Ecological Management Action Plans

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EM-7 Marsh Management

EVALUATION METHODS

• Utilize water control structures to control water levels inside marsh areas.
• Conduct studies of water control structure design to address fisheries access issues.

Benefits to vegetation and wildlife may be accompanied by adverse impacts to fisheries and sediment inputs. May be less necessary as hydrologic restoration and diversion projects are implemented.

The following criteria will be used to determine if plan implementation steps were accomplished:

• BTMC works to ensure that studies are initiated to evaluate the design of water control structures in order to address fisheries access issues.
• BTMC ensures the dissemination of the results of these studies to various agencies and entities involved in the design of future water control structures.

Should the construction of any marsh management projects be supported in the future by BTMC under this Action Plan, the following criteria would be used to evaluate their effectiveness. Specific criteria may vary depending upon the characteristics of individual projects.

• Water level fluctuations are reduced.
• Salinity fluctuations are reduced.
• Cover of emergent vegetation is increased.
• Growth/vigor of emergent vegetation is increased.
• Cover of SAV is increased.

Plan Implementation - The activities of the BTMC in implementing the plan in accordance with the above criteria will be monitored by an independent Third Party.

Project Effectiveness - Steyer and Stewart (1992) list variables which may be measured to monitor marsh management projects implemented under CWPPRA. It is recommended that this model be followed, whether or not any particular project is funded by CWPPRA. Measurable parameters identified by Steyer and Stewart (1992) have been prioritized by Steyer et al. (1995) into Essential Variables or Additional Variables or Substitutions as shown in Table EM7-xxx1. These have been assigned a priority for monitoring under the CCMP Action Plan. The priorities have been assigned based upon the broader mission of CCMP compared to CWPPRA (restoration creation or enhancement of vegetated wetlands is not necessarily the primary goal of CCMP Action Plans) and the objectives of the project as described in the Action Plan.

Table EM7-xxx1. Steyer et al. (1995) classification of monitoring variables for marsh management.

Table EM7-xxx1 includes parameters to document not only the effectiveness of the project in achieving its stated goals but also parameters which identify any adverse impacts to fisheries and sediment inputs associated with achieving project benefits.

This section provides guidance on the types of data collection methods which are currently available and appropriate for monitoring these types of projects. There may be alternative existing or new techniques which could be adopted as long as they conform to the data quality objectives described under QA/QC.

Plan Implementation - The activities of the BTMC in implementing the plan in accordance with the above criteria will be monitored by an independent Third Party.

Habitat Mapping - The procedures and methods outlined by Handley (1992) and Steyer et al. (1995) should be followed.

Salinity - The procedures and methods outlined by Powell (1992) and Steyer et al. (1995) should be followed. At least one continuous recording salinity gauge should be installed at each project and control site.

Water Level - The basic procedures and methods outlined by Powell (1992) and Steyer et al. (1995) should be followed with the following detailed recommendations. At least one continuous water level gauge should be installed at each project and control site. These gauges should be sufficiently accurate to record changes in water level of 1 cm and pressure transducers should be vented to allow for automatic correction of changes due to atmospheric pressure. If unvented transducers are used, data must be corrected for changes in barometric pressure.

Vegetation - For emergent vegetation the recommendations of Steyer (1992) concerning species composition, relative abundance and aboveground biomass and of Steyer et al. (1995) concerning biomass measurements should be followed. Measurements of relative abundance incorporate assessment of coverage. For SAV, species composition can be obtained by transect sampling (USEPA, 1993) using an airboat-rake method (Chabreck and Hoffpauir, 1962) to collect the samples. The frequency of occurrence of individual species should be recorded. The methods described by USEPA (1993) for estimating density of SAV in beds can also be used, depending upon water clarity.

Fisheries - Minello (1992) provides details of high gear-efficiency techniques for fisheries sampling which are appropriate for marsh management projects and these are recommended. Sampling methods should focus on identification of density, size and biomass of nekton (Steyer et al., 1995). Enclosure devices are the most appropriate gear to be used and care should be taken to control for variations in water level both between sampling periods and between samples on a given day, as this can greatly impact catch efficiency (Minello, 1992). If long-term data sets already exist for the project area using other gear, these techniques should be considered in the development of individual monitoring plans.

Accretion/Elevation Change - Any adverse impacts of the projects related to sediment input, will be reflected in rates of marsh accretion so the feldspar marker horizon technique may be most appropriate. This method is described in detail by both Reed (1992) and Steyer et al. (1995). Feldspar marker measurements should be combined with measures of soil bulk density and organic content (Reed, 1992) to allow for the calculation of organic and inorganic accumulation. However, sediment-erosion table techniques (Boumans and Day, 1993; Reed, 1992; Steyer et al., 1995) are appropriate for long-term measurements of the response of marsh elevation to accretionary processes. These should be employed where the marsh environment is appropriate (i.e., attached marshes) and where sampling design includes comparison with a reference area.

Plan Implementation - There are no relevant sampling design or statistical analyses for the evaluation of plan implementation.

Project Effectiveness - The sampling design for monitoring project effectiveness must include comparison of the project area with an appropriate reference area. Monitoring projects without the use of a reference area can lead to misinterpretation of monitoring data through the lack of a comparative site to identify natural interannual changes in marsh processes, and/or other difficulties (Steyer et al., 1995). It is necessary to ensure that reference and project areas are comparable. Both project and reference areas should be divided into marsh habitats and replicate samples randomly selected within each habitat type. Comparison between project and reference areas should then be based at the sub-area or habitat scale (e.g., brackish marsh sub-area in project is compared to brackish marsh sub-area in reference area). If it is impossible to select a suitable reference area, as may be the case with projects implemented in areas with highly modified hydrology or where a number of restoration projects are adjacent to one another, then either pre-project monitoring or baseline monitoring (Steyer et al., 1995) may be adopted as an alternative. Both of these approaches reduce the validity of the monitoring results as the monitoring then fails to account for natural interannual variability in marsh processes.

The size of the project area, the number of habitats included in the area, and heterogeneity of those habitats determine the number of samples which need to be taken and the validity of the statistical analyses. Steyer et al. (1995) describe appropriate procedures for the determination of sample size within the project area. The use of parametric (e.g., ANOVA, Student’s t-test) or non-parametric (e.g., Mann-Whitney U-test, Kolmogorov-Smirnov test) statistical procedures will depend upon the character of the datasets. If data are not normally distributed, as may frequently be the case with the collected data (e.g., salinity in a fresh or intermediate marsh), then transformations, such as logarithmic and square root transformations, should be applied and the transformed data tested for normality. If a normal distribution cannot be achieved in this manner, non-parametric tests should be pursued. The most basic statistical design for project evaluation is a two-tail test of whether the mean value for a measurable parameter within the project areas is equal to the mean for the reference area. If inequality is identified, further analyses can then determine if the effect of the project is to increase the parameter or decrease the parameter. In the case of projects where no reference site can be identified, comparisons may be made between one time interval and the next in order to identify progressive changes in vegetative parameters. In this case, trend analysis is appropriate. Standard linear regression models can be used to detect trends once sufficient annual data points have been obtained (fifteen years is considered the minimum for such trend analysis by Rabalais et al., 1995). Models having probability values of > 0.05 should be rejected, allowing determination of a trend significantly different from zero (i.e., change through time as opposed to no change through time).

Plan Implementation - The cost estimate is based upon attendance at approximately 2 BTMC meetings per year, contacting appropriate agencies and institutions, and appropriate reporting. The level of effort is estimated at 40 person-hours and costs including salary, fringe benefits, overhead and associated expenses are approximately $2,000.

Project Effectiveness - Estimated costs for evaluating marsh management have been developed for CWPPRA by Steyer and Stewart (1992). The actual costs depend upon the size of the project and the number of stations sampled/samples collected. These estimates have been revised where possible in consideration of the recommendations presented here regarding measurable parameters and data collection methods. Ranges are presented for cost estimates on an annual or per sample basis (Steyer and Stewart, 1992) in Table EM7-xxx2.

Table EM7-xxx2. Cost estimates for monitoring marsh management projects.

^a Includes species composition, relative abundance, and aboveground biomass.

^b Includes precipitation, wind speed/direction, water level, bathymetry, topography, and discharge.

^c Includes accretion, bulk density, soil organic matter content.

For marsh management projects implemented by CWPPRA, average annual monitoring costs shall not exceed $25,875. This amount is pro-rated according to project size (Steyer et al., 1995) as follows: less than 1000 acres - 60%; 1000-5000 acres - 70%; 5000-15,000 acres - 80%; and greater than 15,000 acres - 100%. These requirements have constrained the development of monitoring plans for CWPPRA projects to below ideal levels which are more realistically reflected in the cost estimates of Steyer and Stewart (1992).

Monitoring of plan implementation will be undertaken by an independent Third Party who will prepare semi-annual reports describing actions of the BTMC in relation to studies of water control structures relevant to marsh management. Evaluation of monitoring reports concerning project effectiveness will be conducted by qualified individuals representing organizations independent of any agencies or institutions funding the project construction, operation and/or maintenance. Semi-annual reports will be prepared. The monitoring reports will be submitted not less than 15 days prior to a regularly scheduled meeting of the BTMC and the parties responsible for monitoring will appear at the scheduled meeting of the BTMC to discuss the report. Monitoring reports concerning project effectiveness will also be provided to the agencies or institutions funding project construction, operation, and/or maintenance, as well as landowners for the project and references areas (as appropriate).

The Quality Assurance Plan involves the following components:

• Clear identification of effectiveness criteria (as outlined above).
• Use of qualified and experienced personnel to collect and report data (to be determined and assessed annually by BTMC).
• Review of monitoring data and reports by BTMC (as outlined above).
• Reporting of significant problems identified during the monitoring period to the BTMC before the next report is due.
• Maintaining a semi-annual schedule for reporting on BTMC activities (as outlined above).

The Quality Assurance Plan involves the following components:

Project Description - (as provided in Action Plan).

Project Organization and Responsibility - (to be prepared by monitor in association with lead implementor).

Data Quality Objectives - For the measurable parameters recommended in this monitoring strategy, Table EM7-xxx3 presents these objectives as determined by Steyer et al. (1995).

Table EM7-xxx3. Data Quality Objectives for identified measurable parameters (all from Steyer et al., 1995).

Sampling Procedures - The data collection methods are as described above. The sampling design will be determined for each individual project by a committee composed of BTMC representatives, the lead implementor of the project, and the monitor.

Sample Custody - Collected samples will be in the custody of the monitor from collection to sample processing. Should contractors be utilized for sample processing, written documentation of sample transmission and receipt shall be maintained by the monitor.

Calibration Procedures - Routine calibration of field and laboratory equipment will be undertaken in accordance with manufacturer’s instructions or at least annually. Written documentation of the calibration procedures and records shall be maintained by the monitor.

Analytical Procedures - The procedures described by Steyer et al. (1995) and references therein will be followed for analysis of the identified measurable parameters.

Data Review, Validation and Verification - The general procedures described by Steyer et al. (1995) and references therein will be followed. Data will be entered into a DIMS compatible database and statistical analysis will follow procedures agreed to by the BTMC, lead implementor and the monitor.

Problem Identification - Any significant problems identified during the monitoring period, either with monitoring procedures or project effectiveness, will be reported to the BTMC and lead implementor before the next regularly scheduled report is due.

Reporting - Semi-annual reports will be prepared. The monitoring reports will be submitted not less than 15 days prior to a regularly scheduled meeting of the BTMC and the parties responsible for monitoring will appear at the meeting to discuss the report. Monitoring reports will also be provided to the agencies or institutions funding project construction, operation, and/or maintenance, as well as landowners for the project and reference areas.

Boumans, R.M.J. and J.W. Day, Jr. 1993. High precision measurements of sediment elevation in shallow coastal areas using a sedimentation-erosion table. Estuaries 16(2): 375-380.

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