LAKE ECOSUMMARY

Piney Z Lake

City of Tallahassee Lakes Monitoring group conduct chemical

and biological sampling at Piney Z Lake. The lake is

sandwiched between and separated from Upper Lake

Lafayette to the west and Lower Lake Lafayette to the east by

man-made earthen berms. Piney Z Lake has a surface area of

approximately 240 acres with a drainage basin of 1,000 acres.

This lake’s maximum depth is 8 feet, with an average depth of

approximately 5 feet at mean pool elevation. Overall, the

water quality and indicate that the lake falls a little short of

meeting expected nutrient values, however plant community

and recreational fish populations data reveals a healthy, well-

balanced lake.

Background

Although healthy, well balanced lake communities may be

maintained even with some level of human disturbance,

human activities may result in lake degradation. Human

stressors include increased inputs of nutrients, sediments

and/or pesticides from watershed runoff, undesirable

removal of native shoreline and/or upland buffer vegetation,

and introduction of nuisance (generally exotic) plants and

animals. DEP has methods to evaluate if human activities

have resulted in the condition where a particular waterbody

has exceeded water quality criteria (Chapter 62-302, Florida

Administrative Code), including whether adverse impacts to

biological communities have occurred. DEP water quality

standards are designed to protect designated uses of the

waters of the state (e.g., recreation, aquatic life support), and

exceedances of these standards are associated with

interference with the designated use. Chlorophyll a is a

measure of algal biomass in the water column. In clear, low

alkalinity lakes (lakes where color is < 40 PCU and alkalinity is

< 20 mg/L CaCO2), a healthy system is expected to have < 6

µg/L of chlorophyll a. In colored (> 40 PCU) lakes or clear,

high alkalinity (>20 mg/L CaCO2) lakes, healthy systems are

expected to have < 20 µg/L of chlorophyll a. Chlorophyll a

values greater than those shown above may result in

unwanted shading of aquatic plants and/or greater potential

for harmful algal blooms. The Lake Vegetation Index (LVI)

assesses how closely the plant community of a lake resembles

a native undisturbed community. These tools are often used

in conjunction with one another because it is possible to

detect imbalance in the plant community while the algal

community appears healthy (and vice versa).

Below is the chart for the FL Department of Environmental

Protection’s Numeric Nutrient Criteria (NNC) for the state’s

lakes.

Methods

This lake is sampled quarterly each year. Surface water

samples are collected for analysis of [nutrients, chlorophyll a,

color, etc.] following DEP Standard Operating

Procedures(SOPs;seehttp://www.dep.state.fl.us/water/sas/q

a/sops.htm) quality control standards (see

http://www.dep.state.fl.us/water/sas/qa/index.htm ).For the

LVI, species lists were developed for four of twelve sections

of the lake (Figure 1), and the following information was

derived from those lists: percent native species, percent

invasive exotic species, percent sensitive species, and the

coefficient of conservatism (C of C; a measure of how tolerant

a species is to disturbance) of the dominant species.

According to DEP SOP LT 7000, the LVI score ranges and

categories are: (78-100) Exceptional; (43-77) Healthy; and (0-

42) Impaired. DEP’s revised impairment threshold score of 43

and higher fully meet the expectation of a healthy, well

balanced community, and scores below 42 are considered

impaired. The LVI was sampled per DEP SOP FS7310 and

calculated per DEP SOP LT7000.

Below Figure 1. Map of Piney Z Lake. Sampling sites are

numbered 1,2,3,4. Water quality samples are collected

from each site along with water parameters such as

Dissolved Oxygen, Conductivity, pH level, Temperature,

Secchi Disk reading and depth.

Results

Water Quality

The water quality samples generally exceed the water quality

numeric nutrient criteria standards (Table 1). Lake Piney Z is

classified as a: “low color and low alkaline lake”. This water

quality classification is the most difficult of the three

descriptive levels to attain. The applicable nutrient limits are

Chlorophyll a standard of 6 ug/L and Total Nitrogen, Total

Phosphorus standards of 0.51 mg/L and 0.01 mg/L,

respectively. Lake Piney Z is a waterbody with sub-standard

management practices by FWCC as far as meeting FLDEP

numeric criteria for nutrients, however, the lake itself is great

as a fishery for recreational activity. Frequent algal blooms

have a direct correlation with abundant fish populations

within Piney Z. Large-mouth Bass, Black Crappie, “Redear”

Sunfish are just a few species that are monitored by FWCC for

population management. There are other possible

anthropogenic influences to help explain nutrient

exceedances. Piney Z subdivision is a somewhat large single-

family home community that has storm-water outlets that

discharge directly toward the lake. Heavy rain events dispose

lawn cuttings, fertilizer deposition and leaf litter into the lake

via the storm-water culverts. The once heavily vegetated lake

prior to Tropical Storm (TS) Fay (2008) is now completely

devoid of floating and submerged vegetation. The once

heavy vegetation within Piney Z, filtered the nutrient laden

water runoff before it assimilated within the water column.

Post TS Fay (2008), the usage of aquatic herbicide application

and an overabundant deployment of triploid carp, to keep

vegetation at bay, has left the lake barren of helpful nutrient

removing plants. Natural biological occurrences, such as

regular blue-green algal blooms within the lake, can produce

a self-eutrophic system. Eutrophic lake systems are not

necessarily bad, depending on the desired usage. FWCC

deems eutrophic lakes great for fishery development,

however this school of thought clashes with FLDEP’s nutrient

restrictions for our area’s lakes. Table 1 below shows the last

9 years of NNC data. Lake Piney Z balances to a slight

eutrophic system, which for the fishery management is good.

Looking at “color” within Table 1, the data is showing a

decreasing trend of darker colored water that has maybe

kept Piney Z from allowing light dependent submerged

aquatic vegetation from reestablishing.

Above: photo is the southeastern portion of Piney Z just

before Lower Lake Lafayette.

Below:

Fishing dock on one of the formed peninsulas.

Table 1. Water quality results from Piney Z Lake

*DEP’s Numeric Nutrient Criteria (Data based on annual

geometric means calculated on minimum of 4 samples.)

Year Chlorophyll * Color Alkalinity TN * TP*

2011 33 38 7 1.07 0.060

2012 25 38 8 0.72 0.050

2013 12 38 9 0.55 0.040

2014 13 38 7 0.75 0.050

2015 8 29 6 0.57 0.030

2016 19 19 7 0.76 0.030

2017 11 20 8 0.64 0.050

2018 14 12 7 0.49 0.030

2019 8 10 6 0.89 0.070

Yearly Geomeans of Total Nitrogen and Total Phosphorus for

Lake Piney Z

Lake Vegetation Index

The 2019 LVI score for this lake was 55 out of a possible 100

points, corresponding with a "Healthy" designation. This

score indicates that about 85% of the vegetative taxa are

native to Florida, that there are invasive exotic taxa present in

the lake and that roughly 15% of the counted taxa are

determined “sensitive” to human disturbance. Table 2

contains the species list and occurrence information for this

sampling event. Majority of the plants observed are within

the littoral zone of the lake’s bank side. Very few floating

plants were observed and virtually no submerged vegetation.

However, in some parts of the lake “American Lotus” is

making a resurgence along with White Waterlily. This is

important to note, maybe the added triploid carp are

decreasing in numbers allowing these surface water plants to

reestablish. Several invasive exotic plant species were

observed in the lake: ex. Colocasia esculenta (Wild Taro),

Eichornia crassipes (Water Hyacinth), Sapium sebiferum

(Chinese Tallow).

Table 2. Species list for the [year] LVI at Piney Z. An asterisk

(*) indicates an invasive exotic plant species. P = present, D

= dominant, C = codominant.

Photos below courtesy of FL-FWCC:

1. Red-ear Sunfish above

2. Black Crappie above during a FWCC fish assessment study.

Lake Piney Z Year 2019

Scientific Name Common Name 2 5 8 11

Acer rubrum RED MAPLE P P P P

Alternanthera philoxeroides ALLIGATOR WEED P

Boehmeria cylindrica FALSE NETTLE; BOG HEMP P

Cephalanthus occidentalis COMMON BUTTONBUSH P C P P

Colocasia esculenta WILD TARO; ELEPHANT EAR P

Decodon verticillatus WILLOW HERB; SWAMP LOOSESTRIFE P

Diodia virginiana VIRGINIA BUTTONWEED P P

Eichhornia crassipes WATER HYACINTH P

Eleocharis baldwinii SPIKERUSH P

Hydrocotyle sp. MARSHPENNYWORT P P P

Juncus effusus SOFT RUSH P P

Juncus marginatus SHORE RUSH; GRASSLEAF RUSH P

Liquidambar styraciflua SweetGum P P

Ludwigia leptocarpa SWEETGUM P P P P

Myrica cerifera SOUTHERN BAYBERRY; WAX MYRTLE P P P P

Nelumbo lutea AMERICAN LOTUS P C D P

Nymphaea odorata AMERICAN WHITE WATERLILY P P P

Panicum hemitomon MAIDENCANE P P P

Panicum repens TORPEDO GRASS P P P

Paspalum urvillei VASEYGRASS P P

Persicaria glabra DENSEFLOWER KNOTWEED P P C

Persicaria hydropiperoidesMILD WATERPEPPER; SWAMP

SMARTWEEDP P

Pontederia cordata PICKERELWEED P P P P

Rhexia mariana PALE MEADOWBEAUTY P P

Rhynchospora inundata NARROWFRUIT HORNED BEAKSEDGE P P

Sacciolepis striata AMERICAN CUPSCALE P P P P

Sagittaria latifolia COMMON ARROWHEAD; DUCK POTATO P P P P

Salix carolinianaCAROLINA WILLOW; COASTALPLAIN

WILLOWP P P P

Sambucus nigra AMERICAN ELDER; ELDERBERRY P

Sapium sebiferum CHINESE TALLOW P P P

Scirpus cyperinus WOOLGRASS P C

Taxodium BALD-CYPRESS D P P

Typha c.f. latifolia BROADLEAF CATTAIL P P

Woodwardia virginica VIRGINIA CHAIN FERN P P

Sections

3. Deployment of fish attraction devices below.

Thank you for your interest in maintaining the water quality

of City of Tallahassee area lakes.

DEP publications on Best Management Practices and Environmental Stewardship and Education: http://www.dep.state.fl.us/water/nonpoint/pubs.htm DEP biological assessment resources: http://www.dep.state.fl.us/water/bioassess/index.htm FWCC Aquatic Plant Management: http://myfwc.com/wildlifehabitats/habitat/invasive-plants/aquatic-plant/ Freshwater Algal Bloom information: http://www.dep.state.fl.us/labs/biology/hab/index.htm