 2019-December 2019)

Figure 6. Florida SPRINGSWATCH Program Weeki Wachee River Specific Conductance Measurements (uS/cm) (January 2019-December 2019)


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3.1.2 Secchi Disk Visibility

Horizontal Secchi disk visibility measurements were collected by SPRINGSWATCH volunteers on multiple dates at 3 river stations (Table 2, Figure 7). These measurements provide additional information concerning water clarity and the light attenuation properties of the spring run.

0

5

10

15

20

25

30

35

40

45

Secc

hi R

ead

ing

(m)

WW-1 WW-9 WW-14 WW-15

Date WW-1 WW-9 WW-14 WW-151/13/2019 28.04 12.19 5.87 ----

2/17/2019 38.22 9.63 5.39 ----

3/10/2019 36.76 9.63 ---- ----

4/14/2019 41.33 4.69 3.6 ----

5/11/2019 31.24 4.08 4.08 ----

8/18/2019 38.15 5.33 ---- 2.139/22/2019 28.8 6.03 ---- ----

10/13/2019 35.97 6.86 8.35 ----

11/17/2019 36.42 8.23 8.07 ----

12/15/2019 34.9 9.6 7.1 ----

Average 34.98 7.63 6.07 2.13

Table 2. Horizontal Secchi Measurements in the Weeki Wachee River

Figure 7. Florida SPRINGSWATCH program Weeki Wachee River Secchi Disk Measurements (m) (January 2019-December 2019)


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3.1.3 Florida SPRINGSWATCH Weeki Wachee River Light Measurements

Figure 8 displays the diffuse attenuation coefficient (k) and percent transmittance estimates collected by the Florida SPRINGSWATCH program along the Weeki Wachee River from January 2019 to December 2019. Percent transmittance refers to the amount of light that is able to pass through the water column. The diffuse attenuation coefficient (k) is calculated via the Lambert-Beer equation (Wetzel 2001) to measure how readily light dissipates throughout the water column. Higher values of percent transmittance tend to correspond with lower values of coefficient k. Higher k values, or lower percent transmittance values, can indicate poor water clarity since light cannot pass as easily through the water column, often due to an increase in suspended solids (turbidity) in the water. Moving downstream away from the head spring, WW-1 towards WW-15, and decrease in Percent Transmittance was observed with a corresponding increase in diffuse attenuation coefficient k.

P-95

P-75

AVG

P-50

P-25

P-5

0

1

2

3

4

5

WW-1 WW-2 WW-3 WW-4 WW-5 WW-6 WW-7 WW-8 WW-9 WW-10 WW-12 WW-13 WW-14 WW-15

k (d

iffu

se a

tte

nu

atio

n c

oe

ffic

ien

t)

0

10

20

30

40

50

60

70

80

90

100

WW-1 WW-3 WW-4 WW-5 WW-6 WW-7 WW-8 WW-9 WW-10 WW-11 WW-12 WW-13 WW-14 WW-15

Pe

rce

nt

Tran

smit

tan

ce

Figure 8. Florida SPRINGSWATCH program Weeki Wachee River Attenuation Coefficient (k) and Percent Transmittance Measurements (January 2019 - December 2019)


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3.2 Fish Survey

The Weeki Wachee SPRINGSWATCH volunteers conducted visual fish counts monthly in the Weeki Wachee River between stations WW-2 and WW-3. Table 3 presents a summary of fish observed, including the total number, estimated density, and estimated biomass.

Crevalle Jack Caranx hippos 7 6 6.32

Florida Gar Lepisosteus platyrhincus 2 2 4.27

Gizzard shad Dorosoma cepedianum 40 39 0.46

Golden Shiner Notemigonus crysoleucas 3 3 2.20

Lake Chubsucker Erimyzon sucetta 2 2 0.64

Largemouth Bass Micropterus salmoides 16 15 1.44

Mangrove Snapper Lutjanus griseus 22 22 3.41

Minnows Notropis sp. 186 182 0.30

Mullet Mugil cephalus 127 124 68.03

Needlefish Potamorrhaphis guianensis 95 93 2.34

Sheepshead Archosargus probatocephalus 96 94 59.91

Snook Centropomus undecimalis 2 2 2.68

Spotted Sucker Minytrema melanops 9 8 2.62

Sunfish sp. Lepomis sp. 92 90 2.61

Tilapia Tilapia sp. 3 2 2.33

Grand Total 700 685 160

Common Name Scientific NameAverage of

Counts

Average of

Density (#/ha)

Average of

Biomass (kg/ha)

Table 3. Summary of Fish Survey Results from stations WW-2 to WW-3 (January 2019 – December 2019)


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3.3 Aquatic Vegetation Survey

3.3.1 Florida SPRINGSWATCH Weeki Wachee River Vegetation Survey

Vegetation cover was estimated at the Florida SPRINGSWATCH Weeki Wachee River stations from January 2019 to December 2019 using underwater photographs taken at each station. Algae percentage may result in a total coverage greater than 100%, accounting for a percentage of vegetation cover (typically Sagittaria or Eelgrass) that is also covered in algae. Table 4 and Figure 9 represent the average percent cover of vegetation at each station over the period of study.

Station ID Alg

ae

Co

on

tail

(Cer

ato

ph

yllu

m d

emer

sum

)

Stra

p-l

eaf

sagi

ttar

ia

(Sag

itta

ria

kurz

ian

a)

Eelg

rass

(Val

lisn

eria

am

eric

ana)

Wat

erth

yme

(Hyd

rilla

ver

tici

llata

)

Sou

ther

n N

aiad

(Naj

as g

uad

alu

pen

sis)

Bar

e G

rou

nd

Veg

etat

ion

To

tal

WW-1 28% 6% 1% 72% 0% 0% 12% 78%

WW-2 24% 0% 1% 98% 0% 0% 0% 98%

WW-3 9% 0% 0% 75% 0% 0% 21% 75%

WW-4 15% 0% 0% 62% 1% 0% 18% 63%

WW-5 47% 0% 5% 10% 0% 5% 30% 19%

WW-6 41% 2% 0% 10% 0% 2% 51% 14%

WW-7 32% 0% 0% 2% 0% 6% 75% 8%

WW-8 44% 3% 0% 0% 0% 3% 57% 6%

WW-9 27% 0% 0% 9% 0% 0% 75% 9%

WW-10 52% 1% 0% 0% 0% 0% 47% 1%

WW-11 21% 0% 9% 7% 11% 0% 78% 27%

WW-12 13% 1% 0% 1% 25% 0% 59% 26%

WW-13 17% 10% 0% 0% 34% 6% 45% 49%

WW-14 6% 0% 0% 0% 8% 0% 84% 8%

WW-15 35% 0% 1% 23% 0% 34% 38% 58%

Table 4. Average Percent Cover of Vegetation at Florida SPRINGSWATCH Weeki Wachee River Stations (January 2019 to December 2019)


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Section 4.0 References Howard T. Odum Florida Springs Institute (FSI). (2015), Florida Springs Baseline Ecological Assessment: Standard Operating Procedures. Unpublished manuscript.

Froese, R., & Pauly, D. (2000). FishBase 2000: concepts, design and data sources. (R. Froese, & D. Pauly, Eds.) Los Baños, Laguna, Philippines. Retrieved from fishbase.org

Wetzel, R. G. (2001). Limnology: Lake and River Ecosystems. Third Edition. San Diego, CA, CA: Academic Press.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%


Per

cen

t C

ove

rage

Algae Coontail (Ceratophyllum demersum) Strap-leaf sagittaria (Sagittaria kurziana) Eelgrass (Vallisneria americana)

Waterthyme (Hydrilla verticillata) Southern Naiad (Najas guadalupensis) Bare Ground Vegetation Total

Figure 9. Average Percent Cover of Vegetation at Florida SPRINGSWATCH Weeki Wachee River Stations (January 2019 to December 2019)

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WEEKI WACHEE RIVER MONITORING SUMMARY