In developing specific monitoring objectives, it is critical to establish a hierarchical structure to the planning and program development process. The development of appropriate and achievable monitoring objectives for Lake Tarpon must be clearly linked to, and driven by, the defined management issues and goals adopted by the LTMC. For each of the adopted goals, there must also be defined criteria by which attainment of a given goal can be measured. These measures are herein referred to as "targets," as discussed in Section 4.1 above. Since targets are specific units of measure that define progress towards a management goal, all targets must be linked to, and supported by, one or more monitoring objectives. Conversely, all monitoring objectives must cleary support a target. The planning hierarchy of the monitoring program development process can be summarized as follows:

Management Issue

In the sub-sections that follow, specific targets and monitoring objectives addressing the adopted management goals are proposed, and the rationale for each are discussed.

5.2.1 Water Quality

Under the targets developed for the Water Quality issue twelve specific monitoring objectives are proposed, with some targets being associated with more than one monitoring objective. The rationale for each proposed monitoring objective is discussed below.

Rationale: Nitrogen (N) and phosphorus (P) are the primary nutrients required by plants for growth and reproduction. In excessive concentrations, N and P can cause nuisance algae blooms. The measure of all chemical forms of these nutrients (total N and P, or TN and TP) in the water column is a measure of the algal growth potential, and thus is an important indicator of trophic state. TN and TP concentrations are two of four parameters used to calculate a multi-parametric TSI value, with chlorophyll-a and Secchi disk depth being the other two. While the collection and measurement of TN and TP samples is programmed into the existing monitoring program, previous monitoring data are of limited value due to problems with laboratory detection limits and other analytical problems. This situation has, however, been recently corrected.

Objective 2B: Measure monthly in-lake Secchi disk depths.

Rationale: Secchi disk depth serves as a simple measure of lake water clarity. The degree of water transparency is one of the most important attributes of water. Water transparency allows the penetration of light, which supports life through the photosynthetic process. The degree of water transparency has a direct impact on the growth and distribution of submerged aquatic vegetation. Water transparency also allows organisms with visual organs to see in order to search for food and shelter. Water transparency can be affected by suspended organic (e.g., algae) and inorganic (e.g., silt) matter in the water column, as well as tannins and dissolved substances. Secchi disk depth is one of four parameters used to calculate a multi-parametric TSI value. While the measure of Secchi disk depth is already programmed into the existing monitoring program, previous monitoring data are of limited value due to inconsistencies in field methodology. This situation, however, has recently been corrected.

Objective 3A: Estimate mean annual loads of TN and TP to Lake Tarpon from tributaries and nonpoint source runoff.

Rationale: It is possible to estimate external TN and TP loads from tributaries (e.g., Brooker Creek) and nonpoint source runoff through direct measurement at points of discharge to the lake. Since tributary discharges plus nonpoint source runoff represent approximately 59% and 27% of the total annual external TN and TP loads, respectively, and since these loads are both measurable and manageable to some extent, long term trends in these loading sources should be monitored to evaluate the effectiveness of load reduction strategies.

Objective 3B: Estimate mean annual loads of TN and TP to Lake Tarpon from groundwater seepage.

Objective 5A: Estimate the monthly frequency, duration, and magnitude of bottom dissolved oxygen concentrations in Lake Tarpon that fall below regulatory minima of 5.0 mg/l.

Rationale: In addition to phytoplankton biomass, the concentration of dissolved oxygen in the deepest portions of the lake is often a good indicator of overall lake water quality. Any dissolved oxygen concentrations below 5 mg/l are in exceedance of Class-III State water quality standards, and may result in fish kills and other adverse impacts on biota.

Objective 5B: Estimate for Lake Tarpon and the outfall canal: 1) the monthly trend in pH; and 2) the frequency, duration, and magnitude that monthly pH varies by more than one unit above or below natural background levels.

Rationale: A rapid or large change in lake pH may have severe adverse effects on lake biota. In 1990 a significant drop in pH (e.g., >2 pH units) was observed during the summer following an accidental lake level drawdown. Since then pH has continued to rise. The cause(s) of this pH trend, nor the impacts of these changes on lake biota, is not known. Ongoing monitoring is needed to determine the importance and possible causes of pH fluctuations in Lake Tarpon.

Objective 5C: Estimate for Lake Tarpon and the outfall canal: 1) the monthly trend in chloride concentration; and 2) the frequency, duration, and magnitude that monthly chloride concentrations exceed background level by 10% or more.

Rationale: A rise in mean chloride concentrations above existing and historical levels (between about 200-250 mg/l) may have adverse effects on lake biota. Although mean annual lake chloride levels have remained essentially the same since 1988, future increases of in-lake chloride concentrations are possible due the proximity of the lake to saltwater. If a trend of increasing lake chloride levels is detected, it may be an indicator of potential degradation to existing lake flora and fauna.

Objective 5D: Estimate for Lake Tarpon and the outfall canal: 1) the monthly trend in specific conductance; and 2) the frequency, duration, and magnitude that monthly specific conductance exceeds 1,275 µmhos/cm.

The goals, targets and monitoring objectives related to the Water Quality management issue are summarized in Table 5-1 below.

Under the targets developed for the Aquatic Vegetation issue four specific monitoring objectives are proposed. The rationale for each proposed monitoring objective is discussed below.

Objective 1: Estimate the status and trends in areal coverage, spatial distribution, and species composition of desirable, endemic submerged aquatic vegetation every two years.

Rationale: No quantitative survey of the coverage of submerged aquatic vegetation has ever been performed in Lake Tarpon. Given the importance of submerged aquatic vegetation to the overall ecology of the lake, quantitative monitoring is needed to assess status and trends in areal coverage, spatial distribution, and species composition on an annual basis. A key management principle for Lake Tarpon will be to drive the system away from phytoplankton dominance, and towards macrophyte dominance, with respect to primary production. Monitoring the status and trends in desirable, endemic submerged aquatic species is warranted to determine progress towards this overall management goal.

Objective 2: Estimate the status and trends in areal coverage and spatial distribution of hydrilla every two years.

Rationale: Currently, the FDEP and SWFWMD qualitatively monitor the coverage of hydrilla on an as-needed basis for the purposes of defining herbicide application needs. The methods used are not statistically valid, and therefore the results are not suitable for accurately quantifying trends or relating trends to other ecological conditions (e.g., water quality). Given the potential and observed impact of hydrilla and its treatment on lake water quality and fisheries, there is a need to quantify trends in the areal coverage and spatial distribution of this aggressive species at least every two years.

Objective 3: Estimate the status and trends in areal coverage, spatial distribution, and species composition of desirable, endemic emergent aquatic vegetation every two years.

Rationale: Currently no quantitative monitoring of emergent aquatic vegetation is being performed in Lake Tarpon on a regular basis. Given the importance of emergent aquatic vegetation as fish and wildlife habitat, as well as the potential for rapid changes in areal coverage, there is a need to assess the status and trends in areal coverage, species composition and spatial distribution of EAV at least every two years.

Objective 4: Estimate the status and trends in areal coverage and spatial distribution of cattail every two years.

Rationale: The dominance of cattail negatively impacts local fish and wildlife utilization, impedes human recreational usage, and detracts from visual aesthetics. Other than special diagnostic/feasibility studies, no quantitative monitoring of emergent aquatic vegetation in Lake Tarpon is conducted on a regular basis. Areal coverage and spatial distribution of cattail should be monitored every two years so that deviations from the target coverage will be recognized, and appropriate management actions implemented. Combined with Target 3 above, this target implicitly states that cattail should be managed so as to account for no more than 60 acres (or about 50%) of the minimal EAV areal coverage target of 120 acres.

The goals, targets and monitoring objectives related to the Aquatic Vegetation management issue are summarized in Table 5-2 below.

Table 5-2. Goals, targets and monitoring objectives for the Aquatic Vegetation issue.

5.2.3 Fisheries

Under the targets developed for the Fisheries issue five specific monitoring objectives are proposed. The rationale for each proposed monitoring objective is discussed below.

Objective 1: Estimate the F/C ratio and the Fishery Quality Index (FQI) in Lake Tarpon every two years.

Rationale: The F/C ratio and the FQI are measures of fish community balance which can also serve as an indicator of lake trophic state. The F/C ratio and the FQI are calculated through quantitative sampling techniques typically using a stratified random design with block net and rotenone fish collection. The FGFWFC has conducted population studies for estimating the F/C ratio and FQI in Lake Tarpon on an irregular basis, approximately every five years. It is recommended that this quantitative sampling program continue on a regular basis, every two years at a minimum, so as to be coordinated with the sequencing of other monitoring programs.

Objective 2: Estimate the indices of Relative Stock Density (RSD) for major sport fish species in Lake Tarpon every two years.

Rationale: The Relative Stock Density index provides a numerical expression of population size structure, and is another quantitative measure of the population balance of major sport fish species. RSDs are determined through quantitative sampling techniques typically using a stratified random design with block net and rotenone fish collection. The FGFWFC has conducted population studies for estimating RSDs in Lake Tarpon on an irregular basis, approximately every five years. It is recommended that this quantitative sampling program continue on a regular basis, every two years at a minimum, so as to be coordinated with Objective 1 above as well as the sequencing of other monitoring programs.

Objective 3: Estimate the voluntary angler catch and release rate for largemouth bass in Lake Tarpon every two years.

Rationale: Voluntary angler catch and release of sport fish - primarily largemouth bass - promotes desirable F/C ratios and maintains a healthy sport fishery. Voluntary angler catch and release rates can be assessed relatively easily through various types of creel survey techniques. Given the rapidity by which lake water quality and the fish community structure can change, it is recommended that voluntary angler catch and release rates be assessed as a component of a comprehensive recreational fishery assessment to be performed every two years in combination with the quantitative sampling programs recommended for Objectives 1 and 2 above.

Objective 4: Estimate fishing effort in Lake Tarpon every two years.

Rationale: Fishing effort, or the number of hours fished per acre per year, can be assessed through various types of creel and recreational survey techniques. The measure of fishing effort forms the basis for calculating angler success rates. In combination with Objective 3 above, it is recommended that fishing effort be assessed as a component of a comprehensive recreational fishery assessment to be performed every two years.

Objective 5: Estimate the angler success rates for largemouth bass and panfish in Lake Tarpon every two years.

Rationale: Angler success rates are a function of both fish population structure and fishing pressure; and they are a direct measure of the recreational value of the sport fishery. Angler success rates, or catch per unit effort, can be assessed relatively easily through creel surveys. In combination with Objective 3 and 4 above, it is recommended that angler success rates be assessed as a component of a comprehensive recreational fishery assessment to be performed every two years.

Under the targets developed for the Wildlife and Associated Habitat issue six specific monitoring objectives are proposed. The rationale for each proposed monitoring objective is discussed below.

Rationale: As roadways in the drainage basin require improvement, the construction or retrofitting of strategically located wildlife underpasses should significantly improve the mobility, expansion and genetic variability of wildlife populations by providing linkages for wildlife dispersion. Additionally, wildlife mortality due to vehicular collision would decrease with an alternative to crossing an unprotected and busy highway. A simple annual accounting of the number of constructed wildlife underpasses is recommended.

The goals, targets and monitoring objectives related to the Wildlife and Associated Habitat management issue are summarized in Table 5-4 below.

Table 5-4. Goals, targets and monitoring objectives for the Wildlife and Associated Habitat issue.

5.2.5 Flood Control

Under the targets developed for the Flood Control issue two specific monitoring objectives are proposed. The rationale for each proposed monitoring objective is discussed below.

Objective 1: Annually assess flood damage (dollars) to all properties within the Lake Tarpon drainage basin.

 

Rationale: The aggregate sum of property damage (in dollars) from flooding in the Lake Tarpon drainage basin should be assessed and reported annually to monitor the possible impacts of other lake management actions (e.g., water level fluctuations) on flood protection.

Objective 2: Estimate monthly compliance with the prescribed Lake Tarpon water level fluctuation schedule.

Rationale: Strict compliance with the prescribed water level fluctuation schedule will allow lake managers to assess the effectiveness of altering water levels as a means of improving water quality and aquatic vegetation conditions. Average daily water level records from the Lake Tarpon outfall control structure are needed to assess monthly compliance with the prescribed schedule.

The goals, targets and monitoring objectives related to the Flood Control management issue are summarized in Table 5-5 below.

Table 5-5. Goals, targets and monitoring objectives for the Flood Control issue.

Under the targets developed for the Recreation and Aesthetics issue four specific monitoring objectives are proposed. The rationale for each proposed monitoring objective is discussed below.

Rationale: The total annual number of boating accidents reported on Lake Tarpon is a reasonably good measure of public safety and enforcement effectiveness.

Objective 2: Estimate for Lake Tarpon and the outfall canal: 1) the monthly trends in coliform bacteria; and 2) the frequency, duration, and magnitude that monthly total and fecal coliform concentrations exceed 2,400/100 ml and 800/100 ml, respectively.

Rationale: Previous water quality surveys have indicated that coliform concentrations in Lake Tarpon periodically exceed State water quality standards, however, routine measurements are currently not being performed. The monthly measurement of coliform bacteria concentrations in Lake Tarpon should be performed to ensure continued public health and safety with respect to water contact recreation. It should be noted that some uncertainty currently exists within the regulatory community as to the validity of coliform testing as an indicator of contamination. Statewide investigations are in progress to develop more meaningful water quality standards with regard to the public health risks of water contact recreation. Consideration should be given to delaying the implementation of coliform monitoring until the findings of these investigations are published.

Objective 3: Assess recreational user and lakefront resident satisfaction every four years.

Rationale: Pinellas County and the FGFWFC have periodically conducted recreational user surveys, and Pinellas County has recently completed a lakefront resident survey. The survey format should be refined and implemented every four years to assess trends in public opinion.

Objective 4: Annually estimate the number of recreational users visiting the lake.

 

Rationale: Both Chesnut and Anderson Parks keep daily records of user trips, and the use generated from these two parks probably represents over 80% of the total user population at any given time. Park user data, and other available recreational user data (e.g., ski clubs, fishing guides, etc.) should be summed annually to estimate the total number of recreational users annually visiting the lake. This objective must also incorporate the user satisfaction data collected under Objective 3 above.

The goals, targets and monitoring objectives related to the Recreation and Aesthetics management issue are summarized in Table 5-6 below.

Table 5-6. Goals, targets and monitoring objectives for the Recreation and Aesthetics issue.

5.2.7 Public Education

Under the targets developed for the Public Education issue two specific monitoring objectives are proposed. The rationale for each proposed monitoring objective is discussed below.

Objective 1: Annually determine the number of public education/media events conducted.

The goals, targets and monitoring objectives related to the Public Education management issue are summarized in Table 5-7 below.

Table 5-7. Goals, targets and monitoring objectives for the Public Education issue.

The existing monitoring programs currently being implemented by the various responsible agencies only partially address the data needs of the comprehensive Lake Tarpon Drainage Basin Management Plan. Many data gaps exist which must be addressed through the modification of existing monitoring programs, as well as the implementation of new monitoring programs. In addition, the existing monitoring programs in most cases lack clearly articulated monitoring objectives which are logically linked to management goals and level-of-service targets. This lack of focus has resulted in a less than cost-effective expenditure of available funding resources for monitoring activities.

A total of 13 monitoring program elements have been identified to fill data needs with respect to the implementation of the Lake Tarpon Drainage Basin Management Plan. Table 5-8 below summarizes the monitoring objectives addressed, the sampling frequency, and the recommended agency responsibility(s) for each monitoring element. Key differences between the existing monitoring activities and the proposed comprehensive Lake Tarpon Monitoring Program are summarized below:

• The existing ambient in-lake water quality monitoring program implemented by PCDEM is the most rigorous program currently in effect. Although the number and distribution of sampling stations are defensible, it is recommended that the sampling frequency be reduced from the current biweekly regime to a monthly regime. This reduction in effort will address the monitoring objectives while making funds available for other monitoring activities.

• Additional sampling programs are recommended to assess pollutant loadings from: 1) nonpoint sources and tributaries; 2) groundwater; and 3) atmospheric deposition. Furthermore, an additional in-lake sampling station is recommended at the outfall structure to measure the nutrient mass discharged from lake. This combined sampling network will allow for the calculation of current annual water and nutrient budgets.

• An additional sampling program is recommended for assessing in-lake dissolved oxygen minima and compliance with other applicable State water quality standards.

• Additional sampling programs are recommended for assessing the status and trends in the coverage and composition of submerged and emergent aquatic vegetation.

• The frequency of the existing FGFWFC fish population monitoring program is recommended to be changed from approximately every five years to every four years, at a minimum, on a regular basis.

• Coordination of bird census data obtained by volunteers from the local chapter of the Audubon Society is recommended for regularly assessing bird populations.

• An additional monitoring program is recommended for assessing the status and trends of natural upland and wetland habitat in the watershed.

• Modification and improvement of the recreational user and lakefront resident surveys currently employed by PCDEM are recommended to expand the utility and statistical validity of these tools for assessing public opinion and responsiveness with regard to recreational, aesthetic and environmental education issues.

• Numerous other accounting measures are recommended for assessing progress towards the full implementation of the Lake Tarpon Drainage Basin Management Plan.

• Financial and logistical responsibility for the Lake Tarpon Monitoring Program should rest primarily with Pinellas County at the local level. However, the SWFWMD and FGFWFC should continue or expand their financial and logistical support with regard to certain monitoring components. The following specific intergovernmental coordination measures are recommended.

- Cost-sharing for laboratory analyses between Pinellas County and SWFWMD was anticipated in the Lake Tarpon SWIM Plan, and SWFWMD currently provides laboratory analyses associated with the nonpoint source/tributary and groundwater loading monitoring programs. For consistency with historic data, it is recommended that Pinellas County continue to provide laboratory analyses for all in-lake samples.

- Because of their extensive in-house expertise in groundwater monitoring, as well as their specific diagnostic work on the Lake Tarpon groundwater system, it is recommended that SWFWMD be responsible for the installation and maintenance of, and collection of samples from, the proposed groundwater seepage meters.

- Because of their extensive in-house expertise and experience in fishery biology, as well as their history in monitoring trends in the Lake Tarpon sport fishery, it is recommended that the FGFWFC continue to be responsible for the quantitative assessment of fish populations. It is, however, also recommended that the collection of angler use data be delegated to PCDEM and incorporated into a comprehensive recreational use and lakefront resident survey program to be conducted every four years.

• The PCDEM should publish an annual State-of-the-Lake report which summarizes all of the monitoring data collected during the previous calendar year. In addition to monitoring data summaries, the annual report should include at a minimum:

- Calculated water and nutrient budget for the previous calendar year; and ,

- An assessment of compliance with each of the established level-of-service targets.

• Pinellas County (PCDEM) should designate a Lake Tarpon Data Manager who serves as the point of contact for coordinating the collection, management and reporting of all monitoring data associated with the Lake Tarpon Drainage Basin Management Plan. Furthermore, PCDEM should serve as a depository of all monitoring data associated with the Plan.

The detailed sampling protocols for each of the recommended monitoring elements are provided in the Task 3.2.11 Interim Report. It should be noted that since the publication of the Task 3.2.11 Interim Report, PCDEM has implemented several components of the recommended monitoring programs. For example, beginning in January 1997, PCDEM initiated sampling programs to assess pollutant loadings from: 1) nonpoint sources and tributaries; 2) groundwater; and 3) atmospheric deposition. Furthermore, an additional in-lake sampling station was added at the outfall structure to measure the nutrient mass discharged from lake. Full implementation of all recommended monitoring programs are recommended to meet the requirements of the Plan.

Table 5-8. Summary of recommended monitoring program elements.